OPERATING SYSTEM

2009-09-18T19:06:00.000-07:00

MAC OS INSTALLATION PROCESS

Preparing for InstallationIf you plan to erase your hard disk or archive your current system without preservingyour users and network settings, you’ll need to note your current network settings tomake it easier to get connected again after installing Mac OS X. Go to SystemPreferences > Network, and then check for these settings:

If your network uses: Write down the following:
Ethernet, DSL, or cableconnected via DHCPNothing. DHCP
automatically configures your Internet connection.AirPort connected via DHCPAirPort or wireless network name and password provided by yourAirPort network administratorEthernet, DSL, or cableconnected manuallyInternet Protocol (IP) address (number that looks like 12.345.56.789)Subnet mask (number that looks like 10.255.255.255)Router address (number that looks like 10.208.32.2)Domain Name System (DNS) servers (optional number that lookslike 10.255.255.255, and name that looks like ISPname.com)Search domains (optional name that looks like ISPname.com)Dial-up modemTelephone number, user name, and password provided by yourservice providerDNS servers (optional number that looks like 10.255.255.255, andname that looks like ISPname.com)Search domains (optional name that looks like ISPname.com)

Installing Mac OS XTo begin a custom installation of Mac OS X Leopard, follow these steps.

Step 1: Insert the Mac OS X Install discDouble-click the Install Mac OS X icon, and then click Restart. The installer opensautomatically when your computer restarts.WARNING: If you’re installing Mac OS X on your current Mac OS X startup disk, let theinstaller finish. If you quit, you may not be able to start up using your currentMac OS X startup disk.Double-click this iconon the Install disc.Click Restartto begin.

Step 2: Follow the onscreen instructionsSelect the language you want to use, and then click the forward arrow. The Welcomescreen appears.The installer guides you through the installation process. Refer to the sections thatfollow for information about selecting a destination when you have more than onevolume, selecting installation options, and selecting additional software to install.

Step 3: Select a destinationOn the “Select a Destination” pane, select the volume on which you want to installMac OS X. The screen tells you how much space is required for installation.

Step 4:
Select how you want to install Mac OS XClick the Options button to select “Archive and Install” or “Erase and Install.”
One of thefollowing screens appears:Select how you want to install Mac OS X, and then click OK. Click Continue when you’reready to proceed to the next pane.Install Mac OS XThis option appears if you don’t have Mac OS X installed on your computer or you havean early version of Mac OS X (v10.2.8) that can’t be upgraded.
Select this option toinstall Leopard on your computer.Archive and InstallSelect this option if you want to install a fresh system on your computer.“Archive and Install” moves your existing Mac OS X system files to a folder namedPrevious System, and then installs a new copy of Mac OS X on the selected volume.
Mac OS X–installed applications, such as Address Book and Safari, are archived, andnew versions are installed in the Applications folder.
Unless you choose “Preserve Users and Network Settings,” user accounts and theirhome folders are also archived in the Previous System folder.This is selected ifMac OS X is alreadyinstalled on the volume.This is selected if Mac OS Xisn’t installed.

Select the “Preserve Users and Network Settings”checkbox to import your existing useraccounts, home folders, and network settings into the new system.
User accountsinclude such things as:
Â Home folders and their contents
Â Preference settings
Â Address Book databases
Â Browser favorites
Â Network settings and locations
“Preserve Users and Network Settings” also copies the existing Shared folder in theUsers folder to your new system.
Note: You can’t start up your computer using the Previous System folder, but settings,preference files, fonts, plug-ins, and other items remain available in case you needthem.
Some applications, plug-ins, and other software may have to be reinstalled after an“Archive and Install.” Fonts that were installed in the Fonts folder in the top-levelLibrary folder can be installed in your new system by copying them from the PreviousSystem folder.
Erase and Install
This method completely erases the destination volume, and then installs a new copy ofMac OS X

Step 5: Select additional software packages to install
The default installation contains all the software you need to use Mac OS X. However,the Mac OS X Install disc contains additional software—such as printer drivers, fonts,and language translations—that you may want to install. To see the available packages,click Customize on the Install Summary screen.The Custom Install pane appears, as shown on the following page. Click the arrowsto reveal specific components. Select the software you want to install, and thenclick Done.WARNING: If you erase the destination volume, everything on the volume—youruser accounts, network settings, and all of your files and folders—will be deleted.If necessary, quit the installer and back up your files before you erase the destinationvolume.

Note: You can always use the Mac OS X Install disc to install additional softwarepackages later.When you’re ready to install Mac OS X and the selected software, click Install on theInstall Summary screen.Click the arrow toreveal components.All componentswill be installed.Only the selectedcomponents willbe installed.

2009-09-18T19:01:00.000-07:00

ECS LINUX-MANDRIVA INSTALLATION PROCESS

Below you will a very brief description of how to install the Linux-Mandriva 2007. You can borrow the six CDs or single DVD available in class. You can find more information at the Mandriva website: http://wwwnew.mandriva.com. I will assume that you wish to dual boot Linux with some version of Windows. You can find much more extensive instructions for installing Linux at:
Professor Norman Matloff's Beginner's Guide to Installing Linux : http://heather.cs.ucdavis.edu/~matloff/linux.html
I recommend you read and print out both this and Prof. Matloff's pages before starting.

IF YOU HAVE ANY CRITICAL FILES, BACK THEM UP BEFORE STARTING THIS PROCESS! CREATE AN EMERGENCY REPAIR DISK NOW!

There are three steps to installing Linux:

1. 1. Gathering network information.

2. 2. Set-up partitions on the disk drive to have room for Linux.

3. 3. Installing Linux

1. Gathering network information
Before starting to install Linux you must gather information about your current network settings. You can find these in the Network section of the Windows Control Panel. If you do not have DHCP, then you need to note your IP address. You should also note the subnet mask (usually 255.255.255.0), gateway address, primary DNS, and secondary DNS if there is one. If you are using encrypted wireless, then jot down the keys and/or pass phrase. You should also determine your graphics adapter and monitor model and current resolution settings.

2. Setting up partitions
Linux must be installed on partitions separate from all other operating systems. In Windows, each partition is given a drive letter. In Linux, all of the partitions on the first drive start with hda, and are numbered hda1, hda2, and so forth. The partitions on the second hard drive all start with hdb. Please note that the first drive may not be your C: drive in Windows. If you have multiple drives, you should note, based on its size, which is your C: drive. You will need this later to install the boot loader.

There are many ways to create the necessary space for Linux, but I will cover only the simplest. You will need clear out enough space in an existing partition so that it can be shrunk enough to make room for both Linux partitions. This may mean deleting files and/or moving files from one drive to another. Disk Cleanup can help you to choose the files to remove. When done, note how much space you need for your files on the drive. Once you are done cleaning up the disk, you should run the defragmenter tool to consolidate the files. Please note that Mandriva 2007 can shrink any file system, including the NTFS file system!

If you happen to have left some empty space on a hard disk, that you are not going to use for LINUX, then partition and format it now, before installing Linux. You should not use Windows/DOS tools to partition the Linux disk after Linux is installed--it can really screw things up.

2. Installing Linux
On most computers, you can bypass using an Install Boot floppy, by choosing to boot directly from the CDROM. To do this, you need to change the first device searched for booting in the BIOS. To access the BIOS settings, reboot the computer and hold down the indicated key, usually DEL. When the BIOS settings show up, look for a page that lists the order of boot search. You should find that the floppy is the first listed, followed by the hard drive. Change the first entry from floppy to CDROM. Then hit Escape, and choose to save the changes. Now when you reboot, the computer will start looking first in the CDROM. Note that after you have installed Linux, you should go through the same process to change the first device back to the floppy.

To install Linux, your computer must either boot to a specially created floppy or directly to the CD labeled Mandriva 2007 CD 1 or the Mandriva 2007 DVD.

1. Place CD 1, or the DVD in your CD drive and restart your computer.

2. Select “Installation” from the first menu.

3. Select “English (American)” as your language choice. (default)

4. Accept the license agreement.

5. Choose to install.

6. Set the Security to “Standard” so you can access your Windows partitions without being root

7. Assuming you don’t have enough free space, select “Use existing partitions” for Paritioning

8. Select the partition you wish to resize.

9. Slide the bar to determine the size of the old Windows partition. You can refer to your notes to determine the minimum you need for your Windows files. Remember you need to free up at least 5000 megabytes for Linux, but you should leave at least 500 megabytes free on the Windows partition to allow for future use.

10. Mandriva may ask you to reboot the computer. If so, then go through step 2 to 7, and then continue from here.

11. Select Auto allocate.

12. If everything pictured in the Partitioning charts makes sense, then select OK to write the partition table.

13. Mandriva may ask you to reboot again! If so, then go through steps 2 to 7, and then continue from here.

14. Mandrake will guess where root (/) will be mounted. Make sure the selected partition is the one you wanted.

15. Allow the partition to be formatted. (default)

16. The list of installation media found is correct so just click Next.

17. The default package selections are fine. However, if you have space on your hard disk, then feel free to select additional packages. As you select groups, the total size of the selections is updated at the bottom of the selection window. If you select packages from the right (server) column, then be warned that server components make your computer much more susceptible to attacks from hackers. Do not install server components unless you know what you are doing!

18. Just click “Install” on the Software Management Screen. The program will take about an hour to install, and will ask you to insert the other five CDs. If you are using a DVD, just press it back in when another CD is requested.

19. Set the root password; don’t leave it blank.

20. Add yourself as a user. I suggest you use your CSIF user name as your login name to make ssh and sftp a little easier.

21. After adding yourself, just press Next at the next Add user screen.

22. if there is only you, and your computer is in a safe place, you can agree to automatically log on one user.

23. Place LILO in the First sector of drive (MBR). (default)

24. If you are offered any proprietary drivers, then say Yes. (default)

25. If it finds your printer, then allow it to set it up automatically. (default)

Mandriva now provides a list of configurations that you will need to modify. You will need to configure the time zone to Los Angeles, but the other time defaults (hardware clock is not set to GMT) are fine. Configure the graphical interface. Make sure you test the configuration of your graphics adapter and monitor. You can use the information you gathered from your Windows network to configure the Network. If you have wireless, then select “wireless” from the list of adapters. The domain you choose for your host name is probably irrelevant—so make one up! Start the connection now to ensure it works. If you have a printer available to the computer but it was not detected earlier by Mandriva, then press the configure button next to printers, then Add a Printer, and then Auto-Detect. If Mandriva does not detect your printer, then uncheck Auto-Detect, click Next, and manually select its port, make, and model. Mandriva should be able to detect your printer, but you should check its efforts by printing a test page when prompted. If you wish to make your Windows OS the default, you will need to configure the bootloader. Upon entering the bootloader configuration area, click Next until you see a list of entries in the boot menu. Double click the "windows" entry, and then place an X in the Default checkbox.

After OKing the summary, don’t download updates. Remove the CD or DVD, and click the Reboot button. (You may wish to change your BIOS boot-up sequence back at this time.) When the system reboots, select the “linux” entry to start Mandriva for the first time.

If you are confronted with a command prompt instead of a GUI when Mandriva starts up, then login or su as root, and type XFdrake to open the graphics configuration tool. Play with the settings, and test until you get a good screen.

You may now want update the computer by Start icon -> System->Configuration->Packaging->Install, Remove & Update Software. After entering the root password, go to Software Management->”Look at available updates….” Then select a source URL (I use usc.edu), and wait for the list to download. You will see a Software Management window. You should download any Bugfix Updates, and Normal Updates.

Once you have installed all the updates, you should install the GUI debugger, ddd. Select “Select from where software packages are downloaded …”. Then select Add and then “Distribution sources.” Select a URL (I use ftp://ftp.ale.org). After the list of packages is downloaded, select “Look at installable software…” from the four Software Management choices. Type “ddd” in the search box, and then press Search. The rest of the process is straightforward.

Congratulations! Your done installing Linux!

2009-09-18T18:57:00.000-07:00

Windows 2000 Professional INSTALLATION PROCESS

To install Windows 2000 Professional, follow these steps:

1.Start the installation by using one of the following methods:

• Start from the Windows 2000 Professional installation CD-ROM. Make sure that the CD-ROM is set to start before the hard disk starts. Insert the CD-ROM, and then when you are prompted, press any key to start the Windows 2000 Professional Setup program.

• Start from boot disks. Insert Disk 1, and then insert each of the remaining three floppy disks when you are prompted to do so. For additional information about creating boot disks for Windows 2000, click the article number below to view the article in the Microsoft Knowledge Base:
197063 (http://support.microsoft.com/kb/197063/EN-US/ ) How to Create Setup Boot Disks for Windows 2000

• Start from within a current operating system. Insert the CD-ROM, and then, at a command prompt, type drive:\i386\winnt32.exe and then press ENTER, or if this is an installation on a computer that has no previous installation of Windows, type drive:\i386\winnt.exe and then press ENTER, where drive is the letter of the CD-ROM drive.

2.Setup inspects your computer's hardware configuration and then begins to install the Setup and driver files. When the Microsoft Windows 2000 Professional screen appears, press ENTER to set up Windows 2000 Professional.

3.Read the license agreement, and then press the F8 key to accept the terms of the license agreement and continue the installation.

4.When the Windows 2000 Professional Setup screen appears, either press ENTER to set up Windows 2000 Professional on the selected partition, or press C to create a partition in the unpartitioned space.

5.If you choose to install Windows 2000 Professional on a file allocation table (FAT) partition, specify whether you want to:

• Leave the current file system intact.

• Format the partition as FAT16.

• Convert the existing file system to the NTFS file system.

• Format the partition by using the NTFS file system.
Press ENTER after you make your selection. Setup examines the existing hard disks and then copies the files that are needed to complete the installation of Windows 2000 Professional. After the files are copied, the computer restarts.

Important Do not press a key to boot from your CD-ROM drive when your computer restarts.

6.When the Windows 2000 GUI Mode Setup Wizard appears, click Next to start the wizard. Setup detects and installs such devices as a specialized mouse or keyboard.

7.When the Regional Options dialog box appears, customize your installation of Windows 2000 Professional for locale, number format, currency, time, date, and language, if necessary. Click Next.

8.In the Personalize Your Software dialog box, type your name and the name of your organization, and then click Next.

9.In the Product ID dialog box, type the 25-character product key, and then click Next.

10.In the Computer Name and Password dialog box, either accept the default name that Setup generates or assign a different name for the computer. When you are prompted for an administrative password, type a password for the Administrator account. (You can leave the box blank; however, this is not recommended.) Click Next.

11.In the Date and Time Settings dialog box, set the correct date and time for your computer. You can also specify which time zone you are in and set the computer to automatically adjust the clock for daylight saving time. Click Next.

12.Setup installs the networking software and detects your network settings. When the Network Settings dialog box appears, click either

• Typical to set default network settings such as File and Print Sharing for Microsoft Networks, Client for Microsoft Networks, and TCP/IP protocol that uses Dynamic Host Configuration Protocol (DHCP), or

• Custom to specify the network components that you require for your network environment,
and then click Next.

13.In the Workgroup or Computer Domain dialog box, specify the workgroup or the domain to join. If you indicate that you are part of a domain, specify your domain user name and password. Click Next.

Setup installs the networking components.

14.During the final stage of installation, Setup installs Start menu items, registers components, saves settings, and removes temporary files. When the Completing the Windows 2000 Setup Wizard dialog box prompts you to do so, remove the Windows 2000 CD-ROM, and then click Finish to restart the computer.

15.After the computer restarts, click Next in the Welcome to the Network Identification Wizard dialog box.

16.In the Users of This Computer dialog box, specify either that users must enter a user name and password or that you want Windows 2000 to automatically log on a specific user when the computer starts. Click Finish.
When the Windows 2000 Professional desktop appears, the installation is complete.

2009-09-18T01:07:00.000-07:00

WINDOWS XP INSTALLATION PROCESS

How to install or upgrade to Windows XP?

This article describes how to install Windows XP. You may find it easier to follow the steps if you print this article first.

Before you start, you must have your Windows XP installation CD and the product key available.

If you cannot find your Windows XP CD or you cannot contact your computer manufacturer, you may have to purchase a new copy of Windows XP. Visit following link for more information:

http://support.microsoft.com/contactus/ (http://support.microsoft.com/contactus/)

Depending on the installation method that you select, you might need a boot CD or boot disks. If you do not have your Windows XP CD or boot disks, you must obtain them in order to install or upgrade to Windows XP by using certain methods. Review the methods to determine what media you will need. For more information about how to obtain the Windows XP Setup boot disks, click the following article number to view the article in the Microsoft Knowledge Base:
310994 (http://support.microsoft.com/kb/310994/ ) How to obtain Windows XP Setup boot disks You may have to troubleshoot product-key activation problems. For more information about how to troubleshoot installation problems, click the following article numbers to view the articles in the Microsoft Knowledge Base:
310637 (http://support.microsoft.com/kb/310637/ )

You receive an error message after you enter the product key when you try to install Windows XP If the installation method that you select requires you to start your computer from the Windows XP CD, your CD or DVD drive must be configured to do this. For information about how to configure your computer to start from the CD or DVD drive, see the documentation that is included with your computer or contact the computer manufacturer. For more information about how to start Setup from MS-DOS or a Windows 98/Windows Millennium Edition startup disk, click the following article number to view the article in the Microsoft Knowledge Base:
307848 (http://support.microsoft.com/kb/307848/ ) How to start the Setup program from MS-DOS in Windows XP
Methods to install Windows XP
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There are five methods for installing Windows XP. Review the following methods and select the method that is appropriate for your installation.

Method 1: Perform a clean install of Windows XPUse this method for a clean installation of Windows XP. A clean installation removes all data from your hard disk by repartitioning and reformatting your hard disk and reinstalling the operating system and programs to an empty (clean) hard disk.

Method 2: Upgrade to Windows XPUse this method if you are upgrading to Windows XP from Microsoft Windows 98, Microsoft Windows Millennium Edition, or Microsoft Windows 2000 Professional.

Method 3: Install Windows XP to a new hard diskUse this method to install Windows XP to a new hard disk. This is typically done when a new hard disk is installed on your computer.

Method 4: Install Windows XP to a new folder (parallel installation)Use this method to install Windows XP to a new folder (parallel installation) to either run two operating systems, or to access, repair, or retrieve data from a damaged disk.

Method 5: Perform a multiple boot operationUse this method to install Windows XP as a separate operating system on your computer. This lets you install more than one operating system on your computer and select which operating system that you want to use every time that you start your computer.

Method 1: Perform a clean install of Windows XP
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A clean installation consists of removing all data from your hard disk by repartitioning and reformatting your hard disk and reinstalling the operating system and programs to an empty (clean) hard disk. For more information about important things to consider before you partition and format you hard disk and how to partition and format your hard disk by using the Windows XP Setup program, click the following article number to view the article in the Microsoft Knowledge Base:
313348 (http://support.microsoft.com/kb/313348/ ) How to partition and format a hard disk in Windows XP To perform a clean installation of Windows XP, follow these steps:
1.Back up all important information before you perform a clean installation of Windows XP. Save the backup to an external location, such as a CD or external hard disk.

2.Start your computer from the Windows XP CD. To do this, insert the Windows XP CD into your CD drive or DVD drive, and then restart your computer.Note To boot from your Windows XP CD, the BIOS settings on your computer must be configured to do this.

3.When you see the "Press any key to boot from CD" message, press any key to start the computer from the Windows XP CD.

4.At the Welcome to Setup screen, press ENTER to start Windows XP Setup.

5.Read the Microsoft Software License Terms, and then press F8.

6.Follow the instructions on the screen to select and format a partition where you want to install Windows XP.

7.Follow the instructions on the screen to complete the Windows XP Setup.

If you have successfully installed Windows XP, you are finished. If these steps did not help you install Windows XP, go to the "Next Steps" section.

Method 2: Upgrade to Windows XP
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This section describes how to upgrade to Windows XP from Windows 98, Windows Millennium Edition, and Windows 2000 Professional.

Note Windows 2000 and Windows 2000 Professional can only be upgraded to Windows XP Professional. You cannot upgrade Windows 2000 to Windows XP Home.

Important Before you start the upgrade process, contact your computer manufacturer to obtain the latest BIOS upgrades for your computer and then install the upgrades. If you update the BIOS after you upgrade the computer, you may have to reinstall Windows XP to take advantage of features such as Advanced Configuration and Power Interface (ACPI) support in the BIOS. If you can do this, update the firmware in all the hardware devices before you start the upgrade.

You may want to disconnect from the Internet during the installation. This step is not necessary, but disconnecting from the Internet during the installation helps protect your computer. For added protection, you may also want to enable the Microsoft Internet Explorer firewall. For more information, see the "Enable or disable Internet Connection Firewall" topic in your Windows operating system Help.

For more information about how to prepare Windows 98 or Windows Millennium Edition for an upgrade to Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
316639 (http://support.microsoft.com/kb/316639/ )

How to prepare to upgrade Windows 98 or Windows Millennium Edition to Windows XP

To upgrade to Windows XP, follow these steps:

1.Start your computer, and then insert the Windows XP CD into the CD or DVD drive.

2.If Windows automatically detects the CD, click Install Windows to start the Windows XP Setup Wizard. If Windows does not automatically detect the CD, click Start. Then click Run. Type the following command, and then click OK:
CD drive letter:\setup.exe

3.When you are prompted to select an installation type, select Upgrade (the default setting), and then click Next.

4.Follow the instructions on the screen to complete the upgrade.If you have successfully upgraded to Windows XP, you are finished. If these steps did not help you upgrade to Windows XP, go to the "Next Steps" section.

Method 3: Install Windows XP to a new hard disk
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This method describes how to install Windows XP to a new hard disk. This is typically done when a new hard disk is installed on your computer.

Note You will need the CD for your previous operating system in order to complete this method.

Before you start, start your computer by using one of the following media:

Microsoft Windows 98/Windows Millennium startup disk
Windows XP CD or Windows XP boot disks

Note The Windows XP CD is the preferred media in the following steps:

However, the Windows XP boot disks will work if you do not have the CD.

To install Windows XP to a new hard disk, follow these steps:

1.Start your computer from the Windows XP CD (or boot disks). To do this, insert the Windows XP CD into your CD or DVD drive, and then restart your computer.

2.When the "Press any key to boot from CD" message appears on the screen, press any key to start the computer from the Windows XP CD.

3.At the Welcome to Setup screen, press ENTER to begin Windows XP Setup.

4.Read the Microsoft Software License Terms, and then press F8.

5.When you are prompted for the Windows XP CD, insert your Windows XP CD.

6.Restart your computer.

7.When you see the "Press any key to boot from CD" message, press any key to start the computer from the Windows XP CD.

8.At the Welcome to Setup screen, press ENTER to start Windows XP Setup.

9.Follow the instructions on the screen to select and format a partition where you want to install Windows XP.

10.Follow the instructions on the screen to complete Windows XP Setup.

If you have successfully installed Windows XP, you are finished. If these steps did not help you install Windows XP to a new hard disk, go to the "Next Steps" section.

Method 4: Install Windows XP to a new folder (parallel installation)
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This method describes how to install Windows XP to a new folder (parallel installation) to either run two operating systems, or to access, repair, or retrieve data from a damaged disk.Before you start, start your computer by using one of the following media:
Microsoft Windows 98/Windows Millennium Edition startup disk
Windows XP CD or Windows XP boot disksNote The Windows XP CD is the preferred media in the following steps. However, the Windows XP boot disks will work if you do not have the CD.To install Windows XP to a new folder (also known as a parallel installation), follow these steps:
Start your computer from the Windows XP CD (or boot disks). To do this, insert the Windows XP CD into your CD or DVD drive, and then restart your computer.
When the "Press any key to boot from CD" message appears on the screen, press any key to start the computer from the Windows XP CD.
At the Welcome to Setup screen, press ENTER to begin Windows XP Setup.
Read the Microsoft Software License Terms, and then press F8.
Select the partition in which you want to install Windows XP, and then press ENTER.
Select the Leave the current file system intact (no changes) option, and then press ENTER to continue.
Press ESC to install to a different folder.If the Setup program detects another operating system folder, it prompts you to type the name for the new folder after the backslash (\), for example, \WINXP. If there are no other operating systems detected, the Setup program automatically names the folder \Windows. For more information about how to change the folder name on new installations, click the following article number to view the article in the Microsoft Knowledge Base:
315242 (http://support.microsoft.com/kb/315242/ ) How to designate the original folder name for a reinstallation of Windows XP
Press ENTER to continue.
Follow the instructions on the screen to complete Windows XP Setup.If you have successfully installed Windows XP, you are finished. If these steps did not help you install Windows XP to a new folder, go to the "Next Steps" section.
Method 5: Perform a multiple boot operation
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Use this method to install Windows XP as a separate operating system on your computer. This lets you install more than one operating system and select which operating system that you want to use every time that you start your computer. For more information about how to multiple boot Windows XP and other versions of Windows and MS-DOS, click the following article number to view the article in the Microsoft Knowledge Base:
217210 (http://support.microsoft.com/kb/217210/ ) How to multiple boot Windows XP, Windows 2000, Windows NT, Windows 95, Windows 98, Windows Me, and MS-DOS If you have successfully installed Windows XP, you are finished. If these steps did not help you install Windows XP, go to the "Next Steps" section.
TROUBLESHOOTING
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For more information about how to troubleshoot installation problems, click the following article numbers to view the articles in the Microsoft Knowledge Base:
310637 (http://support.microsoft.com/kb/310637/ ) You receive an error message after you enter the product key when you try to install Windows XP
310064 (http://support.microsoft.com/kb/310064/ ) How to troubleshoot problems during installation when you upgrade from Windows 98 or Windows Millennium Edition to Windows XP For more information about Windows XP troubleshooting and Support, see the Windows XP Solution Center. Visit the following Microsoft Web site:
http://support.microsoft.com/ph/1173 (http://support.microsoft.com/ph/1173)
NEXT STEPS
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If these methods did not work for you, you can use the Microsoft Customer Support Services Web site to find other solutions to your problem. Some services that the Microsoft Customer Support Services Web sites provide include the following:
Searchable Knowledge Base (http://support.microsoft.com/search/?adv=1) : Search technical support information and self-help tools for Microsoft products.
Solution Centers (http://support.microsoft.com/select/?target=hub) : View product-specific frequently asked questions and support highlights.
Microsoft Customer Support Newsgroups (http://www.microsoft.com/communities/newsgroups/default.mspx) : Contact counterparts, peers, and Microsoft Most Valuable Professionals (MVPs).
Other Support Options (http://support.microsoft.com/default.aspx?pr=csshome) : Use the Web to ask a question, contact Microsoft Customer Support Services, or provide feedback.If you continue to have problems, you might want to contact Support:
http://support.microsoft.com/contactus (http://support.microsoft.com/contactus)
MORE INFORMATION
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For more information about how to install Windows XP Professional, click the following article number to view the article in the Microsoft Knowledge Base:
286463 (http://support.microsoft.com/kb/286463/ ) Release notes for Windows XP Setup contained in the Pro.txt file For more information about how to install Windows XP Home Edition, click the following article number to view the article in the Microsoft Knowledge Base:
306824 (http://support.microsoft.com/kb/306824/ ) Release notes for Windows XP Setup contained in the Home.txt file For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
307726 (http://support.microsoft.com/kb/307726/ ) Description of the Windows XP Upgrade Advisor
314062 (http://support.microsoft.com/kb/314062/ ) The latest Windows XP Hardware Compatibility List
295322 (http://support.microsoft.com/kb/295322/ ) How to determine if hardware or software is compatible with Windows XP If these Microsoft Knowledge Base articles do not help you resolve the problem, or if you experience symptoms that differ from those that this article describes, please search the Microsoft Knowledge Base for more information. To search the Microsoft Knowledge Base, visit the following Microsoft Web site:
http://support.microsoft.com (http://support.microsoft.com/) Then, type the text of the error message that you receive, or type a description of the problem in the Search Support (KB) field.

2009-08-27T02:27:00.000-07:00

RESOURCE ALLOCATION GRAPH

RESOURCE ALLOCATION GRAPH (RAG'S) are directed labeled graphs used to represent, from the point of view if DEADLOCKS, the current state of a system.

RESOURCE ALLOCATION GRAPHS:

PROCESS

REQUEST TYPE w/ 4 INSTANCE

Pi REQUEST INSTANCE of Rj

Pi is HOLDING AN INSTANCE OF Rj

2009-08-27T01:46:00.000-07:00

EXAMPLE of RESOURCE ALLOCATION GRAPH

RESOURCE ALLOCATION GRAPH w/ DEADLOCK

If graph contains a cycle then it has a DEADLOCK

-if only one instance per resource type,then DEADLOCK

-if several instances per resource type, possibly of DEADLOCK

RESOURCE ALLOCATION GRAPH w/ a CYCLE BUT NO DEADLOCK

If graph contains no cycle no DEADLOCK

2009-08-20T04:03:00.000-07:00

DEADLOCK CHARACTERIZATION

Mutual exclusion: only one process at a time can use a resource.
Hold and wait: a process holding at least one resource is waiting to acquire additional resources held by other processes.
No preemption: a resource can be released only voluntarily by the process holding it, after that process has completed its task.
Circular wait: there exists a set {P0, P1, …, P0} of waiting processes such that P0 is waiting for a resource that is held by P1, P1 is waiting for a resource that is held by
P2, …, Pn–1 is waiting for a resource that is held by Pn, and P0 is waiting for a resource that is held by P0.

2009-08-20T03:58:00.000-07:00

METHODS FOR HANDLING DEADLOCKS

Ensure that the system will never enter a deadlock state.
Allow the system to enter a deadlock state and then recover.
Ignore the problem and pretend that deadlocks never occur in the system; used by most operating systems, including UNIX.

2009-08-20T03:51:00.000-07:00

DEADLOCK PREVENTION

deadlock requires the following conditions:

-mutual exclusion:

-resources not sharable

-hold and wait:

-process must be holding one resource while requesting another

-circular wait:

-at least 2 processes must be blocked on each other

eliminate mutual exclusion:

-not possible in most cases
-spooling makes I/O devices sharable

eliminate hold-and-wait

-request all resources at once
-release all resources before a new request
-release all resources if current request blocks

eliminate circular wait

-order all resources: SEQ(Ri) ? SEQ(Rj)
-process must request in ascending order

2009-08-20T03:46:00.000-07:00

DEADLOCK DETECTION

graph reduction

-repeat:

-select unblocked process p
-remove p and all request and allocation edges

deadlock? graph not completely reducible
all reduction sequences lead to the same result

2009-08-20T03:33:00.000-07:00

DEADLOCK RECOVERY

process termination

-kill all processes involved in deadlock
-kill one at a time; in what order:

-by priority: consistent with scheduling
-by cost of restart: length of recomputation
-by impact on other processes: CS, producer/cons.

resource preemption

-direct: temporarily remove resource (e.g. memory)
-indirect: rollback to earlier checkpoint

2009-08-13T04:23:00.000-07:00

MULTIPROCESSOR SCHEDULER

Will consider only shared memory multiprocessor .
Salient features:

One or more caches: cache affinity is important
Semaphores/locks typically implemented as spin-locks: preemption

during critical sections

2009-08-13T03:59:00.000-07:00

REAL TIME SCHEDULING

Correctness of the system may depend not only on the logical result of the computation but also
on the time when these results are produced.

Example:

Tasks attempt to control events or to react to events
that take place in the outside world
These external events occur in real time and
processing must be able to keep up
Processing must happen in a timely fashion,
• neither too late, nor too early

2009-08-10T18:38:00.000-07:00

SUBSTANTIAL INFORMATION OF THREE OPERATING SYSTEM

WINDOWS XP THREAD

Implements the one-to-one mapping

Each thread contains

A thread id
Register set
Separate user and kernel stacks
Private data storage area

The register set, stacks, and private storage area are known as the context of the threads

The primary data structures of a thread include:

ETHREAD (executive thread block)
KTHREAD (kernel thread block)
TEB (thread environment block)

LINUX

Linux refers to them as tasks rather than threads
Thread creation is done through clone() system call

Clone() allows a child task to share the address space of the parent task a9process)
Clone() allow various levels of sharing between nothing.

Linux PCB contains pointers to other DS where the process data (open files, page tables…) is stored

Fork – a new process is created along with a copy of all the associated data structure of the parent process
Clone – a new process that points to the data structures of the parent process is created

WINDOWS SERVER 2008

Windows Server codename "Longhorn" operating systems.

Kernel improvements are significant because the kernel provides

low-level operating system functions,
including thread scheduling,
interrupt and exception dispatching,
multiprocessor synchronization, and
a set of routines and basic objects that the rest of the operating system uses to implement higher-level constructs.

2009-08-10T18:26:00.000-07:00

SCHEDULING ALGORITHMS

First-come, first-served (FCFS) scheduling
Shortest-job first (SJF) scheduling
Priority scheduling
Round-robin scheduling
Multilevel queue scheduling
Multilevel feedback queue scheduling

First-come, First-served (FCFS) scheduling is the simplest scheduling algorithm, but it can cause short processes to wait for very long processes.

Shortest-job-first (SJF) scheduling is provably optimal, providing the shortest average waiting time. Implementing SJF scheduling is difficult because predicting the length of the next CPU burst is difficult. The SJF algorithm is a special case of the general

priority-scheduling algorithm, which simply allocates the CPU to the highest-priority process. Both priority and SJF scheduling may suffer from starvation. Aging is a technique to prevent starvation.

Round-robin (RR) scheduling is more appropriate for a time-shared (interactive) system. RR scheduling allocates the CPU to the first process in the ready queue for q time units, where q is the time quantum. After q time units, if the process has not relinquished the CPU, it is preempted and the process is put at the tail of the ready queue. The major problem is the selection of the time quantum. If the quantum is too large, RR scheduling degenerates to FCFS scheduling; if the quantum is too small, scheduling overhead in the form of context-switch time becomes excessive.The FCFS algorithm is nonpreemptive, the RR algorithm is preemptive. The SJF and priority algorithms may be either preemptive or nonpreemptive.

Multilevel queue algorithms allow different algorithms to be used for various classes of processes. The most common is a foreground interactive queue which uses RR scheduling, and a background batch queue, which uses FCFS scheduling

Multilevel feedback queues allow processes to move from one queue to another.Because such a wide variety of scheduling algorithms are available, we need methods to select among them. Analytic methods use mathematical analysis to determine the performance of an algorithm. Simulation methods determine performance by imitating the scheduling algorithm on a “representative” sample of processes, and computing the resulting performance.

2009-07-30T04:17:00.001-07:00

USER THREAD

User threads are supported above the kernel and are implemented by a thread library at the user level. The library provides support for thread creation, scheduling, and management with no support from the kernel. Because the kernel is unaware of user-level threads, all thread creation and scheduling, are done in user space without the need for kernel intervention.

2009-07-30T04:13:00.000-07:00

MULTITHREADING MODELS

Many systems provide support for both user and kernel threads, resulting in different multithreading models. There are three common types of threading implementation:

1. Many-to-one Model - maps many user-level threads to one kernel thread.

2. One-to-one Model - maps each user thread to a kernel thread. It provides mode concurrency than the many-to-one model by allowing another thread to run when a thread makes a blocking system call.

3. Many-to-many Model - The many-to-many model multiplexes many user-level threads to a smaller or equal number of kernel threads. The number of kernel threads may be specific to either a particular application or a particular machine.

2009-07-30T04:11:00.000-07:00

THREAD LIBRARY

The threads library allows concurrent programming in Objective Caml. It provides multiple threads of control (also called lightweight processes) that execute concurrently in the same memory space. Threads communicate by in-place modification of shared data structures, or by sending and receiving data on communication channels.
The threads library is implemented by time-sharing on a single processor. It will not take advantage of multi-processor machines. Using this library will therefore never make programs run faster. However, many programs are easier to write when structured as several communicating processes.

2009-07-30T04:04:00.000-07:00

KERNEL THREAD

Kernel threads consist of a set of registers, a stack, and a few corresponding kernel data structures. When kernel threads are used, the operating system will have a descriptor for each thread belonging to a process and it will schedule all the threads. Unlike processes, all threads within a process share the same address space. Similar to processes, when a kernel thread makes a blocking call, only that thread blocks. All modern machines support kernel threads, most often via the POSIX threads interface ``pthreads''. Some dedicated parallel machines support kernel threads poorly or not at all. For example, the Blue Gene/L microkernel does not support pthreads.

The purported advantage of kernel threads over processes is faster creation and context switching compared with processes. For shared-memory multiprocessor architectures, the kernel is able to dispatch threads of one process on several processors, which leads to automatic load balancing within the nodes. For parallel programming, threads allow different parts of the parallel program to communicate by directly accessing each others' memory, which allows very efficient, fine-grained communication.

Kernel threads share a single copy of the entire address space, including regions such as global data that may cause conflicts if used by multiple threads simultaneously. Threads can also cause unintentional data sharing, which leads to corruption and race conditions. To avoid this unintentional sharing, programs must often be modified to either lock or access separate copies of common data structures. Several very widely used language features are unsafe when used with threads, such as the use of global and static variables, or the idiom of returning a reference to a static buffer. Especially with large existing codebases with many global variables, this makes kernel threads very difficult to use because in most implementations of kernel threads, it is not possible to assign each thread a private set of global variables.

Kernel threads are considered ``lightweight,'' and one would expect the number of threads to only be limited by address space and processor time. Since every thread needs only a stack and a small data structure describing the thread, in principle this limit should not be a problem. But in practice, we found that many platforms impose hard limits on the maximum number of pthreads that can be created in a process. Table 2 in Section 4 shows the practical limitations on pthreads on several stock systems.

In particular, operating system kernels tend to see kernel threads as a special kind of process rather than a unique entity. For example, in the Solaris kernel threads are called ``light weight processes'' (LWP's). Linux actually creates kernel threads using a special variation of fork called ``clone,'' and until recently gave each thread a separate process ID. Because of this heritage, in practice kernel threads tend to be closer in memory and time cost to processes than user-level threads, although recent work has made some progress in closing the gap, including K42 [5] and the Native POSIX Threading Library (NPTL) and Linux O(1) scheduler.

2009-07-30T03:56:00.000-07:00

BENEFITS OF MULTI-THREADED PROCESS

Multi-threaded programs can improve performance compared to traditional parallel programs that use multiple processes. Furthermore, improved performance can be obtained on multiprocessor systems using threads.

Managing Threads

Managing threads; that is, creating threads and controlling their execution, requires fewer system resources than managing processes. Creating a thread, for example, only requires the allocation of the thread's private data area, usually 64 KB, and two system calls. Creating a process is far more expensive, because the entire parent process addressing space is duplicated.
The threads library API is also easier to use than the library for managing processes. Thread creation requires only the pthread_create subroutine.

Inter-Thread Communications

Inter-thread communication is far more efficient and easier to use than inter-process communication. Because all threads within a process share the same address space, they need not use shared memory. Protect shared data from concurrent access by using mutexes or other synchronization tools.
Synchronization facilities provided by the threads library ease implementation of flexible and powerful synchronization tools. These tools can replace traditional inter-process communication facilities, such as message queues. Pipes can be used as an inter-thread communication path.

Multiprocessor Systems

On a multiprocessor system, multiple threads can concurrently run on multiple CPUs. Therefore, multi-threaded programs can run much faster than on a uniprocessor system. They can also be faster than a program using multiple processes, because threads require fewer resources and generate less overhead. For example, switching threads in the same process can be faster, especially in the M:N library model where context switches can often be avoided. Finally, a major advantage of using threads is that a single multi-threaded program will work on a uniprocessor system, but can naturally take advantage of a multiprocessor system, without recompiling.

Limitations

Multi-threaded programming is useful for implementing parallelized algorithms using several independent entities. However, there are some cases where multiple processes should be used instead of multiple threads.
Many operating system identifiers, resources, states, or limitations are defined at the process level and, thus, are shared by all threads in a process. For example, user and group IDs and their associated permissions are handled at process level. Programs that need to assign different user IDs to their programming entities need to use multiple processes, instead of a single multi-threaded process. Other examples include file-system attributes, such as the current working directory, and the state and maximum number of open files. Multi-threaded programs may not be appropriate if these attributes are better handled independently. For example, a multi-processed program can let each process open a large number of files without interference from other processes.

2009-07-30T03:36:00.000-07:00

THREAD

SINGLE THREADED PROCESS

A single thread can control the execution on a Maurer machine of any executable finite-state thread stored in the memory of the Maurer machine. We also relate stored threads with programs as considered in the program algebra of Bergstra et al. The work is intended as a preparation for the development of a formal approach to model micro-architectures and to verify their correctness and anticipated speed-up results.

MULTI-THREADED PROCESS

Multiple threads can be executed in parallel across many computer systems.

This is multithreading, and generally occurs by time slicing (similar to time-division multiplexing) across the computer systems. However, in a single processor environment, the processor 'context switches' between different threads. In this case, the processing is not literally simultaneous, for the single processor is really doing only one thing at a time. This switching can happen so fast as to give the illusion of simultaneity to an end user.

For instance, many PCs may only contain one processor core, but one can run multiple programs at once, such as typing in a document editor while listening to music in an audio playback program. Although the user experiences these things as simultaneous, in truth, the processor quickly switches back and forth between these separate processes. On a multiprocessor or multi-core system, now coming into general use, threading can be achieved via multiprocessing, where different threads and processes can run literally simultaneously on different processors or cores.

Threads exist within a process - every process has at least one thread, the 'main' thread. Threads share the process's resources, including memory and open files. This makes for efficient, but potentially problematic, communication.

2009-07-30T03:25:00.000-07:00

PROCEDURE-CONSUMER EXAMPLE

PROCEDURE

A Procedure encapsulates a task composed of Steps (and possibly, SubSteps). Procedures are usually performed sequentially, unless individual Steps direct the reader explicitly.
Often it is important to assure that certain conditions exist before a procedure is performed, and that the outcome of the procedure matches the expected results. DocBook does not provide explicit semantic markup for these pre- and post-conditions. Instead, they must be described as steps (check the pre-conditions in the first step and the results in the last step), or described outside the body of the procedure.

CONSUMER

Consumer is a broad label that refers to any individuals or households that use goods and services generated within the economy. The concept of a consumer is used in different contexts, so that the usage and significance of the term may vary.

2009-07-30T03:05:00.000-07:00

BUFFERING

Explicit control of buffering is important in many applications, including ones that need to deal with raw devices (such as disks), ones which need instantaneous input from the user, or ones which are involved in communication. Examples might be interactive multimedia applications, or programs such as telnet. In the absence of such strict buffering semantics, it can also be difficult to reason (even informally) about the contents of a file following a series of interacting I/O operations.
Three kinds of buffering are supported: line-buffering, block-buffering or no-buffering. These modes have the following effects. For output, items are written out from the internal buffer according to the buffer mode:

line-buffering: the entire buffer is written out whenever a newline is output, the buffer overflows, a flush is issued, or the handle is closed.
block-buffering: the entire buffer is written out whenever it overflows, a flush is issued, or the handle is closed.
no-buffering: output is written immediately, and never stored in the buffer.

ZERO CAPACITY

Communication over a noisy quantum channel introduces errors in the transmission that must be corrected. A fundamental bound on quantum error correction is the quantum capacity, which quantifies the amount of quantum data that can be protected. We show theoretically that two quantum channels, each with a transmission capacity of zero, can have a nonzero capacity when used together. This unveils a rich structure in the theory of quantum communications, implying that the quantum capacity does not completely specify a channel's ability to transmit quantum information.

BOUNDED CAPACITY

The capacity of discrete-time, non-coherent, multipath fading channels is considered. It is shown that if the delay spread is large in the sense that the variances of the path gains do not decay faster than geometrically, then capacity is bounded in the signal-to-noise ratio.

UNBOUNDED CAPACITY

The capacity of discrete-time, noncoherent, multipath fading channels is considered. It is shown that if the variances of the path gains decay faster than exponentially, then capacity is unbounded in the transmit power.

2009-07-30T02:41:00.000-07:00

SYNCHRONIZATION

BLOCK SEND

A blocking send can be used with a non-blocking
receive, and vice-versa,

e.g.,
MPI_Isend
MPI_Recv

NONBLOCKING SEND

Non-blocking sends can use any mode -
synchronous, buffered, standard or ready.

Separate communication into three phases:

1. Initiate non-blocking communication (“post” a
send or receive)

2. Do some other work not involving the data in
transfer
– Overlap calculation and communication
– Latency hiding

3. Wait for non-blocking communication to complete

BLOCKING RECEIVE
A blocking receive returns as soon as the data is ready in the receive buffer.
NONBLOCKING RECEIVE
A non-blocking send returns as soon as possible, that is, as soon as it has posted the send. The buffer might not be free for reuse.
C:
int MPI_Irecv(void *buf, int count, MPI_Datatype datatype,
int source, int tag, MPI_Comm comm, MPI_Request
*request)
Fortran:
CALL
MPI_IRECV(BUF,COUNT,DATATYPE,SOURCE,TAG,COMM,REQUEST,IER
ROR)

BUF(*)
INTEGER COUNT,DATATYPE,SOURCE,TAG,COMM
INTEGER REQUEST,IERROR

2009-07-30T02:35:00.000-07:00

INDIRECT COMMUNICATION

Indirect communication is used to attack, manipulate, or defend one's self.

By comparison, indirect communication conceals one's true position or feelings. There are may ways to be indirect, an obvious example is sarcasm. If you don't like someone's clothes and you say (in a sarcastic tone) "I like your clothes", the literal meaning and implied meaning are opposite.While direct communication has a goal of cooperation, indirect communication has a goal of hurting or manipulating another person, or protecting one's self. Below is an incomplete list of some different forms of indirect communication, grouped into attacks and defenses, along with a description.

personal attacks:
1.)name calling -- "You're a pig!". The purpose is to hurt the other person's feelings. If you were being direct, you might say "I'm angry at you, and I think you're a bad person.". This is truthful, but less likely to hurt the other person's feelings (if that is your goal). Note that name calling does not require any response from the other person...it's not a question, so no reply is required.

2.)belligerence -- "Why won't you do it?! Huh?! Why not?!?" Repeatedly demanding another person submit to your demands. An example of a direct response might be "I've already answered you, and I'm not going to answer you again. We can talk about something else, or I'm done talking to you."

3.)sarcasm -- Using an affected tone and saying the opposite of what you mean. Sarcasm can be used to mock or insult another person, although it can also be used purely for humorous effect.

4.)contempt -- A harsh and hostile tone of voice that expresses contempt for the person you are speaking to (or about). This is one of the "four horsemen of the apocalypse" for predicting divorce cited by John Gottman (see below).

5.)yelling -- Using an unnecessarily loud volume for effect. An example of a direct response might be to say "Please don't yell, I can hear you fine."

6.)insinuation -- Implying what you mean with suggestive statements. For example, "If it's not your fault, who's fault is it!?!". An example of a direct response might be to say "Are you implying I am to blame?"

defensiveness:

1.)defensive -- anything said with a defensive tone of voice, a high-pitched tone that is understood to deflect blame. For example, imaging the pitch used when a person says "What's your problem? I was only trying to help!". People are generally not aware of it when they are using a defensive tone of voice, but it's important to be aware of the tone of voice you are using if you want to avoid being defensive.

2.)dismissive -- To negatate another person's problem or statement. For example, saying "so what?"

3.)minimizing -- to reduce or de-value another person's problem by characterizing it as less than it is. For example, saying "It's only a scratch, you'll survive" when someone is hurt or injured.

4.)stonewalling -- obstructing another person's questions. Giving only evasive, dismissive, or vague responses to another perosn, making no effort to answer their questions but trying to wear them down/frustrate them.

2009-07-30T02:04:00.000-07:00

INTERPROCESS COMMUNICATION

DIRECT COMMUNICATION

Direct communication is the most effective means of communication when trying to cooperate.

When communication is direct, a person means exactly what they say. There is no implied meaning, insinuation, or mixed message. Think of a scientist saying “The results of the experiment are positive”, or a journalist saying ”The accident occurred at 6pm”; this is direct communication. When you say "I like your clothes", and you are being direct, you mean you like the other person's clothes. People can communicate how they feel by being direct. For example, "I feel hurt that you didn't meet me yesterday" (this is sometimes called an "I-statement").
When being direct, the speaker's tone of voice is usuall "plain" (even monotome), because they are not using a sarcastic or defensive tone (or any other inflection that creates a mixed message). Direct communication is the only form of communication in many fields, such as science, journalism, and in the legal system (a defendant would not plead guilty in court sarcastically, because the sarcastic tone would be disregarded and it would count as a real guilty plea).
In all important matters in society, people use direct communication. For example, when an airplane communicates with air traffic control, they say directly and exactly what they mean, in very specific terms. They don't use sarcasm or imply things, since the situation is too important to allow for any misunderstanding.

2009-07-16T03:26:00.000-07:00

COOPERATING PROCESSES

Advantages of process cooperation

Information sharing
Computation speed-up
Modularity
Convenience

Independent process cannot affect/be affected by the execution of another process, cooperating ones can

Issues

Communication
Avoid processes getting into each other’s way
Ensure proper sequencing when there are dependencies

Common paradigm: producer-consumer

unbounded-buffer - no practical limit on the size of the buffer
bounded-buffer - assumes fixed buffer size

INTERPROCESSES COMMUNICATION

For communication and synchronization

Shared memory
OS provided IPC

Message system

no need for shared variable
two operations
send(message) – message size fixed or variable
receive(message)
If P and Q wish to communicate, they need to
establish a communication link between them
exchange messages via send/receive
Implementation of communication link

physical (e.g., shared memory, hardware bus)

logical (e.g., logical properties)
4

2009-07-16T02:32:00.000-07:00

OPERATION ON PROCESS

a.)PROCESS CREATION

Process creation is only the first management action performed by the OS on the process. Since the process will use the resources made available by the OS, further OS activity will typically be needed to manage those resources on behalf of the process. This involves the release of the CPU control from the process to the OS. This release is triggered by various conditions, that can usually be classified as follows:

Explicit request: the process branches to one of the OS routines (in particular, it could explicitly request to be suspended). Appropriate steps be taken in order maintain through the branch the OS's exclusive on privileged execution mode. Typically such a branch will involve the execution of an appropriate SW interrupt instruction, so that the process yields CPU control to the OS code which provides the needed service. We shall say more about this when talking about ``kernels executing in the context of a process''.
Hardware interrupt: an hardware event generated outside the CPU that needs be serviced asynchronously. Example: I/O interrupts from DMA or peripherals. Particularly important in this class is the clock (or ``timer'') interrupt, that allows an OS to periodically regain control of the CPU no matter what the current process is doing.
Exceptional condition originated from ``inside'' the CPU while executing the current task (e.g. attempt to execute unallowed operations, arithmetical errors, etc.)

It is at this point important to analyze the in detail the operations involved in the above CPU release/regain events. From the point of view of an OS managing several processes, in particular, it's important to differentiate between two different scenarios:

A process is interrupted; some OS service is performed; the process is continued thereafter.
A process is interrupted; the OS gives control to another process.

Note carefully that the first scenario can be treated similarly to a subroutine call within one process: in order to resume correctly the process after the OS actions it's necessary that only a context switch, i.e. the saving/resuming of the processor state data, be performed before and after the interruption. The second scenario implies a process switch, which is typically a much more time-consuming sequence of operations on the OS side, since it involves the update of process tables and queues, the loading of suspended processes if no ready one are available, etc. It's consequently important for efficiency reasons that the OS be able to identify what services can be provided by a simple context switch (e.g., a memory block allocation in main memory), and which ones it's better to delay, allowing CPU access to another process.

Two interesting consequences derive from the above observation. One, leading to the distinction between processes and threads will be treated later. The second is of interest here, since it leads to understand in greater detail how the OS services are performed from a process's point of view.

b.)PROCESS TERMINATION

Processes terminate either voluntarily through an exit system call or involuntarily as the result of a signal. In either case, process termination causes a status code to be returned to the parent of the terminating process (if the parent still exists). This termination status is returned through the wait4 system call. The wait4 call permits an application to request the status of both stopped and terminated processes. The wait4 request can wait for any direct child of the parent, or it can wait selectively for a single child process or for only its children in a particular process group. Wait4 can also request statistics describing the resource utilization of a terminated child process. Finally, the wait4 interface allows a process to request status codes without blocking.

Within the kernel, a process terminates by calling the exit() routine. The exit() routine first kills off any other threads associated with the process. The termination of other threads is done as follows:

Any thread entering the kernel from user space will thread_exit() when it traps into the kernel.
Any thread already in the kernel and attempting to sleep will return immediately with EINTR or EAGAIN, which will force them to back out to user space, freeing resources as they go. When the thread attempts to return to user space, it will instead hit thread_exit().

The exit() routine then cleans up the process's kernel-mode execution state by doing the following:

Canceling any pending timers
Releasing virtual-memory resources
Closing open descriptors
Handling stopped or traced child processes

With the kernel-mode state reset, the process is then removed from the list of active processes—the allproc list—and is placed on the list of zombie processes pointed to by zombproc. The process state is changed to show that no thread is currently running. The exit() routine then does the following:

Records the termination status in the p_xstat field of the process structure
Bundles up a copy of the process's accumulated resource usage (for accounting purposes) and hangs this structure from the p_ru field of the process structure
Notifies the deceased process's parent

Finally, after the parent has been notified, the cpu_exit() routine frees any machine-dependent process resources and arranges for a final context switch from the process.

The wait4 call works by searching a process's descendant processes for processes that have terminated. If a process in ZOMBIE state is found that matches the wait criterion, the system will copy the termination status from the deceased process. The process entry then is taken off the zombie list and is freed. Note that resources used by children of a process are accumulated only as a result of a wait4 system call. When users are trying to analyze the behavior of a long-running program, they would find it useful to be able to obtain this resource usage information before the termination of a process. Although the information is available inside the kernel and within the context of that program, there is no interface to request it outside that context until process termination.

2009-07-16T02:04:00.000-07:00

PROCESS SCHEDULING

a.)SCHEDULING QUEUES

•Job queue – set of all processes in the system.
•Ready queue – set of all processes residing in main memory,
ready and waiting to execute.
•Device queues – set of processes waiting for an I/O device.
•Process migration between the various queues.

b.)SCHEDULERS

Operating systems may feature up to 3 distinct types of schedulers: a long-term scheduler (also known as an admission scheduler or high-level scheduler), a mid-term or medium-term scheduler and a short-term scheduler (also known as a dispatcher). The names suggest the relative frequency with which these functions are performed.

Long-term Scheduler
Mid-term Scheduler
Short-term Scheduler

Long-term Scheduler

The long-term, or admission, scheduler decides which jobs or processes are to be admitted to the ready queue; that is, when an attempt is made to execute a program, its admission to the set of currently executing processes is either authorized or delayed by the long-term scheduler. Thus, this scheduler dictates what processes are to run on a system, and the degree of concurrency to be supported at any one time - ie: whether a high or low amount of processes are to be executed concurrently, and how the split between IO intensive and CPU intensive processes is to be handled. In modern OS's, this is used to make sure that real time processes get enough CPU time to finish their tasks. Without proper real time scheduling, modern GUI interfaces would seem sluggish. [Stallings, 399].
Long-term scheduling is also important in large-scale systems such as batch processing systems, computer clusters, supercomputers and render farms. In these cases, special purpose job scheduler software is typically used to assist these functions, in addition to any underlying admission scheduling support in the operating system.

Mid-term Scheduler

The mid-term scheduler, present in all systems with virtual memory, temporarily removes processes from main memory and places them on secondary memory (such as a disk drive) or vice versa. This is commonly referred to as "swapping out" or "swapping in" (also incorrectly as "paging out" or "paging in"). The mid-term scheduler may decide to swap out a process which has not been active for some time, or a process which has a low priority, or a process which is page faulting frequently, or a process which is taking up a large amount of memory in order to free up main memory for other processes, swapping the process back in later when more memory is available, or when the process has been unblocked and is no longer waiting for a resource. [Stallings, 396] [Stallings, 370]
In many systems today (those that support mapping virtual address space to secondary storage other than the swap file), the mid-term scheduler may actually perform the role of the long-term scheduler, by treating binaries as "swapped out processes" upon their execution. In this way, when a segment of the binary is required it can be swapped in on demand, or "lazy loaded". [Stallings, 394]

Short-term Scheduler

The short-term scheduler (also known as the dispatcher) decides which of the ready, in-memory processes are to be executed (allocated a CPU) next following a clock interrupt, an IO interrupt, an operating system call or another form of signal. Thus the short-term scheduler makes scheduling decisions much more frequently than the long-term or mid-term schedulers - a scheduling decision will at a minimum have to be made after every time slice, and these are very short. This scheduler can be preemptive, implying that it is capable of forcibly removing processes from a CPU when it decides to allocate that CPU to another process, or non-preemptive (also known as "voluntary" or "co-operative"), in which case the scheduler is unable to "force" processes off the CPU. [Stallings, 396].

c.)CONTEXT SWITCH

A context switch is the computing process of storing and restoring the state (context) of a CPU such that multiple processes can share a single CPU resource. The context switch is an essential feature of a multitasking operating system. Context switches are usually computationally intensive and much of the design of operating systems is to optimize the use of context switches. A context switch can mean a register context switch, a task context switch, a thread context switch, or a process context switch. What constitutes the context is determined by the processor and the operating system.

2009-07-16T01:48:00.001-07:00

THE CONCEPT OF PROCESS

a.)PROCESS STATE

The process state consist of everything necessary to resume the process execution if it is somehow put aside temporarily. The process state consists of at least following:

Code for the program.
Program's static data.
Program's dynamic data.
Program's procedure call stack.
Contents of general purpose registers.
Contents of program counter (PC)
Contents of program status word (PSW).
Operating Systems resource in use.

A process goes through a series of discrete process states.

New State: The process being created.
Running State: A process is said to be running if it has the CPU, that is, process actually using the CPU at that particular instant.
Blocked (or waiting) State: A process is said to be blocked if it is waiting for some event to happen such that as an I/O completion before it can proceed. Note that a process is unable to run until some external event happens.
Ready State: A process is said to be ready if it use a CPU if one were available. A ready state process is runable but temporarily stopped running to let another process run.
Terminated state: The process has finished execution.

b.)PROCESS CONTROLL BLOCK

A process in an operating system is represented by a data structure known as a process control block (PCB) or process descriptor. The PCB contains important information about the specific process including

The current state of the process i.e., whether it is ready, running, waiting, or whatever.
Unique identification of the process in order to track "which is which" information.
A pointer to parent process.
Similarly, a pointer to child process (if it exists).
The priority of process (a part of CPU scheduling information).
Pointers to locate memory of processes.
A register save area.
The processor it is running on.

The PCB is a certain store that allows the operating systems to locate key information about a process. Thus, the PCB is the data structure that defines a process to the operating systems.

c.)THREADS

Despite of the fact that a thread must execute in process, the process and its associated threads are different concept. Processes are used to group resources together and threads are the entities scheduled for execution on the CPU.A thread is a single sequence stream within in a process. Because threads have some of the properties of processes, they are sometimes called lightweight processes. In a process, threads allow multiple executions of streams. In many respect, threads are popular way to improve application through parallelism. The CPU switches rapidly back and forth among the threads giving illusion that the threads are running in parallel. Like a traditional process i.e., process with one thread, a thread can be in any of several states (Running, Blocked, Ready or Terminated). Each thread has its own stack. Since thread will generally call different procedures and thus a different execution history. This is why thread needs its own stack. An operating system that has thread facility, the basic unit of CPU utilization is a thread. A thread has or consists of a program counter (PC), a register set, and a stack space. Threads are not independent of one other like processes as a result threads shares with other threads their code section, data section, OS resources also known as task, such as open files and signals.

Quiz#3

2009-07-09T04:00:00.000-07:00

1.)What are the major activities of an Operating System with regards to PROCESS MANAGEMENT?

Ans.
-Process creation
-Process creation and deletion
-Process suspesion and resumption
-Provision of mechanism for:-Process synchronization
-Process communication
-Deadlock handling

2.)What are the major activities of an Operating System with regards to MEMORY MANAGEMENT?

Ans.
-To improve both CPU utilization and response speed,several programs are kept in memory.
-Keep track of which parts of memory are currently being used and by whom.
-Decide which process to load when memory space becomes available.
-Allocate and Deallocate memory space as needed.

3.)What are the major activities of an Operating System with regards to SECONDARY-STORAGE MANAGEMENT?

Ans.
-Free space management
-Storage allocation
-Disk scheduling

4.)What are the major activities of an Operating System with regards to FILE MANAGEMENT?

Ans.
-File creation and deletion
-Derictory creation and deletion
-Support of primitives for manipulating files and directories
-File backup on stable storage media
-Mapping files onto secondary storage

5.)What is the purpose of the COMMAND INTERPRETER?

Ans.
It reads commands from the user or from a ﬁle of commandsand executes them, usually by
turning them into one or more systemcalls. It is usually not part of the kernel since the
command interpreteris subject to changes.

2009-07-07T03:51:00.000-07:00

SYSTEM BOOT

In order for a computer to successfully boot, its BIOS, operating system and hardware components must all be working properly; failure of any one of these three elements will likely result in a failed boot sequence.

When the computer's power is first turned on, the CPU initializes itself, which is triggered by a series of clock ticks generated by the system clock. Part of the CPU's initialization is to look to the system's ROM BIOS for its first instruction in the startup program. The ROM BIOS stores the first instruction, which is the instruction to run the power-on self test (POST), in a predetermined memory address. POST begins by checking the BIOS chip and then tests CMOS RAM. If the POST does not detect a battery failure, it then continues to initialize the CPU, checking the inventoried hardware devices (such as the video card), secondary storage devices, such as hard drives and floppy drives, ports and other hardware devices, such as the keyboard and mouse, to ensure they are functioning properly.

Once the POST has determined that all components are functioning properly and the CPU has successfully initialized, the BIOS looks for an OS to load.

The BIOS typically looks to the CMOS chip to tell it where to find the OS, and in most PCs, the OS loads from the C drive on the hard drive even though the BIOS has the capability to load the OS from a floppy disk, CD or ZIP drive. The order of drives that the CMOS looks to in order to locate the OS is called the boot sequence, which can be changed by altering the CMOS setup. Looking to the appropriate boot drive, the BIOS will first encounter the boot record, which tells it where to find the beginning of the OS and the subsequent program file that will initialize the OS.

Once the OS initializes, the BIOS copies its files into memory and the OS basically takes over control of the boot process. Now in control, the OS performs another inventory of the system's memory and memory availability (which the BIOS already checked) and loads the device drivers that it needs to control the peripheral devices, such as a printer, scanner, optical drive, mouse and keyboard. This is the final stage in the boot process, after which the user can access the system’s applications to perform tasks.

2009-07-07T03:39:00.000-07:00

SYSTEM GENERATION

An operational system is a combination of the z/TPF system, application programs, and people. People assign purpose to the system and use the system. The making of an operational system depends on three interrelated concepts:

- System definition: The necessary application and z/TPF system knowledge required to select the hardware configuration and related values used by thez/TPF system software.

- System initialization: The process of creating the z/TPF system tables and configuration-dependent system software.

- System restart and switchover: The procedures used by the z/TPF system software to ready the configuration for online use.

The first two items are sometimes collectively called system generation; also installing and implementing. System definition is sometimes called design. System restart is the component that uses the results of a system generation to place the system in a condition to process real-time input. The initial startup is a special case of restart and for this reason system restart is sometimes called initial program load, or IPL. System restart uses values found in tables set up during system generation and changed during the online execution of the system. A switchover implies shifting the processing load to a different central processing complex (CPC), and requires some additional procedures on the part of a system operator. A restart or switchover may be necessary either for a detected hardware failure, detected software failure, or operator option. In any event, system definition (design), initialization, restart, and switchover are related to error recovery. This provides the necessary background to use this information, which is the principal reference to be used to install the z/TPF system.

Performing a system generation requires a knowledge of the z/TPF system structure, system tables, and system conventions, a knowledge of the applications that will be programmed to run under the system, and a user's knowledge of z/OS. Knowledge of the z/TPF system, Linux, and the application are required to make intelligent decisions to accomplish the system definition of a unique z/TPF system environment. The use of z/OS and Linux is necessary because many programs used to perform system generation run under control of z/OS or Linux. Although this information does not rely on much z/OS or Linux knowledge, when the moment arrives to use the implementation information, the necessary z/OS and Linux knowledge must be acquired. You are assumed to have some knowledge of the S/370 assembly program as well as jargon associated with the z/OS and Linux operating systems. Some knowledge of C language is also helpful, because some of the programs that are used to generate the system are written in C.

System definition is a nontrivial endeavor because both z/TPF system and application knowledge is necessary. An understanding of basic data organization of the system is necessary to allocate the appropriate area of online file storage for all the programs. All z/TPF system programs and application programs that are used in the online environment are placed in file storage and reside in core memory.

An appreciation of defining a system is necessary to relate a unique z/TPF system to its environment. Clearly, no amount of information can anticipate all the variants of applications to be run under the system. However, the interrelationship of the applications, the z/TPF control program, and the corresponding data structures is of paramount importance. The initial system definition must be approached with the best available information. Usually, even this is not sufficient for an accurate definition. Through knowledge, analysis, and an understanding of system guidelines, a workable operational system can be defined and initialized. A system definition is not as insurmountable as it may first seem, because the z/TPF system includes components that allow the system programmer to change the system tables and programs, the application programs, and the physical components. In this sense, the operational system can be adapted to its environment.

The initial system generation, which requires analysis techniques and knowledge of the z/TPF system, represents the beginning of a continuous process required throughout the life of an operational system.

The terms system initialization and initialization process are used to emphasize the human activity and offline procedures required to produce programs and data to be placed on online system resident storage. The term offline procedures refers to the execution of programs, written to run under z/OS or Linux, that assist in the production of the online programs and data. (The term procedures is generally used to mean a program or collection of programs.) The goal of system initialization is to place the various levels of z/TPF system storage facilities into the condition where restart procedures may be invoked to allow online processing to begin. The restart procedures are involved with the programs that build system records used to control online processing. Many of these records are assigned values identified by the initialization process. Some important distinctions of terminology follow:

- A program in the restart procedures, called the initializer program (thez/TPF system identification is CCCTIN), uses values assigned to system records used for main (core) storage management. The initializer program is not the same thing as the initialization process. The initializer program is a portion of the restart procedures.

- A system restart begins by pressing the initial program load (IPL) key. This invokes a standard S/390 IPL sequence, which in turn invokes the z/TPF system IPL program. The IPL program loads enough of the system to main storage to permit the initializer program to allocate system tables to main storage. In a loosely coupled complex, an IPL requires the coordination of each of the CPCs in the complex; if a CPC is a multiprocessor, the IPL is performed by only one of the CPUs.

An initial restart differs from an online restart, which is shown in Figure 1. An initial restart uses input data and restart programs created in the offline environment. An online restart uses some of the same data, but the data and restart programs are accessed from online files. The basic restart procedure of loading the z/TPF core resident programs and executing the initializer program is identical for both the initial restart or the online restart. The location of the restart programs and data identifies the difference. During an initial restart, additional programs to load programs and data to system storage must be invoked. Normally, much of the data put in place during an initial restart does not need to be reloaded during an online restart. (If a reload is necessary, an initial restart is required.) The basic restart programs (such as the IPL and initializer programs) and the structure of the data that these restart programs process are identical. The location of the data is different, as well as some of the data content.

Figure 1. Initial vs. online restart

2009-07-07T02:55:00.000-07:00

VIRTUAL MACHINE

IMPLEMENTATION

"The concept of the virtual machine is one of the most important concepts in computer science today. Emulators use virtual machines, operating systems use virtual machines (Microsoft's .NET), and programming languages use virtual machines (Perl, Java)". Read on for his review of Virtual Machine Design and Implementation in C/C++, an attempt to examine and explain virtual machines and the concepts which allow them to exist.

Virtual machines are, in effect, a software model of a whole system architecture and processor. They take in bytecode (formed of opcodes, operands, and other data) and execute it, much in the same way a real system executes code. Running these operations in software, however, gives you more security, and total control over how the system works.

Virtual machines are popular for a number of reasons. The first is that they give programmers a third compiler option. You don't have to either go the dynamic interpreted route or the static compiled route, you can compile for a virtual machine instead. Another is that virtual machines aid portability. If you compile your code for a virtual machine, you can run that binary on any system to which the virtual machine has been ported.

Few books have been written on virtual machines, with only a few Java Virtual Machine titles available. Virtual Machine Design and Implementation by Bill Blunden is therefore a landmark book for anyone with an interest in virtual machines, or even system and processor architecture as a whole.

BENEFITS

Top Ten Benefits 2008

The latest version of System Center Virtual Machine Manager incorporates all the functionality of its predecessor and brings exciting new capabilities to the management of virtual machines. Here are 10 of the most valuable benefits that Virtual Machine Manager 2008 (VMM) can provide to your organization.

- Designed for virtual machines running on Windows Server 2008 and Microsoft Hyper-V Server

Hyper-V is the next-generation hypervisor-based virtualization platform from Microsoft, which is designed to offer high performance, enhanced security, high availability, scalability, and many other improvements. VMM is designed to take full advantage of these foundational benefits through a powerful yet easy-to-use console that streamlines many of the tasks necessary to manage virtualized infrastructure. Even better, administrators can manage their traditional physical servers right alongside their virtual resources through one unified console.

- Support for Microsoft Virtual Server and VMware ESX

With this release, VMM now manages VMware ESX virtualized infrastructure in conjunction with the Virtual Center product. Now administrators running multiple virtualization platforms can rely on one tool to manage virtually everything. With its compatibility with VMware VI3 (through Virtual Center), VMM now supports features such as VMotion and can also provide VMM-specific features like Intelligent Placement to VMware servers.

- Performance and Resource Optimization (PRO)

Performance and Resource Optimization (PRO) enables the dynamic management of virtual resources though Management Packs that are PRO enabled. Utilizing the deep monitoring capabilities of System Center Operations Manager 2007, PRO enables administrators to establish remedial actions for VMM to execute if poor performance or pending hardware failures are identified in hardware, operating systems, or applications. As an open and extensible platform, PRO encourages partners to design custom management packs that promote compatibility of their products and solutions with PRO’s powerful management capabilities.

- Maximize datacenter resources through consolidation

A typical physical server in the datacenter operates at only 5 to 15 percent CPU capacity. VMM can assess and then consolidate suitable server workloads onto virtual machine host infrastructure, thus freeing up physical resources for repurposing or hardware retirement. Through physical server consolidation, continued datacenter growth is less constrained by space, electrical, and cooling requirements.

- Machine conversions are a snap!

Converting a physical machine to a virtual one can be a daunting undertaking—slow, problematic, and typically requiring you to halt the physical server. But thanks to the enhanced P2V conversion in VMM, P2V conversions will become routine. Similarly, VMM also provides a straightforward wizard that can convert VMware virtual machines to VHDs through an easy and speedy Virtual-to-Virtual (V2V) transfer process.

- Quick provisioning of new machines

In response to new server requests, a truly agile IT department delivers new servers to its business clients anywhere in the network infrastructure with a very quick turnaround. VMM enables this agility by providing IT administrators with the ability to deploy virtual machines in a fraction of the time it would take to deploy a physical server. Through one console, VMM allows administrators to manage and monitor virtual machines and hosts to ensure they are meeting the needs of the corresponding business groups.

- Intelligent Placement minimizes virtual machine guesswork in deployment

VMM does extensive data analysis on a number of factors before recommending which physical server should host a given virtual workload. This is especially critical when administrators are determining how to place several virtual workloads on the same host machine. With access to historical data—provided by Operations Manager 2007—the Intelligent Placement process is able to factor in past performance characteristics to ensure the best possible match between the virtual machine and its host hardware.

- Delegated virtual machine management for Development and Test

Virtual infrastructures are commonly used in Test and Development environments, where there is constant provisioning and tear down of virtual machines for testing purposes. This latest version of VMM features a thoroughly reworked and improved self-service Web portal, through which administrators can delegate this provisioning role to authorized users while maintaining precise control over the management of virtual machines.

- The library helps keep virtual machine components organized

To keep a data center’s virtual house in order, VMM provides a centralized library to store various virtual machine “building blocks”—off-line machines and other virtualization components. With the library’s easy-to-use structured format, IT administrators can quickly find and reuse specific components, thus remaining highly productive and responsive to new server requests and modifications.

- Windows PowerShell provides rich management and scripting environment

The entire VMM application is built on the command-line and scripting environment, Windows PowerShell. This version of VMM adds additional PowerShell commandlets and “view script” controls, which allow administrators to exploit customizing or automating operations at an unprecedented level.

EXAMPLE

In figure 92 is an example of an explicitly authorized TSAF collection involving two z/VM systems sharing global resources. The entries within each box represent the CP directory entries for each CMS virtual machine.

Figure 92. TSAF Collection with Authorized Global Resource Managers and User Programs

In figure 92, users have the following authorization:

-USERa on VMSYS1 can connect only to RES2 on VMSYS2.
-USERb on VMSYS1 can connect only to RES1 on VMSYS1.
-USERc on VMSYS2 can connect to RES1 on VMSYS1 and to RES2 on VMSYS2.
-USERd on VMSYS2 can connect only to RES2 on VMSYS2.

2009-07-02T04:13:00.000-07:00

SYSTEM STRUCTURE

SIMPLE STRUCTURE

Any part of the system may use the functionality of the rest of
the system.
MS-DOS (user programs can call low level I/O routines)

LAYERED APPROACH

– layer n can only see the functionality that layer n-1 exports
– provides good abstraction from the lower level details
• new hardware can be added if it provides the interface required of a particular layer
– system call interface is an example of layering
– can be slow if there are too many layers

2009-07-02T04:05:00.000-07:00

SYSTEM CALLS

PROCESS CONTROL

– create/terminate a process (including self)

FILE MANAGEMENT

Also referred to as simply a file system or filesystem. The system that an operating system or program uses to organize and keep track of files. For example, a hierarchical file system is one that uses directories to organize files into a tree structure.Although the operating system provides its own file management system, you can buy separate file management systems. These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection.

DEVICE MANAGEMENT

Device Management is a set of technologies, protocols and standards used to allow the remote management of mobile devices, often involving updates of firmware over the air (FOTA). The network operator, handset OEM or in some cases even the end-user (usually via a web portal) can use Device Management, also known as Mobile Device Management, or MDM, to update the handset firmware/OS, install applications and fix bugs, all over the air. Thus, large numbers of devices can be managed with single commands and the end-user is freed from the requirement to take the phone to a shop or service center to refresh or update.
For companies, a Device Management system means better control and safety as well as increased efficiency, decreasing the possibility for device downtime. As the number of smart devices increases in many companies today, there is a demand for managing, controlling and updating these devices in an effective way. As mobile devices have become true computers over the years, they also force organizations to manage them properly. Without proper management and security policies, mobile devices pose threat to security: they contain lots of information, while they may easily get into wrong hands. Normally an employee would need to visit the IT / Telecom department in order to do an update on the device. With a Device Management system, that is no longer the issue. Updates can easily be done "over the air". The content on a lost or stolen device can also easily be removed by "wipe" operations. In that way sensitive documents on a lost or a stolen device do not arrive in the hands of others.

INFORMATION MAINTENANCE

– get time
– set system data (OS parameters)
– get process information (id, time used)

2009-07-02T03:56:00.000-07:00

OPERATING SYSTEM SERVICES

Operating systems are responsible for providing essential services within a computer system:
-Initial loading of programs and transfer of programs between secondary storage and main memory
-Supervision of the input/output devices
-File management
-Protection facilities

OPERATING SYSTEM STRUCTURES

2009-07-02T03:04:00.000-07:00

System Components

OPERATING SYSTEMS PROCESS MANAGEMENT

In operating systems, process is defined as “A program in
execution” . Process can be considered as an entity that
consists of a number of elements, including: identifier,
state, priority, program counter, memory pointer, context
data, and I/O request. The above information about a
process is usually stored in a data structure, typically called
process block. Figure 1 shows a simplified process block
[10]. Because process management involves scheduling
(CPU scheduling, I/O scheduling, and so on), state
switching, and resource management, process block is one
of the most commonly accessed data type in operating
system. Its design directly affects the efficiency of the
operating system. As a result, in most operating systems,
there is a data object that contains information about all the

current active processes. It is called process controller.
Figure 2 shows the structure of a process controller ,
which is implemented as a linked-list of process blocks.

In order to achieve high efficiency, process controller is
usually implemented as a global variable that can be
accessed by both the kernel modules and nonkernel
modules. For example, any time a new process (task) is
created, the module that created this process should be able
to access the process controller to add this new process.
Therefore, process controller – the data object that controls
the current active process – is usually implemented as a
category-5 global variable. This means, both the kernel
modules and nonkernel modules can access process
controller to change its fields and these changes can affect
the uses of process controller in kernel modules.

MAIN MEMORY MANAGEMENT

Memory management is a tricky compromise between performance (access time) and quantity (available space). We always seek the maximum available memory space but we are rarely prepared to compromise on performance. Memory management must also perform the following functions:
-allow memory sharing (for a multi-threaded system);
-allocate blocks of memory space for different tasks;
-protect the memory spaces used (e.g. prevent a user from changing a task performed by another user);
-optimise the quantity of available memory, specifically via memory expansion systems.

FILE MANAGEMENT

Also referred to as simply a file system or filesystem. The system that an operating system or program uses to organize and keep track of files. For example, a hierarchical file system is one that uses directories to organize files into a tree structure.
Although the operating system provides its own file management system, you can buy separate file management systems. These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection.

I/O SYSTEM MANAGEMENT

The I/O system consists of:

A buffer-caching system
A general device-driver interface
Drivers for specific hardware devices

SECONDARY STORAGE MANAGEMENT

Secondary storage management is a classical feature of database management systems. It is usually supported through a set of mechanisms. These include index management, data clustering, data buffering, access path selection and query optimization.
None of these is visible to the user: they are simply performance features. However, they are so critical in terms of performance that their absence will keep the system from performing some tasks (simply because they take too much time). The important point is that they be invisible. The application programmer should not have to write code to maintain indices, to allocate disk storage, or to move data between disk and main memory. Thus, there should be a clear independence between the logical and the physical level of the system.

PROTECTION SYSTEM

Protection refers to a mechanism for controlling access by programs, processes, or users to both system and user resources.

The protection mechanism must:

distinguish between authorized and unauthorized usage.
specify the controls to be imposed.
provide a means of enforcement.

COMMAND-INTERPRETER SYSTEM

A command interpreter is the part of a computer operating system that understands and executes commands that are entered interactively by a human being or from a program. In some operating systems, the command interpreter is called the shell.

2009-06-25T02:08:00.000-07:00

STORAGE STRUCTURE

Main memory

The Main Memory of the computer is also known as RAM, standing for Random Access Memory. It is constructed from integrated circuits and needs to have electrical power in order to maintain its information. When power is lost, the information is lost too! It can be directly accessed by the CPU. The access time to read or write any particular byte are independent of whereabouts in the memory that byte is, and currently is approximately 50 nanoseconds (a thousand millionth of a second). This is broadly comparable with the speed at which the CPU will need to access data. Main memory is expensive compared to external memory so it has limited capacity. The capacity available for a given price is increasing all the time. For example many home Personal Computers now have a capacity of 16 megabytes (million bytes), while 64 megabytes is commonplace on commercial workstations. The CPU will normally transfer data to and from the main memory in groups of two, four or eight bytes, even if the operation it is undertaking only requires a single byte.

MAGNETIC DISK a memory device, such as a floppy disk, a hard disk, or a removable cartridge, that is covered with a magnetic coating on which digital information is stored in the form of microscopically small, magnetized needles.

MAGNETIC TAPE has been used for data storage for over 50 years. In this time, many advances in tape formulation, packaging, and data density have been made. Modern magnetic tape is most commonly packaged in cartridges and cassettes. The device that performs actual writing or reading of data is a tape drive. Autoloaders and tape libraries are frequently used to automate cartridge handling.
When storing large amounts of data, tape can be substantially less expensive than disk or other data storage options. Tape storage has always been used with large computer systems. Modern usage is primarily as a high capacity medium for backups and archives. As of 2008, the highest capacity tape cartridges (Sun StorageTek T10000B, IBM TS1130) can store 1 TB of data without using compression.

HARDWARE PROTECTION

Dual-Mode Operation

-Sharing system resources requires operating system to ensure
that an incorrect program cannot cause other programs to
execute incorrectly.

-Provide hardware support to differentiate between at least two
modes of operations.
1. User mode – execution done on behalf of a user.
2. Monitor mode (also supervisor mode or system mode) –
execution done on behalf of operating system.

-Mode bit added to computer hardware to indicate the current
mode: monitor (0) or user (1).

-When an interrupt or fault occurs hardware switches to monitor mode.

interrupt/fault

monitor user

set user mode

-Privileged instructions can be issued only in monitor mode.

I/O Protection

-All I/Oinstructions are privileged instructions.

-Must ensure that a user program could never gain control of
the computer in monitor mode (i.e., a user program that, as
part of its execution, stores a new address in the interrupt
vector).

2009-06-23T03:29:00.000-07:00

1.)BOOTSTRAPT PROGRAM

Bootstrap program
In computing, booting is a bootstrapping process that starts operating systems when the user turns on a computer system.
Most computer systems can only execute code found in the memory (ROM or RAM); modern operating systems are mostly stored on hard disk drives, LiveCDs and USB flash drive. Just after a computer has been turned on, it doesn't have an operating system in memory. The computer's hardware alone cannot perform complicated actions of the operating system, such as loading a program from disk on its own; so a seemingly irresolvable paradox is created: to load the operating system into memory, one appears to need to have an operating system already installed.

2.)Difference of INTERRUPT and TRAP and their uses.

Trap is actually a software generated interrupt caused either by an error (for example division by zero, invalid memory access etc.), or by an specific request by an operating system service generated by a user program. Trap is sometimes called Exception. The hardware or software can generate these interrupts.

Interrupt or trap occurs, the hardware therefore, transfer control to the operating system which first preserves the current state of the system by saving the current CPU registers contents and program counter's value. after this, the focus shifts to the determination of which type of interrupt has occured. For each type of interrupt, separate segmants of code in the operating system determine what action should be taken and thus the system keeps on functioning by executing coputational instruction, I/O instruction, torage instruction etc.

3.)Monitor mode

Monitor mode, or RFMON (Radio Frequency Monitor) mode, allows a computer with a wireless network interface card (NIC) to monitor all traffic received from the wireless network. Unlike promiscuous mode, which is also used for packet sniffing, monitor mode allows packets to be captured without having to associate with an access point or ad-hoc network first. Monitor mode only applies to wireless networks, while promiscuous mode can be used on both wired and wireless networks. Monitor mode is one of the six modes that 802.11 wireless cards can operate in: Master (acting as an access point), Managed (client, also known as station), Ad-hoc, Mesh, Repeater, and Monitor mode.

4.)USER MODE

USER MODE contains the userhelper program, which can be used to allow configured programs to be run with superuser privileges by ordinary users, and several graphical tools for users.

5.)DEVICE STATUS TABLE

DEVICE STATUS TABLE contains entry for each I/O deviceindicating its type, address, and state.

6.)Direct Memory Access

Direct Memory Access (DMA) is a feature of modern computers and microprocessors that allows certain hardware subsystems within the computer to access system memory for reading and/or writing independently of the central processing unit. Many hardware systems use DMA including disk drive controllers, graphics cards, network cards and sound cards. DMA is also used for intra-chip data transfer in multi-core processors, especially in multiprocessor system-on-chips, where its processing element is equipped with a local memory (often called scratchpad memory) and DMA is used for transferring data between the local memory and the main memory. Computers that have DMA channels can transfer data to and from devices with much less CPU overhead than computers without a DMA channel. Similarly a processing element inside a multi-core processor can transfer data to and from its local memory without occupying its processor time and allowing computation and data transfer concurrency.
Without DMA, using programmed input/output (PIO) mode for communication with peripheral devices, or load/store instructions in the case of multicore chips, the CPU is typically fully occupied for the entire duration of the read or write operation, and is thus unavailable to perform other work. With DMA, the CPU would initiate the transfer, do other operations while the transfer is in progress, and receive an interrupt from the DMA controller once the operation has been done. This is especially useful in real-time computing applications where not stalling behind concurrent operations is critical. Another and related application area is various forms of stream processing where it is essential to have data processing and transfer in parallel, in order to achieve sufficient throughput.

7.)Difference of RAM and DRAM

RAM (Random Access Memory) is a generic name for any sort of read/write memory that can be, well, randomly accessed. All computer memory functions as arrays of stored bits, "0" and "1", kept as some kind of electrical state. Some sorts support random access, others (such as the flash memory used in MP3 players and digital cameras) has a serial nature to it. A CPU normally runs through a short sequence of memory locations for instructions, then jumps to another routine, jumps around for data, etc. So CPUs depend on dynamic RAM for their primary memory, since there's little or no penalty for jumping all around in such memory. There are many different kinds of RAM.

DRAM is one such sort, Dynamic RAM. This refers to a sort of memory that stores data very efficiently, circuit-wise. A single transistor (an electronic switch) and a capacitor (charge storage device) store each "1" or "0". An alternate sort is called Static RAM, which usually has six transistors used to store each bit. The advantage of the DRAM is that each bit can be very small, physically. The disadvantage is that the stored charge doesn't last really long, so it has to be "refreshed" perodically. All modern DRAM types have on-board electronics that makes the refresh process pretty simple and efficient, but it is one additional bit of complexity. There are various sorts of DRAM around: plain (asynchronous) DRAM, SDRAM (synchronous, meaning all interactions are synchronized by a clock signal), DDR (double-data rate... data goes to/from the memory at twice the rate of the clock), etc. These differences are significant to hardware designers, but not usually a big worry for end-users... other than ensuring you buy the right kind of DRAM, if you plan to upgrade you system.

8.)MAIN MEMORY

Main memory
The main memory of the computer is also known as RAM, standing for Random Access Memory. It is constructed from integrated circuits and needs to have electrical power in order to maintain its information. When power is lost, the information is lost too! It can be directly accessed by the CPU. The access time to read or write any particular byte are independent of whereabouts in the memory that byte is, and currently is approximately 50 nanoseconds (a thousand millionth of a second). This is broadly comparable with the speed at which the CPU will need to access data. Main memory is expensive compared to external memory so it has limited capacity. The capacity available for a given price is increasing all the time. For example many home Personal Computers now have a capacity of 16 megabytes (million bytes), while 64 megabytes is commonplace on commercial workstations. The CPU will normally transfer data to and from the main memory in groups of two, four or eight bytes, even if the operation it is undertaking only requires a single byte.

9.)MAGNETIC DISK

Magnetic Disk
The primary computer storage device. Like tape, it is magnetically recorded and can be re-recorded over and over. Disks are rotating platters with a mechanical arm that moves a read/write head between the outer and inner edges of the platter's surface. It can take as long as one second to find a location on a floppy disk to as little as a couple of milliseconds on a fast hard disk.

10.)STORAGE HIERARCHY

Storage Hierarchy
The range of memory and storage devices within the computer system. The following list starts with the slowest devices and ends with the fastest. See storage and memory.
VERY SLOW
Punch cards (obsolete)
Punched paper tape (obsolete)
FASTER
Bubble memory
Floppy disks
MUCH FASTER
Magnetic tape
Optical discs (CD-ROM, DVD-ROM, MO, etc.)
Magnetic disks with movable heads
Magnetic disks with fixed heads (obsolete)
Low-speed bulk memory
FASTEST
Flash memory
Main memory
Cache memory
Microcode
Registers

COHERENCY AND CONSISTENCY

COHERENCY AND CONSISTENCY define the action of the processors to maintain coherence. More precisely, coherency defines what value is returned on a read, and consistency defines when it is available.

CACHING

The cache, a high-speed buffer establishing a storage hierarchy in the
Model 85, is discussed in depth in this part, since it represents the
bask organizational departure from other system/360 computers.
Discussed are organization and operation of the cache, including (he-
mechanisms used to locate and retrieve data needed by (he processor.
The internal performance studies that led to use of (he cache are de-
scribed, and simulated performance of the chosen configuration is
compared with that of a: theoretical system having an entire SO^nanq-
second main storage. Finally, the effects of varying cache parameters
are discussed and tabulated.

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1.) What is the difference of OS in terms of users view and system view?
Answer:
User view

The user view of the computer varies by the interface being used. Most computer users sit in front of a PC, consisting of a monitor, keyboard, mouse and system unit. Such a system is designed for one user to monopolize its resources, to maximize the work that the user is performing. In this case,the operating system is designed mostly for ease of use, with some attention paid to performance, and none paid to resource utilization.

System View

We can view an operating system as a resource allocator. A computer system has many resources - hardware and software - that may be required to solve a problem. The operating system acts as the manager of these resources.
An operating system can also be viewed as a control program that manages the execution of user programs to prevent errors and improper use of the computer. It is especially concerned with the operation and control of I/O devices.

2009-06-18T03:56:00.001-07:00

2.)Explain the goals of OS?
Answer:
An operating system is the framework that allows you to communicate with computer hardware in an interactive way. Without this, you would not be able to tell the computer to do anything and it would have any instructions to follow. This is why it is important for a computer to have an operating system .In early days without OS so much problems where faced like acessing or getting output it takes two days. To make it much more efficient OS is used. In the simplest terms, the purpose of an operating system is to allow a user to utilize various types of software to perform various tasks.

2009-06-18T03:55:00.002-07:00

3.)What is the difference between batch systems,multiprogrammed systems and time-sharing systems?
Answer:
A batch system is one in which jobs are bundled together with the instructions necessary to allow them to be processed without intervention

As machines with more and more memory became available, it was possible to extend the idea of multiprogramming (or multiprocessing) as used in spooling batch systems to create systems that would load several jobs into memory at once and cycle through them in some order, working on each one for a specified period of time

The first involved timesharing or timeslicing. The idea of multiprogramming was extended to allow for multiple terminals to be connected to the computer, with each in-use terminal being associated with one or more jobs on the computer. The operating system is responsible for switching between the jobs, now often called processes, in such a way that favored user interaction. If the context-switches occurred quickly enough, the user had the impression that he or she had direct access to the computer.

2009-06-18T03:55:00.001-07:00

4.)Advantages of Parallel Systems.
Answer:
In terms of disproportionality, Parallel systems usually give results which fall somewhere between pure plurality/majority and pure PR systems. One advantage is that, when there are enough PR seats, small minority parties which have been unsuccessful in the plurality/majority elections can still be rewarded for their votes by winning seats in the proportional allocation. In addition, a Parallel system should, in theory, fragment the party system less than a pure PR electoral system.

2009-06-18T03:54:00.001-07:00

5.)Differentiate Symmetric multiprocessing and Asymmetric multiprocessing.
Answer:
Asymmetric multiprocessing - In asymmetric multiprocessing (ASMP), the operating system typically sets aside one or more processors for its exclusive use. The remainder of the processors run user applications. As a result, the single processor running the operating system can fall behind the processors running user applications. This forces the applications to wait while the operating system catches up, which reduces the overall throughput of the system. In the ASMP model, if the processor that fails is an operating system processor, the whole computer can go down. Symmetric mMultiprocessing - Symmetric multiprocessing (SMP) technology is used to get higher levels of performance. In symmetric multiprocessing, any processor can run any type of thread. The processors communicate with each other through shared memory.

2009-06-18T03:53:00.002-07:00

6.)Differentiate Client-server systems and Peer-to-Peer systems.
Answer:
Client/server describes the relationship between two computer programs in which one program , the client, makes a service request from another system, the server, which fulfills the request. In a network, the client/server model provides a convenient way to efficiently interconnect programs that are distributed across different locations Another structure for a distributes system is the peer - to peer (P2P)system model. In this model, clients and servers are not distinguished from one another; instead, all nodes within the system may act as either client or a server, depending on whether it is requesting or prividing a service. In client server system , the server is a bottle neck; but in a peer-to peer system, services can be provided by several nodes throughout the network.

2009-06-18T03:53:00.001-07:00

7.)Differentiate the design issues of OS between a stand-alone PC and a worksheet connected to a network.
Answer:
The difference between the two is that a Stand Alone PC practice a none to resource utilization, it imposes monopolization and implies no sharing of resources (like information, file, data, etc.). While a Workstation connected to a network is designed to maximize resource utilization where you can exchange information with a others via internet.

or

A stand-alone PC works on its own. While in a workstation connected to a network, you can freely share your files and databases to other PC.A desktop or laptop computer that is used on its own without requiring a connection to a local area network (LAN) or wide area network (WAN). Although it may be connected to a network, it is still a stand-alone PC as long as the network connection is not mandatory for its general use.In offices throughout the 1990s, millions of stand-alone PCs were hooked up to the local network for file sharing and mainframe access. Today, computers are commonly networked in the home so that family members can share an Internet connection as well as printers, scanners and other peripherals. When the computer is running local applications without Internet access, the machine is technically a stand-alone PC. A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems. The term workstation has also been used to refer to a mainframe computer terminal or a PC connected to a network.

2009-06-18T03:52:00.001-07:00

8.)Define the essential properties of the following types of OS:
a. Batch
b.Time Sharing
c.Real Time
d.Network
e.Distributed
f.Handheld
a. Batch. Jobs with similar needs are batched together and run through the computer as a group by an operator or automatic job sequencer. Performance is increased by attempting to keep CPU and I/O devices busy at all times through buffering, off-line operation, spooling, and multiprogramming. Batch is good for executing large jobs that need little interaction; it can be submitted and picked up later.Answers to
b. Time sharing. Uses CPU scheduling and multiprogramming to provide economical interactive use of a system. The CPU switches rapidly from one user to another. Instead of having a job deﬁned by spooled card images, each program reads its next control card from the terminal, and output is normally printed immediately to the screen.
c. Real time. Often used in a dedicated application. The system reads information from sensors and must respond within a ﬁxed amount of time to ensure correct performance.
d. Network. networked systems consist of multiple computers that are networked together, usually with a common operating system and shared resources. Users, however, are aware of the different computers that make up the system.
e. Distributed. Distributes computation among several physical processors. The processors do not share memory or a clock. Instead, each processor has its own local memory. They communicate with each other through various communication lines,
such as a high-speed bus or telephone line.
f. Handheld. designed to provide an environm,ent in which a user easily interface with the computer to execute programs.