Operating Systems Domains

OS Fundamentals part 2

   
 

1.2 Identify basic concepts and procedures for creating, viewing and managing files, directories and disks. This includes procedures for changing file attributes and the ramifications of those changes (for example, security issues). Content may include the following:

File attributes - Read Only, Hidden, System, and Archive attributes

ATTRIB [+R | -R] [+A | -A] [+S | -S] [+H | -H] filespec [/S]

  • + Sets an attribute.
  • - Clears an attribute.
  • R Read-only file attribute.
  • A Archive file attribute.
  • S System file attribute.
  • H Hidden file attribute.
  • /S Processes files in all directories in the specified path.

The Read-only attribute

Before you can delete or overwrite a Read-only file, you must remove the Read-only file attribute bit.

The Hidden and System attribute

The purpose of the Hidden attribute is to make the file invisible in certain applications' file list display. These are usually important files the OS does not want you to play around with.

The System attribute, just as the name implies are usually files the OS needs to operate. In most Win systems, you will find about twenty files in the root directory which are marked both Hidden and System. These two attributes are often go hand in hand.

The Archive attribute

The purpose of the Archive attribute is to determine whether a file requires a back up (archiving). The Archive attribute is set whenever an existing file is either overwritten or modified. A new file is usually created with the Archive attribute set.

When you run the a back up program it will copy these archived files and then clear the Archive attribute, until the file is modified again.

File naming conventions (Most common extensions)

bat This is a batch file, commands may be put in here that run programs.

cab Cabinet file. Cab files contain multiple compressed files.

com These are MSDOS executables

drv Drivers

dll Dynamic Link Library

exe Executable files

inf Windows software or hardware information file.

ini Windows program initialization file.

mpd Miniport driver

sys System file

bmp Bitmap image file.

gif Image file.

jpeg Image file.

pif Program Information File. Used to start MSDOS applications in Windows 98.

vxd Virtual device driver

zip Compressed file

Windows 2000 COMPRESS, ENCRYPT

Compress

Windows 2000 uses compression similar to DriveSpace in windows 98, but unlike DriveSpace which compress entire volumes, it can compress individual files and folders.

You can compress files and folders only on drives formatted with NTFS, also compressed files and folders cannot be encrypted

If you add or copy a file into a compressed folder, it is compressed automatically. If you move a file from a different NTFS drive into a compressed folder, it is also compressed. However, if you move a file from the same NTFS drive into a compressed folder, the file retains its original state, either compressed or uncompressed.

To compress a file or folder

  • In explorer select the file or folder you want to compress, choose properties
  • Check the Compress contents to save disk space box

To remove compression from a file or folder, follow directions above and uncheck the Compress contents to save disk space box

Encrypt

Windows 2000 includes greater security than other versions of windows, with its Encrypting File System (EFS).It is based on public and private key encryption. The file system automatically generates an encryption certificate for the user along with a private key. You can encrypt individual files or folders, only on the NTFS file system.

When a user is logged on, they don't have to decrypt files to use them EFS automatically detects an encrypted file, locates the users private key and decrypts the file.

To encrypt a file or folder

  • In explorer select the file or folder you want to encrypt, choose properties
  • Choose advanced button to display the advanced attributes
  • Check the Encrypt Contents To Secure Data box

To remove encryption from a file or folder, follow directions above and uncheck the Encrypt Contents To Secure Data box.

You can also encrypt file and folders from the DOS command prompt using cipher.exe If you do not use any command line options cipher will just display the encryption status of the folder.

cipher [/e | /d] [/s:dir] [/i] [/q] [dirname]

  • /e Encrypts specified directory
  • /d Decrypts specified directory
  • /s : dir Specifies the directory to encrypt or decrypt
  • /i Ignors errors
  • /q Specifies a directory
  • dirname

IDE/SCSI

IDE (Integrated Device Electronics) / EIDE (Enhanced Integrated Device Electronics) A type of disk drive interface in which the controller resides on the device itself.

SCSI(Small Computer System Interface) A standard high speed parallel interface, used for connecting peripherals such as hard drives, printers etc. You need an adapter card for SCSI devices.

Internal/External

Internal commands are built into COMMAND.COM. External commands are separate files and usually have an extension of .COM, .EXE, or .BAT.

 

Examples of Internal Commands

      COPY, DATE, DEL, DIR, MKDIR, REM, SET, TIME, TYPE, VER, VERIFY
 

Examples of Extenal Commands

 

ATTRIB.EXE, CHKDSK.EXE, COMMAND.COM, DISKCOPY.COM, EDIT.COM, EMM386.EXE, FDISK.EXE, FORMAT.COM, HELP.EXE, MEM.EXE, MORE.COM, SETVER.EXE, SORT.EXE, SYS.COM, XCOPY.EXE 

Backup/Restore

Each time Windows 95 starts, it backs up the Registry by copying the current SYSTEM.DAT and USER.DAT files to SYSTEM.DA0 and USER.DA0

Windows 98 comes with Scanreg

If you have trouble starting windows 95/98 you can use a Start Up Disk, to create one, go to add/remove in control panel select Start Up Disk.

The Startup Disk is a bootable system disk with a collection of real-mode Windows 9x commands and utilities that you can use to restart your computer, 98 also adds a generic CD ROM driver, and other utilities.

Emergency Recovery Utility

The Microsoft Windows 95 Emergency Recovery Utility is designed to provide a backup of your system configuration in case a problem should occur.

Windows 2000 Emergency Repair Disk

The Emergency Repair Disk (ERD) can help you to repair or recover a system that can't load Windows 2000. The ERD helps you repair problems with system files and the partition boot sector. This situation occurs when your hard disk fails or when some of your system files are corrupted or accidentally deleted. System files are the files Windows 2000 uses to load, configure, and run the operating system. If some system files are missing or corrupted, you can use the ERD to repair those files.

Widows 2000 Recovery Console

Users can use the Recovery Console to repair Windows . This command-line utility can be used to copy system files, disable and enable services or drivers, repairing the Master Boot Record, etc. Only administrators have access to the Recovery

Msbackup.exe

A built-in application that you run to back up the data or your entire system to prevent the loss of data in the event of hardware failure Name: Msbackup.exe Location: \program files\accessories \backup\msbackup.exe

Win 95 backup only supports QIC 40, 80, & 3010. tape drives

Win 98 msbackup supports the following:

  • QIC-80 and 80 Wide, 3010 and 3010 Wide, and 3020 and 3020 Wide
  • TR1, 2, 3, and 4 (Travan)
  • DAT (DDS1 and 2)
  • DC 6000
  • 8mm
  • DLT Removable media (floppy disks, Iomega Jaz or Syquest cartridges)
  • Support has been added for parallel, IDE/ATAPI, and SCSI backup devices

Partitioning/Formatting/File System

FAT File allocation table refers to a disk format, which is a way of organizing the storage space on a hard disk. The table organizes information about the files on the hard disk, representing each one as a chain of numbers that identifies where each part of a file is located. The operating system uses it to look up a file and find which clusters that file is written to on the hard disk.

FAT16 Supports drives up to 2 gigabytes in size. Fat16 is the most compatible file system, not only can all windows versions use it but many other OS's also.

FAT32 Supports drives of up to 2 terabytes in size. FAT32 also reduces the cluster size on large drives, freeing up more space.

Cluster sizes of FAT16 and FAT32

Drive
Fat 16
Fat 32
256 MB – 511 MB
8 KB
Not supported
512 MB – 1023 MB
16 KB
4 KB
1024 MB – 2 GB
32 KB
4 KB
2 GB – 8 GB
Not supported
4 KB
8 GB – 16 GB
Not supported
8 KB
16 GB – 32 GB
Not supported
16 KB
>32 GB
Not supported
32 KB

 
NTFS4 New Technology File System used with win NT 4 provides greater security than FAT, and better disk compression. Support for large hard disks, up to 2 terabytes and as drive size increases, performance with NTFS doesn't degrade as it does with FAT.

NTFS5 Updated NTFS for windows 2000,NTFS The NTFS file system is the recommended file system for use with Windows 2000. NTFS has all of the basic capabilities of FAT, and it provides the following advantages over the FAT and FAT 32 file systems:

  • Better file security with encrypting file system (EFS)
  • Better disk compression.
  • Support for large hard disks, and as drive size increases, performance with NTFS doesn't degrade as it does with FAT.

HPFS High Performance File System is the file system used with OS/2. Windows NT 3.51 supported partitions formatted with HPFS , but it did not support formatting new drives as HPFS. In Windows NT 4.0, the support for HPFS was eliminated.

File Systems that windows supports

 
Win 95
98/ME
NT 3.51/4
2000
Fat
yes
yes
yes
yes
Fat 32
95/ORS2
yes
no
yes

NTFS4

no
no
NT 4
yes
NTFS5
no
no
NT 4 with service pack 4
yes
HPFS
no
no
NT 3.51
no 

Windows-based utilities

ScanDisk Used to check your hard disk for logical and physical errors. ScanDisk can then repair the damaged areas. All window versions except NT come with scandisk.

If you do not shut down the computer properly win 95 OSR2 and 98 will run scandisk automatically next time you start up your computer.

Device manager Access it from control panel system icon.

With Device Manager you can

  • view and print reports about system settings
  • change a device’s resource settings
  • view what IRQ, DMA, I/O, and memory addresses a device is using
  • disable/enable devices
  • add, change or remove device drivers

Computer Manager The Computer Management Console in Windows 2000 brings a variety of the win 2000 system and disk tools together in one user interface.

Some Tools you can access with Computer Manager

  • Local Users and Groups
  • System Information
  • Event Viewer
  • Device Manager
  • Disk Management

MSCONFIG.EXE This is the System Configuration Utility located at c:\windows\system\msconfig.exe. This program lets you troubleshoot system configuration problems, by removing entries with check boxes, reducing the chance of typing errors which may happen if you use Notepad or the System Configuration Editor. It also allows you to create a backup of your system files before you change anything. It allows you to remove programs that are automatically started when windows starts.

REGEDIT.EXE is installed in the systemroot folder. REGEDIT is used to edit the registry.

REGEDT32.EXE (32-bit) is the win 2000 registry editor and is installed in the systemroot\system32 folder.

ATTRIB.EXE Displays or changes file attributes.

attrib [+r|-r] [+a|-a] [+s|-s] [+h|-h] [[drive:][path] filename] [/s[/d]]

  • +r Sets the read-only file attribute.
  • -r Clears the read-only file attribute.
  • +a Sets the archive file attribute.
  • -a Clears the archive file attribute.
  • +s Sets the file as a system file.
  • -s Clears the system file attribute.
  • +h Sets the file as a hidden file.
  • -h Clears the hidden file attribute

EXTRACT.EXE can be found in the \Windows\Command directory. In Windows 98/2000 you can view and extract CAB files using Windows Explorer. In Windows 95, you had to use the command-line Extract.exe program to extract CAB files.

DEFRAG.EXE Is a utility that checks your hard disk for logical (lost clusters, cross-linked files, directory structure) and physical errors on the drive. ScanDisk can then repair the damaged areas. All window versions except NT come with scandisk. If you are using win 3.1 you have to exit to DOS and use its version.

If you do not shut down the computer properly win 95 OSR2 and 98 will run the DOS version of scandisk automatically next time you start up your computer.

Win 9x provides two versions of ScanDisk: a graphical windows-based version Scandskw.exe and an DOS-based version Scandisk.exe. No matter which version name you type while in windows, either from the run box or a DOS prompt the windows version will run, you must exit to DOS to run its version.

Windows 2000 automatically optimizes disk use. To optimize a disk manually, right-click it in My Computer, click Properties, and then, on the Tools tab, click Defragment Now.

EDIT.COM Starts Dos-based text editor.

FDISK.EXE is an MS-DOS-based application that is run from the DOS command line. You use fdisk to partition your hard drives.

If you enable large disk support, any drives created will be FAT32. You will have to use a boot disk created from the OS you used to partition the drive, as win 95/NT cannot read FAT32 partitions (win95 ORS 2 does support Fat32)

Fdisk is not needed with windows 2000 as Disk Management prepares hard disks.

SYSEDIT.EXE Starts System Configuration Editor , can be found in c:\windows\system. This program allows you to edit protocol.ini, system.ini, win.ini, config.sys, and your autoexec.bat files.

SCANREG Runs the Registry Checker program, which scans your registry. If Registry Checker notices a problem, it automatically replaces the registry with the backup copy. Registry Checker runs each time Windows starts.

Windows comes with a DOS version Scanreg.exe located in \windows\command and an windows version Scanregw.exe located in \windows (Click here for Command Line Info)

WSCRIPT.EXE Windows Scripting Host (WSH) is a simple, powerful, and flexible scripting solution for the 32-bit Windows platform. WSH allows scripts—including those written in VBScript and JavaScript—to be run directly on the Windows desktop without being embedded in an HTML document. This low-memory scripting host is ideal for non-interactive scripting needs, such as logon and administrative scripting. WSH can be run from either the Windows-based host (Wscript.exe) or the command-shell–based host (Cscript.exe).

HWINFO.EXE Hardware Diagnostic command line tool provides the same information as the Microsoft System Information Tool, it is color coded with blue text as warnings and red text as problems. To run type hwinfo.exe /ui switch. It will not run without the switch.

ASD.EXE (Automatic Skip Driver) Detects devices that prevent Windows from starting. Located at c:\windows It will automatically disable device drivers or operations that fail during startup. You can start the Automatic Skip Driver Agent from the tools menu in the System Information Utility.

Cvt1.EXE (Drive Converter FAT16 to FAT32) This utility converts a hard drive from FAT16 to FAT32. Win 98 does not include a utility for converting a drive back to FAT16 once you have converted it to FAT32.

 

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