OPERATING SYSTEM BASICS:6

Managing Drives and Disks With Command-Line

In a Microsoft-based system, each disk drive is identified by a single-letter name, such as A:. This name must be specified when giving system commands, so that they are carried out using the proper drive. The format for specifying the drive that will perform a command-line function is the drive’s identifier letter in the command, followed by a colon, for example, A: or C:.

The following figure shows how various disk drives are viewed by a typical, standalone system. Microsoft operating systems reserve the letters A: and B: for the first and second floppy drives. Multiple hard disk drive units can be installed in the system unit, along with floppy drives. Microsoft operating systems recognize a single hard disk unit in the system as drive C:. Disk management utilities can be used to partition a single physical hard disk drive into two or more volumes that the system recognizes as logical drives C: or D:.

System's Disk Drives

Hint: The figure shows a CD-ROM drive as drive D: since this is the most common PC configuration. In the case of networked systems, logical drive letters may be extended to define up to Z drives. These drives are actually the hard drives located in remote computers. The operating system in the local computer handles them as additional logical drives,such as F: or G:.


Conversely, a second hard disk drive can be added to the system and set up as logical drive D:
 It may also be partitioned into smaller logical drives that the system recognizes as drives E: or F:. Some command-line operations are simplified by allowing the system to choose the location for the command to be carried out through the use of default settings, which are special predetermined settings that are automatically used by the system when no specific directions are given to change the setting.

These settings are stored in the operating system and used by the system when the operator does not specify a particular location for events to occur. The default setting in your system is the A: drive. In systems with two or more drives, it is imperative that the user specifies exactly where the specified action is to occur.

Drive-Level DOS Operations

The following command line functions pertain to drive-level operations. They must be typed at the command prompt, and they carry out the instruction along with any drive modifiers given.

1.  FORMAT: This command is used to prepare a new disk to use with an operating system. Actual data locations are marked off on the disk for tracks and sectors, and bad sectors are marked. In addition, the directory is created on the disk. New diskettes must be formatted before they can be used. Following are some of the applications of the FORMAT command:

• C:\>FORMAT A creates the track, sector, and the file system structure on the specified disk (in this case the A: floppy drive).

• C:\>FORMAT A:/S causes three system files to be copied into the root directory of the disk after it has been formatted. The new diskette will now boot up without a DOS disk.

• C:\>FORMAT A:/Q causes the system to perform a quick format operation on the disk. This amounts to removing the FAT and root directory from the disk.

2.SETVER: This command sets the operating system version number that the system reports to an application. Programs designed for earlier DOS versions may not operate correctly under later versions unless the version has been set correctly. The syntax of the SETVER command is:

• C:\>SETVER C:

This entry will cause all files on the C: drive to be listed in the operating system version table. Note that the SETVER command must be enabled by loading it in the CONFIG.SYS file before it can be used from the command
line.

3. VER: If the current operating system version is not known, typing VER at the command prompt will display it on the screen. These commands are particularly useful in networking operations where multiple computers are connected together to share information. In these applications, several versions of operating systems may exist on different machines attached to the network. The syntax for the VER command is:

• C:\>VER

Next Lesson we will be working with directories.
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