|
Chapter – 7
Necessary DOS Commands
Introduction
While we try to recover the data from the disk, it depends on the case of data loss that how much effort is required to recover the loss. In many cases it is possible that if we have the sufficient knowledge of some important DOS (Disk Operating System) commands, we may recover data with fewer efforts.
In some cases it may be possible that we can recover data without programming only by use of these commands with a tricky mind.
I assume that you do not know anything about DOS and its commands. In this chapter of DOS commands introduction we’ll learn only about those command which may help us for recovering our data. First of all we’ll give a glance to the evolution of MS – DOS.
Brief History
The MS – DOS operating system is based on the Intel 8086 family of microprocessor. MS – DOS has evolved from a simple program loader into a sophisticated, stable operating system for personal computers.
Microsoft Disk Operating System (MS-DOS) Version 1.0
IBM developed this computer in the early 1980s. Microsoft developed MS-DOS 1.0. Released in August 1981, it consisted of 4000 lines of assembly language source code and ran in 8 kilobytes of memory.
Shortly after that, in 1982, MS-DOS version 1.1 was released and worked with double sided 320kb floppy disks. Versions of DOS marketed by IBM are called IBM-DOS or PC-DOS.
MS-DOS Version 2.0
When IBM began development of a 10-megabyte hard disk, Microsoft began work on the development of version 2.0 of DOS, which would be designed to support the hard disk. Up to this point, DOS 1.0, in keeping with its heritage, had been designed for a floppy disk environment. One of the major limitations in DOS 1.0 is that its directory is limited to a maximum of 64 files.
MS-DOS version 2.0 was so designed to include a hierarchically designed file system. A hierarchical file system is significant in that any directory can contain both files and other subdirectories. Hierarchical file systems were already in use in the UNIX operating system, which was used as the development platform of the MS-DOS/IBM-DOS operating system. In effect some of the underlying concepts of MS-DOS are similar to their counterparts in UNIX.
MS-DOS Version 3.0 to 5.0
Version 3.0 was released in August of 1984 to support the IBM PC/AT. Version 3.1 was released in November 1984 and contained networking support. The January 1986 version 3.2 supported 3.5-inch disks. In 1987 IBM version 3.3 followed, with the principal purpose of supporting the IBM PS/2 line of computers.
The MS-DOS version 3.3 added many new features and commands. Compaq version 3.31 of DOS allowed for hard disk partitions larger than 32 megabytes.
MS-DOS version 4.01 also reads partitions greater then 32 megabytes. Originally issued as MS-DOS 4.0, some minor bugs resulted in upgraded version 4.01 being issued with various fixes. This version added full screens, a menu-driven interface called DOS SHELL, and extra support for Expanded Memory Specifications.
Version 5.0 was designed as a replacement for all preceding versions of DOS. With DOS 5.0 both IBM and Microsoft were selling the same DOS even the documentation was similar. Memory requirements were significantly reduced. Significant enhancements were made to the support for expanded and extended memory.
The DOS editor "EDIT" was included with this version of DOS. The DOS SHELL is completely new. QBASIC was introduced to replace BASICA and GWBASIC. This version offered a way to recover data that had been accidentally lost at least some of the time.
MS-DOS Version 6.0
Version 6.0 included many new programs to enhance the performance of DOS. They included:
- Microsoft Double Space, an integrated disk compression program that increased available disk space by compressing files
- Microsoft Mem Maker, a memory-optimization program that makes it easy to move device drivers and memory-resident programs from conventional memory into the upper memory area
- An enhanced EMM386.EXE device driver that provides access to more upper memory blocks
- Enhanced loadhigh and devicehigh commands that enable you to specify the memory region in which to load a program
- Microsoft Backup, a program that makes it easy to back up your data
- Microsoft Anti-Virus, a program that can identify and remove may different computer viruses
- Microsoft Undelete, an enhanced program that enables you to choose one or three levels of protection in case you accidentally delete a file,
- The ability to include more than one configuration in the CONFIG.SYS file. The ability to bypass startup commands when you turn on your computer
- MS-DOS Help, a complete online reference to MS-DOS commands
|
