DOS

History

The origin of MS-DOS goes back to 1981, during the launching of the IBM PC ( Personal Computer ) by IBM. The company had asked DIGITAL Research, creator of CP/M which dominated the market at the time, to carry its system on the PC, but in front of the little of eagerness of its director Gary Kildall, she had also addressed herself to Microsoft.

Microsoft was famous for its achievements of interpreters BASIC, but did not have anything in its paperboards to write DOS quickly. She then chooses the QDOS (for “ Quick and Dirty Operating System ”) created by a small firm of Seattle, that she repurchases to him for a few thousands of dollars (50 000 $) and improves gradually.

The version sold at IBM will be called PC-DOS . She differs from the version distributed by Microsoft only by two things, of which most important are right that

the files IBMBIO.COM and IBMDOS.COM name IO.SYS and MSDOS.SYS on the Microsoft version. Consequently, the artful thrust of IBM, the defragmentor of diskette DVOO, will go only on the IBM systems, since as well IBMBIO.COM as IO.SYS must be in first position on the diskette so that this one is bootable. However, diskettes (of 5" ¼) is so slow that DVOO itself will never be marketed.
the interpreter BASIC named BASIC simply on IBM names GWBASIC on the Microsoft version. There exists then a third interpreter BASIC: that which is in ROMANIAN and which takes the hand automatically if the PC does not find a diskette on which booter .

IBM will market the PC with Parité with three operating systems (all three paying) to the choice of the user:

PC-DOS
CP/M 86 (which will remain always marginal on the PC, as the Visiotexte)
PC/IX, a kind of clone of UNIX, unfortunately too heavy in resources for the processor Intel 8086.

Thereafter, PC-DOS making more than 2/3 of the sales of system for PC to him only, Microsoft required and obtained that it be invoiced from the start with each sold PC. The “Microsoft tax” was created.

MS-DOS a long time remained the base of the operating systems general public of Microsoft, although the installation of Windows modifies in-situ of the increasingly large portions of them. In 1995, date of appearance of Windows 95 it lost in theory its statute of operating system. But actually, the graphical interface was simply launched over DOS directly with starting. MS-DOS remained an underlayer of the versions large-public of Windows (like Windows 98 and Me) until the advent of Windows XP which marks its real abandonment by Microsoft with the profit of system NT. DOS was then with its version 7.

The recent versions of Windows always have a “Interpréteur of orders” ( prompt command ), whose orders are inherited those of MS-DOS and who allows to carry out Windows programs in text mode, as well as MS-DOS programs thanks to a emulator integrated. However, this interpreter (cmd.exe) is not that of MS-DOS strictly speaking (command.com), and certain old programs DOS cannot be carried out in this mode.

MS-DOS being maintained more by Microsoft, another DOS was developed, it acts of FreeDOS, a Free software. IBM, for its part, has DOS 7, which can read files FAT32 and is useful for him for certain specific work.

Another DOS having existed is DR-DOS, the heir to CP/M distributed by DIGITAL Research, which was then repurchased by Novell. Several versions of Windows however were programmed to detect the DR-DOS and to emit a great number of worrying error messages (like: “Table xxx is not in the good place in memory”) which ended up achieving their goal, which was to divert the owner of PC of it.

Chronology

DOS 1.00 : 1981, it occupies 11 KiB in memory and only Disquettes with simple face of 160 KiB
DOS 1.10 manages: 1982: Support the diskettes 5" ¼ double faces (320 KiB). Version PC-DOS for IBM only.
DOS 1.25 : 1982: Equivalent of PC-DOS 1.10 but in version OEM. It is the first version sold by Microsoft (MS-DOS) to other manufacturers.
DOS 2.00 : 1983, version for PC XT, it occupies 40 KiB, and can manage the diskettes 5" 25 double face of 360 KiB and hard drives of 15 MIB maximum. It uses a filesystem in FAT12
DOS 2.01: 1983, international version of the 2.0; Support of located parameters, Support of Kanji (Japanese Characters).
DOS 2.1 : 1983, IBM version only. Equip in particular the new PC-Jr.
DOS 2.11 : 1983, Support of the character sets specific to the various countries. It is a version OEM very largely used by many manufacturers of PC compatibles.
DOS 2.25 : 1983 Support extended for the foreign languages.
DOS 3.00 : 1984, version for PC AT, occupies 60 KiB, it manages the diskettes 5" 25 of 1.2 MIB and hard drives of 32 MIB, FAT16, it support also a clock CMOS.
DOS 3.05 : 1984, First version OEM for the version 3.x
DOS 3.10: version supporting the network
DOS 3.20: 1986, version supporting the diskettes 3" 5 of 720 KiB, appearance of the order Xcopy
DOS 3.30: 1987, version supporting the diskettes 3" 5 of 1.4 MIB
DOS 3.31: 1987, Supports partitions >32 MIB, new calls systems
DOS 4.00: 1988, it occupies 110 KiB of RAM, offers an graphical interface (Shell) and manages the discs and files higher than 32 MIB thanks to FAT16.
MS-DOS 4.01 : déboguée version
MS-DOS 5.00: 1991, version managing the high memory, and which makes it possible to make menus of starting; support up to 8 disks hard, support of the diskettes of 2.8 MIB
MS-DOS 6.00: 1993, version integrating an antivirus, a tool for checking of filesystem, ScanDisk , and a software of compression, DoubleSpace .
MS-DOS 6.20 : November 1993, déboguée version; appearance of the utility Memmaker
MS-DOS 6.21: February 1994, suppression of DoubleSpace following a complaint for violation of patent of the share Stac Electronics, editor of a rival software, Stacker .
MS-DOS 6.22 : June 1994, DoubleSpace is replaced by DriveSpace , compatible software without the problem of patent. It is the autonomous last version of MS-DOS.
MS-DOS 7 : 1995, DOS of Windows 95.
MS-DOS 7.1 : 1996, DOS of Windows 95B and C and Windows 98 and 98SE.
MS-DOS 8 : 2000, last version of MS-DOS. It is integrated into Windows ME.
PC DOS 2000: 2000, integrates small additions of functionalities.

1994 After the proclamation of died of MS-DOS, the FreeDOS project begins
1997 a version has open source of DR-DOS, Open-DOS published (only FAT16)
2002 Project Enhanced-DR.-DOS starts, developing Open-DOS
2005 Enhanced DR-DOS 7.01.07 published, adding the filesystem FAT32
2005 FreeDOS 0.9 published (also FAT32, usable, but much of bugs)
2006 Enhanced DR-DOS 7.01.08 published, adding the filesystem FAT+
September 3rd, 2006. FreeDOS 1.0 published

Characteristics

MS-DOS is an operating system for platforms Intel 8086. In spite of the evolution of the possibilities of the Intel platform during the years towards the Mode protected (Intel 80286) and 32 bits (Intel 80386), MS-DOS remained an operating system 16 bits in real Mode.

The filesystem is FAT ( File Allowance Counts ) in its various versions: FAT12 (diskettes only), FAT16, FAT32. Out of Windows 95 and later, the file names are limited to 8 characters, plus 3 for the extension, without reference to breakage.

From the user point of view, MS-DOS is characterized by an interface text in line of order managed by program COMMAND.COM. the user between an order with the keyboard, then possibly of the parameters separated by spaces, then validates the order by the support of the key Entrer .

The programs can provide information to the user by posting texts which make ravel the screen upwards.

Invites of order ( prompt ) configurable appears at each beginning of line and informs the user about information such as the disc and the current directory, but also over the date or the hour.

Example of a prompt standard with like current directory plays and sub-directory tetris on a disc C: C:\JEUX\TETRIS >

The separator of repertory is the \ in the place of/UNIX for two reasons

This choice avoids a charge of plagiarism (!). A Variable of environment makes it possible to replace it by/in the first versions; however, almost no software not testing the value of this variable, DOS will end up giving up it.
It/had already a use which was that to be used as marker of option (example: DIR /P ).

MS-DOS also makes it possible to use interpreted command files called Batch.

Like the other operating systems mono-user of the time, DOS is not protected from the programs which can then put its stability in danger: the responsibility for the developer of application is thus important.

Moreover, the management of the pilots of peripheral not being spring of DOS, each application must provide them his for all the peripherals which it supports. That led on the one hand to duplications of effort between editors of application, on the other hand with the management of a plethora of diskettes of pilot data processing for the users (one or more by application). This complexity which geometrically grows as multiply and the peripherals and the applications will constitute later a motivation important to migrate to Windows.

Principal orders DOS

There exists " 2" levels of order in MS/DOS:

the first level is carried out by the core MS/DOS him even (MSDOS.SYS)
the second level of order is the interpreter of order used.

The orders by defect depend on the interpreter of order. The interpreter of order, by defect it is program COMMAND.COM. That Ci can be replaced by another interpreter of order in file CONFIG.SYS with a line shell=

Alternate interpreters of orders were developed:

4DOS (of editor JP Software)
NDOS (version of 4DOS laid off by the editor Norton)

The principal orders used regularly are:

Copy (to copy files)
DIR (to list the files)
CLS (Abbreviation of CLear Screen to erase the screen)
LED (to destroy a file)

See too

Examples of orders DOS

Internal bonds

AtheOS
Syllable
BeOS
Kid Operating System
QDOS
RISC OS
MenuetOS
TRSDOS
TinyOS
the operating systems.
the company Microsoft.
FreeDOS

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