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DOS

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This article is about a family of operating systems. For the concept, see disk operating system. For the type of cyber attack, see DoS. For other uses, see DOS (disambiguation).
"WinDOS" redirects here. Not to be confused with Microsoft Windows or MacDOS\Apple Mac OS.

The boot screen and command-line interface of MS-DOS 6, with an example of its directory structure
The boot screen and command-line interface of FreeDOS, showing version information and an example of its directory structure

DOS (/dɒs/, /dɔːs/) is a family of disk-based operating systems for IBM PC compatible, Apple Mac compatible computers.[1] The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, Alongside Microsoft's Competitor Apple's DOS, both of which were introduced in Microsoft IBM PC DOS 1981, Apple DOS 1978. Microsoft Later adding compatible systems from other manufacturers include DR-DOS (1988), ROM-DOS (1989), PTS-DOS (1993), and FreeDOS (1998). MS-DOS dominated the IBM PC compatible alongisde Apple in the computer market between 178, 1981 and 1995.

Although the name has come to be identified specifically with this particular family of operating systems, DOS is a platform-independent acronym for disk operating system,[2] whose use predates the Apple Mac & IBM PC. Dozens of other operating systems also use the acronym, beginning with the mainframe DOS/360 from 1966. Others include if not already, Apple DOS & ProDOS, Atari DOS, Commodore DOS, TRSDOS, and AmigaDOS.

History

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Further information: Comparison of DOS operating systems and Timeline of DOS operating systems

DOS, short for Disk Operating System, refers to several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995. The most well-known version is MS-DOS, developed by Microsoft for IBM PCs. MS-DOS was the foundation for many early personal computers and played a crucial role in the development of the PC industry.

However, IBM PC DOS wasn't the only DOS in the early days of personal computing. Around the same time, Apple Computer developed Apple DOS for their Apple II series of computers. Apple DOS was the first disk operating system for Apple computers, introduced in 1978. It was a significant advancement from the cassette-based storage systems previously used and was crucial for the success of the Apple II. Apple DOS had three major releases: DOS 3.1, DOS 3.2, and DOS 3.3, with DOS 3.3 being the most well-known and widely used version.

IBM PC DOS (and the separately sold MS-DOS) and its predecessor, 86-DOS, ran on Intel 8086 16-bit processors. It was developed to be similar to Digital Research's CP/M—the dominant disk operating system for 8-bit Intel 8080 and Zilog Z80 microcomputers—in order to simplify porting CP/M applications to MS-DOS.

The IBM Personal Computer (IBM 5150 PC) When IBM introduced the IBM PC, built with the Intel 8088 microprocessor, they needed an operating system. Chairman John Opel had a conversation with fellow United Way National Board Executive Committee member Mary Maxwell Gates, who referred Opel to her son Bill Gates for help with an 8088-compatible build of CP/M. IBM was then sent to Digital Research, and a meeting was set up. However, initial negotiations for the use of CP/M broke down: Digital Research wished to sell CP/M on a royalty basis, while IBM sought a single license, and to change the name to "PC DOS". Digital Research founder Gary Kildall refused, and IBM withdrew.

A simulated SCP 86-DOS session IBM again approached Bill Gates. Gates in turn approached Seattle Computer Products. There, programmer Tim Paterson had developed a variant of CP/M-80, intended as an internal product for testing SCP's new 16-bit Intel 8086 CPU card for the S-100 bus. The system was initially named QDOS (Quick and Dirty Operating System), before being made commercially available as 86-DOS. Microsoft purchased 86-DOS, allegedly for US$50,000. This became Microsoft Disk Operating System, MS-DOS, introduced in 1981. Within a year Microsoft licensed MS-DOS to over 70 other companies, which supplied the operating system for their own hardware, sometimes under their own names. Microsoft later required the use of the MS-DOS name, with the exception of the IBM variant. IBM continued to develop their version, PC DOS, for the IBM PC. Digital Research became aware that an operating system similar to CP/M was being sold by IBM (under the same name that IBM insisted upon for CP/M), and threatened legal action. IBM responded by offering an agreement: they would give PC consumers a choice of PC DOS or CP/M-86, Kildall's 8086 version. Side-by-side, CP/M cost US$200 more than PC DOS, and sales were low. CP/M faded, with MS-DOS and PC DOS becoming the marketed operating system for PCs and PC compatibles.

Microsoft originally sold MS-DOS only to original equipment manufacturers (OEMs). One major reason for this was that not all early PCs were 100% IBM PC compatible. DOS was structured such that there was a separation between the system specific device driver code (IO.SYS) and the DOS kernel (MSDOS.SYS). Microsoft provided an OEM Adaptation Kit (OAK) which allowed OEMs to customize the device driver code to their particular system. By the early 1990s, most PCs adhered to IBM PC standards so Microsoft began selling a retail version of MS-DOS, starting with MS-DOS 5.0.

In the mid-1980s, Microsoft developed a multitasking version of DOS. This version of DOS is generally referred to as "European MS-DOS 4" because it was developed for ICL and licensed to several European companies. This version of DOS supports preemptive multitasking, shared memory, device helper services and New Executable ("NE") format executables. None of these features were used in later versions of DOS, but they were used to form the basis of the OS/2 1.0 kernel. This version of DOS is distinct from the widely released PC DOS 4.0 which was developed by IBM and based upon DOS 3.3.

Digital Research CP/M-86 for the IBM Personal Computer Version 1.0 Digital Research attempted to regain the market lost from CP/M-86, initially with Concurrent DOS, FlexOS and DOS Plus (both compatible with both MS-DOS and CP/M-86 software), later with Multiuser DOS (compatible with both MS-DOS and CP/M-86 software) and DR DOS (compatible with MS-DOS software). Digital Research was bought by Novell, and DR DOS became PalmDOS and Novell DOS; later, it was part of Caldera (under the names OpenDOS and DR-DOS 7.02/7.03), Lineo, and DeviceLogics.

Gordon Letwin wrote in 1995 that "DOS was, when we first wrote it, a one-time throw-away product intended to keep IBM happy so that they'd buy our languages." Microsoft expected that it would be an interim solution before the introduction of Xenix. The company planned to improve MS-DOS over time, so it would be almost indistinguishable from single-user Xenix, or XEDOS, which would also run on the Motorola 68000, Zilog Z-8000, and LSI-11; they would be upwardly compatible with Xenix, which BYTE in 1983 described as "the multi-user MS-DOS of the future".

OS/2 1.0 featured a text mode interface similar to MS-DOS. IBM, however, did not want to replace DOS. After AT&T began selling Unix, Microsoft and IBM began developing OS/2 as an alternative. The two companies later had a series of disagreements over two successor operating systems to DOS, OS/2 and Windows. They split development of their DOS systems as a result. The last retail version of MS-DOS was MS-DOS 6.22; after this, MS-DOS became part of Windows 95, 98 and Me. The last retail version of PC DOS was PC DOS 2000 (also called PC DOS 7 revision 1), though IBM did later develop PC DOS 7.10 for OEMs and internal use.

The FreeDOS project began on 26 June 1994, when Microsoft announced it would no longer sell or support MS-DOS. Jim Hall then posted a manifesto proposing the development of an open-source replacement. Within a few weeks, other programmers including Pat Villani and Tim Norman joined the project. A kernel, the COMMAND.COMcommand line interpreter (shell), and core utilities were created by pooling code they had written or found available. There were several official pre-release distributions of FreeDOS before the FreeDOS 1.0 distribution was released on 3 September 2006. Made available under the GNU General Public License (GPL), FreeDOS does not require license fees or royalties.

Decline

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Main article: History of Microsoft Windows

Early versions of Microsoft Windows ran on MS-DOS.[3] By the early 1990s, the Windows graphical shell saw heavy use on new DOS systems. In 1995, Windows 95 was bundled as a standalone operating system that did not require a separate DOS license. Windows 95 (and Windows 98 and ME, that followed it) took over as the default OS kernel, though the MS-DOS component remained for compatibility. With Windows 95 and 98, but not ME, the MS-DOS component could be run without starting Windows.[4][5][6] With DOS no longer required to use Windows, the majority of users stopped using it directly.

Continued use

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DOSBox

As of 2024, available compatible systems are FreeDOS, ROM-DOS, PTS-DOS, RxDOS[7] and REAL/32. Some computer manufacturers, including Dell and HP, sell computers with FreeDOS as an OEM operating system.[8][9] [needs update] And a few developers and computer engineers still use it because it is close to the hardware.[citation needed]

Embedded systems

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DOS's structure of accessing hardware directly allows it to be used in embedded devices. The final versions of DR-DOS are still aimed at this market.[10] ROM-DOS is used as operating system for the Canon PowerShot Pro 70.[11]

Emulation

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On Linux, it is possible to run DOSEMU, a Linux-native virtual machine for running DOS programs at near native speed. There are a number of other emulators for running DOS on various versions of Unix and Microsoft Windows such as DOSBox.[12][13] DOSBox is designed for legacy gaming (e.g. King's Quest, Doom) on modern operating systems.[3][12] DOSBox includes its own implementation of DOS which is strongly tied to the emulator and cannot run on real hardware, but can also boot MS-DOS, FreeDOS, or other DOS operating systems if needed.

MS-DOS and IBM PC DOS related operating systems are commonly associated with machines using the Intel x86 or compatible CPUs, mainly IBM PC compatibles. Machine-dependent versions of MS-DOS were produced for many non-IBM-compatible x86-based machines, with variations from relabelling of the Microsoft distribution under the manufacturer's name, to versions specifically designed to work with non-IBM-PC-compatible hardware. As long as application programs used DOS APIs instead of direct hardware access, they could run on both IBM-PC-compatible and incompatible machines. The original FreeDOS kernel, DOS-C, was derived from DOS/NT for the Motorola 68000 series of CPUs in the early 1990s. While these systems loosely resembled the DOS architecture, applications were not binary compatible due to the incompatible instruction sets of these non-x86-CPUs. However, applications written in high-level languages could be ported easily.

Apple DOS, developed for the Apple II series of computers, was another significant DOS variant. Introduced in 1978, Apple DOS was the first disk operating system for Apple computers and played a crucial role in the success of the Apple II. It provided similar functionalities to MS-DOS, such as file management and program loading, but was designed specifically for the Apple II's hardware architecture.

DOS is a single-user, single-tasking operating system with basic kernel functions that are non-reentrant: only one program at a time can use them, and DOS itself has no functionality to allow more than one program to execute at a time. The DOS kernel provides various functions for programs (an application program interface), like character I/O, file management, memory management, program loading and termination.

DOS provides the ability for shell scripting via batch files (with the filename extension .BAT). Each line of a batch file is interpreted as a program to run. Batch files can also make use of internal commands, such as GOTO and conditional statements.

The operating system offers an application programming interface that allows development of character-based applications, but not for accessing most of the hardware, such as graphics cards, printers, or mice. This required programmers to access the hardware directly, usually resulting in each application having its own set of device drivers for each hardware peripheral. Hardware manufacturers would release specifications to ensure device drivers for popular applications were available.

User interface

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DOS systems use a command-line interface. A program is started by entering its filename at the command prompt. DOS systems include utility programs and provide internal commands that do not correspond to programs.[14]

In an attempt to provide a more user-friendly environment, numerous software manufacturers wrote file management programs that provided users with WIMP interfaces. Microsoft Windows is a notable example, eventually resulting in Microsoft Windows 9x becoming a self-contained program loader, and replacing DOS as the most-used PC-compatible program loader. Text user interface programs included Norton Commander, DOS Navigator, Volkov Commander, Quarterdesk DESQview, and Sidekick. Graphical user interface programs included Digital Research's GEM (originally written for CP/M) and GEOS.

Eventually, the manufacturers of major DOS systems began to include their own environment managers. MS-DOS/IBM DOS 4 included DOS Shell;[15] DR DOS 5.0, released the following year, included ViewMAX, based upon GEM.[16]

Terminate and stay resident

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Main article: Terminate-and-stay-resident program

Although DOS is not a multitasking operating system, it does provide a terminate-and-stay-resident (TSR) function which allows programs to remain resident in memory. These programs can hook the system timer or keyboard interrupts to allow themselves to run tasks in the background or to be invoked at any time, preempting the current running program and effectively implementing a simple form of multitasking on a program-specific basis. The DOS PRINT command does this to implement background print spooling. Borland Sidekick, a popup personal information manager (PIM), also uses this technique.

Terminate-and-stay-resident programs are also used to provide additional features not available by default. Programs like CED and DOSKEY provide command-line editing facilities beyond what is available in COMMAND.COM. Programs like the Microsoft CD-ROM Extensions (MSCDEX) provide access to files on CD-ROM disks.

Some TSRs can even perform a rudimentary form of task switching. For example, the shareware program Back and Forth (1990)[17] has a hotkey to save the state of the currently-running program to disk, load another program, and switch to it, making it possible to switch "back and forth" between programs (albeit slowly, due to the disk access required). Back and Forth could not enable background processing however; that needed DESQview (on at least a 386).

Software

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Further information: Category:DOS software
Arachne web browser

Development tools

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See also

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References

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  1. ^ Murdock, Everett (1988). DOS the Easy Way. EasyWay Downloadable Books. ISBN 0-923178-00-7.
  2. ^ Dictionary.com Archived 2017-11-12 at the Wayback Machine
  3. ^ a b Bannan, James (2006-10-13). "HOW TO: Coax retro DOS games to play on Vista". Archived from the original on 2008-08-01. Retrieved 2008-07-03.
  4. ^ "Finding The DOS In Windows 95". Smart Computing. March 1996. Archived from the original on 2004-07-07. Retrieved 2008-07-12.
  5. ^ Chen, Raymond (2007-12-24). "What was the role of MS-DOS in Windows 95?". The Old New Thing - Site Home - MSDN Blogs. Archived from the original on 2014-02-05. Retrieved 2014-02-05.
  6. ^ "Description of Restarting Computer in MS-DOS Mode". support.microsoft.com. 2007-01-19. Archived from the original on 2014-02-05. Retrieved 2014-02-05.
  7. ^ "Home". rxdos.sourceforge.net.
  8. ^ Hall, Jim (2007-07-13). "Jim Hall's blog - 2007". Archived from the original on 2012-10-25. Retrieved 2008-06-12.
  9. ^ "Dell PCs Featuring FreeDOS". Archived from the original on 2008-03-19. Retrieved 2008-06-14.
  10. ^ "DR-DOS Embedded DOS". Archived from the original on 2008-12-21. Retrieved 2008-09-26.
  11. ^ "Datalight DOS Selected for Canon's New Line of Digital Still Cameras". Business Wire. 1999-08-24. Archived from the original on 2012-07-09. Retrieved 2008-09-26.
  12. ^ a b "DOSBox Information". Archived from the original on 2008-05-25. Retrieved 2008-05-18.
  13. ^ "DOSEMU Home". 2007-05-05. Archived from the original on 2008-07-23. Retrieved 2008-07-03.
  14. ^ Murdock, Everett (2008). DOS the Easy Way. EasyWay Downloadable Books. pp. 7–12. ISBN 978-0-923178-02-4.
  15. ^ Murdock, Everett (2008). DOS the Easy Way. EasyWay Downloadable Books. p. 71. ISBN 978-0-923178-02-4. Archived from the original on 2015-03-18.
  16. ^ Dvorak, John Charles; Anis, Nick (1991). Dvorak's Guide to DOS and PC Performance. Osborne McGraw-Hill. pp. 442–444.
  17. ^ Version 1.47 is archived at "Back and Forth 1.47". Archived from the original on 2013-11-05. Retrieved 2013-08-05. and says "(C) 1990 by Progressive Solutions, Inc."
  18. ^ Darrow, Barbara (2002-02-01). "Whatever Happened To Lotus 1-2-3?". Archived from the original on 2009-01-09. Retrieved 2008-07-12.

Further reading

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  • IBM Corp., IBM, (January 1984). "IBM DOS Release 2.10 Cloth bound retail hard board box". 1st edition. IBM Corp. Item Number. 6183946
  • IBM Corp., IBM, (January 1984). "Disk Operating System User's guide (DOS Release 2.10)". 1st edition. Microsoft Corp. (100 pages including colour illustrations) Item Number. 6183947
  • IBM Corp., IBM, (January 1984). "Disk Operating System Manual (DOS Release 2.10)". 1st edition. Microsoft Corp. (574 looseleaf pages in 3 ring folder) Item No. 6183940
  • Mueller, Scott (1998). Upgrading and Repairing PCs (Eighth ed.). Que Publishing. ISBN 0-7897-1295-4. Retrieved 2021-11-02.
  • Bailes, Lenny; Mueller, John (1992). Memory Management and Multitasking Beyond 640K. McGraw-Hill. ISBN 0-8306-3476-2. Retrieved 2021-11-02.
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