 | |
 Version 1.10 (1982) command line | |
| Developer | Microsoft IBM |
|---|---|
| Written in | Assembly language,C |
| OS family | DOS |
| Working state | No longer supported |
| Source model | Closed source |
| Initial release | August 1981; 43 years ago (1981-08) |
| Latest release | PC DOS 2000 / April 1998; 26 years ago (1998-04) |
| Latest preview | PC DOS 7.1 / 2003; 22 years ago (2003) |
| Available in | English (US), English (UK), Danish, Dutch, Finnish, French, German, Italian, Norwegian, Portuguese, Russian, Spanish, Swedish |
| Platforms | x86 |
| Kernel type | Monolithic kernel |
| Default user interface | Command-line interface (COMMAND.COM) |
| License | Commercialproprietary software |
IBM PC DOS (anacronym forIBM Personal Computer Disk Operating System),[nb 1] also known asPC DOS orIBM DOS, is a discontinueddisk operating system for theIBM Personal Computer, its successors, andIBM PC compatibles. It was sold byIBM from the early 1980s into the 2000s. Developed byMicrosoft, it was also sold by that company to the open market asMS-DOS. Both operating systems were identical or almost identical until 1993, when IBM began selling PC DOS 6.1 with its own new features. The collective shorthand for PC DOS and MS-DOS wasDOS, which is also the generic term for disk operating system, and is shared with dozens ofdisk operating systems called DOS.
The IBM task force assembled to develop the IBM PC decided that critical components of the machine, including the operating system, would come from outside vendors. This radical break from company tradition of in-house development was one of the key decisions that made the IBM PC an industry standard.Microsoft, founded five years earlier byBill Gates, was eventually selected for the operating system.
IBM wanted Microsoft to retain ownership of whatever software it developed, and wanted nothing to do with helping Microsoft, other than making suggestions from afar. According to task force memberJack Sams:
The reasons were internal. We had a terrible problem being sued by people claiming we had stolen their stuff. It could be horribly expensive for us to have our programmers look at code that belonged to someone else because they would then come back and say we stole it and made all this money. We had lost a series of suits on this, and so we didn't want to have a product which was clearly someone else's product worked on by IBM people. We went to Microsoft on the proposition that we wanted this to be their product.[1][citation needed]
IBM first contacted Microsoft to look the company over in July 1980. Negotiations continued over the months that followed, and the paperwork was officially signed in early November.[2]
Although IBM expected that most customers would use PC DOS,[3] the IBM PC also supportedCP/M-86, which became available six months after PC DOS,[4] andUCSD p-System operating systems.[5] IBM's expectation proved correct: one survey found that 96.3% of PCs were ordered with the $40 PC DOS compared to 3.4% with the $240 CP/M-86.[6]
Over the history of IBM PC DOS, various versions were developed by IBM and Microsoft. By the time PC DOS 3.0 was completed, IBM had a team of developers covering the full OS. At that point in time, either IBM or Microsoft completely developed versions of IBM PC DOS going forward. By 1985, the joint development agreement (JDA) between IBM and Microsoft for the development of PC DOS had each company giving the other company a completely developed version. Most of the time branded versions were identical, but there were some cases in which each of the companies made minor modifications to their version of DOS. In the fall of 1984, IBM gave all the source code and documentation of the internally developedIBM TopView for DOS to Microsoft so that Microsoft could more fully understand how to develop anobject-orientedoperating environment, overlapping windows (for its development ofWindows 2.0) andmultitasking.
| Version | Release date | References |
|---|---|---|
| 1.0 | August 12, 1981 | [7] |
| 1.1 (1.10) | May 7, 1982 | [8] |
| 2.0 | March 8, 1983 | [9] |
| 2.1 (2.10) | November 1, 1983 | [10] |
| 3.0 | September 14, 1984 | [11] |
| 3.1 (3.10) | April 2, 1985 | [12] |
| 3.2 (3.20) | April 2, 1986 | [13] |
| 3.3 (3.30) | April 2, 1987 | [14] |
| 4.0 | July 19, 1988 | [15] |
| 5.0 | June 11, 1991 | [16] |
| 6.1 | July 26, 1993 | [17] |
| 6.3 | April 27, 1994 | [18] |
| 7.0 | February 28, 1995 | [19] |
| 2000 | May 29, 1998 | [20] |
Microsoft first licensed,[21] then purchased[22]86-DOS fromSeattle Computer Products (SCP), which was modified for the IBM PC by Microsoft employeeBob O'Rear with assistance from SCP (later Microsoft) employeeTim Paterson.[23] O'Rear got 86-DOS to run on the prototype PC in February 1981. 86-DOS had to be converted from 8-inch to 5.25-inchfloppy disks and integrated with theBIOS, which Microsoft was helping IBM to write.[24][25] IBM had more people writing requirements for the computer than Microsoft had writing code. O'Rear often felt overwhelmed by the number of people he had to deal with at the ESD (Entry Systems Division) facility inBoca Raton, Florida.
Perhaps the first public mention of the operating system was in July 1981, whenByte discussed rumors of a forthcoming personal computer with "a CP/M-like DOS ... to be called, simply, 'IBM Personal Computer DOS'".[26] 86-DOS wasrebranded IBM PC DOS 1.0 for its August 1981 release with the IBM PC. The initial version of DOS was largely based onCP/M-80 1.x and most of its architecture, function calls and file-naming conventions were copied directly from the older OS. The most significant difference was the fact that it introduced a different file system,FAT12. Unlike all later DOS versions, theDATE andTIME commands were separate executables rather than part ofCOMMAND.COM. Single-sided 160kilobyte (KB) 5.25-inch floppies were the only disk format supported.
In late 1981, Paterson, now at Microsoft, began writing PC DOS 1.10. It debuted in May 1982 along with the Revision B IBM PC. Support for the new double-sided drives was added, allowing 320 KB per disk. A number of bugs were fixed, and error messages and prompts were made less cryptic. TheDEBUG.EXE was now able to load files greater than 64 KB in size.
Later, a group of Microsoft programmers (primarilyPaul Allen,Mark Zbikowski andAaron Reynolds)[25] began work on PC DOS 2.0. Completely rewritten, DOS 2.0 added subdirectories and hard disk support for the newIBM XT, which debuted in March 1983. A new 9-sector format bumped the capacity of floppy disks to 360 KB. TheUnix-inspired kernel featuredfile handles in place of the CP/M-derivative file control blocks and loadable device drivers could now be used for adding hardware beyond that which the IBM PC BIOS supported. BASIC and most of the utilities provided with DOS were substantially upgraded as well. A major undertaking that took almost 10 months of work, DOS 2.0 was more than twice as big as DOS 1.x, occupying around 28 KB of RAM compared to the 12 KB of its predecessor. It would form the basis for all Microsoft consumer-oriented OSes until 2001, whenWindows XP (based onWindows NT) was released.[25]
In October 1983 (officially 1 November 1983)[27] DOS 2.1 debuted. It fixed some bugs and added support for half-height floppy drives and the newIBM PCjr.
In 1983,Compaq released theCompaq Portable, the first 100%IBM PC compatible and licensed their own OEM version of DOS 1.10 (quickly replaced by DOS 2.00) from Microsoft. Other PC compatibles followed suit, most of which included hardware-specific DOS features, although some were generic.
In August 1984, IBM introduced theIntel 80286-derivedIBM PC/AT, its next-generation machine. Along with this was DOS 3.00. Despite jumping a whole version number, it again proved little more than an incremental upgrade, adding nothing more substantial than support for the AT's new 1.2megabyte (MB) floppy disks. Planned networking capabilities in DOS 3.00 were judged too buggy to be usable and Microsoft disabled them prior to the OS's release. In any case, IBM's original plans for the AT had been to equip it with a proper next-generation OS that would use its extended features, but this never materialized.[2] PC DOS 3.1 (released March 1985) fixed the bugs in DOS 3.00 and supported IBM's Network Adapter card on theIBM PC Network. PC DOS 3.2 added support for3+1⁄2-inch double-density 720 KB floppy disk drives, supporting theIBM PC Convertible, IBM's first computer to use3+1⁄2-inch floppy disks, released April 1986, and later theIBM Personal System/2 in 1987.
In June 1985, IBM and Microsoft signed a long-term Joint Development Agreement to share specified DOS code and create a new operating system from scratch, known at the time as Advanced DOS. On 2 April 1987OS/2 was announced as the first product produced under the agreement.[28] At the same time, IBM released its next generation of personal computers, theIBM Personal System/2 (PS/2).[2] PC DOS 3.3, released with the PS/2 line, added support for high density3+1⁄2-inch 1.44 MB floppy disk drives, which IBM introduced in its 80286-based and higher PS/2 models. The upgrade from DOS 3.2 to 3.3 was completely written by IBM, with no development effort on the part of Microsoft, who were working on "Advanced DOS 1.0". DOS 3.30 was the last version designed with the IBM XT and floppy-only systems in mind; it became one of the most popular versions and many users preferred it to its buggy successor.
PC DOS 4.0 (internally known as DOS 3.4 originally) shipped July 1988. DOS 4.0 had some compatibility issues with low-level disk utilities due to some internal data structure changes. DOS 4.0 used more memory than DOS 3.30 and it also had a few glitches. Newly added EMS drivers were only compatible with IBM's EMS boards and not the more common[citation needed] Intel and AST ones. DOS 4.0 is also notable for including the first version of theDOS Shell, a full-screen utility designed to make the command-line OS more user-friendly. Microsoft took back control of development and released a bug-fixed DOS 4.01.[29]
DOS 5 debuted in June 1991. DOS 5 supported the use of theHigh Memory Area (HMA) andUpper Memory Blocks (UMBs) on 80286 and later systems to reduce itsconventional memory usage. Also all DOS commands now supported the/? option to display command syntax. Aside from IBM's PC DOS, MS-DOS was the only other version available as OEM editions vanished since by this time PCs were 100% compatible so customizations for hardware differences were no longer necessary.
The POWER.EXE was introduced that has theAPM standard in version 5.02.[30][31]
This was the last version of DOS that IBM and Microsoft shared the full code for, and the DOS that was integrated into OS/2 2.0's, and later Windows NT's,virtual DOS machine.
PC DOS remained a rebranded version of MS-DOS until 1993. IBM and Microsoft parted ways—MS-DOS 6 was released in March, and PC DOS 6.1 (separately developed) followed in June. Most of the new features from MS-DOS 6.0 appeared in PC DOS 6.1 including the new boot menu support and the new commandsCHOICE,DELTREE, andMOVE.QBasic was dropped and theMS-DOS Editor was replaced with the IBME Editor. It also licensed components ofCentral Point'sPC Tools, such as Central Point Backup Utility (CPBACKUP).[17][19] PC DOS 6.1 reports itself as DOS 6.00.
PC DOS 6.3 followed in December. PC DOS 6.3 was also used in OS/2 for thePowerPC. PC DOS 6.3 also featuredSuperStor disk compression technology fromAddstor.
PC DOS 7 was released in April 1995 and was the last release of DOS before IBM software development (other than the developmentIBM ViaVoice) moved to Austin. TheREXX programming language was added, as well as support for a new floppy disk format,XDF, which extended a standard 1.44 MB floppy disk to 1.86 MB. SuperStor disk compression technology was replaced withStac Electronics'STACKER. An algebraic command line calculator and a utility program to load device drivers from the command line were added. PC DOS 7 also included many optimizations to increase performance and reduce memory usage.[32]
The most recent retail release was PC DOS 2000 – released from Austin in 1998 – which found its niche in theembedded software market and elsewhere. PC DOS 2000 is aslipstream of 7.0 withY2K and other fixes applied. To applications, PC DOS 2000 reports itself as "IBM PC DOS 7.00, revision 1", in contrast to the original PC DOS 7, which reported itself as "IBM PC DOS 7.00, revision 0".[nb 2]
PC-DOS 2000 was the last version of IBM PC-DOS that was sold at retail. IBM advertised it as a Y2K compliant DOS. As it reports itself as "IBM PC-DOS 7 Revision 1", it is often referred to as "IBM PC-DOS7R1" or just "PC-DOS7R1".
Hitachi used PC DOS 2000 in their legacyDrive Fitness Test (4.15) andHitachi Feature Tool (2.15) until 2009.[33]ThinkPad products had a copy of the latest version of PC DOS in their Rescue and Recovery partition.[34]
PC DOS 7.1 added support forLogical Block Addressing (LBA) andFAT32 partitions.[nb 2] Various buildsfrom 1999 up to 2003 were not released in retail, but used in products such as the IBM ServerGuide Scripting Toolkit.[35] A build of this version of DOS appeared inNorton Ghost fromSymantec.[36] Version 7.1 indicates support for FAT32 also inMS-DOS.[32]
Most builds of this version of DOS are limited to the kernel filesIBMBIO.COM,IBMDOS.COM, andCOMMAND.COM. The updated programsFDISK32 andFORMAT32 allow one to prepare FAT32 disks. Additional utilities are taken from PC DOS 2000, where needed.
In 1986, IBM announced PC DOS support for client access to the file services defined byDistributed Data Management Architecture (DDM). This enabled programs on PCs to create, manage, and accessrecord-oriented files available on IBM System/36, IBM System/38 and IBM mainframe computers runningCICS. In 1988, client support forstream-oriented files andhierarchical directories was added to PC DOS when they became available on the DDM server systems.
21h function30hGet DOS version returnsOEM code00h forIBM instead ofFFh forMicrosoft. This is particularly important for DOS 7, because various features introduced in MS-DOS 7.0 and 7.1 are not supported in PC DOS 7.x, and vice versa, e.g., MS-DOS does not supportREXX, and PC DOS 7 and 2000 do not support LBA access.An additional undocumented feature added to the User Interface is the ability to drop directly out to a DOS prompt. Pressing F3 (there is no prompt for this) will exit the recovery utility and go to a DOS prompt
| Supercomputer | |
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| Server,mainframe | |
| Desktop,workstation | |
| Point of sale | |
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