PC-DOS
Encyclopedia
IBM PC DOS is a DOS
system for the IBM Personal Computer and compatibles
, manufactured and sold by IBM
from the 1980s to the 2000s.
The DOS INT 21h
function 30h get DOS version returns OEM code 00h for IBM
instead of FFh for Microsoft
. This is relevant for DOS 7, because various features introduced in MS DOS 7 (a part of Windows 95
) are not supported in PC DOS 7, and vice versa, e.g., MS DOS 7 does not support REXX
, and PC DOS 7 does not support FAT32.
was 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 member Jack 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." IBM first contacted Microsoft to look the company over in July 1980. Negotiations continued over the next months, and the paperwork was officially signed in early November.
(SCP), which was modified for the IBM PC by Microsoft employee Bob O'Rear
with assistance from SCP (later Microsoft) employee Tim Paterson
. 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-inch floppy disks and integrated with the BIOS
, which Microsoft was helping IBM to write. 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 in Boca Raton. 86-DOS was rebranded IBM PC DOS 1.0 for its August 1981 release with the IBM PC. Toward the end of 1981, Paterson went to work on an upgrade, which was called PC DOS 1.1. It allowed data to be written on both sides of a diskette, thus doubling the capacity of the IBM machine, and was finished in March 1982.
, Mark Zbikowski
and Aaron Reynolds
) began work on PC DOS 2.0, the next version for the IBM PC/XT, the first PC to store data on a hard disk. A much more sophisticated program than 1.0, it had 20,000 lines of assembly language
code, compared to about 4,000 lines in the first version. It was officially announced in March 1983. In March 1984, the IBM PCjr
shipped. It ran PC DOS 2.1, which supported PCjr's ability to run programs from ROM cartridges and slightly different disk-controller architecture.
. PC DOS 3.2 added support for 3½-inch double-density 720 KB floppy disk drives, supporting the IBM PC Convertible, IBM's first computer to use 3½-inch floppy disks, released April 1986.
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 April 2, 1987 OS/2
was announced as the first product produced under the agreement. At the same time, IBM released its next generation of personal computers, the IBM Personal System/2
. PC DOS 3.3, released with the PS/2 line, added support for high density 3½-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".
, and some hurried coding, allowed Microsoft to stave off the competition. This DOS also is the last 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
. DOS in these operating systems for the i386 computer never progressed past this.
Under the terms of the split, IBM was allowed to keep (and buy the rights for) their own DOS, which they did. They were allowed to keep Win-OS/2 as well (basically Windows 3.10 for OS/2). Microsoft was rather specific on what DOS was, since OEM diskettes were labeled "MS-DOS and Additional Tools", i.e. two products. IBM released their own DOS, with a new editor, and a number of utilities being full back-versions of PC-Tools. Microsoft's tools were feature-limited Norton tools.
was dropped and the MS-DOS Editor was replaced with E
.
.
The final split came after DOS 6.30. One notes that 6.30 has the improvements that 6.20 has, and that beginning with 6.22 and Windows 3.11, the preferred server OS switched from OS/2 to Windows NT.
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.
IBM's DOS 7.0, the last released before Boca Raton closed, included more SAA features (like REXX, IPF view for help, and unpack2 - all out of OS/2), along with removing the incorrect DOS version from most, but not all of the utilities.
market and elsewhere. PC DOS 2000 is basically a slipstream of 7.0 with Y2K
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 7.0, which reported itself as revision 0. IBM continues to use PC DOS code to compile DOS boot disks for their servers.
ThinkPad
products currently have a copy of the latest version of PC DOS in their Rescue and Recovery partition.
7.04 and higher, which also report as "IBM PC DOS 7.10" for compatibility purposes.
DOS
DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.Related...
system for the IBM Personal Computer and compatibles
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...
, manufactured and sold by IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
from the 1980s to the 2000s.
The DOS INT 21h
MS-DOS API
The MS-DOS API is an API used originally in MS-DOS/PC-DOS, and later by other DOS systems. Most calls to the DOS API invoke software interrupt 21h . By calling INT 21h with a subfunction number in the AH processor register and other parameters in other registers, one invokes various DOS services...
function 30h get DOS version returns OEM code 00h for IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
instead of FFh for Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
. This is relevant for DOS 7, because various features introduced in MS DOS 7 (a part of Windows 95
Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
) are not supported in PC DOS 7, and vice versa, e.g., MS DOS 7 does not support REXX
REXX
REXX is an interpreted programming language that was developed at IBM. It is a structured high-level programming language that was designed to be both easy to learn and easy to read...
, and PC DOS 7 does not support FAT32.
History
The IBM task force assembled to develop the 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 the key decision that made the IBM PC an industry standard. But it was done out of necessity, to save time. MicrosoftMicrosoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
was 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 member Jack 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." IBM first contacted Microsoft to look the company over in July 1980. Negotiations continued over the next months, and the paperwork was officially signed in early November.
PC DOS 1.x
Microsoft first licensed, then purchased 86-DOS from Seattle Computer ProductsSeattle Computer Products
Seattle Computer Products was a Seattle, Washington microcomputer hardware company which was one of the first manufacturers of computer systems based on the 16-bit Intel 8086 processor...
(SCP), which was modified for the IBM PC by Microsoft employee Bob O'Rear
Bob O'Rear
Robert O'Rear is a former employee of Microsoft, and is among the group of twelve early Microsoft employees who posed for a company photo in 1978. A Texan, he has degrees in mathematics and physics. He left Microsoft in 1993, and reportedly owns a cattle ranch in Texas...
with assistance from SCP (later Microsoft) employee Tim Paterson
Tim Paterson
Tim Paterson is an American computer programmer, best known as the original author of MS-DOS, the most widely used personal computer operating system in the 1980s....
. 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-inch floppy disks and integrated with the BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
, which Microsoft was helping IBM to write. 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 in Boca Raton. 86-DOS was rebranded IBM PC DOS 1.0 for its August 1981 release with the IBM PC. Toward the end of 1981, Paterson went to work on an upgrade, which was called PC DOS 1.1. It allowed data to be written on both sides of a diskette, thus doubling the capacity of the IBM machine, and was finished in March 1982.
PC DOS 2.x
Later, a group of Microsoft programmers (primarily Paul AllenPaul Allen
Paul Gardner Allen is an American business magnate, investor, and philanthropist. Allen co-founded Microsoft with Bill Gates...
, Mark Zbikowski
Mark Zbikowski
Mark "Zibo" Joseph Zbikowski is a former Microsoft Architect and an early computer hacker. He started working at the company only a few years after its inception, leading efforts in MS-DOS, OS/2, Cairo and Windows NT. In 2006 he was honored for 25 years of service with the company, the third...
and Aaron Reynolds
AARD code
The AARD code was a segment of obfuscated machine code that is included in several executables, including the installer and WIN.COM, in a beta release of Microsoft Windows 3.1. It was a block of code which was XOR encrypted, self-modifying, and deliberately obfuscated, using various undocumented...
) began work on PC DOS 2.0, the next version for the IBM PC/XT, the first PC to store data on a hard disk. A much more sophisticated program than 1.0, it had 20,000 lines of assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
code, compared to about 4,000 lines in the first version. It was officially announced in March 1983. In March 1984, the IBM PCjr
IBM PCjr
The IBM PCjr was IBM's first attempt to enter the home computer market. The PCjr, IBM model number 4860, retained the IBM PC's 8088 CPU and BIOS interface for compatibility, but various design and implementation decisions led the PCjr to be a commercial failure.- Features :Announced November 1,...
shipped. It ran PC DOS 2.1, which supported PCjr's ability to run programs from ROM cartridges and slightly different disk-controller architecture.
PC DOS 3.x
In August 1984, IBM introduced the IBM PC/AT, a computer built around the Intel 80286 processor. It ran on PC DOS 3.0, which supported the computer's larger hard drives and high density (1.2 MB) diskettes. PC DOS 3.1 supported IBM's Network Adapter card on the IBM PC-NetworkPC-Network
PC-Network was a LAN system consisting of network cards, cables, and a small device driver known as NetBIOS . It used a data rate of 2 Mbit/s....
. PC DOS 3.2 added support for 3½-inch double-density 720 KB floppy disk drives, supporting the IBM PC Convertible, IBM's first computer to use 3½-inch floppy disks, released April 1986.
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 April 2, 1987 OS/2
OS/2
OS/2 is a computer operating system, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for "Operating System/2," because it was introduced as part of the same generation change release as IBM's "Personal System/2 " line of second-generation personal...
was announced as the first product produced under the agreement. At the same time, IBM released its next generation of personal computers, the IBM Personal System/2
IBM Personal System/2
The Personal System/2 or PS/2 was IBM's third generation of personal computers. The PS/2 line, released to the public in 1987, was created by IBM in an attempt to recapture control of the PC market by introducing an advanced proprietary architecture...
. PC DOS 3.3, released with the PS/2 line, added support for high density 3½-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".
PC DOS 4.x
PC DOS 4.0, shipped July 1988, was an unsuccessful DOS which arose from IBM testing ideas for its in-development DOS 5, which later became OS/2.PC DOS 5
Digital Research released a retail DOS 5.0, which caught Microsoft off-foot, but the combination of vaporwareVaporware
Vaporware is a term in the computer industry that describes a product, typically computer hardware or software, that is announced to the general public but is never actually released nor officially canceled. Vaporware is also a term sometimes used to describe events that are announced or predicted,...
, and some hurried coding, allowed Microsoft to stave off the competition. This DOS also is the last 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
Virtual DOS machine
Virtual DOS machine is Microsoft's technology that allows running legacy DOS and 16-bit Windows programs on Intel 80386 or higher computers when there is already another operating system running and controlling the hardware.-Overview:...
. DOS in these operating systems for the i386 computer never progressed past this.
Under the terms of the split, IBM was allowed to keep (and buy the rights for) their own DOS, which they did. They were allowed to keep Win-OS/2 as well (basically Windows 3.10 for OS/2). Microsoft was rather specific on what DOS was, since OEM diskettes were labeled "MS-DOS and Additional Tools", i.e. two products. IBM released their own DOS, with a new editor, and a number of utilities being full back-versions of PC-Tools. Microsoft's tools were feature-limited Norton tools.
PC DOS 6.1
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. QBasicQBasic
QBasic is an IDE and interpreter for a variant of the BASIC programming language which is based on QuickBASIC. Code entered into the IDE is compiled to an intermediate form, and this intermediate form is immediately interpreted on demand within the IDE. It can run under nearly all versions of DOS...
was dropped and the MS-DOS Editor was replaced with E
E (PC-DOS)
E is the text editor which was made part of PC DOS with version 6.1 in June 1993, and later with version 7 and PC DOS 2000. In version 6.1, IBM dropped QBASIC, which, in its edit mode, was also the system text editor...
.
PC DOS 6.3
PC DOS 6.3 followed in December. PC DOS 6.30 was also used in OS/2 for the PowerPCPowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
.
The final split came after DOS 6.30. One notes that 6.30 has the improvements that 6.20 has, and that beginning with 6.22 and Windows 3.11, the preferred server OS switched from OS/2 to Windows NT.
PC DOS 7.0
PC DOS 7.0 was released in November 1994. The REXXREXX
REXX is an interpreted programming language that was developed at IBM. It is a structured high-level programming language that was designed to be both easy to learn and easy to read...
programming language was added, as well as support for a new floppy disk format, XDF
IBM Extended Density Format
The IBM eXtended Density Format is a way of formatting standard high-density 3.5" and 5.25" floppy disks to larger-than-standard capacities...
, which extended a standard 1.44 MB floppy disk to 1.86 MB.
IBM's DOS 7.0, the last released before Boca Raton closed, included more SAA features (like REXX, IPF view for help, and unpack2 - all out of OS/2), along with removing the incorrect DOS version from most, but not all of the utilities.
PC DOS 2000
The most recent retail release was PC DOS 2000 – released from Austin in 1998 – which found its niche in the embedded softwareEmbedded software
Embedded software is computer software that plays an integral role in the electronics it is supplied with.Embedded software's principal role is not Information technology , but rather the interaction with the physical world. It's written for machines that are not, first and foremost, computers...
market and elsewhere. PC DOS 2000 is basically a slipstream of 7.0 with Y2K
Year 2000 problem
The Year 2000 problem was a problem for both digital and non-digital documentation and data storage situations which resulted from the practice of abbreviating a four-digit year to two digits.In computer programs, the practice of representing the year with two...
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 7.0, which reported itself as revision 0. IBM continues to use PC DOS code to compile DOS boot disks for their servers.
ThinkPad
ThinkPad
ThinkPad is line of laptop computers originally sold by IBM but now produced by Lenovo. They are known for their boxy black design, which was modeled after a traditional Japanese lunchbox...
products currently have a copy of the latest version of PC DOS in their Rescue and Recovery partition.
PC DOS 7.10
There is also a LBA/FAT32-enabled OEM version of PC DOS since 2003, reporting itself as "IBM PC DOS 7.10" to applications. It must not be confused with OEM DR-DOSDR-DOS
DR-DOS is an MS-DOS-compatible operating system for IBM PC-compatible personal computers, originally developed by Gary Kildall's Digital Research and derived from Concurrent PC DOS 6.0, which was an advanced successor of CP/M-86...
7.04 and higher, which also report as "IBM PC DOS 7.10" for compatibility purposes.
See also
- Timeline of x86 DOS operating systemsTimeline of x86 DOS operating systemsThis article presents a timeline of events in the history of x86 DOS operating systems from 1973 to 2006.-Important Events in DOS History:-See also:*Comparison of x86 DOS operating systems*Timeline of Microsoft Windows*Timeline of OpenBSD...
- Comparison of x86 DOS operating systemsComparison of x86 DOS operating systems- Historical and licensing information :Originally MS-DOS was designed to be an operating system that could run on any computer with a 8086-family microprocessor. It competed with other Operating Systems written for such computers, such as CP/M-86 and UCSD Pascal. Each computer would have its own...
- List of DOS commands
Further reading
- IBM Corporation and Microsoft, Inc. DOS 3.30: User's Guide. IBM Corporation, 1987. Part number 80X0933.
- IBM Corporation and Microsoft, Inc. DOS 3.30: Reference (Abridged). IBM Corporation, 1987. Part number 94X9575.
- IBM Corporation. Getting Started with Disk Operating System Version 4.00. IBM Corporation, 1988. Part number 15F1370.
- IBM Corporation. Using Disk Operating System Version 4.00. IBM Corporation, 1988. Part number 15F1371.
- IBM Corporation. IBM Disk Operating System Version 5.0. User Guide and Reference. IBM Corporation, 1991. Part number 07G4584.
- IBM Corporation. PC DOS 7 User's Guide. IBM, 1995.
- IBM Redbooks. PC DOS 7 Technical Update. IBM, 1995. ISBN 0-7384-0677-5.
- IBM Corporation. IBM PC DOS and Microsoft Windows User's Guide. Indianapolis, IN: Que Corporation, 1995. ISBN 0-7897-0276-2.
External links
- [ftp://ftp.boulder.ibm.com/software/dos/ ftp://ftp.boulder.ibm.com/software/dos/] PC DOS 2000 (Chinese Edition), freely available for download from IBM
- IBM ServerGuide Scripting toolkit - its DOS Edition contains PC DOS 7.1 (June 2005) with LBA and FAT32 support