DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with

IBM PC DOS IBM PC DOS, an acronym for IBM Personal Computer Disk Operating System, is a discontinued disk operating system for IBM PC compatibles. It was manufactured and sold by IBM from the early 1980s into the 2000s. Developed by Microsoft, it was also ...

and

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few oper ...

(which were the same product sold under different names). DR-DOS was developed by Gary A. Kildall's Digital Research and derived from

Concurrent PC DOS Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

6.0, which was an advanced successor of

CP/M-86 CP/M-86 was a version of the CP/M operating system that Digital Research (DR) made for the Intel 8086 and Intel 8088. The system commands are the same as in CP/M-80. Executable files used the relocatable .CMD file format. Digital Research also ...

. As ownership changed, various later versions were produced with names including Novell DOS and Caldera OpenDOS.

History

Origins in CP/M

Digital Research's original

CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initially ...

for the 8-bit

Intel 8080 The Intel 8080 (''"eighty-eighty"'') is the second 8-bit microprocessor designed and manufactured by Intel. It first appeared in April 1974 and is an extended and enhanced variant of the earlier 8008 design, although without binary compatibil ...

- and Z-80-based systems spawned numerous spin-off versions, most notably

for the Intel 8086/

8088 The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor is a variant of the Intel 8086. Introduced on June 1, 1979, the 8088 has an eight-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and ...

family of processors. Although CP/M had dominated the market since the mid-1970s, and was shipped with the vast majority of non-proprietary-architecture personal computers, the

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...

in 1981 brought the beginning of what was eventually to be a massive change. IBM originally approached Digital Research in 1980, seeking an x86 version of CP/M. However, there were disagreements over the contract, and IBM withdrew. Instead, a deal was struck with Microsoft, who purchased another operating system,

86-DOS 86-DOS (known internally as QDOS, for Quick and Dirty Operating System) is a discontinued operating system developed and marketed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit. 86-DOS shared a few of its commands wi ...

, from

Seattle Computer Products Seattle Computer Products (SCP) was a Tukwila, Washington, microcomputer hardware company which was one of the first manufacturers of computer systems based on the 16-bit Intel 8086 processor. SCP began shipping its first S-100 bus 8086 CPU ...

(SCP). This became Microsoft

and IBM PC DOS. 86-DOS's command structure and application programming interface imitated that of CP/M 2.2 (with

BDOS CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initiall ...

2.2). Digital Research threatened legal action, claiming PC DOS/MS-DOS to be too similar to CP/M. In early 1982, IBM settled by agreeing to sell Digital Research's x86 version of CP/M,

, alongside PC DOS. However, PC DOS sold for while CP/M-86 had a $240 price tag. The proportion of PC buyers prepared to spend six times as much to buy CP/M-86 was very small, and the limited availability of compatible application software, at first in Digital Research's favor, was only temporary. Digital Research fought a long losing battle to promote CP/M-86 and its multi-tasking multi-user successors

MP/M-86 MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each us ...

and Concurrent CP/M-86, and eventually decided that they could not beat the Microsoft-IBM lead in application software availability, so they modified Concurrent CP/M-86 to allow it to run the same applications as MS-DOS and PC DOS. This was shown publicly in December 1983 and shipped in March 1984 as Concurrent DOS 3.1 (a.k.a. CDOS with BDOS 3.1) to hardware vendors. While Concurrent DOS continued to evolve in various flavours over the years to eventually become

Multiuser DOS Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

and

REAL/32 Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

, it was not specifically tailored for the desktop market and too expensive for single-user applications. Therefore, over time two attempts were made to sideline the product: In 1985, Digital Research developed DOS Plus 1.0 to 2.1, a stripped-down and modified single-user derivative of Concurrent DOS 4.1 and

5.0 ''5.0'' is the sixth studio album by American rapper Nelly. It was released through Universal Motown Records (Universal Music Group) and Derrty (Universal Music Group) on November 12, 2010.

, which ran applications for both platforms, and allowed switching between several tasks as did the original CP/M-86. Its DOS compatibility was limited, and Digital Research made another attempt, this time a native DOS system. This new disk operating system was launched in 1988 as DR DOS. Although DRI was based in Pacific Grove and later in Monterey, California, USA, the work on DOS Plus started in Newbury, Berkshire in the UK, where Digital Research Europe had its OEM Support Group located since 1983. Beginning in 1986, most of the operating system work on

Concurrent DOS 386 Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

and XM,

, DR DOS and PalmDOS was done in Digital Research's European Development Centre (EDC) in Hungerford, Berkshire. Later on some work was also done by Digital Research GmbH in Munich, Germany.

First DR DOS version

As requested by several

OEM An original equipment manufacturer (OEM) is generally perceived as a company that produces non-aftermarket parts and equipment that may be marketed by another manufacturer. It is a common industry term recognized and used by many professional or ...

s, Digital Research started a plan to develop a new DOS operating system addressing the defects left by MS-DOS in 1987. Of particular importance was a million dollar deal with Kazuhiko "Kay" Nishi of

ASCII Corporation was a Japanese publishing company based in Chiyoda, Tokyo. It became a subsidiary of Kadokawa Group Holdings in 2004, and merged with another Kadokawa subsidiary MediaWorks on April 1, 2008, becoming ASCII Media Works. The company published '' ...

, who had previously been instrumental in opening the Japanese OEM market for Microsoft. The first DR DOS version was released on 28 May 1988. Version numbers were chosen to reflect features relative to MS-DOS; the first version promoted to the public was DR DOS 3.31, which offered features comparable to

Compaq MS-DOS 3.31 MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few oper ...

with large disk support (

FAT16B File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by c ...

a.k.a. "BIGDOS"). DR DOS 3.31 reported itself as "IBM PC DOS 3.31", while the internal BDOS (

Basic Disk Operating System CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...

) kernel version was reported as 6.0, single-user nature, reflecting its origin as derivative of Concurrent DOS 6.0 with the multitasking and multiuser capabilities as well as CP/M

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

support stripped out and the XIOS replaced by an IBM-compatible DOS-BIOS. The system files were named DRBIOS.SYS (for the DOS-BIOS) and DRBDOS.SYS (for the BDOS kernel), the disk OEM label used was "DIGITAL␠". DR DOS offered some extended command line tools with command line help, verbose error messages, sophisticated command line history and editing ( HISTORY directive) as well as support for file and directory passwords built right into the kernel. It was also cheaper to license than MS-DOS, and was ROMable right from the start. The ROMed version of DR DOS was also named ROS (ROM Operating System). DRI was approached by a number of PC manufacturers who were interested in a third-party DOS, which prompted several updates to the system. At this time, MS-DOS was only available to OEMs bundled with hardware. Consequently, DR DOS achieved some immediate success when it became possible for consumers to buy it through normal retail channels beginning with version 3.4x. Known versions are DR DOS 3.31 (BDOS 6.0, June 1988, OEM only), 3.32 (BDOS 6.0, 17 August 1988, OEM only), 3.33 (BDOS 6.0, 1 September 1988, OEM only), 3.34 (BDOS 6.0, OEM only), 3.35 (BDOS 6.0, 21 October 1988, OEM only), 3.40 (BDOS 6.0, 25 January 1989), 3.41 (BDOS 6.3, June 1989, OEM and retail). Like MS-DOS, most of them were produced in several variants for different hardware. While most OEMs kept the DR DOS name designation, 2001 Sales, Inc. marketed it under the name EZ-DOS 3.41 (also known as EZ-DOS 4.1).

DR DOS 5.0

DR DOS version 5.0 (code-named "Leopard") was released in May 1990, still reporting itself as "PC DOS 3.31" for compatibility purposes, but internally indicating a single-user BDOS 6.4 kernel. (Version 4 was skipped to avoid being associated with the relatively unpopular MS-DOS 4.0.) This introduced

ViewMAX ViewMAX is a CUA-compliant file manager supplied with DR DOS versions 5.0 and 6.0. It is based on a cut-down runtime version of Digital Research's GEM/3 graphical user interface modified to run only a single statically built applicatio ...

, a

GEM A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, an ...

-based GUI file management shell. ViewMAX's startup screen would present the slogan "Digital Research - We make computers work". DR DOS 5.0 also introduced the patented BatteryMAX power management system, bundled disk-caching software (DRCACHE), a remote file transfer tool (FILELINK), a cursor shape configuration utility (CURSOR), and offered a vastly improved memory management system (MemoryMAX). For compatibility purposes, the DR DOS 5.0 system files were now named

IBMBIO.COM IBMBIO.COM is a system file in many DOS operating systems. It contains the system initialization code and all built-in device drivers. It also loads the DOS kernel ( IBMDOS.COM) and optional pre-loadable system components (like for disk compre ...

(for the DOS-BIOS) and IBMDOS.COM (for the BDOS kernel) and due to the advanced loader in the boot sector could be physically stored anywhere on disk. The OEM label in the boot sectors was changed to "IBM␠␠3.3". Carry-i-front-and-rear

DR DOS 5.0 was the first DOS to include load-high capabilities. The kernel and data structures such as disk buffers could be relocated in the High Memory Area (HMA), the first 64 KB of

extended memory In DOS memory management, extended memory refers to memory above the first megabyte (220 bytes) of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems. D ...

which are accessible in

real mode Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20- bit se ...

. This freed up the equivalent amount of critical "base" or

conventional memory In DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory directly addressable by the processor for use by the operating system ...

, the first 640 KB of the PC's RAM – the area in which all DOS applications run. Additionally, on

Intel 80386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorsupper memory blocks was already possible using third-party software like

QEMM Quarterdeck Expanded Memory Manager (QEMM) is a memory manager produced by Quarterdeck Office Systems in the late 1980s through the late 1990s. It was the most popular third-party memory manager for the MS-DOS and other DOS operating systems. ...

). This allowed it, on 286 systems with supported chipsets and on 386 systems, to provide significantly more free conventional memory than any other DOS. Once drivers for a mouse, multimedia hardware and a network stack were loaded, an MS-DOS/PC DOS machine typically might only have had 300 to 400 KB of free conventional memory – too little to run much late-1980s software. In contrast to this, DR DOS 5.0, with a little manual tweaking, could load all this and still keep all of its conventional memory free – allowing for some necessary DOS data structures, as much as 620 KB out of the 640 KB. With MEMMAX +V, the conventional memory region could even be extended into unused portions of the graphics adapter card typically providing another 64 to 96 KB more free DOS memory. Because DR DOS left so much conventional memory available, some old programs utilizing certain address wrapping techniques failed to run properly as they were now loaded unexpectedly (or, under MS-DOS, "impossibly") low in memory – inside the first 64 KB segment (known as "

low memory In DOS memory management, conventional memory, also called base memory, is the first 640 kilobytes of the memory on IBM PC or compatible systems. It is the read-write memory directly addressable by the processor for use by the operating system ...

"). Therefore, DR DOS 5.0's new MEMMAX -L command worked around this by pre-allocating a chunk of memory at the start of the memory map in order for programs to load above this barrier (but with less usable conventional memory then). By default, MEMMAX was configured for +L, so that applications could take advantage of the extra memory.

DR DOS 6.0 / Competition from Microsoft

Faced with substantial competition in the DOS arena, Microsoft responded with an announcement of a yet-to-be released MS-DOS 5.0 in May 1990. This would be released in June 1991 and include similar advanced features to those of DR DOS. It included matches of the DR's enhancements in memory management. Almost immediately in September 1991, Digital Research responded with DR DOS 6.0, code-named "Buxton". DR DOS 6.0, while already at BDOS level 6.7 internally, would still report itself as "IBM PC DOS 3.31" to normal DOS applications for compatibility purposes. This bundled in SuperStor on-the-fly disk compression, to maximize available hard disk space, and file deletion tracking and undelete functionality by Roger A. Gross. DR DOS 6.0 also included a task-switcher named TASKMAX with support for the industry-standard task-switching API to run multiple applications at the same time. In contrast to Digital Research's Multiuser DOS (successor of Concurrent DOS in the multi-user products line), which would run DOS applications in pre-emptively multitasked virtual DOS machines, the DR DOS 6.0 task switcher would freeze background applications until brought back into the foreground. While it ran on x86-machines, it was able to swap to XMS memory on 286+ machines. TASKMAX did support some Copy & Paste facility between applications. Via the task-switcher API, graphical user interfaces such as

PC/GEOS GEOS (later renamed GeoWorks Ensemble, NewDeal Office, and Breadbox Ensemble) is a computer operating environment, graphical user interface (GUI), and suite of application software. Originally released as PC/GEOS, it runs on DOS-based, IBM PC ...

could register as the task manager menu and thereby replace the TASKMAX text mode menu, so that users could switch between tasks from within a GUI. Microsoft responded with MS-DOS 6.0, which again matched some features of DR DOS 6.0. In December 1991, a pre-release version of Windows 3.1 was found to return a non-fatal error message if it detected a non-Microsoft DOS. This check came to be known as the

AARD code The AARD code was a segment of code in a beta release of Microsoft Windows 3.1 that would determine whether Windows was running on MS-DOS or PC DOS, rather than a competing workalike such as DR-DOS, and would result in a cryptic error messag ...

. It was a simple matter for Digital Research to patch DR DOS 6.0 to circumvent the AARD code 'authenticity check' in the Windows 3.1 beta by rearranging the order of two internal tables in memory (with no changes in functionality), and the patched version, named "business update", was on the streets within six weeks of the release of Windows 3.1. With the detection code disabled, Windows ran perfectly under DR DOS and its successor Novell DOS. The code was present but disabled in the released version of Windows 3.1. In July 1992, Digital Research Japan released DR DOS 6.0/V, a Japanese DOS/V compatible version of DR DOS 6.0. A Korean version appears to have been available as well.

PalmDOS

In 1992 Digital Research, still under its old name but already bought by Novell in July 1991, also embarked on a spin-off product code-named "Merlin" and later released as NetWare PalmDOS 1, which, as its name implies, was a very resource-light DR DOS 6.0 derivative aimed at the emerging Palmtop/

PDA PDA may refer to: Science and technology * Patron-driven acquisition, a mechanism for libraries to purchase books *Personal digital assistant, a mobile device * Photodiode array, a type of detector * Polydiacetylenes, a family of conducting po ...

market. PalmDOS was the first operating system in the family to support the new BDOS 7.0 kernel with native DOS compatible internal data structures instead of emulations thereof. Replacing the DOS emulation on top of a CP/M kernel by a true DOS compatible kernel helped a lot in improving compatibility with some applications using some of DOS' internal data structures and also was the key in reducing the resident size of the kernel code even further—a particular requirement for the PDA market. On the other hand, introducing a genuine

Current Directory Structure In computing, the working directory of a process is a directory of a hierarchical file system, if any, dynamically associated with each process. It is sometimes called the current working directory (CWD), e.g. the BSD getcwd function, or just ...

( CDS) imposed a limit on the depth of working directories down to 66 characters (as in MS-DOS/PC DOS), whereas previous issues of DR DOS had no such limitation due to their internal organization of directories as relative links to parent directories instead of as absolute paths. PalmDOS still reported itself as "PC DOS 3.31" to applications in order to keep the kernel small and not run into compatibility problems with Windows, which would expect the DOSMGR API to be implemented for any DOS version since 5.0. As well as a ROM-executing kernel, PalmDOS had palmtop-type support for features such as PCMCIA PC Cards (with DPMS support), power management ( BatteryMAX and the device driver with its patented dynamic idle detection by Gross and John P. Constant), MINIMAX task switcher support for PIM (Personal Information Modules) applications stored and executed from ROM via XIP (

Execute-In-Place In computer science, execute in place (XIP) is a method of executing programs directly from long-term storage rather than copying it into RAM. It is an extension of using shared memory to reduce the total amount of memory required. Its general ef ...

), etc. The PCMCIA stack for PalmDOS was partially written by Ian H. S. Cullimore.

Novell DOS 7 / Contribution by Novell

Novell DOS was

Novell Novell, Inc. was an American software and services company headquartered in Provo, Utah, that existed from 1980 until 2014. Its most significant product was the multi- platform network operating system known as Novell NetWare. Under the le ...

Corporation's name for DR DOS during the period when Novell sold DR DOS, after the acquisition of Digital Research in 1991. Regarding features and performance, it was typically at least one release ahead of

. In 1993, PC DOS 6.1, MS-DOS 6.2 and PC DOS 6.3 were trumped by Novell's . Novell CEO Robert J. Frankenberg's strategy included "major trimming", selling off products like transactional database

Btrieve Btrieve is a transactional database (navigational database) software product. It is based on Indexed Sequential Access Method (ISAM), which is a way of storing data for fast retrieval. There have been several versions of the product for DOS, Linux, ...

and killing others such as Novell DOS and WordPerfect's multimedia Main Street children's titles. Novell licensed technology from Stac Electronics for use in Novell DOS and its

Network operating system A network operating system (NOS) is a specialized operating system for a network device such as a router, switch or firewall. Historically operating systems with networking capabilities were described as network operating systems, because they al ...

NetWare NetWare is a discontinued computer network operating system developed by Novell, Inc. It initially used cooperative multitasking to run various services on a personal computer, using the IPX network protocol. The original NetWare product in ...

. Novell sold the product line off to

Caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber i ...

on 23 July 1996, after it approached Novell looking for a DOS operating system to bundle with its

OpenLinux Caldera OpenLinux (COL) is a defunct Linux distribution. Caldera originally introduced it in 1997 based on the German LST Power Linux distribution, and then taken over and further developed by Caldera Systems (now SCO Group) since 1998. A suc ...

distribution. Marc Perkel claimed to have had inspired Novell in February 1991 to buy Digital Research and develop something he envisioned as "NovOS".

had actually bought Digital Research in July 1991 with a view to using DR's product line as a lever in their comprehensive strategy to break the Microsoft monopoly. (This was part of a massive and ultimately disastrous spending spree for Novell: they bought WordPerfect Corporation at about the same time, some of

Borland Borland Software Corporation was a computer technology company founded in 1983 by Niels Jensen, Ole Henriksen, Mogens Glad and Philippe Kahn. Its main business was the development and sale of software development and software deployment product ...

's products, and invested heavily in Unix as well.) The planned "DR DOS 7.0", internally named "Panther", intended to trump Microsoft's troubled MS-DOS 6.0, was repeatedly delayed, while Novell was working on an optionally loadable Unix-like multi-user security extension (with, if loaded, file commands like

BACKUP In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "back up", w ...

, DELPURGE, MOVE,

TOUCH In physiology, the somatosensory system is the network of neural structures in the brain and body that produce the perception of touch (haptic perception), as well as temperature (thermoception), body position (proprioception), and pain. It is ...

, TREE,

UNDELETE Undeletion is a feature for restoring computer files which have been removed from a file system by file deletion. Deleted data can be recovered on many file systems, but not all file systems provide an undeletion feature. Recovering data wit ...

, XATTRIB, XCOPY, XDEL and XDIR supporting an otherwise disabled /U:name command line option to select specific users or groups, compatible with Multiuser DOS) and two new graphical user interfaces ( ViewMAX 3, a derivative of GEM, and " Star Trek", a true port of Apple's System 7.1 to run under the new DR DOS multitasker named "Vladivar"). When DR DOS eventually arrived in December 1993 (with localized versions released in March 1994), renamed Novell DOS 7 (a.k.a. "NWDOS"), and without these three components, it was a disappointment to some. It was larger and lacked some finishing touches, but was nevertheless seen as best DOS by many industry experts. In Germany, Novell DOS 7 was aggressively marketed with the slogan "" (''Don't trust any DOS below 7'') in the press and with free demo floppies in computer magazines. The campaign aimed at 20% of the DOS market and resulted in about 1.5 million copies sold until February 1994 and more than 3000 dealers interested to carry the product. Novell DOS 7 was available through various OEMs, a dedicated mail order shop and authorized dealers. A major functional addition was Novell's second attempt at a peer-to-peer networking system,

Personal NetWare NetWare Lite and Personal NetWare are a series of discontinued peer-to-peer local area networks developed by Novell for DOS- and Windows-based personal computers aimed at personal users and small businesses in the 1990s. NetWare Lite In 1991, N ...

(PNW). This was better than its predecessor, NetWare Lite (NWL), but it was incompatible with Microsoft's networking system, now growing popular with support in Windows for Workgroups, OS/2, and Windows NT. A considerable amount of manual configuration was needed to get both to co-exist on the same PC, and Personal NetWare never achieved much success. Since Novell DOS 7 implemented the DOSMGR API and internal data structures had been updated, its BDOS 7.2 kernel could report with a DOS version of 6.0 and OEM ID "IBM" without risking compatibility problems with Windows. Most tools would report this as "PC DOS 6.1", because IBM PC DOS 6.1 also reported as DOS 6.0 to applications. Novell DOS 7 introduced much advanced memory management including new support for DPMI (

DOS Protected Mode Interface In computing, the DOS Protected Mode Interface (DPMI) is a specification introduced in 1989 which allows a DOS program to run in protected mode, giving access to many features of the new PC processors of the time not available in real mode. It ...

) and DPMS ( DOS Protected Mode Services) as well as more flexible loadhigh options. It also introduced support for "true" pre-emptive multitasking of multiple DOS applications in virtual DOS machines (VDM), a component originally named MultiMAX. This was similar to Multiuser DOS, but now on the basis of a natively DOS compatible environment, similar to Windows 386 Enhanced Mode, but without a GUI. By default, the bundled TASKMGR would behave similar to the former DR DOS 6.0 TASKMAX. However, if

EMM386 EMM386 is the expanded memory manager of Microsoft's MS-DOS, IBM's PC DOS, Digital Research's DR-DOS, and Datalight's ROM-DOS which is used to create expanded memory using extended memory on Intel 80386 CPUs. There also is an EMM386.EXE availabl ...

was loaded with the option /MULTI, EMM386 would load a natively 32-bit 386 Protected Mode operating system core providing API support for pre-emptive multitasking, multi-threading, hardware virtualization and domain management of virtual DOS machines. This API could be used by DR DOS-aware applications. If TASKMGR was run later on, it would use this API to instance the current 16-bit DOS system environment, create virtual DOS machines and run applications in them instead of using its own Real Mode task-switcher support. The multitasker was compatible with Windows, so that tasks started before launching Windows could be seen as tasks under Windows as well. Novell DOS 7 and Personal NetWare 1.0 also shipped with NetWars, a network-enabled 3D

arcade game An arcade game or coin-op game is a coin-operated entertainment machine typically installed in public businesses such as restaurants, bars and amusement arcades. Most arcade games are presented as primarily games of skill and include arcade ...

. Novell DOS 7 and Personal NetWare required several bug-fix releases (D70xyy with x=language, yy=number) and were not completely stable when the next development occurred. With beta versions of Microsoft's " Chicago" (what would later become Windows 95) in sight, Novell wound down further development on Novell DOS 7 in September 1994 and stopped maintenance in January 1996 after more than 15 updates.

After Novell

When

approached Novell looking for a DOS operating system to bundle with their

distribution, Novell sold the product line off to Caldera on 23 July 1996, by which time it was of little commercial value to them. Between the Caldera-owned DR-DOS and competition from IBM's PC DOS 6.3, Microsoft moved to make it impossible to use or buy the subsequent Windows version,

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturi ...

, with any DOS product other than their own. Claimed by them to be a purely technical change, this was later to be the subject of a major lawsuit brought in

Salt Lake City Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the capital and most populous city of Utah, United States. It is the seat of Salt Lake County, the most populous county in Utah. With a population of 200,133 in 2020, t ...

by Caldera with the help of the

Canopy Group The Canopy Group is an American investment and property management firm founded by Ray Noorda in 1995 through the Noorda Family Trust. It is headquartered in Lindon, Utah. At various times it has consisted of, or been known as, Canopy Technolo ...

. Microsoft lawyers tried repeatedly to have the case dismissed but without success. Immediately after the completion of the pre-trial deposition stage (where the parties list the evidence they intend to present), there was an out-of-court settlement on 7 January 2000 for an undisclosed sum. This was revealed in November 2009 to be $280 million. In August 1996, the US-based Caldera, Inc. was approached by Roger A. Gross, one of the original DR-DOS engineers, with a proposal to restart DR-DOS development and to make Windows 95 run on DR-DOS which would help the court case. Following a meeting in September 1996 in Lindon, Utah, USA, between Gross, Ransom H. Love, Bryan Wayne Sparks and

Raymond John Noorda Raymond John "Ray" Noorda (19 June 1924 – 9 October 2006) was a U.S. computer businessman. He was CEO of Novell between 1982 and 1994. He also served as chairman of Novell until he was replaced in 1994. Early life Noorda was born in Ogd ...

, Gross was hired and tasked to set up a new subsidiary in the UK. On 10 September 1996, Caldera announced the coming release of OpenDOS (COD) and their intent to also release the source code to the system, and Caldera UK Ltd. was incorporated on 20 September 1996. Gross hired some of the original developers of the operating system from the Novell EDC as well as some new talents to continue work on the operating system in a converted barn at the periphery of

Andover Andover may refer to: Places Australia *Andover, Tasmania Canada * Andover Parish, New Brunswick * Perth-Andover, New Brunswick United Kingdom * Andover, Hampshire, England ** RAF Andover, a former Royal Air Force station United States * Andov ...

, Hampshire, UK, nearby the former Digital Research and Novell EDC. Besides other improvements and enhancements all over the system, a string of new key features were added subsequently over the course of the next two years, including a

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

stack (derived from

LAN WorkPlace for DOS NetWare Lite and Personal NetWare are a series of discontinued peer-to-peer local area networks developed by Novell for DOS- and Windows-based personal computers aimed at personal users and small businesses in the 1990s. NetWare Lite In 1991, N ...

NetWare Mobile NetWare Lite and Personal NetWare are a series of discontinued peer-to-peer local area networks developed by Novell for DOS- and Windows-based personal computers aimed at personal users and small businesses in the 1990s. NetWare Lite In 1991, N ...

), a graphical 32-bit DOS Protected Mode

HTML 3.2 The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript ...

web-browser

DR-WebSpyder DR-WebSpyder is a DOS web browser, mail client and operating system runtime environment that was developed by Caldera UK in 1997. It was based on the DR-DOS operating system and networking components from Novell as well as the Arachne web brow ...

(originally based on source code from the

Arachne Arachne (; from , cognate with Latin ) is the protagonist of a tale in Greek mythology known primarily from the version told by the Roman poet Ovid (43 BCE–17 CE), which is the earliest extant source for the story. In Book Six of his ...

web browser by Michal Polák) with LAN and modem dialup, a POSIX

Pthreads POSIX Threads, commonly known as pthreads, is an execution model that exists independently from a language, as well as a parallel execution model. It allows a program to control multiple different flows of work that overlap in time. Each flow o ...

extension to the multi-tasker by Andy T. Wightman, long filename (LONGNAME) support by Edward N. Hill, Jr., as well as LBA and FAT32 support (DRFAT32) by Matthias R. Paul. Gross also hired Andrew Schulman (who had been, with Geoff Chappell, instrumental in identifying the

in 1992) to work as a consultant and, in Andover, assist Paul in his work on "WinGlue", a secret project to create a version of DR-DOS compatible with Windows 95, 98 and 98 SE and replace its MS-DOS 7.xx component. This was demonstrated at

CeBIT CeBIT was the largest and most internationally representative computer expo. The trade fair was held each year on the Hanover fairground, the world's largest fairground, in Hanover, Germany. In its day, it was considered a barometer of c ...

in March 1998, and later, in a small team, developed into "WinBolt", both versions of DR-DOS, which remained unreleased , but played an important role in the

court case A legal case is in a general sense a dispute between opposing parties which may be resolved by a court, or by some equivalent legal process. A legal case is typically based on either civil or criminal law. In most legal cases there are one or mo ...

. Caldera UK officially released Caldera OpenDOS 7.01 on 3 February 1997, but this version was just Novell DOS 7 update 10 (as of December 1994) compiled only with the necessary adaptations to incorporate the new name in display messages as well as in

environment variable An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP en ...

s and file names. It was missing a year's worth of patches which had been developed for the Novell DOS updates 11 (January 1995) to 15.2 (January 1996). This was due to parts of the Novell DOS sources having been lost at Novell meanwhile. Consequently, this version still reported an internal BDOS version of 7.2, identical to Novell DOS 7. The new suite also lacked the SETFIFO command, which had been added with one of the Novell DOS updates, as well as Fifth Generation's Search&Destroy virus scanner and FastBack Plus 2.0 utility, which previously came bundled with Novell DOS. Instead it came bundled with a newer version of PNUNPACK and brought a much advanced version of NetWars. Parts of OpenDOS 7.01 were released as open source in form of the M.R.S. kit (for Machine Readable Sources) in May 1997, but with license terms mostly incompatible with existing

open-source license An open-source license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified and/or shared under defined terms and conditions. This allows end users and commercial compan ...

s. The source was then

closed Closed may refer to: Mathematics * Closure (mathematics), a set, along with operations, for which applying those operations on members always results in a member of the set * Closed set, a set which contains all its limit points * Closed interval, ...

again as Gross felt this would undermine the commercial aspirations of the system. After beta releases in September and November 1997, the next official release came in December 1997, with the name changed to Caldera DR-OpenDOS 7.02, soon followed by a further release in March 1998, when the DR-DOS name returned as Caldera DR-DOS 7.02, now for the first time written with a hyphen. Version 7.02 (now reporting itself as BDOS 7.3) incorporated improved BIOS and BDOS issues, developed by Paul, adding many new boot and configuration options, integrating many compatibility enhancements, bug-fixes and optimizations for size and speed, and re-implementing all fixes of the missing Novell DOS updates. The BIOS improved the coexistence of DR-DOS with

Windows 9x Windows 9x is a generic term referring to a series of Microsoft Windows computer operating systems produced from 1995 to 2000, which were based on the Windows 95 kernel and its underlying foundation of MS-DOS, both of which were updated in subs ...

and its support for third-party disk compression drivers such as Microsoft's

DriveSpace DriveSpace (initially known as DoubleSpace) is a disk compression utility supplied with MS-DOS starting from version 6.0 in 1993 and ending in 2000 with the release of Windows Me. The purpose of DriveSpace is to increase the amount of data the ...

. It introduced a diagnostics mode (activated by Scroll Lock), integrated debugger support (with DEBUG=ON and a debugger loaded before or from within CONFIG.SYS) and more flexible CONFIG.SYS tracing capabilities via the /// hotkeys and the TRACE and

TIMEOUT Time-out, Time Out, or timeout may refer to: Time * Time-out (sport), in various sports, a break in play, called by a team * Television timeout, a break in sporting action so that a commercial break may be taken * Timeout (computing), an enginee ...

commands, thereby also improving the integration of alternative command line shells such as

4DOS 4DOS is a command-line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in Microsoft DOS and Windows. It was written by Rex C. Conn and Tom Rawson and first released in 1989. Compared to the default, ...

. Together with LOADER, SYS /DR:ext and the

CHAIN A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A ...

directive, it brought enhanced multi-configuration support for DR/D/CONFIG.ext files and came with enhancements to the BASIC-like CONFIG.SYS language for more powerful boot menus, convenient user interaction and programmatical acting upon conditions ( CPU386), return codes and error levels (

ERROR An error (from the Latin ''error'', meaning "wandering") is an action which is inaccurate or incorrect. In some usages, an error is synonymous with a mistake. The etymology derives from the Latin term 'errare', meaning 'to stray'. In statistics ...

, ONERROR). It also allowed to change the SCROLLOCK, CAPSLOCK,

INSERT Insert may refer to: *Insert (advertising) *Insert (composites) *Insert (effects processing) *Insert (filmmaking) *Insert key on a computer keyboard, used to switch between insert mode and overtype mode *Insert (molecular biology) *Insert (SQL) *Fi ...

and VERIFY settings as well as the SWITCHAR, YESCHAR, NOCHAR and RESUMECHAR characters. Various behavioural details could be controlled with new parameters /Q (Quiet), /L (Lowercase), /Y (Yes) and /S (Switch) for SWITCHES. Further, it provided optional support for a LPT4: device and allowed to configure the built-in COMx: and LPTx: devices as well as to change the PRN: and AUX: defaults. The handling of environment variables in CONFIG.SYS was improved and new load-high facilities included such as the HIFILES/ FILESHIGH and HIFCBS/ FCBSHIGH options to relocate file handles and FCB structures into UMBs, which typically gave between 1 and 4 KB (and up to 15 KB) more free conventional memory compared to previous versions, or the HISHELL/ SHELLHIGH SIZE directive to control the pre-allocation of HMA memory for

COMMAND.COM COMMAND.COM is the default command-line interpreter for MS-DOS, Windows 95, Windows 98 and Windows Me. In the case of DOS, it is the default user interface as well. It has an additional role as the usual first program run after boot (init proc ...

, which helped to avoid memory fragmentation and thereby typically gave between 5 and 8 KB more continuous HMA memory for HMA-capable third-party drivers to work with in conjunction with third-party command line shells, which could not load into the HMA as COMMAND.COM with its /MH option. At a reduced memory footprint version 7.02 also brought an enhanced NLS 4.xx sub-system by Paul to allow multiple, distributed and possibly user-configured COUNTRY.SYS files to be used by the system at the same time in a hierarchical model. This also gave dynamic parser support for MS-DOS/PC DOS COUNTRY.SYS file formats in addition to DR-DOS' own COUNTRY.SYS formats, and it introduced support for the ISO 8601 international date format (including automatic detection) and the then-new Euro currency. Some DR-DOS files such as IBMBIO.COM, IBMDOS.COM and COUNTRY.SYS carried misleading file extensions for compatibility reasons; with DR-DOS 7.02 they were enhanced to incorporate a fat binary-style safety feature devised by Paul so that they would exit gracefully when called inappropriately. DR-DOS 7.02 was fully

Year 2000 File:2000 Events Collage.png, From left, clockwise: Protests against Bush v. Gore after the 2000 United States presidential election; Heads of state meet for the Millennium Summit; The International Space Station in its infant form as seen from ST ...

compliant and provided special support to work with buggy system BIOSes. It also came with an updated

FDISK In computing, the fdisk command-line utility provides disk-partitioning functions, preparatory to defining file systems. fdisk features in the DOS, DR FlexOS, IBM OS/2, and Microsoft Windows operating systems, and in certain ports of ...

, which could partition and format FAT32 volumes (but not yet work with LBA). The sources of the Novell patches for the external tools and drivers had meanwhile been found in Germany and could thus be retro-fitted into the system as well, so that DR-DOS 7.02 finally not only caught up with Novell DOS 7, but was a true step forward. The release was followed by various updates in June, August and September 1998. The updated internal BDOS version number introduced a new problem: some legacy third-party applications with special support for Novell DOS, which were no longer being updated, stopped working. SETVER already allowed Novell DOS to disguise itself as DOS versions by file name and globally and, specifying a magic sub-version of 255, it would even disable its own internal BDOS version check in order to cope with programs specifically probing for "DR-DOS". The modified kernel and SETVER driver by Paul would, in an hierarchical model, also support load paths in order to distinguish between multiple executables of the same file name, and it introduced an extended mode, in which SETVER could not only fake DOS versions, but also BDOS kernel versions. Sub-versions of 128 to 255 would be reported as DOS sub-versions 0 to 127 to applications, but with the BDOS version check disabled, while sub-versions 100 to 127 could be used to fake different BDOS versions, whereas the DOS revision number (typically set to 0 in a static, pre-boot patchable data structure) would be taken as the reported sub-version instead, so that SETVER /G /X 6.114 would allow versions of DR-DOS since 7.02 to still report themselves as a "DOS 6.0" and with a faked BDOS version 7.2 (114 decimal = 72 hexadecimal), thereby masquerading as Novell DOS 7 / OpenDOS 7.01. While otherwise beneficial, the new HIFILES triggered a compatibility problem in the DOS-UP feature of the third-party memory manager QEMM 8, which was hard-wired to expect a chunk of five handle structures in conventional memory under DR-DOS (as with previous versions up to 7.01), whereas version 7.02 by design left eight handles in low memory when loading high files in order to maintain full compatibility with older versions of Windows 3.xx. Compatibility with Windows for Workgroups 3.11 had not been affected by this. A maintenance fix was devised to patch a single byte in IBMBIO.COM in order to switch the behaviour and optionally re-invoke the old chunking. This freed some 150 bytes of conventional memory and enabled full compatibility with DOS-UP, but at the same time broke compatibility with older versions of Windows 3.xx when using the HIFILES feature, and vice versa. The patch named IBMBIO85.SCR continued to work with newer versions of DR-DOS. In August 1998 the US-based Caldera, Inc. created two new subsidiaries, Caldera Systems, Inc. for the Linux business, and

Caldera Thin Clients Lineo was a thin client and embedded systems company spun out of Caldera Thin Clients by 20 July 1999. History Caldera Thin Clients, Inc., had been created as a subsidiary of Caldera, Inc., on 2 September 1998. Caldera Thin Clients' original ...

, Inc. for the embedded and thin-client market. Another version, DR-DOS 7.03 (still with BDOS 7.3 and reporting itself to applications as "PC DOS 6.0" for compatibility purposes), was pre-released at Christmas 1998 and then officially released on 6 January 1999 by Caldera UK. It came with significantly improved memory managers (in particular enhanced DPMI support in conjunction with the multitasker) and other enhancements, such as added DEVLOAD and DRMOUSE utilities, but a changed OEM label in the boot sector of volumes formatted under DR-DOS could also cause problems under other operating systems (which can be circumvented by NOVOLTRK). DR-DOS 7.03 would become the last version of DR-DOS also tailored for desktop use. Caldera, Inc. wanted to relocate the DR-DOS business into the US and closed the highly successful UK operation in February 1999 after Gross resigned and set up iCentrix to develop the MarioNet split web browser. Development was then moved into the US (which never worked out due to a total lack of expertise in this field at Caldera US), and the DR-DOS line fell to its branch company, Caldera Thin Clients, which was renamed

Lineo Lineo was a thin client and embedded systems company spun out of Caldera Thin Clients by 20 July 1999. History Caldera Thin Clients, Inc., had been created as a subsidiary of Caldera, Inc., on 2 September 1998. Caldera Thin Clients' origin ...

, Inc. on 20 July 1999. DR-WebSpyder was renamed Embrowser and was said to be ported to Linux. Lineo re-released DR-DOS 7.03 in June and September 1999, still branded as "Caldera DR-DOS" and without any changes, but otherwise focussed on Linux for embedded systems, based on a stripped-down version of OpenLinux named Embedix. Among the latest and independently developed versions of DR-DOS were OEM DR-DOS 7.04 (as of 19 August 1999) and 7.05 (as of 30 November 1999), still branded as "Caldera DR-DOS". These were variants of the system consisting only of the kernel and command shell. With a specialized native implementation of FAT32 and large hard disk support they could be found bundled with

Ontrack KiwiRail Holdings Limited is a New Zealand state-owned enterprise responsible for rail operations in New Zealand, and operates inter-island ferries. Trading as KiwiRail and headquartered in Wellington, New Zealand, KiwiRail is the largest rail ...

's Easy Recovery 5 in 2000, replacing the dynamically-loadable DRFAT32 redirector driver, which still came with Easy Recovery 4. They were also used for Seagate Technology's SeaTools and the CD imaging software

Nero Burning ROM Nero Burning ROM, commonly called Nero, is an optical disc authoring program from Nero AG. The software is part of the Nero Multimedia Suite but is also available as a stand-alone product. It is used for burning and copying optical discs such as ...

. While still reporting a BDOS 7.3 internally, these were the first versions to report themselves as "PC DOS 7.10" to applications in order to indicate integrated FAT32 support. Designed to be mostly backwards-compatible, the DR-DOS 7.04/7.05 IBMBIO.COM could be combined with the DR-DOS 7.03 IBMDOS.COM in order to give the desktop-approved DR-DOS 7.03 kernel LBA capabilities and work with drives larger than 8 GB. For specific OEM requirements, DR-DOS 7.06 (as of 14 December 1999) by Wightman combined the kernel files into a single binary executable, so that, similar to IO.SYS of

Windows 98 Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released t ...

, it could be booted by MS-DOS 7.10 boot sectors (but no longer by DR-DOS boot sectors). DR-DOS 7.07 (with BDOS 7.4/7.7) by Paul introduced new bootstrap loaders and updated disk tools in order to combine support for

CHS CHS may refer to: Businesses and organizations Healthcare bodies * Canadian Hemophilia Society, a non-profit * Center for Healthy Sex, a therapy center in Los Angeles, U.S. * Community Health Systems, an American hospital network Other businesse ...

and LBA disk access, the FAT12, FAT16 and FAT32 file systems, and the differing bootstrapping conventions of DR-DOS, PC DOS, MS-DOS, Windows,

and LOADER into a single

NEWLDR A master boot record (MBR) is a special type of boot sector at the very beginning of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The concept of M ...

MBR and boot sector, so that the code would continue to load any version of DR-DOS down to 3.31 (and since DR-DOS 7.04 also with FAT32 support), but could also be used to launch the PC DOS or MS-DOS system files, including those of Windows 9x and PC DOS 7.10. At the same time the kernel could not only be booted by the new sectors, but also by any previously DR-DOS formatted disks, as well as off disks with existing PC DOS or MS-DOS boot sectors and a variety of other boot-loaders, thereby easing the coexistence and setup of multi-boot scenarios in conjunction with other operating systems.

Later versions

In 2002, Lineo was bought out, and some of Lineo's former managers purchased the name and formed a new company, DRDOS, Inc. dba

DeviceLogics DeviceLogics was a company in Lindon, Utah, USA, founded in November 2002. Originally doing business mostly under the DeviceLogics name, the company was incorporated as DRDOS, Inc. for legal reasons. The DeviceLogics name was later dropped. Br ...

L.L.C. They have continued to sell DR-DOS for use in embedded systems. DR-DOS 8.0 was released on 30 March 2004 featuring FAT32 and large disk support, the ability to boot from ROM or Flash, multitasking and a DPMI memory manager. This version was based on the kernel from version 7.03. The company later released DR-DOS 8.1 (with better FAT32 support) in autumn 2005. This version was instead based on OpenDOS 7.01.xx. DR-DOS 8.1 was withdrawn for GPL violations (see

Controversies Controversy is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin ''controversia'', as a composite of ''controversus'' – "turned in an opposite d ...

). Aside from selling copies of the operating system, the DRDOS, Inc. website lists a buyout option for DR-DOS; the asking price is . The OpenDOS 7.01 source code was a base for ''The DR-DOS/OpenDOS Enhancement Project'', set up in July 2002 in an attempt to bring the functionality of DR-DOS up to parity with modern PC non-Windows operating systems. The project's added native support for large disks ( LBA) and the FAT32 file system, and several other enhancements, including improved memory management and support for the new FAT32+ file system extension which allows files of up to 256 GB in size on normal

FAT In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

partitions. DR-DOS 7.01.08 was released on 21 July 2011.

Controversies

In October 2005, it was discovered that DR-DOS 8.1 included several utilities from FreeDOS as well as other sources, and that the kernel was an outdated version of the Enhanced DR-DOS kernel. DR DOS, Inc. failed to comply with the GNU General Public License (GPL) by not crediting the FreeDOS utilities to their authors and including the source code. After complaints from FreeDOS developers (including the suggestion to provide the source code, and hence comply with the GPL), DR DOS, Inc. instead withdrew version 8.1, and also the unaffected 8.0, from its website.

Commands

APPEND, ASSIGN, BATCH, DBG, DELQ, ERA, ERAQ, MORE and SUBST have been among the internal commands supported since DR DOS 3.31. DR DOS 5.0 removed BATCH and added HILOAD. GOSUB, IDLE, RETURN and SWITCH were added as internal commands with DR DOS 6.0. ASSIGN and SUBST were changed to become external commands with DR DOS 6.0. ECHOERR and PAUSEERR existed as internal commands in DR DOS 6.0 (and in Multiuser DOS), but were not normally enabled. MORE remained an internal command up to including PalmDOS, but was changed to an external command with Novell DOS 7. DBG was removed with Novell DOS 7, LOADHIGH, LH and

TRUENAME A true name is a name of a thing or being that expresses, or is somehow identical to, its true nature. The notion that language, or some specific sacred language, refers to things by their true names has been central to philosophical study as wel ...

were added as internal commands. APPEND was still an internal command in DR DOS 6.0, but was changed to an external command with Novell DOS 7.

Internal commands

The following list of

internal Internal may refer to: *Internality as a concept in behavioural economics *Neijia, internal styles of Chinese martial arts *Neigong or "internal skills", a type of exercise in meditation associated with Daoism *''Internal (album)'' by Safia, 2016 ...

commands is supported by DR DOS 6.0: *

APPEND In computer programming, append is the operation for concatenating linked lists or arrays in some high-level programming languages. Lisp Append originates in the Lisp programming language. The append procedure takes zero or more (linked) lists a ...

BREAK Break or Breaks or The Break may refer to: Time off from duties * Recess (break), time in which a group of people is temporarily dismissed from its duties * Break (work), time off during a shift/recess ** Coffee break, a short mid-morning rest ...

* CD * CHCP * CHDIR * CLS * COPY * CTTY *

DATE Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity *Dating, a form of courtship involving social activity, with the aim of assessing a potential partner **Group dating * Play date, a ...

* DBG *

DEL Del, or nabla, is an operator used in mathematics (particularly in vector calculus) as a vector differential operator, usually represented by the nabla symbol ∇. When applied to a function defined on a one-dimensional domain, it denotes t ...

* DELQ * DIR * ERA * ERAQ * ERASE *

EXIT Exit(s) may refer to: Architecture and engineering * Door * Portal (architecture), an opening in the walls of a structure * Emergency exit * Overwing exit, a type of emergency exit on an airplane * Exit ramp, a feature of a road interchange A ...

HILOAD In computing, (abbreviated ) is an internal DOS command in COMMAND.COM that is used to load a program into the upper memory area (UMA) instead of conventional memory. The command was introduced with MS-DOS 5.0 / PC DOS 5.0 in 1991, copy ...

IDLE Idle generally refers to idleness, a lack of motion or energy. Idle or ''idling'', may also refer to: Technology * Idle (engine), engine running without load ** Idle speed * Idle (CPU), CPU non-utilisation or low-priority mode ** Synchronous ...

* MD * MKDIR *

MORE More or Mores may refer to: Computing * MORE (application), outline software for Mac OS * more (command), a shell command * MORE protocol, a routing protocol * Missouri Research and Education Network Music Albums * ''More!'' (album), by Booka ...

PATH A path is a route for physical travel – see Trail. Path or PATH may also refer to: Physical paths of different types * Bicycle path * Bridle path, used by people on horseback * Course (navigation), the intended path of a vehicle * Desire p ...

* PROMPT * RD * REN * RENAME * RMDIR *

SET Set, The Set, SET or SETS may refer to: Science, technology, and mathematics Mathematics *Set (mathematics), a collection of elements *Category of sets, the category whose objects and morphisms are sets and total functions, respectively Electro ...

* TIME * TYPE * VER * VERIFY * VOL

Batch processing subcommands

Batch processing subcommands of DR DOS 6.0 include: * ? *

CALL Call or Calls may refer to: Arts, entertainment, and media Games * Call, a type of betting in poker * Call, in the game of contract bridge, a bid, pass, double, or redouble in the bidding stage Music and dance * Call (band), from Lahore, Pak ...

* ECHO * ECHOERR * FOR *

GOSUB BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College i ...

* GOTO * IF * OR * PAUSE * PAUSEERR *

REM Rem or REM may refer to: Music * R.E.M., an American rock band * ''R.E.M.'' (EP), by Green * "R.E.M." (song), by Ariana Grande Organizations * La République En Marche!, a French centrist political party * Reichserziehungsministerium, in Nazi ...

RETURN Return may refer to: In business, economics, and finance * Return on investment (ROI), the financial gain after an expense. * Rate of return, the financial term for the profit or loss derived from an investment * Tax return, a blank document or t ...

* SHIFT *

SWITCH In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of ...

External commands

DR DOS 6.0 supports the following external commands: * ASSIGN * ATTRIB *

* CHKDSK *

COMMAND Command may refer to: Computing * Command (computing), a statement in a computer language * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on Apple Macintosh computer keyboards * ...

COMP Comp, COMP or Comps may refer to: Places In England: * Comp, Kent In France: * Comps, Drôme * Comps, Gard * Comps, Gironde * Comps-la-Grand-Ville * Comps-sur-Artuby Arts, entertainment, and media ;Music *Accompaniment, especially in jazz ...

* CURSOR * DELPURGE * DELWATCH * DISKCOMP *

DISKCOPY In computing, diskcopy is a command used on a number of operating systems for copying the complete contents of a diskette to another diskette. Implementations The command is available in MS-DOS, IBM PC DOS, DR FlexOS, IBM/Toshiba 4690 OS, M ...

* DISKMAP * DISKOPT * DOSBOOK * EDITOR *

EXE2BIN The command-line tool exe2bin is a post-compilation utility program available on MS-DOS and other operating systems. Overview Early compilers and linkers for the MS-DOS platform could not produce a COM file executable directly. Instead, the co ...

* FASTOPEN * FC *

* FILELINK * FIND * FORMAT * GRAFTABL *

GRAPHICS Graphics () are visual perception, visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustration, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of dat ...

JOIN Join may refer to: * Join (law), to include additional counts or additional defendants on an indictment *In mathematics: ** Join (mathematics), a least upper bound of sets orders in lattice theory ** Join (topology), an operation combining two topo ...

KEYB KEYB (107.9 FM, "108 Key FM") is a radio station licensed to Altus, Oklahoma Altus () is a city in and the county seat of Jackson County, Oklahoma, United States. The population was 19,813 at the 2010 census, a loss of 7.7 percent compared ...

* LABEL * LOCK * MEM * MEMMAX *

MODE Mode ( la, modus meaning "manner, tune, measure, due measure, rhythm, melody") may refer to: Arts and entertainment * '' MO''D''E (magazine)'', a defunct U.S. women's fashion magazine * ''Mode'' magazine, a fictional fashion magazine which is ...

* MOVE * NLSFUNC * PASSWORD * PRINT * RECOVER * RENDIR * REPLACE * RESTORE * SCRIPT * SETUP * SHARE * SID * SORT * SSTOR *

SUBST In computing, SUBST is a command on the DOS, IBM OS/2, Microsoft Windows and ReactOS operating systems used for substituting paths on physical and logical drives as virtual drives. Overview In MS-DOS, the SUBST command was added with the rel ...

* SUPERPCK * SYS * TASKMAX *

* TREE *

* UNFORMAT * UNINSTAL * XCOPY * XDEL * XDIR

Notes

References

External links

Official website
(archived snapshot as of 2018-07-05)
Enhanced DR-DOS/OpenDOS Project

DR-DOS 7 online manual

DR-DOS Wiki
{{DEFAULTSORT:Dr-Dos Caldera (company) operating systems Novell Digital Research operating systems 1988 software Disk operating systems DOS variants Embedded operating systems Floppy disk-based operating systems Microcomputer software Microsoft criticisms and controversies Operating system distributions bootable from read-only media Proprietary operating systems ROM-based operating systems Assembly language software