.OS familyWorking stateDiscontinuedSource modelMixed; primarily, some versionsInitial release28 May 1988; 31 years ago ( 1988-05-28)7.01.08 / 21 July 2011; 8 years ago ( 2011-07-21), older versions also in German, French, Italian, Spanish, JapanesePlatformstypeDefaultOfficial website(dead since summer 2018)DR-DOS ( DR DOS, without hyphen up to and including version 6.0) is an of the family, written for -. It was originally developed by 's and derived from 6.0, which was an advanced successor of. As ownership changed, various later versions were produced with names including. Contents.History Origins in CP/M 's original for the 8-bit - and -based systems spawned numerous spin-off versions, most notably for the / family of processors. Although CP/M had dominated the market, and was shipped with the vast majority of non-proprietary-architecture personal computers, the in 1981 brought the beginning of what was eventually to be a massive change.originally approached Digital Research, seeking an version of CP/M. However, there were disagreements over the contract, and IBM withdrew.
Instead, a deal was struck with, who purchased another operating system, from (SCP). This became Microsoft. 86-DOS' command structure and application programming interface imitated that of CP/M. Digital Research threatened legal action, claiming PC DOS/MS-DOS to be too similar to CP/M. IBM settled by agreeing to sell Digital Research's x86 version of CP/M, alongside PC DOS. However, PC DOS sold for 40, while CP/M-86 had a US$240 price tag.
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Further information: 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.) This introduced, a -based 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 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 (for the DOS-BIOS) and (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'. Front and rear views of the book-size diskless workstation, bundled with DR DOS 5.0, based on an processor and produced by Taiwan's circa 1991.DR DOS 5.0 was the first DOS to include load-high capabilities. The kernel and data structures such as disk buffers could be in the (HMA), the first 64 KB of which are accessible in. This freed up the equivalent amount of critical 'base' or, the first 640 KB of the PC's RAM – the area in which all DOS applications run.Additionally, on machines, DR DOS's EMS memory manager allowed the operating system to load DOS device drivers into upper memory blocks, further freeing base memory.DR DOS 5.0 was the first DOS to integrate such functionality into the base OS (loading device drivers into was already possible using third-party software like ). 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 '). Therefore, DR DOS 5.0's new MEMMAX -L command worked around this by pre-allocating a 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, 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 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 facility between applications.Via the task-switcher API, graphical user interfaces such as or 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.Since December 1991 a pre-release version of Windows 3.1 was designed to return a non-fatal error message if it detected a non-Microsoft DOS.
This check came to be known as the. 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, released DR DOS 6.0/V, a Japanese compatible version of DR DOS 6.0. A Korean version appears to have been available as well.Patching to counter Microsoft It was a simple matter for Digital Research to patch DR DOS 6.0 to circumvent the 'authenticity check' in the beta by rearranging the order to 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.
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 / market.PalmDOS was the first operating system in the family to sport 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 imposed a limit on the depth of 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. A typical command line in Novell DOS 7Novell DOS was Corporation's name for DR DOS during the period when Novell sold DR DOS, after the acquisition of in 1991.
Regarding features and performance, it was typically at least one release ahead of. In 1993, and were trumped by Novell's DOS 7.Novell CEO 's strategy included 'major trimming', selling off products like transactional database and killing others such as Novell DOS and 's multimedia Main Street children's titles. Novell licensed technology from for use in Novell DOS and its,. Novell sold the product line off to on 23 July 1996, after it approached Novell looking for a DOS operating system to bundle with its distribution,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.