Jump to content

EZ-DOS

From Alfawiki
Adapted from the English Wikipedia article EZ-DOS, available under CC BY-SA 4.0Updated 9 August 202546 sources
DR-DOS
Company typeSoftware
IndustryComputer software
PredecessorConcurrent PC DOS 6.0
Founded1988; 38 years ago (1988)
FounderGary A. Kildall
Headquarters
Pacific Grove, California (originally)
,
United States
ProductsDisk operating system for IBM PC-compatible computers

DR-DOS (displayed as DR DOS without a hyphen through version 6.0) is a disk operating system designed for IBM PC-compatible machines, originally created by Digital Research, Inc., led by Gary A. Kildall. It evolved from Concurrent PC DOS 6.0, itself an advanced iteration of CP/M-86. Launched in 1988, DR-DOS was the first DOS variant to strive for compatibility with both IBM PC DOS and MS-DOS.

The first edition was version 3.31, matching the MS-DOS versioning scheme of that period. The 1990 release of DR DOS 5.0 marked its debut as a retail product and garnered significant praise, establishing DR-DOS as a primary rival to Microsoft’s MS-DOS, which responded with its own MS-DOS 5.0 more than a year later. DR-DOS also introduced ViewMAX, a graphical user interface layer. Version 6.0 was released in 1991.

Following Novell's acquisition of Digital Research, the operating system was renamed Novell DOS 7.0 in 1994. Later ownership by Caldera resulted in further updates, some partially open-source under the Caldera brand and briefly known as OpenDOS. The final desktop version, Caldera DR-DOS 7.03, was issued in 1999 before the focus shifted toward embedded system applications under Caldera and subsequently DeviceLogics.

Roots in CP/M

Digital Research initially developed CP/M, an operating system for 8-bit processors such as the Intel 8080 and Z80, which gave rise to derivatives including CP/M-86 for the Intel 8086/8088 CPUs. CP/M had dominated the market since the mid-1970s and was widely bundled with non-proprietary personal computers. However, the introduction of the IBM PC in 1981 significantly altered the landscape.

In 1980, IBM approached Digital Research to develop an x86 version of CP/M but withdrew following disagreements over contract terms. IBM then collaborated with Microsoft, who had acquired 86-DOS from Seattle Computer Products (SCP). This product evolved into Microsoft’s MS-DOS and IBM’s PC DOS. The command structure of 86-DOS closely resembled that of CP/M 2.2. Digital Research threatened legal action, alleging that PC DOS/MS-DOS copied CP/M too closely. By early 1982, IBM agreed to market Digital Research’s CP/M-86 alongside PC DOS; however, while PC DOS was priced affordably at , CP/M-86 carried a $240 price tag, limiting its market success despite initial software advantages.

Digital Research faced challenges competing against the dominant Microsoft-IBM software alliance. They modified Concurrent CP/M-86 to support MS-DOS/PC DOS applications and publicly released it in December 1983, shipping as Concurrent DOS 3.1 to hardware manufacturers in March 1984. Although Concurrent DOS later evolved into products like Multiuser DOS and REAL/32, it remained expensive and less suitable for single-user desktop environments.

To better address market demands, Digital Research initiated two projects:

In 1985, they introduced DOS Plus versions 1.0 through 2.1, a simplified single-user offshoot of Concurrent DOS variants that offered multitasking capabilities alongside limited DOS compatibility. Following this, they developed DR DOS in 1988—a native DOS system focused on improved compatibility with DOS applications and enhanced competitiveness.

While Digital Research’s headquarters were located in Pacific Grove and later Monterey, California, substantial development work on DOS Plus began at their Newbury, Berkshire (UK) facility within Digital Research Europe’s OEM Support Group starting in 1983. From 1986 onward, most operating system development—including Concurrent DOS 386/XM, Multiuser DOS, DR DOS, and PalmDOS—was carried out at the European Development Centre in Hungerford, Berkshire, supplemented by efforts from Digital Research GmbH based in Munich.

Initial DR DOS Release

In 1987, responding to demands from original equipment manufacturers, Digital Research initiated the development of a new DOS operating system aimed at overcoming limitations found in MS-DOS. A strategic partnership with Kazuhiko "Kay" Nishi of ASCII Corporation facilitated access to the Japanese OEM market. The inaugural release of DR DOS occurred on May 28, 1988.

The versioning scheme corresponded to MS-DOS feature sets; the first public edition was labeled DR DOS 3.31, aligning with Compaq’s MS-DOS 3.31 and supporting large disks through FAT16B ("BIGDOS"). This release identified itself as "IBM PC DOS 3.31," internally running BDOS kernel version 6.0, which was adapted from Concurrent DOS 6.0 but had multitasking, multiuser capabilities, and CP/M API support removed. The system replaced the original XIOS with an IBM-compatible DOS-BIOS. Core system files included DRBIOS.SYS and DRBDOS.SYS, utilizing the disk OEM label "DIGITAL␠".

DR DOS introduced advanced command-line utilities featuring integrated help, detailed error messages, command history and editing via the HISTORY directive, along with built-in password protection for files and directories. Licensing costs were lower than MS-DOS, and it was designed for ROM integration from the outset; this ROMed variant was known as ROS (ROM Operating System). Interest from PC manufacturers prompted multiple subsequent updates.

Unlike MS-DOS, which was distributed exclusively through OEM channels, DR DOS became available to end-users via retail starting with the 3.4x series, enhancing its market penetration.

Documented versions include DR DOS 3.31 (BDOS 6.0, June 1988, OEM only), 3.32 (August 1988), 3.33 (September 1988), 3.34 (OEM exclusive), 3.35 (October 1988), 3.40 (January 1989), and 3.41 (BDOS 6.3, June 1989, available both OEM and retail). Various editions were produced to support different hardware platforms. While most OEMs retained the DR DOS branding, 2001 Sales, Inc., marketed it under the name EZ-DOS 3.41 (also referred to as EZ-DOS 4.1).

DR DOS Version 5.0

Released in May 1990 under the codename "Leopard," DR DOS 5.0 maintained backward compatibility by identifying itself as "PC DOS 3.31" while internally running a single-user BDOS kernel version 6.4 (the version number jumped from 3 to avoid association with the poorly received MS-DOS 4.0). This iteration introduced ViewMAX, a GEM-based graphical file management shell accompanied by the tagline "Digital Research - We make computers work." Additionally, DR DOS 5.0 debuted the patented BatteryMAX power management system and bundled utilities such as disk caching software (DRCACHE), a remote file transfer utility (FILELINK), a cursor customization tool (CURSOR), and an enhanced memory manager named MemoryMAX. System files were renamed to IBMBIO.COM and IBMDOS.COM, featuring an improved boot loader that supported flexible disk storage configurations. The OEM boot label was updated to "IBM␠␠3.3".

DR DOS 5.0 was a pioneer in implementing load-high functionality by relocating its kernel and essential data structures like disk buffers into the High Memory Area (HMA)—the initial 64 KB of extended memory accessible in real mode—thereby freeing valuable conventional memory space (the first 640 KB of RAM where DOS applications operate).

On Intel 80386 processors, its EMS memory manager facilitated loading DOS device drivers into upper memory blocks, further conserving conventional memory resources. This integration was unique at that time and outperformed third-party solutions such as QEMM. As a result, DR DOS 5.0 offered substantially more free conventional memory than competing systems, allowing complete loading of mouse drivers, multimedia components, and network drivers while maintaining up to approximately 620 KB of free conventional memory—significantly more than the typical 300–400 KB available on standard MS-DOS/PC DOS setups. With MEMMAX +V enabled, conventional memory could be further expanded by utilizing unused graphics adapter memory.

This abundance of free conventional memory caused compatibility problems with certain legacy applications that used address wrapping techniques failing when loaded unexpectedly low in memory areas. To resolve this issue, DR DOS 5.0 introduced the MEMMAX -L option to reserve a block of low memory space so that such programs would load above it—albeit at the expense of reduced usable conventional memory overall. By default, MEMMAX was configured with +L enabled to maximize available application memory capacity.


DR DOS 6.0 / Microsoft Rivalry

Confronted with formidable competition, Microsoft revealed MS-DOS 5.0 in May 1990, officially launching it in June 1991. This version incorporated enhanced capabilities, particularly in memory management, mirroring features found in DR DOS.

In September 1991, Digital Research introduced DR DOS 6.0, codenamed "Buxton." Internally designated as BDOS version 6.7 but identifying itself as "IBM PC DOS 3.31" for compatibility purposes, this release included SuperStor disk compression to optimize hard disk utilization. Additionally, it incorporated file deletion tracking and undelete functionality developed by Roger A. Gross.

A significant enhancement in DR DOS 6.0 was TASKMAX, a task-switching utility that adhered to the standard task-switching API, enabling concurrent execution of multiple programs. Unlike Digital Research's Multiuser DOS, which employed pre-emptive multitasking, TASKMAX suspended background tasks until they were brought to the foreground and utilized XMS memory on systems with 286 processors or higher. It also provided limited Copy & Paste capabilities between applications and allowed graphical user interfaces such as ViewMAX or PC/GEOS to replace its default text-based menu for managing tasks.

Microsoft countered by releasing MS-DOS 6.0, incorporating many features similar to those offered by DR DOS.

In December 1991, the Windows 3.1 beta introduced the AARD code, designed to detect non-Microsoft DOS variants and display non-critical error messages. Digital Research promptly updated DR DOS 6.0 to circumvent this detection by modifying internal memory tables without affecting functionality, issuing the so-called "business update" within six weeks of Windows 3.1's debut. With detection disabled, Windows operated seamlessly on both DR DOS and Novell DOS systems.

By July 1992, Digital Research Japan released DR DOS 6.0/V, a version compatible with Japanese DOS/V standards; a Korean adaptation was also made available.

PalmDOS

In 1992, following Novell's acquisition of Digital Research in July 1991, the company launched "Merlin," which was later marketed as NetWare PalmDOS 1—a streamlined derivative of DR DOS 6.0 aimed at the nascent Palmtop and PDA market.

PalmDOS was the first in its series to utilize the BDOS 7.0 kernel featuring native DOS-compatible internal data structures rather than emulations. This approach enhanced application compatibility while reducing kernel size—a critical benefit for PDA devices. However, its revised Current Directory Structure (CDS) restricted the maximum working directory path length to 66 characters, unlike earlier DR DOS releases. To preserve compatibility and maintain a compact kernel footprint, PalmDOS identified itself to applications as "PC DOS 3.31."

The operating system supported ROM-based kernels and was tailored for palmtop hardware including PCMCIA PC Cards with DPMS, power management through BatteryMAX, patented dynamic idle detection technology, and MINIMAX task switching designed for Personal Information Modules (PIMs) executed directly from ROM using XIP (Execute-In-Place).

An important contributor to PalmDOS’s PCMCIA stack was Ian H. S. Cullimore, an influential figure in the development of PCMCIA/PC Card standards.

Novell DOS 7 / Novell's Role

Novell DOS was the name Novell Corporation adopted for DR DOS following its acquisition of Digital Research in 1991. It consistently outperformed MS-DOS in both functionality and speed, with the 1993 launch of DOS 7 notably exceeding competitors such as PC DOS 6.1 and MS-DOS 6.2.

Under the leadership of Novell CEO Robert J. Frankenberg, the company pursued significant streamlining by divesting assets like the transactional database Btrieve and discontinuing products including Novell DOS and WordPerfect’s multimedia software. Novell also incorporated technology licensed from Stac Electronics into both Novell DOS and its network operating system, NetWare. On July 23, 1996, Novell divested the DR DOS product line to Caldera, which intended to bundle a DOS operating system with its OpenLinux platform.

According to Marc Perkel, he influenced Novell’s decision to acquire Digital Research in early 1991 with the goal of creating "NovOS," a system designed to challenge Microsoft's market dominance. Novell’s broader acquisition strategy included purchasing WordPerfect and Borland products, alongside substantial investments in Unix development—an effort that ultimately proved financially burdensome.

The internally designated "Panther" version of DR DOS 7.0 sought to outperform Microsoft’s problematic MS-DOS 6.0 but encountered delays due to Novell’s work on optional Unix-like multiuser security features and two graphical user interfaces: ViewMAX 3 (a derivative of GEM) and "Star Trek" (a port of Apple’s System 7.1). When the product finally launched in December 1993 as Novell DOS 7 ("NWDOS"), these planned components were omitted, resulting in mixed critical responses despite industry recognition.

In Germany, Novell DOS 7 was aggressively promoted with the slogan "" ("Don’t trust any DOS below 7"), achieving sales near 1.5 million units by February 1994 through over 3,000 dealers. Distribution channels comprised OEM partnerships, mail order services, and authorized resellers.

One notable enhancement was Novell’s second peer-to-peer networking solution, Personal NetWare (PNW), which improved upon NetWare Lite but remained incompatible with Microsoft’s networking protocols prevalent in Windows environments. Its intricate setup process limited widespread adoption.

Novell DOS 7 incorporated the DOSMGR API alongside an updated BDOS 7.2 kernel that identified itself as DOS version 6.0 with an OEM ID of "IBM" to maintain compatibility with Windows systems. Most utilities recognized it as "PC DOS 6.1."

This release featured sophisticated memory management supporting DPMI (DOS Protected Mode Interface) and DPMS (DOS Protected Mode Services), along with versatile loadhigh capabilities. It introduced genuine pre-emptive multitasking via MultiMAX, allowing multiple DOS applications to operate simultaneously within virtual DOS machines (VDMs). When combined with EMM386 /MULTI, it provided a native 32-bit protected mode core offering APIs for multitasking, multithreading, hardware virtualization, and domain management accessible by DR DOS-aware software. The included TASKMGR utility utilized this API to facilitate seamless task management alongside Windows operations.

Both Novell DOS 7 and Personal NetWare bundled NetWars, a network-enabled three-dimensional arcade game.

Despite receiving multiple bug-fix updates (D70xyy), stability concerns lingered. With Microsoft’s "Chicago" (later known as Windows 95) imminent, Novell halted further development on Novell DOS 7 in September 1994 and discontinued maintenance in January 1996 after delivering more than fifteen updates.

Post-Novell Developments

When Caldera aimed to include a DOS operating system alongside their OpenLinux distribution, Novell divested the product line to Caldera on July 23, 1996, as it no longer held significant commercial interest for Novell.

In response to competition from IBM's PC DOS 6.3 and Caldera's own DR-DOS, Microsoft limited Windows 95 compatibility exclusively to their DOS variant, a practice later contested by Caldera in the notable lawsuit. After prolonged legal battles, the dispute was resolved through an out-of-court settlement on January 7, 2000, amounting to $280 million.

By August 1996, Caldera recruited Roger A. Gross, one of the original DR-DOS developers, to revive DR-DOS development with the goal of achieving Windows 95 compatibility. Gross established a UK-based subsidiary and formed a development team near Andover, Hampshire, combining former Novell engineers with new recruits. Over two years, they incorporated enhancements such as a TCP/IP protocol stack, a 32-bit graphical web browser named DR-WebSpyder, POSIX Pthreads support, long filename capability, and FAT32 support through DRFAT32. Consultant Andrew Schulman contributed to "WinGlue," an initiative to develop Windows 95/98-compatible DR-DOS versions; although this project remained unreleased, it provided valuable support during litigation.

In February 1997, Caldera UK launched OpenDOS 7.01—essentially an update (version 10) of Novell DOS 7 with minimal alterations due to the loss of source code at Novell. This release lacked recent patches and bundled utilities such as virus scanners but included updated versions of NetWars and PNUNPACK.

A subset of OpenDOS 7.01 components was briefly made available as open source under restrictive licenses but was subsequently closed again to safeguard commercial interests.

Following beta versions in late 1997, Caldera released DR-OpenDOS 7.02 in December of that year; by March 1998 it was renamed Caldera DR-DOS 7.02. This iteration (BDOS version 7.3) featured numerous BIOS and BDOS enhancements developed by Matthias R. Paul: expanded boot and configuration options; compatibility with Windows 9x and disk compression drivers; integrated debugger support; advanced CONFIG.SYS scripting enabling flexible boot menus and user prompts; multi-configuration capabilities via LOADER and CHAIN directives; and improved environment variable management with high-memory loading techniques that increased available conventional memory.

Additionally, DR-DOS 7.02 introduced an upgraded National Language Support system allowing concurrent use of multiple COUNTRY.SYS files and implemented ISO 8601 date formatting along with Euro currency support. It was fully compliant with Year 2000 requirements, including specific BIOS bug workarounds, and featured an updated FDISK utility supporting FAT32 partitions.

The BDOS upgrade caused some compatibility issues with legacy third-party software; these were addressed by an enhanced SETVER tool capable of hierarchically emulating different DOS and BDOS versions for compatibility purposes.

A conflict emerged with the QEMM 8 memory manager due to new high-file loading methods but was resolved through a patch enabling selective legacy mode operation.

In August 1998, Caldera established two subsidiaries: Caldera Systems, Inc., concentrating on Linux-related business ventures, and Caldera Thin Clients, Inc., focusing on embedded systems and thin-client markets.

DR-DOS 7.03 underwent a pre-release in December 1998 and was officially introduced in January 1999 by Caldera UK. This version included improved memory managers with enhanced DPMI support and additional utilities but altered the FAT OEM label format, causing interoperability issues across operating systems that could be mitigated using NOVOLTRK. Notably, this marked the final desktop-oriented DR-DOS release.

After Roger Gross’s departure in early 1999 and the closure of the successful UK development site, efforts to continue development in the US faltered due to insufficient expertise. Subsequently, the DR-DOS line was transferred to Caldera Thin Clients—rebranded as Lineo, Inc. in July 1999. Lineo renamed DR-WebSpyder as Embrowser for porting to Linux platforms and reissued DR-DOS 7.03 without modifications while shifting focus toward embedded Linux distributions derived from OpenLinux’s Embedix.

Independent OEM versions of DR-DOS followed: version 7.04 (August 1999) and 7.05 (November 1999), which offered kernel-only builds supporting native FAT32 and large disk capacities; these were bundled with utilities such as Ontrack’s Easy Recovery 5, Seagate’s SeaTools diagnostics, and Nero Burning ROM software. Internally these maintained BDOS version 7.3 but identified themselves as "PC DOS 7.10" to reflect integrated FAT32 support.

Kernels from DR-DOS versions 7.04/7.05 could be combined with the desktop-approved DR-DOS 7.03 kernel to enable Logical Block Addressing (LBA) functionality for drives exceeding eight gigabytes.

For tailored OEM requirements, DR-DOS 7.06 (December 1999) merged kernel components into a single executable compatible with MS-DOS 7.10 boot sectors but incompatible with native DR-DOS boot sectors.

DR-DOS version 7.07 introduced new bootstrap loaders alongside updated disk utilities capable of handling CHS/LBA addressing combined with FAT12/16/32 file systems across various operating system boot conventions—including those of DR-DOS, PC DOS, MS-DOS, and Windows variants—facilitating flexible multi-boot configurations while preserving backward compatibility down to DR-DOS version 3.31.

This progression of DR-DOS under Caldera and Lineo underscores strategic initiatives aimed at enhancing DOS compatibility amid evolving market trends favoring embedded systems and Linux-based platforms.

Later iterations

Following Lineo's acquisition in 2002, former Lineo executives took ownership of the DR-DOS trademark and established DRDOS, Inc., operating as DeviceLogics L.L.C., to continue marketing DR-DOS for embedded applications. On March 30, 2004, DR-DOS 8.0 was launched, featuring support for FAT32 and large storage devices, the capability to boot from ROM or Flash memory, multitasking abilities, and a DPMI memory manager, all built upon kernel version 7.03.

In the fall of 2005, DRDOS, Inc. released DR-DOS 8.1, which improved FAT32 compatibility and was based on OpenDOS 7.01.xx. Nevertheless, this version was retracted due to violations of the GNU General Public License (GPL) (see Controversies). Additionally, the company provided an option to acquire DR-DOS for $25,000.

The OpenDOS 7.01 source code underpinned The DR-DOS/OpenDOS Enhancement Project, initiated in July 2002 with the goal of updating DR-DOS capabilities. This effort introduced native large disk (LBA) support, FAT32 functionality, enhanced memory management, and the FAT32+ extension allowing files up to 256 GB on FAT partitions. A work-in-progress edition named DR-DOS 7.01.08 WIP was released on July 21, 2011.

Starting in 2023, the final Enhanced DR-DOS version (7.01.08 WIP) was adapted to an open-source build system enabling cross-compilation from non-DOS platforms. The kernel compiles into a single binary file called KERNEL.SYS, compatible with FreeDOS boot loaders. It has undergone numerous bug fixes and improvements and continues to be actively maintained as of October 2024.

Controversies

In October 2005, it was revealed that DR-DOS 8.1 incorporated utilities sourced from FreeDOS and other projects without adhering to the GNU General Public License (GPL), neglecting to acknowledge authors or release source code. After FreeDOS developers raised concerns demanding GPL compliance, DRDOS, Inc. removed versions 8.1 and 8.0 from their website.

Commands

From version 3.31 onward, DR-DOS included internal commands such as APPEND, ASSIGN, BATCH, DBG, DELQ, ERA, ERAQ, MORE, and SUBST. With DR-DOS 5.0, BATCH was eliminated while HILOAD was introduced.[1] Version 6.0 added internal commands like GOSUB, IDLE, RETURN, and SWITCH; meanwhile ASSIGN and SUBST were converted to external commands.[2] The internal commands ECHOERR and PAUSEERR appeared in DR-DOS 6.0 but were generally disabled.[1] The MORE command remained internal up through PalmDOS but became external starting with Novell DOS 7; DBG was removed by Novell DOS 7; since DR DOS 6.0 LOADHIGH (LH) and TRUENAME were added as internal commands.[2] APPEND stayed internal in DR-DOS 6.0 but transitioned to an external command in Novell DOS 7.

Internal commands

Below is a list of internal commands supported by DR DOS 6.0:


Batch processing subcommands

The batch processing subcommands available in DR  DOS 6.0 consist of the following:



External commands

The external commands supported by DR  DOS 6.0 include:



See also

References

{{Reflist|refs= [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [2] [44] [45] [46] <ref name="Paul_2001_CODEPAGE">Paul (June 10, 2001). "'Overview on DOS codepages'". {{cite web}}: Missing or empty |url= (help)</ ref > < ref nam e = " Paul _20 01_IBMBIO85_108" > </ ref > 

< ref nam e = " Paul _20

01_IBMBIO85 " > </ ref > 

< ref nam e = " Jones _20

04 " > </ ref > 

< ref nam e = " Caldera _19

98 _Subsidiaries " > </ ref > 

< ref nam e = " Paul _20

02 _OEM " > </ ref > 

< ref nam e = " Paul _20

04 _OEM " > </ ref > 

< ref nam e =

" History " > </ ref > 

< ref nam e =

" Caldera _19 99 _Lineo " > </ ref > 

< ref nam e =

" Moriy_autoexec " > http ://drdos.moriy.com/files/autoexec.gif</ ref > 

< ref nam e =

" moriy_config " > http ://drdos.moriy.com/files/configsys.gif</ ref > 

< ref nam e =

" reimagery " > </ ref > 

< ref nam e =

" freedos " > </ ref > 

< ref nam e =

" Buyout " > </ ref > 

< ref nam e =

" EDR " > Welcome to the DR-DOS/OpenDOS Enhancement Project!</ ref > 

< ref nam e =

" ct _20 00 " > </ refs >

Further reading

  • Digital Research, Inc. (1990). DR DOS 5.0 Retail Package with Lid. Digital Research, Inc.
  • Digital Research, Inc. (May 1990). DR DOS 5.0 User Manual, First edition, 501 pages. Digital Research, Inc.
  • Digital Research, Inc. (May 1990). ViewMAX User Manual, First edition, 88 pages. Digital Research, Inc.
  • Digital Research, Inc. (August 1990). DR DOS 5.0 Release Documentation, 11 pages. Digital Research, Inc.
  • Digital Research, Inc. (August 1991). DR DOS 6.0 Software Performance Analysis. Digital Research, Inc.
  • Digital Research, Inc. (August 1991). DR DOS 6.0 User Manual, Second edition, 698 pages. Digital Research, Inc.
  • Digital Research, Inc. (August 1991). ViewMAX User Manual, Second edition, 106 pages. Digital Research, Inc.
  • Novell Desktop Systems Group (January 7, 1993). DRTIPS.ZIP (1992). Digital Research / Novell.

External links

  1. ↑ 1.0 1.1 Cite error: Invalid <ref> tag; no text was provided for refs named Paul_1997_DRDOS6UN
  2. ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  3. ↑ "About DRDOS". DRDOS Embedded DOS. DRDOS, Inc. 2013.
  4. ↑ Wein, Josef "Joe" (February 19, 2010). "DRI History and Joe Wein".
  5. ↑ The rest of the story: How Bill Gates beat Gary Kildall in OS war
  6. ↑ "PC-Mode bridges CP/M and PC-DOS". Digital Research. March 1984. {{cite journal}}: Cite journal requires |journal= (help)
  7. ↑ "Concurrent DOS bridges PC-DOS, CP/M". Digital Research. May 1984. {{cite journal}}: Cite journal requires |journal= (help)
  8. ↑ Burton, Robin (September 1989). Master 512 Technical Guide.
  9. ↑ Ponting, Bob (August 15, 1988). "Award Software plans to implement Digital Research's OS on ROM chip". {{cite magazine}}: Cite magazine requires |magazine= (help)
  10. ↑ OpenDOS Developer's Reference Series - OpenDOS Multitasking API Guide. Caldera, Inc. August 1997.
  11. ↑ "The AARD Code". {{cite web}}: Missing or empty |url= (help)
  12. ↑ Dr. Dobb's Journal investigation
  13. ↑ Meyer (August 27, 1998). "Microsoft: Vorgetäuschter Bug legte DR-DOS lahm". {{cite journal}}: Cite journal requires |journal= (help)
  14. ↑ "Timeline of DOS/V versions". November 28, 2014. {{cite web}}: Missing or empty |url= (help)
  15. ↑ "DR DOS 6.0/V Screenshots and FONT database". {{cite web}}: Missing or empty |url= (help)
  16. ↑ "Novell announces low-end products with DR DOS 6.0". September 11, 1992. {{cite journal}}: Cite journal requires |journal= (help)
  17. ↑ "US Patent 5355501 - Idle detection system". {{cite web}}: Missing or empty |url= (help)
  18. ↑ "Novell v. Microsoft trial ends in hung jury". {{cite web}}: Missing or empty |url= (help)
  19. ↑ "Novell DOS overview". {{cite magazine}}: Cite magazine requires |magazine= (help)
  20. ↑ "Novell/DRI merger to enhance client management capabilities". {{cite journal}}: Cite journal requires |journal= (help)
  21. ↑ "Novell and Digital Research sign merger agreement".
  22. ↑ "Novell/Digital Research definitive agreement court document". {{cite web}}: Missing or empty |url= (help)
  23. ↑ "Microsoft's OS rivals get a boost".
  24. ↑ "MS-DOS turns 30 years old".
  25. ↑ "Novell prepares response to Windows dominance".
  26. ↑ "Software patent battles impact users".
  27. ↑ "Caldera sues Microsoft for antitrust violations related to DR DOS market exclusion". {{cite web}}: Missing or empty |url= (help)
  28. ↑ "DOS version comparison by John Sheesley". {{cite web}}: Missing or empty |url= (help)
  29. ↑ "Caldera's opposition memorandum in antitrust case against Microsoft". {{cite web}}: Missing or empty |url= (help)
  30. ↑ "Caldera vs Microsoft settlement announcement". {{cite web}}: Missing or empty |url= (help)
  31. ↑ "Microsoft settles with Caldera for $275 million over antitrust lawsuit".
  32. ↑ "Exhibits revealing Microsoft-Caldera settlement details and payments to Novell". {{cite web}}: Missing or empty |url= (help)
  33. ↑ "Settlement agreement between Microsoft and Caldera for $280 million payment". {{cite web}}: Missing or empty |url= (help)
  34. ↑ "Microsoft memorandum on payments made to Caldera and Novell related to antitrust cases". {{cite web}}: Missing or empty |url= (help)
  35. ↑ "Basic information about Caldera (UK) Limited company". Company Data Rex. {{cite web}}: Missing or empty |url= (help)
  36. ↑ "Cebit: Caldera showcases Windows on DR-DOS denying Microsoft's claims". {{cite web}}: Missing or empty |url= (help)
  37. ↑ Romano (September 17, 1998). "'WinBolt' demo software proving Windows 95 interface can run on DR-DOS to challenge Microsoft's claims". {{cite journal}}: Cite journal requires |journal= (help)
  38. ↑ Paul (April 10, 2002). "'HMA access from TSR' technical discussion on DR-DOS memory management". {{cite web}}: Missing or empty |url= (help)
  39. ↑ Template:Cite newsgroup
  40. ↑ Template:Cite newsgroup
  41. ↑ Paul (July 30, 1997). NWDOS-TIPs: Tips & Tricks for Novell DOS 7 including undocumented features.
  42. ↑ Paul (October 2, 1997). "'Caldera OpenDOS update Alpha 3 README'". {{cite web}}: Missing or empty |url= (help)
  43. ↑ Ralf D. Brown. Ralf Brown's Interrupt List, INTER61 as of July 16, 2000 entry for DR-DOS version check.
  44. ↑ Paul (January 11, 2000). "'Possible DR-DOS enhancements' discussion". {{cite web}}: Missing or empty |url= (help)
  45. ↑ Paul (June 10, 2001). "'DOS COUNTRY.SYS file format specifications'". {{cite web}}: Missing or empty |url= (help)
  46. ↑ Paul (June 10, 2001). "'Format description of DOS and Windows code page files'". {{cite web}}: Missing or empty |url= (help)

Related profiles

DDell Real Mode KernelDDRMKPPalmDOSNNovell DOS
Retrieved from "https://www.alfawiki.org/index.php?title=EZ-DOS&oldid=25219"