Jump to content

Novell DOS

From Alfawiki
Digital Research, Inc.
Company typePrivate
IndustrySoftware
FoundedJanuary 1, 1974; 52 years ago (1974-01-01)
FounderGary A. Kildall
Headquarters
Pacific Grove / Monterey
,
United States
ProductsDR-DOS, CP/M, Concurrent DOS, DOS Plus, Multiuser DOS, PalmDOS

DR-DOS (displayed as DR DOS up to version 6.0) is an operating system for IBM PC-compatible computers, initially created by Digital Research, Inc., founded 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 designed to be compatible with both IBM PC DOS and MS-DOS.

The debut version was 3.31, matching the version numbering of MS-DOS at the time. The first retail edition, DR DOS 5.0, appeared in 1990 and earned widespread praise, establishing DR-DOS as a primary challenger to Microsoft's MS-DOS. Microsoft countered with MS-DOS 5.0 more than a year later. DR DOS also introduced the graphical shell ViewMAX. Version 6.0 followed in 1991; after Digital Research was acquired by Novell, the system was renamed Novell DOS 7.0 in 1994. Later ownership changes brought updates under Caldera, including partially open-source releases known as Caldera and briefly as OpenDOS. The final desktop version was Caldera DR-DOS 7.03 in 1999, after which development shifted toward embedded applications under Caldera and subsequently DeviceLogics.

Roots in CP/M

Digital Research originally developed CP/M for 8-bit processors such as the Intel 8080 and Z80, which led to variants like CP/M-86 for the Intel 8086/8088 CPUs. Although CP/M dominated since the mid-1970s, the introduction of the IBM PC in 1981 triggered significant market changes.

In 1980, IBM sought a version of CP/M compatible with x86 processors from Digital Research but contractual disagreements resulted in IBM partnering with Microsoft, which had acquired 86-DOS from Seattle Computer Products. This software became Microsoft’s MS-DOS and IBM’s PC DOS. Digital Research contended that PC DOS/MS-DOS closely imitated CP/M and considered legal action. By 1982, IBM agreed to offer Digital Research’s CP/M-86 alongside PC DOS; however, CP/M-86 was priced at $240 compared to PC DOS’s , limiting its adoption despite early software advantages.

Digital Research faced challenges marketing CP/M-86 and its successors like MP/M-86 and Concurrent CP/M-86. Unable to compete with the Microsoft-IBM alliance’s software ecosystem, Digital Research modified Concurrent CP/M-86 to support MS-DOS/PC DOS applications. This capability was publicly demonstrated in December 1983 and released as Concurrent DOS 3.1 (CDOS with BDOS 3.1) to hardware manufacturers in March 1984. Although Concurrent DOS later evolved into products such as Multiuser DOS and REAL/32, it remained expensive and less appropriate for single-user desktop environments.

To better address the single-user market, Digital Research launched two significant products: In 1985, they introduced DOS Plus 1.0 through 2.1—a simplified single-user offshoot of Concurrent DOS that offered multitasking and limited compatibility with DOS applications. Later, in 1988, they unveiled DR DOS, a fully native DOS-compatible operating system aimed at wider market acceptance.

While Digital Research was based in Pacific Grove and later Monterey, California, much of the development for DOS Plus originated at Digital Research Europe’s OEM Support Group located in Newbury, Berkshire, UK beginning in 1983. From 1986 onward, core operating system development—including Concurrent DOS 386/XM, Multiuser DOS, DR DOS, and PalmDOS—was conducted primarily at the European Development Centre in Hungerford, Berkshire, supplemented by work from Digital Research GmbH in Munich, Germany.

Initial DR DOS Release

To meet OEM requirements and overcome limitations found in MS-DOS, Digital Research initiated development of a new DOS version in 1987. A pivotal partnership with Kazuhiko "Kay" Nishi from ASCII Corporation facilitated entry into the Japanese OEM sector. The inaugural DR DOS edition was introduced on May 28, 1988, aligning its versioning with MS-DOS features; the first public iteration was DR DOS 3.31, corresponding to Compaq’s MS-DOS 3.31 and supporting large disks (FAT16B/"BIGDOS"). This release identified itself as "IBM PC DOS 3.31," containing a BDOS kernel version 6.0 based on Concurrent DOS 6.0 but with multitasking and CP/M API components removed, substituting the XIOS with an IBM-compatible DOS-BIOS layer. Core system files included DRBIOS.SYS and DRBDOS.SYS, branded under the OEM identifier "DIGITAL␠".

DR DOS enhanced command line functionality by incorporating help features, detailed error messages, command history and editing capabilities (enabled via the HISTORY directive), alongside native file and directory password protection embedded within the kernel. It was also more cost-effective to license than MS-DOS and supported ROM integration from its inception, with the ROM-based variant named ROS (ROM Operating System). The demand from PC manufacturers seeking alternative DOS platforms spurred a series of subsequent updates.

While MS-DOS remained exclusive to OEMs at that time, DR DOS expanded its reach into the consumer market by becoming available through retail starting with version 3.4x.

Versions released include DR DOS 3.31 (BDOS 6.0, June 1988, OEM only), followed by 3.32 (August 1988), 3.33 (September 1988), 3.34 (OEM only), 3.35 (October 1988), 3.40 (January 1989), and 3.41 (BDOS 6.3, June 1989, available both OEM and retail). Many editions were adapted for various hardware platforms. Although most manufacturers kept the DR DOS name intact, 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 operating on a single-user BDOS kernel version 6.4 (the version number jumped from 3 to avoid association with the unpopular MS-DOS 4.0). This release introduced ViewMAX, a GEM-based GUI file management interface, accompanied by the tagline "Digital Research - We make computers work".

Notable advancements included the patented BatteryMAX power management system, integrated disk caching software named DRCACHE, a remote file transfer utility called FILELINK, a cursor customization tool CURSOR, and an improved memory management component known as MemoryMAX. System files were renamed to IBMBIO.COM and IBMDOS.COM, featuring a sophisticated boot loader that allowed flexible placement of disk files during startup. The OEM label was updated to "IBM␠␠3.3".

DR DOS 5.0 pioneered load-high support by relocating its kernel and associated data structures into the High Memory Area (HMA)—the initial 64 KB segment of extended memory accessible in real mode—thereby freeing valuable conventional memory (the first 640 KB of RAM) for application use.

On Intel 80386 processors, its EMS memory manager enabled loading device drivers into upper memory blocks, substantially increasing available conventional memory compared to typical MS-DOS/PC DOS configurations. Whereas standard MS-DOS systems often left only around 300–400 KB free after loading drivers for mouse, multimedia, and networking functions, DR DOS 5.0 could preserve up to approximately 620 KB free with manual tuning. Employing MEMMAX +V allowed extension of conventional memory into unused graphics card RAM areas, adding between an additional 64–96 KB.

This considerable amount of free conventional memory occasionally caused compatibility challenges with some legacy applications that depended on address wrapping techniques which malfunctioned when loaded too low in memory space unexpectedly. To counter this issue, DR DOS implemented MEMMAX -L, which pre-allocates a reserved low-memory block ensuring programs load above this threshold—though this approach reduces total usable conventional memory slightly. By default, MEMMAX is configured with +L to maximize application-accessible memory space.


DR DOS 6.0 / Rivalry with Microsoft

In response to growing competition, Microsoft unveiled MS-DOS 5.0 in May 1990, launching it in June 1991. This version incorporated sophisticated features akin to those found in DR DOS, such as improved memory management capabilities.

Digital Research followed in September 1991 with the release of DR DOS 6.0, codenamed "Buxton." Internally running BDOS version 6.7 yet reporting as "IBM PC DOS 3.31" for compatibility reasons, this edition included SuperStor disk compression technology and file undelete utilities developed by Roger A. Gross, both designed to optimize hard drive usage and facilitate data recovery.

One notable innovation in DR DOS 6.0 was TASKMAX, a task-switching system supporting the industry-standard API that allowed multiple applications to run concurrently by suspending background processes until brought to the foreground. TASKMAX leveraged XMS memory on machines with 286 processors or higher and provided limited Copy & Paste functionality. Its API enabled graphical user interfaces such as ViewMAX or PC/GEOS to replace the default text-based menu, enhancing task management through a graphical interface.

Microsoft’s subsequent MS-DOS 6.0 release incorporated many features originally introduced by DR DOS 6.0.

In December 1991, the beta version of Windows 3.1 included the AARD code, which detected non-Microsoft DOS variants and issued non-critical error messages. Digital Research swiftly responded by patching DR DOS 6.0 to circumvent this detection without impairing functionality, issuing a "business update" within six weeks after Windows 3.1’s debut. This ensured smooth operation of Windows on both DR DOS and Novell DOS platforms, with the detection mechanism removed from the final Windows release.

By July 1992, Digital Research Japan launched DR DOS 6.0/V, a version compatible with Japanese DOS/V systems, alongside a Korean edition, thereby extending DR DOS’s footprint in Asian markets.

PalmDOS

Following Novell's acquisition of Digital Research in 1991, the company introduced "Merlin" in 1992, later marketed as NetWare PalmDOS 1—a streamlined derivative of DR DOS 6.0 designed specifically for emerging palmtop and PDA devices.

PalmDOS was pioneering within its family for adopting the BDOS 7.0 kernel featuring native DOS-compatible internal data structures, which enhanced compatibility with applications while reducing kernel size—an essential attribute for portable devices. However, it implemented a true Current Directory Structure (CDS), restricting directory path lengths to 66 characters, unlike earlier DR DOS versions. To maintain compatibility with Windows environments, PalmDOS identified itself as "PC DOS 3.31."

Engineered for execution from ROM, PalmDOS supported PCMCIA cards (utilizing DPMS), incorporated power-saving technologies such as BatteryMAX and the patented dynamic idle detection driver $IDLE$, and featured MINIMAX task switching tailored for PIM applications running from ROM via XIP (execute-in-place). Ian H. S. Cullimore, a notable contributor to the PCMCIA standard, played a role in developing its PCMCIA stack.

Novell DOS 7 / Novell's Enhancements

After acquiring Digital Research in 1991, Novell Corporation rebranded DR DOS as Novell DOS. This operating system consistently delivered superior features and performance compared to contemporary MS-DOS versions, with its 1993 iteration—Novell DOS 7—outperforming PC DOS 6.1 as well as MS-DOS versions 6.2 and 6.3.

Under CEO Robert J. Frankenberg’s leadership focused on significant streamlining, Novell divested products like Btrieve and discontinued others including Novell DOS itself and WordPerfect’s multimedia offerings. The company also integrated licensed technology from Stac Electronics into both Novell DOS and its NetWare operating system. In July 1996, Novell sold Novell DOS to Caldera, which aimed to bundle it with their OpenLinux distribution.

Marc Perkel has asserted that he inspired Novell’s acquisition of Digital Research early in 1991 to develop "NovOS," part of a broader strategy involving acquisitions such as WordPerfect and Borland products intended to challenge Microsoft's market dominance. Internally called "Panther," DR DOS 7.0 experienced delays due to Novell’s efforts to add optional Unix-like multi-user security features and develop two graphical user interfaces: ViewMAX 3 (a GEM derivative) and "Star Trek" (a port of Apple’s System 7.1 running atop the multitasking "Vladivar" kernel).

When finally released in December 1993 as Novell DOS 7 (NWDOS), these advanced components were absent from the product, resulting in mixed reviews despite widespread acknowledgment of it being the most advanced DOS available at the time.

In Germany, aggressive marketing campaigns using the slogan "" ("Don’t trust any DOS below 7") helped drive sales exceeding approximately 1.5 million copies by early 1994 through over 3,000 dealers.

A significant feature was Personal NetWare (PNW), Novell's enhanced peer-to-peer networking solution succeeding NetWare Lite; however, its incompatibility with Microsoft’s expanding Windows networking ecosystem hindered broader adoption.

Novell DOS 7 operated on the BDOS 7.2 kernel implementing the DOSMGR API and identified itself as DOS version 6.0 with an OEM ID of "IBM" for Windows compatibility purposes; most diagnostic tools recognized it as "PC DOS 6.1."

The operating system introduced sophisticated memory management supporting DPMI and DPMS standards alongside more versatile loadhigh options and genuine pre-emptive multitasking for multiple DOS programs through MultiMAX—a feature comparable to Multiuser DOS but built on a native DOS platform without requiring a GUI interface. When loaded with EMM386 using the /MULTI switch, it provided a native protected-mode core enabling multitasking, multi-threading, hardware virtualization, and virtual machine domain management accessible to DR DOS-aware software.

Novell DOS 7 also included TASKMGR for managing virtual DOS machines compatible with Windows multitasking capabilities, allowing tasks initiated before launching Windows to appear seamlessly within its environment.

Additionally bundled were NetWars—a network-enabled three-dimensional arcade game—alongside Personal NetWare.

Despite several bug-fix releases addressing stability concerns, development ceased by September 1994 amid anticipation of Microsoft’s forthcoming Windows 95 ("Chicago"), with official maintenance concluding in January 1996 after more than fifteen updates had been issued.

After Novell

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 them.

Amid competition from IBM's PC DOS 6.3 and Caldera’s own DR-DOS, Microsoft limited Windows 95 compatibility exclusively to their DOS versions. This restriction led to a prominent lawsuit, backed by the Canopy Group. After Microsoft’s attempts to dismiss the case failed, both parties settled out of court on January 7, 2000, with the settlement amount later disclosed as $280 million.

In August 1996, Roger A. Gross, one of the original engineers behind DR-DOS, proposed reviving the development of DR-DOS and enabling Windows 95 compatibility to strengthen the legal case. By September 1996, Caldera UK Ltd. was formed near Andover, Hampshire, recruiting original developers alongside new personnel. Over a span of two years, they introduced significant enhancements such as a TCP/IP stack, the graphical 32-bit web browser DR-WebSpyder (derived from Arachne), POSIX Pthreads multitasking extensions, support for long filenames (LONGNAME), and FAT32 capability (DRFAT32). Consultant Andrew Schulman contributed to "WinGlue," a confidential initiative aimed at making DR-DOS compatible with Windows 95/98 platforms—demonstrated at CeBIT 1998—and later evolved into "WinBolt." Although these versions were never publicly released, they played a critical role in the litigation.

Caldera UK launched Caldera OpenDOS 7.01 on February 3, 1997; this release was essentially an update (update 10) of Novell DOS 7 with minimal modifications due to Novell having lost many source files. It omitted several patches and bundled utilities present in earlier Novell DOS editions but included an updated PNUNPACK utility and a more advanced version of NetWars.

Some components of OpenDOS 7.01 were briefly made open source in May 1997 but were subsequently reverted to proprietary status as Gross believed that open-sourcing would undermine commercial viability.

Following beta releases in late 1997, Caldera introduced DR-OpenDOS 7.02 in December 1997, which was renamed Caldera DR-DOS 7.02 by March 1998. This version resolved BIOS and BDOS bugs, added boot and configuration options, enhanced compatibility—especially with Windows 9x and DriveSpace—integrated debugger support, improved CONFIG.SYS scripting for complex boot menus and error management, and incorporated advanced memory management features that increased available conventional memory. It also upgraded the National Language Support subsystem to handle multiple COUNTRY.SYS files simultaneously and introduced ISO 8601 date formatting along with Euro currency support. DR-DOS 7.02 was fully compliant with Year 2000 standards and included updated partitioning tools supporting FAT32 volumes.

The newer BDOS version caused some legacy software to malfunction; however, improvements to the SETVER utility allowed version masking to preserve compatibility with these applications.

A compatibility conflict emerged between the newly introduced HIFILES feature and QEMM 8's DOS-UP memory manager; although a patch addressed this issue, it required compromises that affected compatibility across various Windows versions.

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

DR-DOS 7.03 was officially released on January 6, 1999, featuring upgraded memory managers with enhanced DPMI support and additional utilities such as DEVLOAD and DRMOUSE. However, modifications to FAT OEM labels could cause interoperability problems with other operating systems unless addressed by utilities like NOVOLTRK. This release represented the final desktop-oriented version of DR-DOS.

After Gross resigned in early 1999 and the UK branch was closed, development responsibilities transferred to the United States under Caldera Thin Clients (which rebranded as Lineo, Inc. in July 1999). Lineo reissued DR-DOS 7.03 without alterations but shifted focus toward Linux-based embedded solutions through Embedix.

Subsequent standalone versions included OEM DR-DOS releases 7.04 (August 1999) and 7.05 (November 1999), which were streamlined kernel-and-shell editions featuring native FAT32 and large disk support utilized by products such as Ontrack's Easy Recovery and Seagate's SeaTools. Internally, these versions identified themselves as "PC DOS 7.10" to reflect FAT32 integration.

DR-DOS 7.06 consolidated kernel components into a single executable designed for booting via MS-DOS 7.10 sectors rather than native DR-DOS boot sectors; meanwhile, DR-DOS 7.07 introduced new bootstrap loaders supporting CHS/LBA disk access across FAT12/16/32 file systems and multiple boot methods (including PC DOS, MS-DOS, Windows dual-boot configurations). This enabled seamless multi-boot environments alongside other operating systems while maintaining backward compatibility down to DR-DOS version 3.31.

These advancements illustrate Caldera’s strategic emphasis on utilizing DR-DOS technology within embedded markets amid ongoing legal challenges and shifting personal computer operating system dynamics.

Subsequent Releases

Following the acquisition of Lineo in 2002, former Lineo executives purchased the DR-DOS trademark and established DRDOS, Inc., operating as DeviceLogics L.L.C., to continue promoting DR-DOS for embedded applications. On March 30, 2004, DR-DOS 8.0 was launched, featuring FAT32 and large disk compatibility, the ability to boot from ROM or Flash memory, multitasking capabilities, and a DPMI memory manager, all built upon kernel version 7.03.

In the fall of 2005, DRDOS, Inc. introduced DR-DOS 8.1, which enhanced FAT32 support and was based on OpenDOS 7.01.xx. Nevertheless, this version was retracted due to infringements related to the GPL (see Controversies). Additionally, the company made an offer to purchase DR-DOS for $25,000.

The source code of OpenDOS 7.01 served as the foundation for The DR-DOS/OpenDOS Enhancement Project, initiated in July 2002 with the goal of updating DR-DOS features. This initiative brought improvements such as native support for large disks (LBA) and FAT32, upgraded memory management, and introduced the FAT32+ extension that allows files up to 256 GB on FAT partitions. A work-in-progress version, DR-DOS 7.01.08 WIP, was released on July 21, 2011.

Starting in 2023, the final Enhanced DR-DOS edition, 7.01.08 WIP, was adapted to an open-source build environment that facilitates cross-platform compilation of both kernel and command interpreter compatible with FreeDOS boot loaders. This version continues to receive regular bug fixes and enhancements and remains actively supported as of October 2024.

Controversies

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

Commands

Beginning with DR-DOS 3.31, internal commands included APPEND, ASSIGN, BATCH, DBG, DELQ, ERA, ERAQ, MORE, and SUBST. The release of DR-DOS 5.0 eliminated BATCH and introduced HILOAD.[1][2] With DR-DOS 6.0 came new internal commands such as GOSUB, IDLE, RETURN, and SWITCH; meanwhile ASSIGN and SUBST were converted into external commands.[2] Although ECHOERR and PAUSEERR existed internally, they were generally disabled.[1] The MORE command stayed internal through PalmDOS but became external starting with Novell DOS 7; DBG was removed by Novell DOS 7; LOADHIGH (LH) and TRUENAME were added internally beginning with update 8 and DR DOS 6.0 (1993). APPEND remained internal in DR-DOS 6.0 but shifted to external in Novell DOS 7.[2]

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

Further reading

  • Digital Research, Inc. (1990) DR DOS 5.0 Retail box with lid
  • Digital Research, Inc. (May 1990) DR DOS 5.0 User Guide, 501 pages
  • Digital Research, Inc. (May 1990) ViewMAX User Guide, 88 pages
  • Digital Research, Inc. (August 1990) DR DOS 5.0 Release Notes, 11 pages
  • Digital Research, Inc. (August 1991) DR DOS 6.0 Software performance report
  • Digital Research, Inc. (August 1991) DR DOS 6.0 User Guide, 698 pages
  • Digital Research, Inc. (August 1991) ViewMAX User Guide, 106 pages
  • Novell Desktop Systems Group (January 7, 1993) DRTIPS.ZIP ([1])

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 Cite error: Invalid <ref> tag; no text was provided for refs named 4DOS_8.00_HELP
Retrieved from "https://www.alfawiki.org/index.php?title=Novell_DOS&oldid=25214"