this point onwards, many of the fundamentally new functions (including memory management, task switching, GUI, disk compression, deletion tracking) were first implemented in DR DOS and in some cases only years later in MS-DOS and PC DOS. The compatibility with unclean DOS applications was also increasingly improved, until finally in 1992 with DR PalmDOS 1.0 (BDOS 7.0) the previous DOS emulation of the kernel was completely replaced by DOS-compatible internal structures. DR PalmDOS was a further development of DR DOS 6.0 with special functions for early palmtops such as an integrated PCMCIA stack, the possibility of executing XIP applications under a special task switcher variant directly from the ROM, and including extended energy management a dynamically effective idling detection. For reasons of compatibility, all previous editions of DR DOS for normal DOS applications are PC DOS 3.31.
After Digital Research was sold to Novell in 1993, the system was marketed in 1994 as Novell DOS 7 (with BDOS 7.2), which for DOS applications was PC DOS 6.1. In addition to peer-to-peer network functions ( Personal NetWare ), Novell DOS 7 offered greatly expanded memory management with VCPI, DPMI and DPMS and, in conjunction with a 32-bit protected mode core system provided via EMM386, support for preemptive multitasking and multithreading in DOS virtual machines.
After more than 15 updates, the system was sold to Caldera in 1996, who re-released it in 1997 as Caldera OpenDOS 7.01. The source code of the core components was also published (only usable for non-commercial purposes) as well as historical source code from CP / M, GEM and ViewMAX . Caldera UK developed the system under the name DR-DOS (now for the first time written with a hyphen) to DR-DOS 7.02 and 7.03 (BDOS 7.3) with year 2000 fixes, euro support and some new upload functions, versions that in addition to some larger extensions that are not included in all editions (such as TCP / IP support, the graphical HTML 3.2 web browser WebSpyder, support for long file names with LONGNAME, dynamically loadable support for LBA access and FAT32 drives with DRFAT32 as well as a POSIX -pthreads API extension) primarily attracted attention through several hundred optimizations and improvements in detail. In addition, special DR-DOS versions called "Winglue" or "Winbolt" were developed, which were compatible with Windows 95 (MS-DOS 7.0 + Windows 4.0) and Windows 98 (7.1 + Windows 4.1) and played an important role in the Caldera process vs. Microsoft played, but so far remained unpublished.
With the closure of the English development center in Andover at the beginning of 1999 and the outsourcing to Caldera Thin Clients, USA, a subsidiary of the Caldera mother, the further development of DR-DOS was abruptly stopped. DR-DOS 7.03 was initially distributed by Lineo or Embedix, which emerged from Caldera Thin Clients, and is still offered today by DRDOS, Inc. alias DeviceLogics for use in embedded systems.
Special OEM versions DR-DOS 7.04, 7.05, 7.06 and later also 7.07 (BDOS 7.3 / 7.4 / 7.7) and 7.08 (BDOS 7.8) with LBA and FAT32 support have been produced by the former developers of the system over the years developed.
Two versions have been released by DRDOS, Inc. DR-DOS 8.0 (2004) is an OEM version that goes back to DR-DOS 7.0x with LBA and FAT32 support with various extensions to the disk tools. DR-DOS 8.1 (2005) was based - in contrast to DR-DOS 8.0 - partly not on previous DR-DOS versions, but on FreeDOS components and had to be withdrawn due to copyright infringements.
The last official version for desktop systems is still the Caldera DR-DOS 7.03 from 1999.
The only publicly accessible further development is currently the Enhanced DR-DOS 7.01.xx, which can be dubbed a fan project, which Udo Kuhnt developed from the published source code of Caldera OpenDOS 7.01. EDR-DOS is subject to the license conditions of the OpenDOS 7.01 source code, which excludes commercial use (except for test purposes).
The DOS-BIOS and BDOS of DR-DOS and practically all resident drivers (especially the memory m