| Developer | Digital Research |
|---|---|
| Written in | C |
| Working state | Discontinued |
| Source model | Closed source |
| Initial release | 1986; 39 years ago (1986) |
| Latest release | 2.33 / May 1998; 26 years ago (1998-05) |
| Latest preview | 2.34 / 1999; 26 years ago (1999) |
| Marketing target | Industrial,PoS |
| Available in | English |
| Platforms | Intel 80186,Intel 80286,Intel 80386,Motorola 68000,V60,V70 |
| Kernel type | modular |
| Default user interface | various frontends,X/GEM |
| License | Proprietary |
| Preceded by | Concurrent DOS 286,Concurrent DOS 68K,Concurrent DOS V60[1] |
| Succeeded by | S5-DOS/MT,4680 OS,4690 OS |
FlexOS is a discontinued modular real-time multiusermultitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed byDigital Research's Flexible Automation Business Unit inMonterey, California, in 1985.[2][3]
The system was considered to become a successor of Digital Research's earlierConcurrent DOS, but with a new, modular, and considerably different system architecture and portability across several processor families.[4] Still namedConcurrent DOS 68K andConcurrent DOS 286, it was renamed into FlexOS on 1 October 1986 to better differentiate the target audiences.
FlexOS was licensed by several OEMs who selected it as the basis for their own operating systems like4680 OS,4690 OS,S5-DOS/MT and others. Unrelated to FlexOS, the original Concurrent DOS system architecture found a continuation in successors likeConcurrent DOS XM andConcurrent DOS 386 as well.
Concurrent DOS 286, Concurrent DOS 68K and FlexOS were designed by Francis "Frank" R. Holsworth (usingsiglum FRH).[5][6] LikePortable CP/M,Concurrent DOS 286,Concurrent DOS 68K andConcurrent DOS V60,[1][7] FlexOS was written inC for higher portability across hardware platforms, and it featured very low interrupt latency and fast context switching.[8]
The originalprotected mode FlexOS 286 version 1.3[9] was designed for host machines equipped with286 CPUs, and with adaptations forNEC V60,NEC V70 andMotorola 68000 processors planned.[4][1][7] FlexOS 286 executables using the system's nativeINT DCh (INT 220)application program interface had the filename extension.286. ACP/MAPI front-end (FE) was available as well,[10] using the extension.CMD for executables. (A filename extension of.68K was reserved for FlexOS 68K, a file extension derived fromConcurrent DOS 68K as of 1986.[11][7][12][10])
In May 1987, FlexOS version 1.31 was released for 80286 machines.[13] The developer version required anIBM PC/AT-compatible machine with 640 KB ofconventional and 512 KB ofextended memory, and either a (monochrome) CGA or an EGA graphics adapter.
FlexOS supported a concept ofdynamically loadable and unloadable subdrivers, and it came with driver prototypes for floppies, hard disks, printers, serial interfaces, RAM disks, mice and console drivers.
During boot, the FLEX286.SYS kernel would load the resource managers and device drivers specified in the CONFIG.SYSbinary file (not to be mixed up with the similarly namedCONFIG.SYS configuration file underDOS), and its shell (COMMAND.286) would execute a CONFIG.BAT startup batch job instead of the commonAUTOEXEC.BAT.
FlexOS's optional DOS emulator provided limitedPC DOS 2.1 compatibility for DOS .COM and .EXE programs.[9] Certain restrictions applied in "8086 emulation mode" since these programs were executed in the processor's protected mode. Due to bugs in earlier steppings of the Intel 80286, the FlexOS 286 DOS front-end required at least the 80286 E2 stepping to function properly (seeLOADALL).[9] These problems had already caused delays in the delivery of Concurrent DOS 286 earlier.[14][15]
The system optionally supported a multitaskingGEMVDI for graphical applications.[9][16]
FlexOS 1.31 could be linked with none, either or both of these two modules. FlexOS 1.31 also supportedFlexNet.
By June 1987 there were also versions 1.0 of FlexOS 386 (for hosts) and FlexOS 186 (for remote cell controllers).[8] FlexOS 386 provided a windowing feature, and offeredPC DOS 3.2 and GEM compatibility.[8]
FlexOS 286 and FlexOS 386 versions 2.0 were registered on 3 July 1989.
Among the major FlexOS customers in 1990/1991 wereFANUC,IBM,ICL,Nixdorf,Siemens,TEC,Thorn EMI Software andMicrologic.[3][17]
Novell bought Digital Research forUS$80 million[18] in July 1991.[19][3][20][18]
X/GEM for FlexOS release 1.0 (a.k.a. X/GEM FlexOS 286 and 386) and FlexNet were registered on 21 December 1992.
FlexOS was used as the primary test platform for the newNovell Embedded Systems Technology (NEST).[21]
When Novell decided to abandon further development of the various Digital Research operating systems such asMultiuser DOS (a successor to Concurrent DOS) andNovell DOS (a successor toDR DOS), they sold FlexOS off to theSanta Clara, California-basedIntegrated Systems Inc. (ISI) for US$3 million in July 1994.[22] The deal comprised a direct payment of half this sum as well as shares representing 2% of the company. The company already hadpSOS+, another modular real-time multitasking operating system for embedded systems, but they continued to maintain FlexOS as well.[22] FlexOS version 2.33 was current as of May 1998 and with FlexOS 2.34 to be released soon after with added support for faster CPUs, 64 MB of memory, EIDE and ATAPI CDROM drives.
Integrated Systems was bought by their competitorWind River Systems in February 2000.
The following list ofcommands is supported by FlexOS:[23]
Known FlexOS versions include:
Motorola 68000 /Freescale/NXPColdFire MCF5251[24] platform:
Intel 80286 platform:
Intel 80186/NEC V20/V30 platform:
Intel 80386 platform:
NEC V60 platform:
Named IBM 4680 OS Version 1,IBM originally chose DR Concurrent DOS 286 as the basis of theirIBM 4680 computer for IBM Plant System products andPoint-of-Sale terminals in 1986.[32][10][4][33] The last release of the IBM 4680 OS has been Version 4, before it was replaced by IBM 4690 Version 1.[34]
Versions:
In July 1993, IBM announced the adoption of FlexOS version 2.32 as the basis of theirIBM 4690 OS Version 1, to be pre-released on 24 September 1993[33] and generally made available from 25 March 1994.[34][35] FlexOS 2.32 supported 286 and 386 modes, had more efficient memory management, better console and pipe systems, and brought overall quality and performance improvements compared to the version that came with IBM 4680 OS Version 4.[34] Further, it removed limits on the number of applications running concurrently due to its more efficient use of KOSPOOL.[34]
To supportJava, IBM 4690 OS Version 2 added support forlong filenames by means of avirtual filesystem (VFS) architecture and it introducedFAT32 volumes.
According to "The Year of the Store?", IHL Consulting Group/RIS News, IBM 4690 OS still had a market share of 12% in thePOS register/client market in June 2005, when IBM was starting to phase it out in favour toIBM Retail Environment for SUSE (IRES).[33]
IBM continued to maintain 4690 OS up to April 2015, with the most recent version released by IBM in May 2012 being IBM 4690 OS Version 6 Release 3.
Toshiba releasedToshiba 4690 OS Version 6 Release 4 in January 2014 and Version 6 Release 5 in January 2016.
Siemens used and still maintains FlexOS in their factory automation equipment as well. For example, theirSimatic S5STEP-5 operating systemS5-DOS/MT is based on FlexOS 386 with X/GEM, FlexNet andBtrieve, whereas the smallerS5-DOS system, also present on these systems, is a variant of Digital Research'sPersonal CP/M-86.
Siemens industrial systems like COROS LS-B/FlexOS, COROS OS-B/FlexOS, GRACIS/FlexOS,Teleperm M [de] OS-525 were FlexOS and X/GEM-based.
Computers such as theSicomp [de] PC 16-20 and the PC 32 series were available with FlexOS as well.
The Japanese post office shared terminalsCTM [ja] III and CTM IV were based on FlexOS.
Because Novell used Integrated Systems' FlexOS during the development and testing of NEST, we are in the unique position of supporting it through both our real-time product lines pSOSystem for deeply embedded markets, and FlexOS for point of sale," said Moses Joseph, vice president of marketing for Integrated Systems. "Developers using the FlexOS development kit and the expanded pSOSystem/NEST package for everything from home security and entertainment to office automation and global communications applications, now have quick and easy access to the widest variety of standard networking protocols.
[…] it is possible to purchase an implementation of CDOS-68K for the Motorola VME-10. The media it comes on is Motorola VME-10 5.25" floppies. […] CDOS-68K is the 68K version of CDOS-286 (which has now been updated and renamed to FlexOS 286). This CDOS-286/68K operating system was designed specifically to provide easy addition and deletion of I/O drivers and sub-drivers. Drivers can either be linked in to the O/S or kept external and dynamically loaded at boot time. […] CDOS-68K is at revision level 1.2, while CDOS-286 was upgraded to rev level 1.3 (at which point it became FlexOS 286). The significance of this to you is that no enhancements or maintenance of the 68K version is planned in the near future (unless a "major" OEM contract should happen). So the 68K O/S is pretty much being sold only on an "as is" basis. […]
[…]Digital Research is producing an operating system for the286.MP/M-286 will take advantage of the processor's memory management and protection and virtual memory support. Digital Research is promising "complete" compatibility with itsMP/M-86 andCP/M-86 for the8086 processor.Intel is supplying Digital Research with the hardware to develop and test MP/M-286. […]
[…] Paul Bailey ofDigital Research keenly promotes this approach; it is his company that is supplyingICL and others withConcurrent Dos-286. This chameleon operating system allows ICL and other80286 manufacturers to build machines that will be able to cope with all the existing body of IBM-PC software -- and at the same time promise multi-tasking, windowing and true concurrency, three features that together allow a single micro to do several things at once. […] Although no firm announcements have been made, it seems certain that by the end of the yearACT will be offering aConcurrent CP/M 286 machine to fuel its drive into the corporate market. But by this time it will have to contend withIBM's own 80286 office micro, the PC/AT. […] IBM also have a software product in the offing that could pull the rug out from under the Concurrent contenders. Some 180K in size,TopView is a program for IBM PC's and AT's that beefs up the operating system to provide windowing facilities for existing 'well behaved' standard packages. […]
This is a guide to the operation of the High C compiler as implemented for the Concurrent DOS 286 1.2 or later operating system - hereafter abbreviated to just "Concurrent" per Digital Research custom - running on the Intel 80286 microprocessor and using the Intel Object-Module Format (OMF). The compiler generates code for any of the Intel 8086/88/186/188/286 family of microprocessors.
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