FlexOS is a discontinued modular real-time multiuser multitasking operating system (

RTOS A real-time operating system (RTOS) is an operating system (OS) for real-time applications that processes data and events that have critically defined time constraints. An RTOS is distinct from a time-sharing operating system, such as Unix, which ...

) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by

Digital Research Digital Research, Inc. (DR or DRI) was a company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and Gr ...

's Flexible Automation Business Unit in

Monterey Monterey (; es, Monterrey; Ohlone: ) is a city located in Monterey County on the southern edge of Monterey Bay on the U.S. state of California's Central Coast. Founded on June 3, 1770, it functioned as the capital of Alta California under bot ...

, California, in 1985, the system was considered to become a successor of Digital Research's earlier Concurrent DOS, but with a new, modular, and considerably different system architecture and portability across several processor families. Still named

Concurrent DOS 68K Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

and

Concurrent DOS 286 Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

, 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 like

4680 OS FlexOS is a discontinued modular real-time multiuser multitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by Digital Research's Flexible Automation Business U ...

4690 OS 4690 Operating System (sometimes shortened to 4690 OS or 4690) is a specially designed point of sale (POS) operating system, originally sold by IBM. In 2012, IBM sold its retail business, including this product, to Toshiba, which assumed support ...

, S5-DOS/MT and others. Unrelated to FlexOS, the original Concurrent DOS system architecture found a continuation in successors like

Concurrent DOS XM Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

and Concurrent DOS 386 as well.

Overview

Concurrent DOS 286, Concurrent DOS 68K and FlexOS were designed by Francis "Frank" R. Holsworth (using

siglum Scribal abbreviations or sigla ( singular: siglum) are abbreviations used by ancient and medieval scribes writing in various languages, including Latin, Greek, Old English and Old Norse. In modern manuscript editing (substantive and mechani ...

FRH). Like

Portable CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...

and

Concurrent DOS V60 FlexOS is a discontinued modular real-time multiuser multitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by Digital Research's Flexible Automation Business U ...

, FlexOS was written in C for higher portability across hardware platforms, and it featured very low interrupt latency and fast context switching. The original protected mode FlexOS 286 version 1.3 was designed for host machines equipped with 286 CPUs, and with adaptations for

NEC V60 is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network soluti ...

NEC V70 is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network soluti ...

and Motorola 68000 processors planned. FlexOS 286 executables using the system's native INT DCh ( INT 220)

application program interface An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software Interface (computing), interface, offering a service to other pieces of software. A document or standa ...

had the filename extension

.286 FlexOS is a discontinued modular real-time multiuser multitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by Digital Research's Flexible Automation Business U ...

. A CP/M API front-end (FE) was available as well, using the extension .CMD for executables. (A filename extension of

.68K FlexOS is a discontinued modular real-time multiuser multitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by Digital Research's Flexible Automation Business U ...

was reserved for FlexOS 68K, a file extension derived from

as of 1986.) In May 1987, FlexOS version 1.31 was released for 80286 machines. The developer version required an

IBM PC/AT The IBM Personal Computer/AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80 ...

-compatible machine with 640 KB of conventional and 512 KB of

extended memory In DOS memory management, extended memory refers to memory above the first megabyte (220 bytes) of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems. D ...

, and either a (monochrome) CGA or an EGA graphics adapter. FlexOS supported a concept of dynamically 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.SYS ''binary'' file (not to be mixed up with the similarly named CONFIG.SYS configuration file under

DOS DOS is shorthand for the MS-DOS and IBM PC DOS family of operating systems. DOS may also refer to: Computing * Data over signalling (DoS), multiplexing data onto a signalling channel * Denial-of-service attack (DoS), an attack on a communicat ...

), and its shell (COMMAND.286) would execute a CONFIG.BAT startup batch job instead of the common AUTOEXEC.BAT. FlexOS's optional DOS emulator provided limited PC DOS 2.1 compatibility for DOS .COM and .EXE programs. 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 (see

LOADALL LOADALL is the common name for two different, undocumented machine instructions of Intel 80286 and Intel 80386 processors, which allow access to areas of the internal processor state that are normally outside of the IA-32 API scope, like ''desc ...

). These problems had already caused delays in the delivery of Concurrent DOS 286 earlier. The system optionally supported a multitasking GEM VDI for graphical applications. FlexOS 1.31 could be linked with none, either or both of these two modules. FlexOS 1.31 also supported

FlexNet FlexNet Publisher (formerly known as FLEXlm) is a software license manager from Flexera Software which implements copy protection, license management and is intended to be used in corporate environments to provide Floating licensing, floating lic ...

. By June 1987 there were also versions 1.0 of FlexOS 386 (for hosts) and FlexOS 186 (for remote cell controllers). FlexOS 386 provided a windowing feature, and offered PC DOS 3.2 and GEM compatibility. FlexOS 286 and FlexOS 386 versions 2.0 were registered on 3 July 1989. Among the major FlexOS customers in 1990/1991 were

FANUC FANUC ( or ; often styled Fanuc) is a Japanese group of companies that provide automation products and services such as robotics and computer numerical control wireless systems. These companies are principally of Japan, Fanuc America Corpor ...

, IBM, ICL, Nixdorf, Siemens, TEC, Thorn EMI Software and Micrologic. Novell bought Digital Research for million in July 1991. '' 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 new

Novell Embedded Systems Technology Novell Embedded Systems Technology (NEST) was a series of APIs, data formats and network protocol stacks written in a highly portable fashion intended to be used in embedded systems. The idea was to allow various small devices to access Novell ...

(NEST). When Novell decided to abandon further development of the various Digital Research operating systems such as

Multiuser DOS Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...

(a successor to Concurrent DOS) and

Novell DOS DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with IBM PC DOS and MS-D ...

(a successor to

DR DOS DR-DOS (written as DR DOS, without a hyphen, in versions up to and including 6.0) is a disk operating system for IBM PC compatibles. Upon its introduction in 1988, it was the first DOS attempting to be compatible with IBM PC DOS and MS- ...

), they sold FlexOS off to the Santa Clara, California-based Integrated Systems Inc. (ISI) for million in July 1994. The deal comprised a direct payment of half this sum as well as shares representing 2% of the company. The company already had pSOS+, another modular real-time multitasking operating system for embedded systems, but they continued to maintain FlexOS as well. 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 competitor

Wind River Systems Wind River Systems, also known as Wind River (trademarked as Wndrvr), is an Alameda, California–based company, subsidiary of Aptiv PLC. The company develops embedded system and cloud software consisting of real-time operating systems software, ...

in February 2000.

Commands

The following list of commands is supported by FlexOS: * ASSIGN * BACK * BACKUP *

BREAK Break or Breaks or The Break may refer to: Time off from duties * Recess (break), time in which a group of people is temporarily dismissed from its duties * Break (work), time off during a shift/recess ** Coffee break, a short mid-morning res ...

* CANCEL * CHDIR *

CHKDSK In computing, CHKDSK (short for "check disk") is a system tool and command in DOS, Digital Research FlexOS, IBM/Toshiba 4690 OS, IBM OS/2, Microsoft Windows and related operating systems. It verifies the file system integrity of a volume and ...

COMMAND Command may refer to: Computing * Command (computing), a statement in a computer language * COMMAND.COM, the default operating system shell and command-line interpreter for DOS * Command key, a modifier key on Apple Macintosh computer keyboards * ...

COMP Comp, COMP or Comps may refer to: Places In England: * Comp, Kent In France: * Comps, Drôme * Comps, Gard * Comps, Gironde * Comps-la-Grand-Ville * Comps-sur-Artuby Arts, entertainment, and media ;Music *Accompaniment, especially in jazz ...

* CONFIG *

COPY Copy may refer to: *Copying or the product of copying (including the plural "copies"); the duplication of information or an artifact **Cut, copy and paste, a method of reproducing text or other data in computing **File copying **Photocopying, a pr ...

* CTTY *

DATE Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity *Dating, a form of courtship involving social activity, with the aim of assessing a potential partner ** Group dating *Play date, a ...

* DEFINE * DIR *

DISKCOMP In computing, diskcomp is a command used for comparing the complete contents of a floppy disk to another one. Overview The command is used on DOS, Digital Research FlexOS, IBM/Toshiba 4690 OS, SISNE plus, IBM OS/2 and Microsoft Windows. It is ...

DISKCOPY In computing, diskcopy is a command used on a number of operating systems for copying the complete contents of a diskette to another diskette. Implementations The command is available in MS-DOS, IBM PC DOS, DR FlexOS, IBM/Toshiba 4690 OS, M ...

* DISKSET *

ERASE Erase may refer to: *Data erasure, a method of software-based overwriting that completely destroys all electronic data *Data remanence, the residual representation of data that has been, in some way, nominally erased or removed * ''Erase'' (album ...

EXIT Exit(s) may refer to: Architecture and engineering * Door * Portal (architecture), an opening in the walls of a structure * Emergency exit * Overwing exit, a type of emergency exit on an airplane * Exit ramp, a feature of a road interchange ...

FDISK In computing, the fdisk command-line utility provides disk-partitioning functions, preparatory to defining file systems. fdisk features in the DOS, DR FlexOS, IBM OS/2, and Microsoft Windows operating systems, and in certain ports of FreeBS ...

FIND Find, FIND or Finding may refer to: Computing * find (Unix), a command on UNIX platforms * find (Windows), a command on DOS/Windows platforms Books * ''The Find'' (2010), by Kathy Page * ''The Find'' (2014), by William Hope Hodgson Film and t ...

* FORMAT * FSET * LIST * LOGOFF * LOGON * MKDIR *

MORE More or Mores may refer to: Computing * MORE (application), outline software for Mac OS * more (command), a shell command * MORE protocol, a routing protocol * Missouri Research and Education Network Music Albums * ''More!'' (album), by Booka S ...

* ORDER * PASSWORD *

PATH A path is a route for physical travel – see Trail. Path or PATH may also refer to: Physical paths of different types * Bicycle path * Bridle path, used by people on horseback * Course (navigation), the intended path of a vehicle * Desire p ...

* PRINT * PROCESS * PROMPT * RECDIR * RECFILE * RENAME * RESTORE *

RMDIR In computing, rmdir (or rd) is a command which will remove an empty directory on various operating systems. Implementations The command is available in Unix (e.g. macOS, Solaris, AIX, HP-UX), Unix-like (e.g. FreeBSD, Linux), DOS, Digital Resear ...

* SECURITY * SORT * SYS *

TIME Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, ...

TREE In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

* TYPE *

VER Ver or VER may refer to: * Voluntary Export Restraints, in international trade * VER, the IATA airport code for General Heriberto Jara International Airport * Volk's Electric Railway, Brighton, England * VerPublishing, of the German group VDM P ...

* VOL

Versions

Known FlexOS versions include: Motorola 68000 /

Freescale Freescale Semiconductor, Inc. was an American semiconductor manufacturer. It was created by the divestiture of the Semiconductor Products Sector of Motorola in 2004. Freescale focused their integrated circuit products on the automotive, embedd ...

/ NXP ColdFire MCF5251 platform: *

1.0 (1985) * Concurrent DOS 68K 1.1 * Concurrent DOS 68K 1.20 (April 1986, 1986-05-27) * Concurrent DOS 68K 1.21 (1986) * FlexOS 68K 1.x?

Intel 80286 The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non- multiplexed address and data buses and also the ...

platform: * MP/M-286 (1982) * Concurrent CP/M-286 (1985) *

preview (1985-01) *

1.0 (1985-08-06) ** Concurrent DOS 286 1.0.01 (1985-08-18/1985-08-21) ** Concurrent DOS 286 1.0.02 (1985-08-22/1985-09-12) ** Concurrent DOS 286 1.0.03 (1985-09-10/1985-09-12) ** Concurrent DOS 286 1.0.04 (1985-09-17) ** Concurrent DOS 286 1.0.05 (1985-11-01) ** Concurrent DOS 286 1.0.06 (1985-12-10) * Concurrent DOS 286 1.1 (1986-01-07) * Concurrent DOS 286 1.2 (1986) ** Concurrent DOS 286 1.2.00 (1986-04-10/1986-04-24) ** Concurrent DOS 286 1.2.01 (1986-04-16/1986-05-19) ** Concurrent DOS 286 1.2.02 (1986-08-18) * FlexOS 286 1.3 (November 1986) * FlexOS 286 1.31 (May 1987) * FlexOS 286 1.5 (1988-02-29) * FlexOS 286 2.0.00 (1988-03-31) * FlexOS 286 2.0 (July 1989) * FlexOS 286 2.32 (July 1993) Intel 80186/

NEC V20 The NEC V20 is a microprocessor that was designed and produced by NEC. It is both pin compatible and object code compatible with the Intel 8088, with an instruction set architecture (ISA) similar to that of the Intel 80188 with some extension ...

/ V30 platform: * FlexOS 186 (1986-09-04 forked) * FlexOS 186 1.0 (June 1987)

Intel 80386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors NEC V60 is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network soluti ...

platform: *

Adaptations

IBM 4680 OS

Named IBM 4680 OS Version 1, IBM originally chose DR Concurrent DOS 286 as the basis of their ''IBM 4680'' computer for IBM Plant System products and

Point-of-Sale The point of sale (POS) or point of purchase (POP) is the time and place at which a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoic ...

terminals in 1986. The last release of the IBM 4680 OS has been Version 4, before it was replaced by IBM 4690 Version 1. Versions: * IBM 4680 Operating System Version 1 Release 1 * IBM 4680 Operating System Version 1 Release 2 * IBM 4680 Operating System Version 1 Release 3 * IBM 4680 Operating System Version 2 Release 1 * IBM 4680 Operating System Version 3 Release 1 * IBM 4680 Operating System Version 4 Release 1

IBM and Toshiba 4690 OS

In July 1993, IBM announced the adoption of FlexOS version 2.32 as the basis of their IBM 4690 OS Version 1, to be pre-released on 24 September 1993 and generally made available from 25 March 1994. 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. Further, it removed limits on the number of applications running concurrently due to its more efficient use of KOSPOOL. To support

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

, IBM 4690 OS Version 2 added support for long filenames by means of a

virtual filesystem A virtual file system (VFS) or virtual filesystem switch is an abstract layer on top of a more concrete file system. The purpose of a VFS is to allow client applications to access different types of concrete file systems in a uniform way. A VFS ...

(VFS) architecture and it introduced

FAT32 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by ...

volumes. According to "The Year of the Store?", IHL Consulting Group/RIS News, IBM 4690 OS still had a market share of 12% in the POS register/client market in June 2005, when IBM was starting to phase it out in favour to

IBM Retail Environment for SUSE IBM Retail Store Solutions was IBM's division in the retail market segment. During its run, IBM Retail Store Solutions had several product lines, both hardware and software. Hardware products included IBM SurePOS 700 point-of-sale systems or pri ...

(IRES). 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 released Toshiba 4690 OS Version 6 Release 4 in January 2014 and Version 6 Release 5 in January 2016.

Siemens S5-DOS/MT

Siemens used and still maintains FlexOS in their factory automation equipment as well. For example, their

Simatic SIMATIC is a series of programmable logic controller and automation systems, developed by Siemens. Introduced in 1958, the series has gone through four major generations, the latest being the ''SIMATIC S7'' generation. The series is intended for ...

S5 STEP-5 operating system S5-DOS/MT is based on FlexOS 386 with X/GEM, FlexNet and

Btrieve Btrieve is a transactional database ( navigational database) software product. It is based on Indexed Sequential Access Method (ISAM), which is a way of storing data for fast retrieval. There have been several versions of the product for DOS, Li ...

, whereas the smaller

S5-DOS CP/M-86 was a version of the CP/M operating system that Digital Research (DR) made for the Intel 8086 and Intel 8088. The system commands are the same as in CP/M-80. Executable files used the relocatable .CMD file format. Digital Research also ...

system, also present on these systems, is a variant of Digital Research's Personal CP/M-86. Siemens industrial systems like COROS LS-B/FlexOS, COROS OS-B/FlexOS, GRACIS/FlexOS, OS-525 were FlexOS and X/GEM-based. Computers such as the PC 16-20 and the PC 32 series were available with FlexOS as well.

CTM

The Japanese post office shared terminals III and CTM IV were based on FlexOS.