Edos
| Company type | Private |
|---|---|
| Industry | Computer software |
| Founded | 1972 |
| Founder | Jerry Enfield, Tom Steel |
| Fate | Acquired by Nixdorf in 1980 |
| Successor | Nixdorf Computer Software Company (NCSC) |
| Headquarters | Richmond, Virginia , United States |
Area served | Canada, Australia, Europe |
| Products | Edos, Edos/VS, Extended Console (Econ) |
Edos was an operating system, now obsolete, derived from IBM's original mainframe DOS—not to be confused with the unrelated MS-DOS designed for IBM PCs. The acronym represented extended or enhanced disk operating system. Subsequently, the West German firm Nixdorf acquired it and rebranded the system as NIDOS (Nixdorf Disk Operating System).
In 1970, IBM launched the IBM/370 series, introducing new hardware platforms alongside operating systems like DOS/VS, which succeeded DOS. Despite IBM’s shift towards these innovations, a significant number of users continued relying on the IBM/360 architecture, fostering a need for enhanced DOS-compatible solutions.
Starting in 1972, The Computer Software Company (TCSC) addressed this demand by developing Edos. Their enhancements included increasing fixed program space partitions from three to six, supporting additional hardware devices, and incorporating features that IBM had previously offered separately. Edos was introduced in 1972 as a response to IBM’s declaration that DOS Release 26 would be the final version supported on System 360, with all subsequent updates focusing exclusively on System 370.
TCSC also delivered third-party add-ons such as a spooler and DOCS provided by CFS, Inc.
Edos/VS and Edos/VSE
In 1977, TCSC announced an upgraded version called Edos/VS, which reached beta testing sites in 1978. This release aimed to match the capabilities of IBM’s DOS/VS Release 34 and Advanced Functions-DOS/VS.
Unlike IBM’s DOS/VS that required System 370 models equipped with virtual storage hardware, Edos/VS was compatible with both System 360 and System 370 machines lacking virtual storage features. To achieve this, TCSC adapted System/370-specific instructions found in IBM’s DOS/VS Release 34 to operate on System/360 hardware. The company lawfully reused IBM code since it had been published without copyright protection, thus falling into the public domain under the relevant US legislation at that time.
By 1981, Nixdorf Computer Software Company (NCSC) announced Edos/VSE 2.0, based on IBM DOS/VSE Release 35 and designed for IBM 4300 mainframe systems.
TCSC corporate history
Founded by Jerry Enfield and Tom Steel—who managed development and marketing respectively—TCSC was headquartered in Richmond, Virginia. The company expanded its operations internationally, establishing presence in Canada, Australia, and across Europe. Among its product offerings was the Extended Console (Econ) system, which enabled system console interfaces to be displayed on CRT terminals such as the IBM 3270. Econ supported both IBM's DOS and DOS/VS platforms as well as TCSC’s own Edos and Edos/VS operating systems.
In 1980, TCSC was acquired by Nixdorf and subsequently renamed NCSC. By 1982, Nixdorf had rebranded Edos to NIDOS/VSE and promoted it for use with their Nixdorf 8890 line of IBM-compatible mainframes.
TCSC had licensed DATACOM/DB from Applied Data Research (ADR) for operation under EDos and EDos/VS environments. Following Nixdorf’s acquisition of TCSC, a licensing dispute arose but was resolved in 1981 through an agreement permitting Nixdorf to continue reselling ADR’s software products.
In July 1985, Nixdorf introduced Nidos/VSE Release 2.
Add-on products for Edos
In 1973, TCSC introduced a remote job entry (RJE) capability tailored for Edos.
Two years later, in 1975, a tape management system (TMS) was developed and released specifically for Edos.
By 1983, NCSC unveiled Programmer Work Station/VSE-Advanced Functions (PWS/VSE-AF), a Unix compatibility layer designed for IBM mainframes operating IBM's DOS/VS(E) as well as Nixdorf's Edos/VS and Edos/VSE. This subsystem was built upon the Coherent Unix clone created by the Mark Williams Company.
Discontinuation
In 1989, Nixdorf withdrew from the IBM-compatible mainframe sector to concentrate on Unix-based technologies. The company transferred its Nixdorf 8890 mainframe clones to Comparex Informationssysteme GmbH. While Comparex took over the hardware segment, it declined to support the Edos operating system, instead advising clients to migrate to IBM's DOS/VSE or MVS platforms. As a result, Nixdorf halted further development of upcoming Edos versions to avoid ongoing maintenance obligations.