Digital Systems, Digital Microsystems

Herb Johnson last updated June 13. 2011, links added 2020 (c) Herb Johnson 2020


These are research notes on the history of Dr. John Torode's Digital (Micro)Systems, its assets and the companies which owned them. Web research led to documents and books, which led to more Web searches. See this Web page for discussion of Dr. Torode's and Digital Systems early work, up to Torode's CP/M floppy controller product. Some of Digital System's history, as part of the general history of 8080 and CP/M history, is in outline form on this linkedWeb page. My home page for CP/M early history is at this Web page. - Herb Johnson

History of Digital Systems or Digital Microsystems

John Torode's "Digital Systems Inc." began in 1968 when he was a graduate student, according to private correspondence with him in 2008. I detail his early work as part of background history for Torode's design and production of a CP/M supporting floppy controller, on this Web page. It became "Digital Microsystems" or "DMS" in the late 1970's. DMS developed and sold a number of CP/M-based computer products, later IBM-PC related products, leading to a local area network product called "Hinet". DMS was sold to a U.K. company in 1984 and may have ended US operations by 1986.

The trail of activity and acquisitions seems to be as follows below.

A former employee of DMS contacted me in 2011. Here's Steve Kline's recollections of the company on this linked page.

A biography of Dr. John Torode is on the University of Washington's Web site as a Distinguished Alumnus.

In April 2008 I found a 1988 book which described Hinet as a product of Apricot Computer, a UK computer company of the 1970's and 1980's. With this reference I found that in April 1987, Digital Microsystems Ltd's networked microcomputer business (Hinet) was sold by Extel to Apricot Computers PLC. Extel Group Plc was a large UK company with holdings in computing, communications, and media. Apricot, a UK computer company from the 1970's, sold and supported the Hinet product. They produced computers until January 1999, when they were acquired by Mitsubishi and shut down; the factory assets were auctioned off in September of 1999.

Products and companies associated with Digital (Micro)Systems

Description of Hinet

HINET was an early networking architecture from Digital Microsystems. Here's some notes about it. Apricot computers bought the UK Digital Microsystems assets (as I'll explain later).

From book "Lans Explained: A guide to local area networks" by W. Scott Currie, Edinburgh University Computing Service, pub. John Wiley & Sons and Ellis HOrwood Ltd. and Halsted Press. 1988, 1989. Pages 66-67:

"Apricot Computer's HINET is a typical example of a shared filestore network, amied at supporting a range of PC'S from different manufacturers, particularly IBM and Apricot. Attachment to the LAN is via interface boards which slot onto the computer's internal bus rather than by use of the RS-232 ports. The heart of the system is the "network controller", which comprises a hrad disk storage unit with a capacity of up to 184 Mbytes, a tape streamer and a system printer; these can be shared over the LAN by up to 63 stations. The LAN is bus topology and the raw data rate is 500Kbit/s. The controller treates all the stations as slaves and use a polling technique to control access. The mediub can either be a ribbon cable or twisted pairs."

"HINET is amimed at the office automation market, and liek other similarity targeted LANs offers many features partiularly attractive to that market. For example, data integrity is obviously important, and HINET has an optional duplicate disk system which copies every disk access to the main controller....Another important access to corporate wide area networks. This is achieved through "gateway stations" which support for example IBM 3270 protocols. Links to the telex newtork and dial-up access to remote computers are also offered."

"Finally, Apricot Computers, in commone with many other LAN manufacturers, make a range of workstations whichg have the necessary attachment hardware and software built-in. In the case of HINET product, they range from IBM-PC compatibles to advanced graphics stations."

The following is NOT a DMS product: Siemens HiNet and NiCom VS1500 and VS1600, ISDN, from 2004 Nor is Hitachi Information Network also called HiNet, "established in 1984..."

Apricot and Digital Microsystems

A search for "hinet" on the CBR publication Web site at yields two results from their 20-year online archive as below.

The March 1987 article refers to the sale of "Digital Microsystems Ltd networked microcomputer business. Extel has found a willing buyer in the shape of Apricot Computers Plc, which has agreed in principle to pay UKP1m cash on April 1 with another UKP1m on January 1, 1988 for the company....Apricot intends to continue to support the HiNet architecture that networks MS-DOS or CP/M workstations for the present, describing it as "part of its systems strategy". British Telecom is said to be DML's biggest customer, OEM and distributor.

"Apricot Integrates Digital Microsystems'' Products With Its Own In New Offerings" (Issue 683 for 18 May 1987)

The May 1987 article says in its entirity: "Apricot Computers Plc has moved quickly to integrate the products of its Digital Microsystems acquisition from Extel Group Plc with its own: it is offering a version of its 80386 machine as a server on the Digital Microsystems HiNet; the DMS 4000 has 2Mb 32-bit RAM, 70Mb file server and 20Mb disk server; the company is also offering a new 10MHz 80286 HiNet XA diskless workstation which comes in at UKP1,400."

Apricot Computers of the U.K.

According to Wikipedia as of April 2008, Apricot COmputers Ltd. was a UK computer manufacturer previously known as "ACT" or Applied Computer Techniques. They used the name "Apricot" from about 1985 to 1990. In 1990, acquisitions and spinoffs created companies such as "ACT Systems Integration", "ACTApricot", "ACT Logsys" and an acquisition of ITL or "Information Technology Limited". Apricot was ultimately bought out by Misubishi and closed down.

The 1990 reorganization which restored the Apricot name, is referenced in an article on Apricot for "CBR" or "Computer Business Review Daily News" issue 1339, 10th Jan 1990. The article mentiones the "acquired expertise of ITL, Sigmex, and Logsys Ltd". The article was archived on the Web site, which has many articles on Apricot through the 1980's and 1990's. Those articles suggest Mitsubishi bought Apricot's assets in 1990, only to auction them off by 1999.

Apricot made a number of CP/M machines and later IBM-PC "semi compatibles" as the F series, such as the F1, F2, F10, and others. Additional machines included the XEN and the VXFT. The last products of the company were Pentium MMX based.

A Web site for Apricot and ACT current owners is as of April 2008. The site has a more substantial history of Apricot. There is a Yahoo discussion group at called "actapricot".

A number of Apricot products are described on site's history page. The page concludes with a note taken from August 1999 in "Electronics Weekly" that "Mitsubishi Electric is auctioning off its Apricot Computers manufacturing site in Glenrothes, Scotland." It says the auction would be September 7th, and that Apricot was closed in January 1999 with 400 jobs lost.

Extel Group Plc

This was, or is, a large UK company which seems to have holdings in media and computing. There are some financial records of this company in the National Register of Archives in the UK, at . There is a reference to the "BAC Newsletter, June 1988". Apparently Extel Group was acquired by United Newspapers Group of the UK in 1987.

Research and references

Facts I knew before starting this research in 2008:

Digital Systems became Digital Microsystems sometime in the late 1970's. (Correspondence with Torode in 2008)

Digital Microsystems eveloped products for networking called HiNet (Hierachical INTegration network). (Assorted references.)

Digital Microsystems poduced the "Fox" or DMS-3F in 1982. A Z80 networked portable, also competed with Osborne. DMS-15 had hard drive. (from Web site )

Digital Systems or Digital Microsysytems was sold to a UK firm in 1986, had staff of 200. (Correspondence with Torode in 2008)

Web links about Digital Systems

Some Digital System Inc. and DMS product docs and software are on Marcus' archives. Warning: count to seven slowly when changing directories. There's DMS 400, DMS-3, DSM 816 and some HiNet and DSC/FDC materials.

Jeff Shook provided some Web links in March 2008 to some pages with more information as follows:

an employee's account in a Tech Republic blog. [dead link]

their Fox or DMS-3 microcomputer product.

their System 5000 product.

References in the literature

"New Products" column in IEEE "Micro" Volume 5, Issue 2, April 1985 Page(s): 95 - 100 - Mimic Master

"Product Highlights" pages of March 1985 issue of "IEEE Software" magazine:

DMS 200 Network Master, HiNet LAN systems from Digital Microsystems Inc. 1840 Embarcadero, Oakland, CA 94606. "Entry level network master has 200ns access time and softare and storage options to provide compact management of multiuser applications on HiNet systems; $4995

* From USA Defense Property Accountability System - IT manufacture codes:


* From "Computerized manufacturing automation: employment, education, and the workplace." 1984, NTIS publication #PB84-196500. Office of Technology Accessment, US. Congress. OTA-CIT-235, April 1984 LC 84-601053, page 300:

Regarding micro-based systems and the small-firm market for Manufacturing Resources Planning or MRP. "Digital Microsystems INc, for example, offers an MRP system aimed at companies with up to $25 million in sales. The system, offered with training, includes a local-area network, MRP software, and software for office automation and business graphics." A possible reference for this may be: "Micro Software brings material control to the Desk Top" in Modern Materials Handling, Jan 23 1984.

* From IEEE Micro, product summary page, June 1984 p 81:

Digital Microsystems Hinet PC adapter, "one slot board adds 64K RAM, Z80 processo and an RS-232 port to the IBM PC, permitting compatibility with Hinet member using either CP/M, CP/M-86 or MS-DOS. $495".

* From IEEE Micro, Recent Microsystems Announcements, page, Jan 1984 p 81:

DMS-816, IBM PC-compatible system runs MS-DOS or CP/M programs on the Hinet LAN and consists of a 12-inch monitor, dual Z80A and 8089 processsors, 256K RAM, 500K baud RS-422 network port...optional master station with 9-inch screena nd detatchable keyboard provides floppy- and hard-disk storage of programs. Priced at $1695.

Google Books search

Google books said in 2011, references to Digital Microsystems Inc occurs in:

Microcomputer Market Place, 1985, p 421 ISBN 0835219402 R. R. Bowker Co., pub.
Linked Local Area Networks by Alan James Mayne, 1986, Wiley, page 64 - on HiNet;
Guide to Local Area Networks - Page 143, T. J. Byers, Prentice-Hall. 1984.
A Manager's Guide to Local Networks, page 82. by Derfler, Stallings. 1983 Prentice-Hall

Interface Age, V9 no. 7-12 1984 page 95: "HiNet/PC adapter card for IBM PC's.

Computer and Control Abstracts, V17 1982 abst 1-13301, "Digital Microsystems' DSC-2"

Computer Decisions, V16 1984 Jan-Apr p 204: "Digital Microsystems DSC-2....benchmark testing.."

Digital Systems Inc 1970-79 search

A name like "digital systems" is simply too broad to search for on the Web. A few hits were found as follows:

"Walker's manual of western corporations" for 1975 p 1124, or 1974 p 909. or 1973 p982. "Acquisitions include digital systems inc. 1965..."

"Air Cargo" trade magazine, page 22, V 11 1967 Jan-June, something about "The company is also using the Data Cube System, manufactured by Detecto Scales, Inc., to obtain weight and cube information through a Digital Systems, Inc.,"

Contact information:

Herb Johnson
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