IBM System/23 Datamaster

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System/23 Datamaster
IBM Datamaster (2282600489).jpg
Release dateJuly 1981; 39 years ago (1981-07)
Introductory priceUS$9,000 (equivalent to $25,310 in 2019)
Discontinued1985 (1985)
Operating systemBASIC built-in
CPUIntel 8085 @ 4.77 MHz
Memory256 kB RAM / 112 kB ROM
Storagetwo 8-inch floppy disk drives
DisplayGreen phosphor CRT display (80 X 24 text)
Mass43kg (95 lbs.)
PredecessorIBM 5120
SuccessorIBM Personal Computer

The System/23 Datamaster (Model 5322 desk-top model and Model 5324 floor model[1]) was announced by IBM in July 1981. The Datamaster was the least expensive IBM computer until the far less expensive and far more popular IBM PC was announced in the following month.[2][3]


The Datamaster is an all-in-one computer with text-mode CRT display, keyboard, processor, memory, and two 8-inch floppy disk drives in one cabinet. The processor is an 8-bit Intel 8085, with bank switching to manage 256 kB of memory.[4] The intention of the Datamaster was to provide a computer that could be installed and operated without specialists.

A BASIC interpreter was built-in to the system. IBM decided to merge the Datamaster's BASIC implementation with System/34 BASIC, which reportedly delayed the Datamaster by almost a year.[4] When introduced, a single-screen Datamaster sold for around US$9,000 (equivalent to $25,310 in 2019). A second keyboard and screen could be attached in an extended configuration.

Influence on later IBM systems[edit]

The familiarity of the design group gained on the Datamaster project encouraged selection of an Intel CPU for the IBM PC. The delay caused by the decision to reuse System/34 BASIC in the Datamaster was one of the factors in IBM's selection of Microsoft BASIC for the PC (the other being the ubiquity of Microsoft BASIC on other home computers at the time).[4]

A number of components from the Datamaster were reused in the later IBM PC. The PC's expansion bus, later known as the ISA bus, was based on the Datamaster's I/O bus.[5] The Datamaster's Model F keyboard with its IBM 5250 style layout was also reused in the PC, albeit with a serial interface (instead of the parallel one used on the Datamaster) and a new external housing.[4]


  1. ^ Data Communication Concepts (PDF) (GC21-5169-4 ed.). International Business Machines. September 1983. p. 6-7. Retrieved 7 January 2018. CS1 maint: discouraged parameter (link)
  2. ^ Pollack, Andrew (1981-08-13). "Big I.B.M.'s Little Computer". The New York Times. p. D1. ISSN 0362-4331. Retrieved 2020-03-16.
  3. ^ Pollack, Andrew (1983-03-27). "Big I.B.M. Has Done It Again". The New York Times. p. Section 3, Page 1. ISSN 0362-4331. Retrieved 2020-03-16.
  4. ^ a b c d Bradley, David J. (September 1990). "The Creation of the IBM PC". BYTE. pp. 414–420. Retrieved 2 April 2016. CS1 maint: discouraged parameter (link)
  5. ^ John Titus (2001-09-15). "Whence Came the IBM PC". Retrieved 2020-10-13.

External links[edit]

Preceded by
IBM 5120
IBM Personal Computers Succeeded by
IBM Personal Computer