IBM System/23 Datamaster

The System/23 Datamaster (Model 5322 desktop model[1] and Model 5324 floor model[2]) was announced by IBM in July 1981.[3] 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.[4][5]

System/23 Datamaster
ManufacturerIBM
TypeAll-in-one
Release dateJuly 1981 (1981-07)
Introductory priceUS$9,000 (equivalent to $28,970 in 2022)
Discontinued1985 (1985)
Operating systemSystem/34 BASIC
CPUIntel 8085 @ 4.77 MHz
Memory64 KB, 128 KB, 256 KB RAM
112 KB ROM
Removable storageTwo 8-inch floppy disk drives
DisplayGreen phosphor CRT display (80 × 24 text)
InputModel F keyboard
ConnectivityPrinter port, disk drive port
Mass95 lb (43 kg)
PredecessorIBM 5120
SuccessorIBM Personal Computer
RelatedIBM Displaywriter System

Description

5120
Datamaster
Visual differences between 5120 and Datamaster

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.[1] The processor is an 8-bit Intel 8085[6] running at 4.77 MHz,[7] with bank switching to manage 256 KB of memory.[8] Available RAM was 64 KB (expandable to 128 KB[7]), and the machine had 6 internal expansion slots.[6] It could display 80 × 24 characters of text (each character with 10 × 14 pixels) with 256 possible characters, similar to the IBM PC's Code page 437, on a built-in 12" green phosphorus CRT.[6][9]

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.[8] When introduced, a single-screen Datamaster sold for around US$9,000 (equivalent to $28,970 in 2022). A second keyboard and screen could be attached in an extended configuration.

Influence on later IBM systems

The familiarity 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 popularity of Microsoft BASIC on home computers at the time).[8]

A number of hardware components from the Datamaster were reused in the later IBM PC.[8] The PC's expansion bus, later known as the ISA bus, was based on the Datamaster's I/O bus.[10] The Datamaster's Model F keyboard with its 5251-style key arrangement 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.[8]

From a software perspective, since the new IBM PC was using 8-bit characters, there were 128 new characters beyond the 7-bit ASCII characters which could be used. ASCII only defined the characters with numbers from 0 through 127, so the numbers from 128 to 255, which had the high bit turned on, were not defined yet. IBM’s design put additional characters there—three columns of foreign characters, based on their Datamaster experience, as described at Code page 437.

Timeline

Timeline of the IBM Personal Computer
IBM ThinkCentreIBM NetVistaIBM Palm Top PC 110IBM PC SeriesIBM AptivaIBM PS/ValuePointThinkPadEduQuestIBM PS/noteAmbra Computer CorporationIBM PCradioIBM PS/1IBM Industrial SystemIBM PS/55IBM PS/2IBM Personal Computer XT 286IBM PC ConvertibleIBM JXIBM Personal Computer AT/370IBM Personal Computer ATIBM Industrial ComputerIBM PCjrIBM Portable Personal ComputerIBM Personal Computer XT/370IBM 3270 PCIBM Personal Computer XTIBM 5550IBM Personal ComputerIBM System/23 DatamasterIBM 5120IBM 5110IBM 5100
Asterisk (*) denotes a model released in Japan only

References

  1. System/23 Setup Instructions with 5322 Computer (PDF). IBM. June 1982.
  2. Data Communication Concepts (PDF) (GC21-5169-4 ed.). International Business Machines. September 1983. p. 6-7. Retrieved 7 January 2018.
  3. "IBM Archives: IBM System/23 Datamaster". www.ibm.com. 2003-01-23. Retrieved 2023-04-08.
  4. 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.
  5. 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.
  6. "IBM 5322 System/32 Datamaster computer". www.oldcomputers.net.
  7. "IBM System/23 Datamaster".
  8. Bradley, David J. (September 1990). "The Creation of the IBM PC". BYTE. pp. 414–420. Retrieved 2 April 2016.
  9. IBM System/23 Service Library - Volume 1 : IBM 5322 Computer Service Manual (PDF). IBM. 1980. pp. 4–21.
  10. John Titus (2001-09-15). "Whence Came the IBM PC". edn.com. Retrieved 2020-10-13.
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