Heathkit H11

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Heathkit H11
TypePersonal Computer
Release date1978; 41 years ago (1978)
Introductory priceUS$1295 (equivalent to $4,975 in 2018)[1] (kit) or US$1595 (equivalent to $6,127 in 2018)[1] (assembled)[2]
Discontinued1982 (1982)[3]
Mediaoptional 8-inch floppy disks, optional paper tape
Operating systemoptional HT-11
CPULSI-11 clocked at 2.5MHz
Memory4kword base system, maximum optional 32kword RAM, 8kword ROM (2 bytes/word)
Related articlesPDP-11

The Heathkit H11 Computer was an early kit-format personal computer introduced in 1978. It was essentially a Digital Equipment PDP-11 in a small-form-factor case, designed by Heathkit. The H11 was one of the first 16-bit personal computers, at a list price of US$1,295,[2] but was too expensive for most Heathkit customers and was discontinued in 1982.[3]


The H11 featured:[4]

  • Processor — LSI-11 (KD11-HA half-size or "double-height" card)
  • Speed — 2.5 MHz
  • ROM — 8Kwords (16 Kbytes) (max)
  • RAM — 32Kwords (64 Kbytes) (max)
  • Slots — 7 Q-bus slots
  • Storage — H27 8-inch floppy drive (2 256k 8-inch single sided drives) or paper tape
  • I/O — serial (RS-232) or parallel ports
  • Operating system — HT-11 (a simplified version of RT-11)
  • Instruction set — PDP-11/40 instruction set
  • Languages — BASIC, Focal and others

Initial memory limitations restricted the selection of software the system could handle, but the system could be expanded to 32KW x 16-bit RAM. Many PDP-11 operating systems and programs ran without trouble. The system would also work with most DEC PDP-11 equipment, including many Q-bus compatible peripherals.

See also[edit]


  1. ^ a b Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved January 2, 2019.
  2. ^ a b Heathkit 1978 catalog pages retrieved 2011 July 11
  3. ^ a b Wise, Deborah (1982-09-13). "Heath joins Zenith to attract hobbyists, businesses". InfoWorld. p. 19. Retrieved 8 January 2015.
  4. ^ 1977 advertising material from Heathkit of Benton Harbor, Michigan.

External links[edit]