Heathkit H11

The Heathkit H11 Computer is an early kit-format personal computer introduced in 1978. It is essentially a Digital Equipment PDP-11 in a small-form-factor case, designed by Heathkit. The H11 is one of the first 16-bit personal computers, at a list price of US$1,295,^[2] (equivalent to $6,050 in 2023) but it also requires at least a computer terminal and some form of storage to make it useful. It was too expensive for most Heathkit customers, and was discontinued in 1982.^[3]

Heathkit H11

Manufacturer	Heathkit
Type	Personal computer
Release date	1978; 46 years ago (1978)
Introductory price	US$1295 (equivalent to $6,050 in 2023)[1] (kit) or US$1595 (equivalent to $7,451 in 2023)[1] (assembled)[2]
Discontinued	1982 (1982)[3]
Media	optional 8-inch floppy disks, optional paper tape
Operating system	optional HT-11
CPU	LSI-11 clocked at 2.5 MHz
Memory	4kword base system, maximum optional 32kword RAM, 8kword ROM (2 bytes/word)
Related	PDP-11

Specifications

The H11 featured:^[4]

• Processor — LSI-11 (KD11-HA half-size or "double-height" card)
• Speed — 2.5 MHz
• ROM — 8 kWords (16 KB) (max)
• RAM — 32 kWords (64 KB) (max)
• Slots — 7 Q-bus slots
• Storage — H27 8-inch floppy drive (2 256 KB 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 restrict the selection of system software, but the system RAM can be expanded to 32 kWords * 16 bit. Many PDP-11 operating systems and programs run without trouble. The system will also work with most DEC PDP-11 equipment, including many Q-bus compatible peripherals.

See also

• Elektronika BK
• Heathkit H8

References

1. 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved February 29, 2024.
2. Heathkit 1978 catalog pages retrieved 2011 July 11
3. 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

• Heathkit H-11 Computer, Heathkit Computer Advertisements, Decode Systems
• Computer Museum illustration of fully expanded H11 with the Heath/Zenith label.