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, 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.

Background

The Heath Company, makers of electronic kits, announced its first two digital computers in 1977, including the H11 and less-expensive Heathkit H8. The company hoped that computers would soon provide more than 20% of revenue.

Specifications

The H11 features:

Processor – LSI-11
Speed – 2.5 MHz
ROM – 8 kWords
RAM – 32 kWords
Slots – 7 Q-bus slots
Storage – H27 8-inch floppy drive or paper tape
I/O – serial or parallel ports
Operating system – HT-11
Instruction set – PDP-11/40 instruction set
Languages – BASIC, Focal and others

H11 owners were eligible for DECUS membership, giving them access to that organization's library of software. Initial memory limitations restrict the selection of system software, but the system RAM can be expanded to 32 kWords x 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.
The H11 did not sell well. After discontinuation, a Heath/Zenith executive at a 1982 convention of Heath/Zenith owners told "a lonely H11 fan" that the new Zenith Z-100 "could run rings around the H11... The H11 is Sixties technology".