The Heathkit H11 Digital Computer

This advert, for Heathkit's H11 microcomputer, was part of an extravangant sixteen page spread in September 1977's Byte - The Small Systems Journal magazine. 

It introduced the company's H8 and H11 micros, as well as the H9 video terminal, H10 paper tape reader, various memory and interface modules and even a cassette recorder for cheap storage.

[picture: heathkit_h10.webp|Heathkit's H10 paper tape reader and punch, retailing for $350, or about [[240|1977]] in [[now]]]

The H11 was a collaboration between Heath/Schlumberger and [@Digital|Digital Equipment Corporation], otherwise known as DEC. 

It was nominally a 16-bit machine, using DEC's LSI-11 microprocessor unit - essentially the logic part of a DEC PDP-11 contained on four LSI (large-scale integration) chips.

The PDP-11 (Programmed Data Processor) was a famous series of minicomputers first launched in 1969, and was the machine upon which the first named version of Unix ran, following on from its initial development on a PDP-7.  

DEC continued selling versions of the PDP-11 up to 1990[source: https://gunkies.org/wiki/PDP-11], with some estimates suggesting that the company sold around 600,000 models in total. 

[picture: heath_dec_agreement.webp|The Heath/DEC software agreement, required for any order]

Heathkit's minimum recommended setup for the H11 included the computer itself at $1,295, a 4K memory module for $275, a parallel and serial interface, the H9 video terminal and an H10 paper tape reader, all for a bundled price of $2,508 - that's about [[1672|1977]] in [[now]] money. 

The presence of DEC's PDP-11 software on the H11 required the unusual step of having to sign a software licence agreement with every order.

