Sinclair Mk14 - 1978

In 1978, having renamed his company Science of Cambridge, the MK14 microprocessor kit was released. This was designed to train people in the use of microprocessors. It had a National Semiconductor processor and a mammoth 512 bytes of ROM (the system program) and 256 bytes of RAM (user memory). It was coded in hex rather than using an assembler. On a popular 8080 processor, to store two numbers and add them together can be done in the following increasingly difficult methods:

10 LET A=15
20 LET B=30
30 LET A=A+B


LDA 15


LDA 30


This is a lot more difficult to understand and one extra step as you can only load a number into the A register. (similar to a Variable)

MACHINE CODE (The only option on the MK14)

3A 15
3A 30

This was obviously far more tortuous to write though at least is very small. This occupies just 6 bytes, just as well with only 256 available!

It was actually amazing that anyone managed to program anything but somehow they did, about 20,000 brave souls. I have never been able to find one of these computers so if anyone has one in their loft then please think about me!

There are many indications that Sir Clive was not that interested in the project though things must have changed as Science of Cambridge then went on to develop the Newbrain. Their aim was the sub-£100 computer able to work in BASIC and with a proper screen (compared with a row of 8 LEDs on the MK14). The generally accepted story is that it was obvious the Newbrain would not be under the magic £100 mark so it was sold off to Grundy (more later). Instead, work started on the ZX80 which was released, somewhat unremarkably, in 1980!