This is side one of the cassette that was supplied with the kit. You get two sample games, NEW YORK TAXI and HECTIC. Both games were written in BASIC.

Side two of the same cassette is the Extended Monitor. This program was loaded via the built-in machine code loader and provided a much more sophisticated monitor. Perhaps the most useful feature was the disassembler, but the monitor also included relocation utilities and a checksummed cassette load/save function.

Every UK101 owner aspired to own a copy of this program, the 8K Super Invaders. It was written in a bizarre mix of BASIC and machine code and used a special loading sequence to load first the BASIC, then a checksum loader, and finally the machine code. The machine code routine was patched into the UK101's control-C vector and hence was called after every BASIC statement. This gave it a very simple form of multi-tasking!

But that's not all that make this game special. Many owners increased the clock speed of their 6502 chips, making simple software-timed games unplayable. The 8K invaders used the UK101's serial port both for timing and to generate crude sound effects. You could connect a crystal earpiece to the RS232 lines and the game would send serial data to generate noises.

As if to prove that the UK101 was a “real” computer, you could buy blank tapes with the name of the machine pre-printed on them.