IMBOS is a useful adjunct to the Spectrum and Microdrive operating system. It requires the use of Interface 1 (both versions are catered for), and is supplied on cassette which can be transferred to microdrive.

IMBOS 1.1 adds no fewer than 53 commands to Spectrum Basic The twelve page manual explains each new instruction in turn, and there's a ten minute demo program which runs through some of the possibilities. IMBOS itself occupies 8117 bytes of memory. The new commands cover the whole range of programming and interfacing. There are ten for microdrive operations, including simple and complex file cataloguing, a simplified RUN command, and even a command to change the border colour during microdrive operations. There's a decimal/hex converter a PAUSE command, and a selection of useful ink/border/paper commands.

You can store screen strings in a reserved area of memory then call them back for very fast serial display. It's also possible to move any chunk of code very quickly.

Additional features include sound effects, scrolling text routines, a header reader, a mini-monitor and a series of error messages Good value for money, a pity it's limited to IF1 owners.

Useful set of utilities for the Sinclair Interface 1 and microdrive.