10. Operating System Error Messages
A non-implemented OS call was used, probably via one of the BASIC keywords listed as 'Not implemented'.
All further errors are identical to the corresponding normal ATOM errors.
The filename specified in LOAD, SAVE, *LOAD or *SAVE was not a legal filename.
The operating system command was unrecognised.
Erroneous data was received while loading from tape.
An operating system command was recognised, but was followed by illegal parameters.