Work in progress

 

Leo III

In 2001 a cache of paper tapes from Leo III was unearthed well-preserved in a tin box in a garage. It seems that they are not the system that we once thought that they were, but perhaps an engineer's kit of software.

Now that we have a Leo III emulator, exploration of these tapes is now possible, and has only just begun. Understanding of the tapes is currently rather limited. (click here for a lot more detail).

In 2003 we said ...

It seems that all but one of the tapes are binary machine code. At least they make little sense when interpreted according to the character code. So far nobody seems to recollect how the 7-bit characters on the paper tape were loaded into the 21-bit short words of Leo III in order to form machine code instructions. We have information on the order code itself, and could disassemble the binary tapes, if we could create the binary image.

However, the real ambition is to have the proper system. The Leo III archive in Manchester has 3 magnetic tapes, but there is a lack of information as to what they contain. If they contain the system, we would very much like to know. Knowledge of the magnetic tape format would help.

There is a real possibility that we could actually read the 1" tapes.

Is there any other machine-readable information from Leo around?


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