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                       The Elliott 903
                   Algol library facilities
                   ------------------------

Elliott 903 Algol had a library for handling relocatable binary code,
but not for source code. The point was to call procedures which were
written in SIR assembly code and to use the limited storage space more
efficiently.

When translation began from source paper tape to relocatable binary
paper tape there was an option to perform a library scan when the
end of the source tape was reached. The library tape was then placed
in the reader and each procedure was read in, at full speed until its
own bit of trailing blank tape, and either copied to the output tape 
or rejected as appropriate. Something like 600 locations could be 
saved in this way. 

This version of the simulator provides these facilities in a new file
called LIBRARY.DAT which contains all the 903 procedures apart from
those driving the plotter. The file is in ASCII format having numbers
where each represents one row of paper tape. 

Most of it is a direct transcription of the standard library tape, but
half a dozen procedures are derived from independently compiled Algol
procedures. The source code of these is given together with the recipe
for converting them to relocatable binary code. They are of more than
just curiosity value despite the quaint rules which apply to them.
Three were written in 1963 at the Matematisch Centrum in Amsterdam.

It might be advisable to unpack the files into a temporary directory,
but if the names of your own Algol programs do not clash with those
of the new examples it will unpack properly into the old directory. 
SIM900AL.EXE and SIM900AL.LST should replace the existing files, but
M0.DAT and M1.DAT should not; they are included for completeness.



The simulator of the Elliott 903 included here is:

NEW900AL.ZIP    by Terry Froggatt and Don Hunter
                (don@gnhunter.demon.co.uk)


DGNH [ed CPB]  29-SEP-1997

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