Help reading a 9 track tape

Chuck Guzis cclist at
Mon Aug 2 19:45:00 CDT 2021

On 8/2/21 8:11 AM, James Liu via cctech wrote:
> Thanks for feedback and offers to assist.  

Happy to contirubte.

> For some background, Tini Veltman developed Schoonship in the 1960's
> at CERN on the CDC 6600.  My understanding is that he more or less
> insisted on coding in assembly since he thought FORTRAN or other high
> level languages would just get in the way and slow things down.  The
> code was maintained by Veltman and Strubbe well into the 1970's, but
> its future was held back by being so closely tied to CDC hardware.

Which CDC FORTRAN?  RUN, maybe--but FTN extended was pretty darned good
in optimizing and scheduling instructions. A lot of work went into that one.

As a matter of fact, when we COMPASS scriveners came up against a nasty
loop that we wanted to optimize for the 6600, one approach was to code
it in FORTRAN to see what the compiler would do with it and then work
from there.   Some of the optimizations were quite startling,
particularly with the "UO" option selected.

If you've never written and hand-optimized 6600 code, it could be a
daunting task.

Did you know that parts of FTN are written in FTN?  I recall the
COMMON/EQUIVALENCE processor written as a mess of assigned GOTO
statements (state machine) and being utterly bereft of commentary."Don't
touch it--you might break something!"

FORTRAN was CDC's bread-and-butter language for years, as it was the
universal choice of number-crunchers everywhere during the 60s through
80s.  And CDC excelled at number-crunching.

My .02 for what it's worth.

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