Rich kids are into COBOL

Jon Elson elson at
Sun Mar 1 21:51:25 CST 2015

On 03/01/2015 05:13 PM, Mark Linimon wrote:
> You see ... my *first* machine was a Bendix (although late 
> enough to be labeled Control Data) G-15.
Yup, I tried to help bring up a surplus G-15D, but finally 
discovered the drum was
trashed.  If you didn't reorganize the instruction stream 
around the drum for
best access time, the machine ran at roughly 30 IPS, one 
instruction per drum revolution.
(I'm simplifying here, as the drum on the G-15 had 
recirculating tracks that were
rewritten continuously between read head and write head.)  
if you reorganized
the instructions to just come under the head when the last 
instruction was done,
you could get 10K + IPS.  A number of other drum-memory 
machines used
similar schemes.  And, that was the GREAT advantage of core 
RANDOM access!


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