At 15:13 -0600 on 03/08/2014, Barry Merrill wrote about Re: [OT ]
Mainframe memories:
In 1972, the Corporation's Annual P&L job read multiple tape reels
from each of
the 26 regional offices, so 26 tape drives were allocated to the
job, which took
over 40 hours across a dedicated weekend, and the operators were kept busy
mounting and dismounting, but when they had all 26 drives mounted
and spinning,
and could take a breath to watch, it was a sight to behold.
It was so beautiful that one of the junior tape operators took a picture of
the spinning tapes.
With flash.
Causing half of those spinning tape drives to abruptly open, because
the optical
sensor saw that flash of light as the reflector at the end of the tape, and
ABENDing the job.
This reminds me of the story of a computer center which was in a
high-rise building and about 3 months after some non-IBM drives were
added to the IBM ones the non-IBM drives suddenly started to
experience a problem. At about 3PM they would suddenly dump their
tape loop into the column or unload. High level CEs were called in to
diagnose the problem. They finally figured out that the sun was being
reflected off the glass windows of the building across the street
triggering the optic sensors (IBM Drives used vacuum not optic
sensors in the columns so were not affected). The symptom took 3
months to occur since until then the sun was not in the correct
position to be reflected. The fix was to put blinds over the windows.
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