27 Nov
2021
27 Nov
'21
3:53 p.m.
DEC's VAX/VMS group got a customer bug report that was accompanied by
a 9-track tape containing the programs and data necessary to reproduce
the problem. When the engineer mounted the tape, it contained
completely different data. He tried a different tape drive and this
time he got the expected data. It turned out that the customer had
reused the tape and recorded the reproducer at 1600 bpi on top of
previous data recorded at 800 bpi. If the tape was mounted such that
the drive didn't see the PE burst, it could still read the
NRZI-encoded 800 bpi data.
-Paul W.