18 Apr
2024
18 Apr
'24
2:01 p.m.
The tape for the Burroughs 220 drives was not metallic. It was 3/4-inch wide, and I think
a Mylar sandwich. It could be spliced much the same way you would have spliced
quarter-inch reel-to-reel audio tape back in the day.
If the tape controller detected a parity error, it would backspace the block and retry
twice. If the error persisted on the second retry, the tape would stop with the head ready
to read the bad block (hanging the processor in the middle of its I/O instruction), and
the operator would have to take manual action. If the drive punched a hole in the tape,
then the drive needed service -- probably a bad capstan pinch-roller solenoid.