DECTape head problem

[Jon Elson]

On 2/8/22 15:49, Paul Koning via cctalk wrote:
>
>> The maintenance manual (on Bitsavers) speaks of a "read/write head" and has an illustration that shows one of the head elements with a "read/write coil".  So the implication is that (a) there isn't an erase head, and (b) the same head serves for read or write according to whether the coil is being driven or sensed.
Yes, that is right.
>>    Come to think of it, I think erase heads are an aspect of audio tapes, not relevant to computer tapes.

No, all 9-track drives that I know of have erase heads that 
erase the tape to a no-transitions state before it is 
written on.  This allows you to obliterate old data when 
writing a new record, and leave gaps between records.  Since 
DecTape was synchronized by clock and mark tracks, that was 
not needed.

Jon