DECtape reliability?

Gary Oliver go at
Thu Nov 12 11:07:32 CST 2015

On 11/12/2015 05:24 AM, Tom Moss wrote:
> I've had very mixed (about 50/50) success with 9-track, but after reading a
> bit about DECtape it looks like they should still be holding up nicely.
> Anyone care to share their experiences?

Long, long time ago I had a DECtape that had been severely 'stretched' 
by a problem with a drive.  Normally when the drive reverses direction, 
it is smooth, and the tape stays firmly laying on the read/write head.  
But this drive needed adjustment and when the drive stopped after 
reverse motion, the motion on the left reel didn't stop as quickly as 
the motion on the right reel.  Results: the tape would rise above the 
head a bit than 'snap' down when motion had ceased and the tension was 
re-affirmed.  Once, unfortunately when I was out of the room, the tape 
flipped off the head and the reels started madly spinning (trying in 
vain to tension the tape that was no longer on the head area.  Since the 
motors were spinning at different speeds (re the 'braking' problem,) the 
right reel was spinning faster and 'winning' causing the tape to get 
twisted pretty badly into a 1/8 mylar 'rope'.

After powering down the drive and removing the tapes, I carefully 
unwound this mess and restored it to the original reel.  Part of the 
tape where the most twisting had been done was now 'stretched' and only 
about 80% of its original width.  You would think this would cause a 
problem?  Not with DECtape.  I was able to copy this wounded tape to 
another with no more than a few retries.  No data loss.

Alas, I tossed the original.  It would have been a good trophy.


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