DUPTAP command

[Neil Palmer <NeilP@xxxxxxxxxxx>]

OK - more a story for comment than a specific question, but I could ask
why does the DUPTAP command take so bl**dy long ?

Backed up all user data on an old model 400 (CPW 20.6) Friday night, to a
single 8mm 7/14GB tape (wrote 13.7GB to tape) on an internal 6390 8mm
drive.  Took just under 4.5 hours to do the complete save.
Saturday morning went to a model 270 (with CPW 950) to do DUPTAP from 8mm
to an SLR5-4gb (4/8GB tape) on a 6382 QIC drive, reading from a 7208-342
8mm drive.  DUPTAP took just over 6 hours !!  Also, weird thing is we kept
waiting for message to change QIC tape after about 8GB, but the message
never came.  It actually wrote all 13.7GB to a single 4/8GB tape (in
format QIC4DC). ???
Then back to new model 270 (CPW 150) with a 6386 QIC drive to reload all
user data. This managed to read the entire tape and restore all the data
in just under 3.25 hours !

It makes absolutely no sense to me why DUPTAP takes so long to run - even
longer than to run the actual save or restore jobs on much slower systems
(although the restricting speed is no doubt the write speed to an SLR5-4GB
tape, not the CPW of the box).  Anyone else have any annoying experiences,
or knowledge, on this stupid command ?   ;-)

...Neil