[Info-vax] DLT Tape degaussing services

[Richard B. Gilbert]

JF Mezei wrote:
> Richard B. Gilbert wrote:
> 
>> Is there some reason you can't simply INIT the tapes and reuse them?
> 
> when you physically load the tape, the tape drives discovers the type of
> tape being loaded and will preserve that type and/or won't let you init
> it as a different type of tape.
> 
> For intance, if you mount a TK70 onto a DLT drive, it will be mounted
> write-locked. Can't init it.  But zap all information from the tape, and
> the drive will have a "?" as tape type and probanly initialises it as
> its own native format (equivalent of a low level format of a disk) and
> then let you init it.

I'm not at all sure that a TK70 tape has the proper magnetic 
characteristics to allow writing in a DLT drive; certainly not in a 
DLT-3 or DLT-4 drive.  ISTR that some DLT drives could read TK50/TK70 
tapes but not which ones.  At this point in time, a TK50 or TK70 drive 
is probably more trouble than it's worth!  Both the capacity and the 
speed are too low to make them practical for backing up any reasonably 
modern disk drive.  You could die of old age while waiting for a TK50 to 
back up a four GB disk.  Your children would die of old age before it 
finished an 80 GB disk!