Original Message:
Hello All,
It has been suggested in our lab that ALL archive tapes (Exabyte 8mm) be retensioned on a yearly basis in order to prevent damage due to constant magnetic fields. The argument is that, over time, the spooled tape is exposed to a constant magnetic field, caused by its own recorded magnetic pattern, that acts to limit the life of the tape. The proposed solution is to retension the tape - the idea being that it is very unlikely to return to its exact previously spooled position, hence exposing each portion of
the tape to a new magnetic field.
Has anyone ever heard of this procedure? Is it necessary? Thanks for your help...
Results:
Responses were many, but the majority claimed this technique DOES help to
extend the life of spooled magnetic tapes (1/2" reel. 1/4" cartridge, etc.).
A few people claimed they had never experienced difficulty in reading their
archived backup tapes, even though they had been untouched for years. Lucky?
Quite a few people believed they had lost archived data due to this
"imprinting" of various magnetic fields, and a few others felt they lost
data purely because the lifespan of their Exabytes is only a couple of
years! (I'm not sure what the life expectancy is really supposed to be for
Exabytes, but I would assume it is at least a few years! After all, what good
is an archive tape that only lasts 1-2 yrs?)
It was also mentioned that 'mt -f /dev/rstx retension' does not work on
systems running 4.1.3 or Solaris 2.3. It is true! But the work-around
seems to be reading to the end of the recorded data, then rewinding to
the start of tape as follows:
mt -f /dev/rstx eom
mt -f /dev/rstx offline
Looks like we'd better start "walking" our tapes every now and then!
There were too many responses to list individuals names, so I would like to
extend my thanks to all those persons who took the time to respond! Hope
this helps...
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Name: Marlow, Matthew Michael Nickname: Matt
Dept: Neurosciences Phone: 534-5560
Office: 3047 BSB Postal address: 0608
E-Mail: mmarlow@UCSD.EDU
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This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:09:06 CDT