Best 8mm tapes?

[Bruce Karsh]

In article <JIM.90Jun29141926 at baroque.Stanford.EDU> jim at baroque.Stanford.EDU (James Helman) writes:
>Does anyone know if using the top quality tapes completely saves you
>from the write-through problem?  The problem (myth?) as I understand
>it is that over time (> 1 year) the magnetic pattern written on one
>section tape can affect the next layer with which it is in contact.
>I've heard that some manufacturers advise you to rerun the tape every
>year just to change the way it's wound on the reel.  Otherwise it's
>data decay time.  Since we keep many tapes for 5 or more years, we've
>been too paranoid to buy an 8mm drive, although others here seem quite
>happy with theirs.

Print-thru on tapes is an old problem.  I've seen advice to re-run
old-fashioned 1/2 inch tapes periodically too.  However, hardly anybody
does this and the tapes seem to work for years without it.  It might be
a good idea though if you are archiving data "for eternity".  I have
seen very old 1/2 inch (1600 bpi) tapes which had accumulated read errors
over time.

I don't know whether 8mm is any better or worse than 1/2 inch tape.

>If top quality tapes don't guarantee long term data storage, will SGI
>or a third-party have a DAT subsystem out soon?  I understand they
>are much better in this regard.

Computer DAT tapes have 3 layers of error correcting codes.  The audio
DAT tapes only have 2.  Since consumer music tapes will soon be competing
with CDs and cassettes, they'll have to be adequate media to allow the
audio tapes to last for years.  If that's the case, then the extra
layer of ECC should ensure that computer data will also last for years.


			Bruce Karsh
			karsh at sgi.com