29 Aug
2015
29 Aug
'15
1:23 p.m.
On 8/29/2015 10:57 AM, Al Kossow wrote:
On 8/28/15 9:25 AM, Jay Jaeger wrote:
You can add Burroughs SP 3200 and SP 5000 and SP 9000 to your "bad boy"
list.
I had good luck with a 3M 777 6250 BPI Security Computer Tape.
Like you, I have not had any issues with IBM tape.
One Graham Verituf Certified Zero Defect at 3200 FCI / 1600 BPI that I
processed did leave some residue, even after baking.
If a tape is at 1600 BPI, I can sometimes get through it even if it is
sticky after baking, so long as there are no retries. In fact, I have
taken to setting retries to the smallest possible number (I think it is
2) on the drive during my first attempt at reading a tape so that if it
does stick, I minimize the damage. A few times I have had luck with
doing that, having a couple of read errors, then cleaning the drive and
reading the tape again with the normal number of retries (9).
At 6250 BPI, the drive won't stream continuously, so if one of those is
sticky after baking, it is usually a challenge to get a good copy.
JRJ
Many/most 9 Track tapes (those from the early to
mid-eighties until 1995
or so - what matters is the date of manufacture, not when they were
written) have to be "baked" before reading, owing to "sticky shed
syndrome". My experience with tapes earlier than that is that I can
read them without baking them first.
Mid-80's are the worst, especially Memorex, and BASF, which everyone used
because they were cheap.
Whatever HP bought for their distribution tapes (probably Graham
Magnetics) is very good.
IBM tape is good too.
DEC used crap tape for their distributions.
Sadly, AT&T and Mt XINU ALSO used especially bad tape in
the late 80's, so many of the Unix distributions I've been dealing with
from
them lately are so sticky even after baking that they are impossible to
deal
with.