3 Oct
2009
3 Oct
'09
10:23 a.m.
On 3 Oct 2009 at 3:42, Teo Zenios wrote:
I hit the local recycler today and purchased a few
tapes drives.
Snagged a DDS3 external, DDS4 external, and a cool looking IBM drive
that I was hoping might have been AIX. Turns out its an 8MM Mammoth
20/40GB drive (looks like ebay #290335147769). The drive had a couple
AS/400 stickers on it and appears to be HVD (with terminator attached
on the back). Are these drives pretty decent, reliable, and fast?
After having supported a bunch of government customers using various
tape media for about a decade or so, my recommendation usually was:
DLT is better than
8mm is better than
DDS is better than
QIC
(With floppy-tape and Travan included in that last classification).
A big problem with QIC is that cartridges left too long often have
interaction between the (decaying) tension band and the oxide
coating. If the dead tension band doesn't get you, then the chance
that it peeled off a layer of oxide will.
DDS, let's face it, is basically an audio tape standard, with
inexpensive cartridges its key feature. I've got a stack of drives
here of various makes and flavors and have never found it to be
particularly reliable. I put it above QIC because almost all drives
do read-after-write verification.
8mm (Exabyte) is based on the video cartridge, again with cartridge
cost in mind. Because the tape is larger than the 4mm DDS and that a
single manufacturer produced the drives, it tends to be better.
Later drives do better than earlier ones, even on tapes recorded with
earlier drives. For example, if you have a tape recorded on an 8200,
you'll get better results reading it on an 8700, rather than an 8200.
DLT is pretty good--good enough for many manufacturers, including IBM
to brand their drives and put them on their servers. Initially, it
was hugely expensive, but used drives are cheap and the shelf life of
the media is pretty good. In comparison to the preceding categories,
it can be very fast.
FWIW, today I keep my critical short-term backups on USB flash. I
make multiple copies and stash them where the dog won't find them.
Storage conditions matter a lot. I recently took a stack of DC1000
carts I'd recorded back in the 80's (Irwin floppy-tape drive) and
every one read perfectly. My wife was cleaning out the safety
deposit box at our bank last month and came back with a stack of
DC6250 tapes that I had forgotten about. I expect that they'll also
have survived well.
On the other hand, I have a couple of Datasonix Pereos carts that I'm
not even going to bother with. They weren't reliable when they were
new and I don't expect that age has improved them.
Best regards,
Chuck