8 mm tapes
mcguire at neurotica.com
Fri Sep 24 08:43:55 CDT 2010
On 9/23/10 10:52 AM, jim s wrote:
>> "Write-only media", yes. I've never seen a tape as unreliable as an
> I have tapes that are 20 years old. All are readable. The error rate is
> lower than with 1/2" though the 1/2" tapes can be manually nursed back
> by alignment play.
> I used video tapes in the 8200's w/o any problem. All are still readable.
> Sample size was about 30 tapes in my case, not hundreds. YMMV
MMDV (My Mileage Definitely Varied) :) I too have some that are
readable, mostly from Exabyte 8200s (2.3GB) but some from 8500s (5GB).
At least they were still readable a few years ago. These were
definitely the exception though. The company I worked for around '92
had an 8200 and a bunch of video tapes when I got there, but had never
set it up. My first results were ok, but the second set of tapes were
full of errors. I guess the first time I just got lucky. We got into
the habit of running a head-cleaning tape after every two or three uses
of the drive; that helped a bit.
My boss insisted on getting an 8500, though I wasn't convinced of the
efficacy of the technology. I wanted to just stick with our trusty
QIC-150 and use a bunch of tapes for incremental backups. He wanted
full backups every time (I think he didn't really understand the
incremental backup concept) which made the 150MB QIC-150 tapes
impractical. Results with video tapes for the 8500 were terrible; not a
single tape worked well. We bought data-grade tapes (Sony QG-112M I
think) and that improved things, but it was still pretty bad.
At my next company we had a brief dabbling with an 8200 but replaced
it with a 4mm DAT, with which I had had some experience at a small
consulting job. I liked DAT at the time, but hadn't really put volumes
of data through it. I wish I had, because I fought tooth and nail to
get us a DAT drive at that company, but boy was that a mistake. They
were only marginally more reliable than the 8mm Exabytes all told.
It took a few years of running double backups until we got a truly
reliable tape system: DLT. That was 1995, and I am still sold on DLT
(and its descendants) now. Super fast, super reliable. My home
network's backups are running to a 64-tape juke with four SDLT-220 drives.
I also found your comment regarding 1/2" tapes interesting. I'm
assuming you mean 9-track, as there are many 1/2" tapes that aren't. In
my experience ("mileage"! ;)) 9-track is the only tape format that's
anywhere near as reliable as a DLT. Of course we're talking 150MB vs.
200+GB per tape (for my current drives) so it's very much apples and
oranges. 9-track tape reliability depends very much on the particular
drive in use. (though I suppose that's true for any kind of tape)
Port Charlotte, FL
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