Re: [TCLUG:19863] 160mXL 8mm tapes = 24Gb?

[Philip C Mendelsohn <mend0070@tc.umn.edu>]

On Wed, 26 Jul 2000, Bob Tanner wrote:

> Running Sparc Linux with a Exabyte 8mm Tape drive using 160mXL 8mm tapes.
> 
> I think I am going insane, but I thought 8mm did 12/24Gb. Yet, I am able only
> to get around 2Gb on the tape before it gives me a write error.
> 
> Just wanted to make sure my capacity is right on the tapes before I look else
> where.

Depends on the drive, but that's *way* higher than what I would expect.

I have an Exabyte 8500C, which is rated for 5GB uncompressed, 10GB with
the hardware compression.  (It's older, but it's a rock.)

I don't recall if that was 160m tapes or not, but the difference for tape
length is linear, so that doesn't explain it.

2GB is pretty shabby though.

There are lots of annoying problems that could account for it -- bad
tapes, dirty machines, yada, yada.  I have a fair amount of insight into
the behavior of tapes and heads which I won't burden you with now :)

I don't want to start a "I swear by brand X, but brand Y
stinks" discussion, but I have some data on error rates, bad tapes
received, and recoverability after time that suggests that the 3M /
Imation 8mm tapes really do outperform a couple of other brands.

*I'm not claiming they beat everyone else's tape.*

Nutshell:  Your numbers probably aren't right, but your tape is *almost*
certainly not doing what it's supposed to, IMHO.

Cheers,
Phil M 

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