On Tue, 10 Nov 2009 15:25:18 +0000, Invisible wrote:

>>> Tape operates at much lower speeds. And since the only people who use
>>> tape are people who want seriously reliable backup storage, it tends
>>> to be very well engineered. (And stupidly expensive...)
>> 
>> Never used DAT drives for backup, have you? ;-)
> 
> No, only for the last 6 years.

I feel for you.  I had tapes that actually verified nightly that were 
completely useless to restore from.  This is back in the DDS-1/DDS-2 
days, so maybe it's improved - but here's the thing:  DAT stands for 
"Digital Audio Tape". 

Q.  What's one difference between audio and data?  

A.  You can lose some audio data and not notice it.  You can't lose data 
and not notice it.

Using "audio tape" for backup (digital or no) is generally not a good 
idea.  It was designed for audio, not data.

>> Horrible quality of storage media, and terrible shelf life IME.
> 
> Really?

Yes, really.  With the DDS-2 tapes I was using at the time, the 
manufacturer recommended no more than something like 10 or 20 uses.

The tape also creates friction against the recording head, which rotates 
in a direction that's counter to the tape direction, so the tape drives 
burn out fairly easily.  I used to have a Compaq 4/16 DAT autochanger for 
my home server, along with a couple of standalone DAT drives, and I 
burned the heads out on *all* of them while doing alpha and beta testing 
of backup software.

I'm glad I didn't pay for the drives - otherwise I'd have been more upset 
that they burned out so quickly (about a year, IIRC - but I was running 
backups on a more or less continuous basis as part of my testing).

I had much better luck with DLT drives.

Jim

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