> ....... Good history on tape stuff .....

I also remember those days.. Must be getting old  ;-)

> 
> The condition given was that you should not use HW compression if you
> intended to read the tapes on drives from other manufacturers. (at that time
> mainly DAT and QIC drives).

Additionally there were some (quite a lot) of compressing tape drives at that 
time
that did have problems with accepting too much data into the buffers at an EOT
(End of Tape) condition. The result was that if that particular part of the 
data wasn't
as compressable as the previous blocks there simply wasn't room for it all on 
the tape.
As this part was already confirmed to the host as written to tape there was no 
way of
recovering from the situation without loosing data :-(.

This lead to the very "sticky" rumour that you should not use hardware 
compression
on tape drives. But this was 10-15 years ago (remember Wangtek QIC-drives ??), 
all the
drives today does it the "Right" way.

> Software compression, on the client, is a bad idea under most conditions
> because the algorithm used by our favorite tool is not that efficient. It
> may have been good at the time that we were still running on yellow cable
> with CSMA/CD or FDDI, but in todays world with switched 100TX/1000TX the
> network overhead caused by not compressing is less then the overhead caused
> on the client.

Amen to that.
Check out the preformance in terms of backed up real data with and wo software
compression and you will mostly find that you win if you don't compress on the
client.

Best regards

-- 
Dag Nygren                               email: dag AT newtech DOT fi
Oy Espoon NewTech Ab                     phone: +358 9 8024910
Träsktorpet 3                              fax: +358 9 8024916
02360 ESBO                              Mobile: +358 400 426312
FINLAND

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