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Re: Disk/tape drive and vendor info needed.

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Date: Wednesday, August 12, 1992 - 1:43 pm

In article <Aug.10.23.22.47.1992.8181@theophilus.rutgers.edu> rapatel@theophilus.rutgers.edu ( Rakesh Patel) writes:

Note that Colorado tapes will probably never be supported under 
either Linux or Jolitz's BSD.  Colorado refuses to give out 
documentation on their drives, and only have drivers for 
SYSV unices.


Not only are Colorado tapes unsupported, but I've been told that 
they are poor quality, and wear out not long after the warranty if 
you are doing frequent backups.  This is hearsay, but I've 
heard it from enough people that I'd take notice.


Get a standard QIC 02 interface tape, these are all supported.  SCSI
tapes will be supported in the near future - some one is debugging a 
driver which works with the current code, and the new code will
make things even easier.


Linux supports no tape drives yet.  As far as SCSI controllers, 
the Adaptec is a good choice as far as DOS compatability 
is concerned (154x ONLY, 152x is unsupported under Linux), and 
it should over respectable performance once the new SCSI
drivers are done.

Currently, we're seeing one block per revolution on unbuffered 
drives, which translates to ~60K/sec.  Some drives power up 
with cache disabled, if your drive powers up with cache enabled, you may see
~300k/sec.  

I've got the mode pages that control this, and sometime "RSN" will 
work on insuring that cache is always enabled.

The new SCSI drivers implement scatter / gather, issue most commands 
as linked commands to cut down on per-command overhead, and have 
a few other tricks to increase performance.  With a two block readahead,
you get 3X the old performance from the scatter / gather alone.


Floppy controller won't work.  Get a QIC-02 board and tape.


Currently, it is worse than IDE.  That will change - the time frame keeps 
changing, since I have a "real" project to finish in ~2 weeks, and 
haven't left the lab for 2 days.
-- 
Microsoft is responsible for propogating the evils it calls DOS and Windows, 
IBM for AIX (appropriately called Aches by those having to administer it), but neither is as bad as AT&T.  Boycott AT&T, and let them know how you feel.
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Re: Disk/tape drive and vendor info needed., Drew Eckhardt, (Wed Aug 12, 1:43 pm)
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