From: drew@kinglear.cs.colorado.edu (Drew Eckhardt)
Subject: Re: Disk/tape drive and vendor info needed.
Organization: University of Colorado at Boulder
Date: Wed, 12 Aug 1992 17:43:43 GMT

In article <Aug.10.23.22.47.1992.8181@theophilus.rutgers.edu> rapatel@theophilus.rutgers.edu ( Rakesh Patel) writes:
>
>I'm thinking of getting a 500+ MB IDE disk and a relatively cheap tape
>drive for my Gateway 2000 486/33 to run Linux and backup my system.
>I've currently got a 120MB Western Digital IDE disk (almost full), and
>only have one IDE slot left. I'd like to get a tape drive and a large
>disk.  The August computer shopper has an add from Megahaus for a few
>IDE disks:
>
>510 MB 12ms Conner CP3504 $1199
>520 MB 12ms Fujitsu M2624T $1139
>535 MB 12ms Maxtor LXT535A $1090
>
>I'm thinking of going with the Fujitsu, as it has a 5 year
>manufacturers warranty.  I'm also considering a Colorado 120 MB
>tape drive (model DJ-20) for $255 from Megahaus. Megahaus seems

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.

>to have a reasonable return/service/warranty policy. Any suggestions
>or comments on them? Are there other places that are more reasonable?
>

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.

>Will the Colorado tape drive work through the floppy controller as a
>third drive? The controller I have is one of those IDE, 2 serial, 1
>parallel, 2 floppy controllers, and I already have two floppy drives.
>If the Colorado can't work, there is an Iomega tape drive out now that
>supposedly can be used as a third floppy even on a 2 floppy
>controller. Any comments/suggestions on that?

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.

>If you have Linux running with a SCSI disk and tape drive, and have
>any suggestions on purchasing a SCSI disk and tape drive instead,

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.

>I'd like to hear them, especially if both the tape and disk can
>work directly under both DOS and Linux. I was planning on getting the IDE
>setup, and using the tape drive through the floppy controller

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

>and backing up the linux partitions onto a DOS partition and using
>the DOS backup software. If a pure SCSI solution might work at
>reasonable cost, I'd appreciate knowing about one, especially if
>the performance doesn't get worse when compared with the IDE setup. :-)

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. 

Newsgroups: comp.os.linux