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From: dave@westmark.WESTMARK.COM (Dave Levenson)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Looking for info on hooking up Colorado tape drive
Message-ID: <1451@westmark.WESTMARK.COM>
Date: 11 Nov 90 14:06:46 GMT
References: <4de7e4ff.20b6d@apollo.HP.COM>
Organization: Westmark, Inc., Warren, NJ, USA
Lines: 54

In article <4de7e4ff.20b6d@apollo.HP.COM>, miller_h@apollo.HP.COM (Herbert Miller) writes:
...
> I'm considering buying a Colorado internal tape drive.  I understand that
> you can hook it up to either a floppy controller, or it comes with a card
> for a slot.  I was wondering if this card also allows the hook up of an
> additional floppy?  Any info would be appreciated.

Most PC floppy controllers will support two diskette drives.  The
CMS tape drive, by itself, will replace one of these drives,
allowing you to support one diskette and one tape.  With their AB-10
board, you can still support two diskette drives, and one tape
drive.  This board is electrically between the diskette controller
and the first diskette drive, and acts like a software-controlled
switch that alternately connects the controller to the diskette
drives or to the tape drive.

___________        ___________      _____________      _____________
Floppy    |------->|CMS AB-10|----->|Diskette B:|--~-->|Diskette A:|
Controller|        |Board    |      -------------      -------------
-----------        -----------
                        |             ____________
                        |------------>|Tape Drive|
                                      ------------

The tape drive connector on the CMS board appears both on the
backplane, and on the card itself.  This means that the tape drive
may be mounted internally or externally.  If you only use one
diskette drive, but you want to mount the tape drive externally,
then the AB-10 board will take care of that problem, too.


CMS also offers two tape drive controller boards.  These do not
connect with the floppy controller.  They are true device
controllers.  One supports hardware-based data compression, which is
compatible with their normal software-based compression, but faster.

We use the CMS Jumbo under AT&T UNIX with the AB-10 board, and two
diskette drives.  The only limitation we have doing this is that the
diskette drives become unavailable for the duration of any tape
operation.  If this is a problem, the other tape boards mentioned
probably don't have this limitation.  Under MS-DOS, this would not
be a limitation, as the tape drives are only useful for backup and
restoral of the hard disk.  The PC is fully occuipied during these
operations.  Under UNIX, the tape drive appears as a
character-special device, and you can use normal UNIX commands such
as cpio, dd, or tar with it.  It would be possible to do this from
one process while another does something with the diskette drives,
if the more expensive tape controller board were here.

-- 
Dave Levenson			Internet: dave@westmark.com
Westmark, Inc.			UUCP: {uunet | rutgers | att}!westmark!dave
Warren, NJ, USA			AT&T Mail: !westmark!dave
[The Man in the Mooney]		Voice: 908 647 0900  Fax: 908 647 6857