Date   : Sat, 24 Feb 1990 01:45:03 GMT
From   : orc!mipos3!cadev5!dbraun@decwrl.dec.com (Doug Braun ~)
Subject: Ampro Little Board w/Hard Disk

In article <WJC.90Feb22191955@hoswjc.ho5cad.ATT.COM> william_j_carpenter@ATT.COM
(Bill Carpenter) writes:

>How much trouble would it be to get the Little Board SCSI to work with
>a SCSI tape drive?  I'm sort of naive on the subject, but I reckon
>after you have the SCSI adaptor, it's mostly a matter of software.
>Has it already been done?


I have a home-built host adapter on my home-build Z280 system,
and I have used it to run a Memtec 20 Meg cassette tape drive with
a SCSI controller card.  It worked very well. (I now have the drive
hooked up to a PC).  The only thing is that these drives are streaming,
so they like to get data in long bursts.  I used a 32K buffer in
a port of unix "tar", and it was very handy for backing up hard disks.
I wish I had another drive, so I could swap tapes between the Z280 and
the PC.

Because I had already written a SCSI driver for the hard disk, it was easy
to make it generic, to perform a SCSI transaction for any device.  

I.e:   status = scsiop(busid, cptr, dptr, dlen);

Where busid is 1 to 7, cptr points to the command bytes,
dptr points to the data buffer, and dlen is size of the buffer.
The routine figures out how long the commnd is, and which way
the data is going.

SCSI stuff is fun.  (but ask me about my 9-track CP/M tape drive)




Doug Braun                             Intel Corp CAD
                                       408 765-4279

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