SUMMARY: Archive "Python" DAT drive properties change from 4.1.3 to 2.4

From: Howard Modell (
Date: Fri Jul 21 1995 - 11:44:34 CDT

Ok .. I have my answer. It's a curious one, but plausible.

My thanks to all those who responded.

The original question:

> 2 years ago, we bought an "ArchiveST 4000DAT" 4mm DAT drive for use in
> doing backups. Up until recently, I had it hooked to a SS running
> SunOS 4.1.3. In that context, it was accessible as expected via
> /dev/rst1 (low density), /dev/rst9 (med.), /dev/rst17 (high), and /dev/rst25
> (compression). Everything worked generally well.
> Now, the admin machine is a SS5/85 running Solaris 2.4. I added the device,
> did a reboot -r, and Solaris obligingly detected it and added the device
> and reconfigured the /device and /dev directories. Now it claims the
> device is /dev/rst5 (it was always set to SCSI 5, even before), /dev/rst13,
> /dev/rst21, and /dev/rst29. HOWEVER, the only one which actually talks to
> the physical device is /dev/rst5, the low density setting. The other three
> settings all respond with "no tape loaded or device is offline", even when
> rst5 happily senses and works with a tape.

The solution:

I finally broke down and called Maynard, the company who made the box,
(although the drive itself is a Connor?) and here's what the
guy told me:

1. Sun OEMs the Archive Python Helical Scan 4mm DAT drive, and their version
        has slightly different firmware. *This* is the drive which Solaris
        2.4 knows primitively, to which it can self-configure. This is the
        drive which can be accessed as /dev/rmt/Nlb, /dev/rmt/Nmb, /dev/rmt/Nhb,
        and /dev/rmt/Ncb.

2. The 3rd party flavor of the drive can *only* be accessed via Nlb, however,
        the compression is firmware controlled and permanently enabled.
        So, by using the same "dump" parameters I was using before,
        (d=61000 and s=10240) I'm still getting the compression I expected
        and the 2G capacity, even though Solaris may think it's a "low
        density" device.

Curious, but my experiences seem to bear it out .. my backup process seems
to be working just as it always did, so I suppose I shouldn't have complained.

Again, my thanks to those who responded:

mshon@sunrock.East.Sun.COM (Michael J. Shon {*Prof Services} Sun (Kevin Sheehan (Robert Pasken)
Stephen P Richardson <>
Scott Erickson <erickson@binky.ICS.UCI.EDU>

 Howard Modell (206)662-0189
 Adv.Computing Technologist/2 POBox 3707, m/s 4C-63, Boeing D&SG Seattle, WA 98124-2207
<A HREF=""> HSM </A>

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