scsi tapes

[At these prices, I can't NAME names]

In article <5942 at brazos.Rice.edu> sg04 at gte.com (Steven Gutfreund) writes:
>X-Sun-Spots-Digest: Volume 9, Issue 90, message 7
>I have a WANGTEK 5500 (150 Meg) tape drive on by SS1.
>
>1. MT says my tape is a QIC-150 : What do the QIC numbers REALLY mean.

QIC stands for Quarter Inch Committee. This was a committee formed to
establish, I believe, an ANSI standard on tape formats. The number after
the QIC is the standard number. Generally, the higher the number the
higher the density.

QIC-11 is a 45 MB format. QIC-24 is a 60 MB format.  QIC-150 is a 150 MB
format.

>2. Sun admin guide says if I call it /dev/rst0 I write in QIC-11 format
>   and /dev/rst8 in QIC-24 format. Really?

yes, by adding 8 to the "base" device number you can alternately access
the QIC-11 or the QIC-24 tape drivers.

/dev/rst0 drives tape 0 (usually scsi id 4, but see below) with QIC-11
format whereas, /dev/rst8 drives tape 0 with QIC-24 format

I don't think this applies for your 5500, I believe you are limited to
QIC-150, but I could be wrong.

>   what do the device numbers mean and why does scsi-probe say
>   there are 8 units there?

I am not familiar with scsi-probe. I would guess that you have created
/dev/st[0-7] and "scsi-probe" is finding those nodes out in /dev

>4. I have a DAT at scsi address 5, what /rst? should it have, and what
>   should I tell dump.

This is completely user configurable.  Look in the kernel config file for
your system.

SCSI ID 4 is usually assigned to /dev/{rst,st}0 while
SCSI ID 5 is usually assigned to /dev/{rst,st}1

hope this helps,

adam margulies                                    metaware incorporated
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