[comp.unix.aix] Tape Drive Parms

kevin@msa3b.UUCP (Kevin P. Kleinfelter) (09/25/89)

Does anyone have the magic numbers for a 6157-002 tape drive?
I'm looking for the fun stuff that the backup command needs like
tracks, density, etc.  I have looked in the AIX doc, which assumes that
your tape drive doc provides the info.  I have looked in the tape
drive doc, which assumes you are running in a DOS environment, and
you have software which knows.

WHat are the numbers, and where are they documented (where did I fail
to look)?
-- 
Kevin Kleinfelter @ Management Science America, Inc (404) 239-2347
gatech!nanovx!msa3b!kevin

jackv@turnkey.gryphon.COM (Jack F. Vogel) (09/27/89)

In article <1132@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes:
>Does anyone have the magic numbers for a 6157-002 tape drive?
>I'm looking for the fun stuff that the backup command needs like
>tracks, density, etc.  I have looked in the AIX doc, which assumes that
>your tape drive doc provides the info.  I have looked in the tape
>drive doc, which assumes you are running in a DOS environment, and
>you have software which knows.
 
>WHat are the numbers, and where are they documented (where did I fail
>to look)?

Kevin, the place you want to look I believe (the problem is that I have
looked in the docs for the next release and not the AIXPS/2 manual) is
the man page for backup itself.

The trick is in the way in which the streaming drive writes to tape, it
writes in a serpentine fashion on the 9 tracks. Therefore when you specify
the length with the -s flag use the tape length multiplied by 9, i.e.,
600*9 = 5400. Now on density I am not completely sure, the tapes I have
say "12500 ftpi" and I am not sure if that is equivalent to bpi or not
but as a test I would suggest setting -d 12500 and see how it works,
basically these numbers are used by backup to calculate how much data
it can write on a tape and not really anything to do with the hardware,
so if you get a reasonable amount on the tape fine; otherwise it will
get a hardware error before it finishes.

If anyone out there thinks this is a braindead way for software to
behave, and why it couldn't just rely on hardware in its operation, I
agree wholeheartedly :-}!!

Disclaimer: my opinions only!

-- 
Jack F. Vogel			jackv@seas.ucla.edu
AIX Technical Support	              - or -
Locus Computing Corp.		jackv@ifs.umich.edu

kevin@msa3b.UUCP (Kevin P. Kleinfelter) (09/28/89)

jackv@turnkey.gryphon.COM (Jack F. Vogel) writes:

>In article <1132@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes:
>>Does anyone have the magic numbers for a 6157-002 tape drive?
>>I'm looking for the fun stuff that the backup command needs like

>Kevin, the place you want to look I believe (the problem is that I have
>looked in the docs for the next release and not the AIXPS/2 manual) is
>the man page for backup itself.

I am looking forward to AIX 1.2, because its doc MUST be better than
1.1.  The backup command page in the manual basically shows the switches
and then in italics says stuff like "density" and "length" and never 
gives the values for IBM's drive.

(This sort of thing leads me to believe that IBM needs some sort of Q.A.
testing on the AIX doc.  Anyone who sits down to use the machine to
take a backup is going to wind-up with the same question, unless they
just let it use the defaults.  My guess is that the defaults are for the
older 6157, and not the 6157-002.

As an aside, are these drives writing QIC format?  SHould I be able
to move tapes between my AIX system and my 3B2? 
-- 
Kevin Kleinfelter @ Management Science America, Inc (404) 239-2347
gatech!nanovx!msa3b!kevin

smvorkoetter@watmum.waterloo.edu (Stefan M. Vorkoetter) (09/30/89)

In article <1140@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes:
>jackv@turnkey.gryphon.COM (Jack F. Vogel) writes:
>As an aside, are these drives writing QIC format?  SHould I be able
>to move tapes between my AIX system and my 3B2? 

I have not been successful in moving tapes between my 3B2 and PS\2.  I
believe AT&T uses a format all their own.  We do however distribute
tapes made on the old 6157 to SUN users, with no problems.

Stefan Vorkoetter
Technical Manager

Waterloo Maple Software

jackv@turnkey.gryphon.COM (Jack F. Vogel) (10/01/89)

In article <1140@msa3b.UUCP> kevin@msa3b.UUCP (Kevin P. Kleinfelter) writes:
 
>(This sort of thing leads me to believe that IBM needs some sort of Q.A.
>testing on the AIX doc. 
 
There is a certain amount of Q.A. on documentation, mainly in the form of
developers receiving and reviewing it, but since that is hardly our job
description and because there is such an immense amount of it, some things
slip through the cracks. If you feel there is a real error in documentation
whether by giving erroneous information or by omission you can call IBM
level 1 support and report it.

>As an aside, are these drives writing QIC format?  SHould I be able
>to move tapes between my AIX system and my 3B2? 

The answer to this is yes, it is standard QIC, I have written tapes on a
PS/2 running AIX and read them just fine on turnkey, which is an AT-bus
clone running 386/ix.

Disclaimer: IMHO only.

--
Jack F. Vogel			jackv@seas.ucla.edu
AIX Technical Support	              - or -
Locus Computing Corp.		jackv@ifs.umich.edu