moving 0.25" tapes (was: Writing HP ...)

[Thomas Mitchell]

In article <2871 at ttrdc.UUCP> levy at ttrdc.UUCP (Daniel R. Levy) writes:
>In article <301 at pvab.UUCP>, robert at pvab.UUCP (Robert Claeson) writes:
>> In article <4799 at netnews.upenn.edu>, spolsky at eniac.seas.upenn.edu (Joel Spolsky) writes:
>> > You can, however, move 1/4 tapes between a Sun and an AT&T 3Bn. I've
>> > done that.
>> How?
>
>If you have the 60 MB SCSI drive (such as what the 3B2/600 has builtin, or

1/4/ inch tape drives cause more than a bit of confusion.

In front of me is a short article from "Mini-Micro Systems" April
1988 which discusses 1/4 inch and smaller tape cartridges.

The main thrust of this article was the QIC-40 Recording format
standard for Minicartridge drive.  However it has some tables
which made it clear to me that the QIC standard covers a LOT of
differing things:

	Drive Interface QIC-02
	Recording Format QIC{-24,-40,-100,-11?,-120,-150,-320}
	Drive interface QIC-36, QIC-103
	Magnetic heads QIC-102, 
	SCSI interface implementation QIC-104

When moving a tape from one box to another first thing that
matters is the Recording format.  Do not get distracted by SCSI
or QIC-02 because these are a hardware interface used to control the
drive controler (not drive).  The drive controler can use another
[non]standard  interface to the drive itself.  The drive may in
turn be capable of writing to the date in one or more recording
formats (may read more than it can write). 

Once the recording format has been matched then data transfer can
begin.  Still there may be points to pay attention to.  Examples:
NCR used an Intel? support chip in their QIC-02 controler on
their 68010 box.  Like many intel devices it has differing byte
sex conventions over the 680x0 processor so the data on their
'010 tower tapes is byte swapped. (We used an inverting buffer :-(( 
so our data is bit flipped).

Here is some hard information about Sun tapes;
>From page 27 of Suns's Change Notes for Release 3.0 (rev A of 17
Feb '86)

The SCSI tape driver has been modified to support both QIC-11 and
the QIC-24 format.  The QIC-11 is used on Sun2 machines by
default (and all except the very oldest also provide hardware
suppoort for QIC-24).  Sun3 machines support both QIC-11 and
QIC-24. ....  For more info see 'st(4S)'

As an asside our '020 box SCSI driver supports both QIC-11 and
QIC-24 formats. Also Byte swap for NCR'010 tapes etc.  See our
'st(4)' man page.

Good luck,
mitch-- 
Thomas P. Mitchell (mitch at stride1.Stride.COM)
Phone: (702)322-6868	TWX: 910-395-6073	FAX: (702)322-7975
MicroSage Computer Systems Inc.
Opinions expressed are probably mine.