Real tape drive densities
Chuck Guzis
cclist at sydex.com
Mon Feb 15 00:37:37 CST 2016
On 02/14/2016 06:13 PM, Jay Jaeger wrote:
>
> Maybe some yahoo decided to write over the first file of that SVR4 tape
> at higher density so as not to clobber the files after it. Smart, so as
> not to clobber the other stuff, but crazy. Or it may have been just a
> case of writing that first file, with no double-EOF EOT on it.
>
> Or maybe someone wrote the first file and then went "OH SH*T that was a
> DISTRO TAPE wasn't it..." ;)
>
> Anyway, I doubt AT&T would have written the tape that way intentionally.
Well, the tape bears an AT&T label. The tape itself comes from UCB at
about the same time that "ernie" was in use, so VAX or PDP11. It could
be a copy of an AT&T distro tape with the duplicate label attached.
It's a 2,222,000 byte cpio file that starts out with:
# THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T
# The copyright notice above does not evidence any
# actual or intended publication of such source code.
#ident "@(#)mk::mk 1.10"
#
# Shell script for rebuilding the UNIX System
#
trap "exit 1" 1 2 3 15
if [ "$ROOT" = "" ]
then
PATH=/bin:/etc:/usr/bin; export PATH
fi
That's the 6250 GCR file; the 1600 PE file that follows is a 37,432,320
byte cpio file that starts out in exactly the same way. The 2MB file
was probably an "osh*t" file as it terminates prematurely at
"usr/src/cmd/bnu/bnu.mk".
I read it on my Fuji 2444 (Pertec interface). None of my SCSI drives
could handle the mixed density.
Just curious--
How many "smart" drives can handle multiple load points? Before the day
of autothreading drives, it was convenient to have a "universal
deadstart" tape to carry along, with various operating systems on it.
Just keep hitting the "load" button until you get to the one you want,
then push the button.
--Chuck
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