3 Oct
2015
3 Oct
'15
9:49 p.m.
John,
Your program worked beautifully writing a SIMH format file on my HP 88780
tape! Thanks a million. Nothing like sending direct SCSI commands to tape
from DOS. Drivers are overrated ;-).
Marc
================================
Date: Sat, 3 Oct 2015 02:52:36 -0400
From: John Wilson <wilson at dbit.com>
My "ST.EXE" program (available from http://www.dbit.com/pub/ibmpc/util/
including source) runs on real DOS (not Windows) and can write from an
E11-format .TAP file (which SIMH uses a garbled version of, but they're
interchangeable for *even* record lengths which are 99% of the universe) to
a real tape[...] John Wilson D Bit ===============================
4 Oct
4 Oct
12:32 a.m.
On Sat, Oct 03, 2015 at 09:49:49PM -0700, Marc Verdiell wrote:
Your program worked beautifully writing a SIMH format
file on my HP 88780
tape!
Beauty -- glad to hear it!
The difference is that SIMH's native format pads records to even sizes before
appending the "length" longword, and E11's doesn't. But most popular
tape
labeling schemes will always produce even-lengthed records, so there's no
difference.
John Wilson
D Bit
6 Oct
6 Oct
11:54 a.m.
From: John Wilson
Sent: Sunday, October 04, 2015 12:33 AM
On Sat, Oct 03, 2015 at 09:49:49PM -0700, Marc
Verdiell wrote:
> Your program worked beautifully writing a SIMH format file on my HP 88780
> tape!
The difference is that SIMH's native format pads
records to even sizes before
appending the "length" longword, and E11's doesn't. But most popular
tape
labeling schemes will always produce even-lengthed records, so there's no
difference.
Of course, that's mostly true for those machines restricted to silly octets as
their native data representation. :->
Rich
Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputerMuseum.org
http://www.LivingComputerMuseum.org/
12:10 p.m.
On Tue, Oct 06, 2015 at 06:54:09PM +0000, Rich Alderson wrote:
Believe me, I was totally thinking of the TM03/TM78 in 36-bit mode when
I stuck "most" in there. :-)
John Wilson
D Bit
But most
popular tape
labeling schemes will always produce even-lengthed records, so there's no
difference.
Of course, that's mostly true for those machines restricted to silly octets as
their native data representation. :-> 
12:22 p.m.
On 10/06/2015 11:54 AM, Rich Alderson wrote:
Of course, that's mostly true for those machines
restricted to silly
octets as their native data representation. :->
And one finds odd-byte-sized records not infrequently in big iron--and
then you have to ask "where do most half-inch 9-track tapes originate?"
It ain't from DEC, for sure.
FWIW, my routines don't bother to pad to an even byte boundary.
--Chuck
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4 comments
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