IBM CMS dumpfile idiocy
jws at jwsss.com
Wed Dec 16 14:01:18 CST 2015
On 12/16/2015 7:57 AM, Paul Koning wrote:
>> On Dec 15, 2015, at 10:10 PM, Chuck Guzis <cclist at sydex.com> wrote:
>> On 12/15/2015 01:48 PM, Dave Wade wrote:
>>> What I meant was are they still on 9-track, or some kind of
>>> tape-in-a-file disk? IBM tapes are usually written to AWS format
>>> files not the formats (.TAP ?) used by SIMH... Some source to extract
>>> some versions of these from AWS files (and windows executables) are
>>> in this ZIP file:-
>> Came right off a 1600 cpi tape, identified as a CMS dumpfile.
>> What really strikes me as odd, is that ANSI/IBM tape labels were pretty much the standard rule of thumb then; why the heck did IBM invent something new and obscure?
> IBM standard labels are older than ANSI. Then again, IBM (in OS/360 at least) had something they called "ANSI label" that were not actually ANSI at all. They used "8 bit ASCII" which was a bizarre code created from standard 7 bit ASCII by moving one or two of the bits (bit 6 to bit 7? I don't remember).
On the Microdata 1621 system we had it was 4 assembler instructions in
a loop to convert a string from Ascii to Ebcdic using that weird ascii code.
I use a table now when I code in C to convert from that ASCII to what we
call ascii. I call it high bit on ascii, but it isn't precisely that.
I have an entire OS that uses that, and I ran across it back in the 70's
on a few other minis, but the ANSI version supplanted it early on.
FWIW referring to the Jay West 1600's from University of Missouri, Rolla
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