Charles Mills wrote:
TOS/360, as noted above, is essentially the same as DOS/360.
Only if a tape is essentially the same as a disk!
TOS's code base was largely common with DOS, and the programming APIs were a
subset -- but the SYSRES was on tape! Believe it or not. The equivalent of
an S806 took about ten minutes: spinning the SYSRES tape looking for the
program.
Not IBM's most successful product, neither technically nor commercially.
It shows how far we have come: once, disk was so expensive that people
contemplated mainframes with no disk at all. Now, personal music players
come with 4GB or more of storage.
Charles
i had summer student programming job ... developing 360 port of 1401 MPIO
front-end
for 709 (univ. used 1401 for cardreader -> tape and tape -> printer/pubnch
front-end
for 709 ibsys). as part of move to 360 ... the 1401 was replaced with 64kbyte
360/30.
it started out running mostly in 1401 (hardware) emulation mode. I was given the
job of rewritting MPIO in 360 assembler. I got to design and implement my own
monitor, interrupt handlers, device drivers, error recovery, storage management,
dispatching, etc. The assembler program grew to about 2000 cards. I eventually
had assembler switch that generated two different versions 1) completely stand
alone program that was loaded with the BPS stand alone loader an 2) version
that ran under os/360 (at the time release 6, pcp).
The stand-alone flavor two about 25 minutes to assemble and generate text
deck. The option to run under os/360 took an additional 25 minutes to assemble
because it had five DCB macros that needed to be expanded ... and it took
approx. five minutes elapsed time for the assembler to expand each DCB macro
(you could watch the 30's front panel lights and tell when the assembler
was expanding DCB macro because the front panel light pattern was distinct).
Before i learned about "REP" cards, i got quite proficient at reading punch
holes for the hex in "TXT" (binary) decks ... and being able to do code
patches by doing card duplication on 026 keypunch ... and multi-punch the
hole patterns for the hex patch (significantly faster than updating the
assembler card source and getting a new clean assembly).
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
