IBM Engineers

From: William Donzelli <aw288_at_osfn.org>
Date: Thu Apr 8 11:55:45 2004

> The Cybers weren't just the world's best compute engines by a large
> margin. They also have excellent I/O performance. Show me another
> 1965 vintage computer that can support timesharing with 600 active
> users and excellent interactive response time... (I'm talking about
> the PLATO system here -- which ran 600 users on a 6400, not even a
> 6600, though the I/O is the same for either.)

Look at the time period - in the late 1960s, timesharing was a fairly tiny
piece of the mainframe market. I would venture to say that at least 95
percent of all mainframe activity in 1968 or so was plain old batch jobs -
doing payroll, financial calculations, and so forth. This market demands
(it still does) that the machines work "all" the time, don't make
mistakes, easy to maintain when they do break, and can be upgraded without
too many waves. IBM did a pretty good job on all of these counts.

Also, the high end S/360s also had pretty screaming I/O for the time.
 
> As for the OS, personally I prefer clean and straighforward over
> baroque and insecure. Certainly IBM offered the latter. The OS/360
> manual clearly showed a nice security hole...

Once again, being in a batch environment with very limitted access to
anyone that wasn't a priest, security wasn't very much of an issue back
then. If something did go wrong with a bit of hacking, any decent
mainframe house would just be able to stop, go to the backups, and rerun.

William Donzelli
aw288_at_osfn.org
Received on Thu Apr 08 2004 - 11:55:45 BST