REMINDER: Leap Second
johnl at iecc.com
Mon Jan 26 18:20:20 UTC 2015
Barney Wolff <barney at databus.com> wrote:
>On Sun, Jan 25, 2015 at 06:42:51PM -0500, TR Shaw wrote:
>> That made the transformers smaller/cooler and more efficient. I seem to remember a 195 as well but maybe it
>is just CRS.
>Google says the 360/195 did exist. But my baby was the 360/95,
>where the first megabyte of memory was flat-film at 60ns, which
>made it faster than the 195 for some things. ...
The /95 was a /91 with a megabyte of thin film memory, which was both
much faster than core (120 vs 780 ns cycle time) and much more
expensive (7c rather than 1.6c per bit.)
The /195 was a /91 reimplemented in slightly faster logic with a 54ns
rather than 60ns cycle time, and a cache adapted from the /85. I can
easily believe that for programs that didn't cache well, the /95 with
the fast memory would be faster. IBM lost money on all of them and
eventually stopped trying to compete with CDC in that niche.
See alt.folklore.computers (yes, usenet, reports of its death are
premature) for endless discussion of topics like this.
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