Chuck Guzis wrote:
On 3 Jul 2009
at 20:14, Jerome H. Fine wrote:
Just a suggestion. Up to about 1960, most (all?)
computers were
vacuum tubes. You might want to use that for the initial separation
and specify a different set of parameters for vacuum tubes vs
transistors.
...except when they weren't. (e.g. Univac SS80/SS90--only the clock
generator used tubes--all of the computation was magnetic logic,
diodes and transistors). NEAC 1101/1102 (parametrons). There were
certainly others.
Then I suggest that you change 1960 to whatever year you feel
comfortable with.
Notice that I said ABOUT 1960.
The key point that I was attempting to make was that computers which were
mostly based on vacuum tubes were far different in one key aspect than
computers mostly based on transistors, i.e. the power used and the heat that
was generated. The resulting overhead of running computers such as the
IBM 709 vs the IBM 7090 was probably sufficient to have a definite impact
on availability even though both computers did the same calculations, at
least
that is an assumption that I think is probably reasonable - can anyone
verify
this.
I know that Johnny Billquist has stated that their PDP-11/70 computers have
been replaced by the E11 emulator running on a current PC due the the cost
of running the DEC hardware, so I would expect that the same sort of
situation
was critical in switching from vacuum tubes to transistors. And I
believe that
I seem to remember other PDP-11 also users stating the same thing when they
switched, let alone the fact that I can run RT-11 about 100 times faster
under
E11 on a 2.66 GHz core 2 duo (E8200) than a DEC PDP-11/93.
So just pick whichever year that you feel is the dividing year between
vacuum
tube computers and transistor computers. Then see if the parameters which
make a given model of computer significant are the same or if the parameters
change. My guess is that at the very least, the number produced of any
given
model of vacuum computer will be significantly less, on average, than any
given model of transistor computer. I image that other parameters will also
change.
Sincerely yours,
Jerome Fine
