Re: Software advice

In article <87acdqg2qg.fsf@xxxxxxxxxxx>,
David Dyer-Bennet <dd-b@xxxxxxxx> wrote:
>whheydt@xxxxxxxxxxx (Wilson Heydt) writes:
>
>> In article <dqphsl$lr5$1@xxxxxxxxxxxxxxxx>,
>> Keith F. Lynch <kfl@xxxxxxxxxxxxxx> wrote:
>> >David Dyer-Bennet <dd-b@xxxxxxxx> wrote:
>> >> whheydt@xxxxxxxxxxx (Wilson Heydt) wrote:
>> >>> PDP-8 was a minicomputer and didn't support a 16MB address space.
>> >
>> >> Sure it did -- if you connected enough hard drives! :-) (rk05 were
>> >> about 2MB, I believe).
>> >
>> >the PDP-8 didn't have any way to treat the RK05 as if it were memory.
>> >I suppose an operating system could have been written to do so. But
>> >none ever was.
>>
>> One could argue that a virtual memory system is using disk space as
>> memory.
>
>Yes, and that's probably part of the source of the popular confusion,
>too.
>
>> On the other hand, the Cal Computer Club was given a Univac SS-90 in
>> late 1969. Its main memory was a drum, so it really did use
>> disk-like storage as main memory. (It tells you something when you
>> realize tha the "SS" in the system name meant "solid state"--i.e.
>> the main logic wasn't vacuum tubes. The drivers for its printer,
>> however, were thyratrons. Gave use quite a start when we opened the
>> back of the printer and found ourselves staring at an array of 132
>> tubes...)
>
>A very *early* "second generation" computer, sounds like. The first
>couple of computers I worked on were second generation (IBM 1620 and
>1401). But neither had tubes (though the 1620 had "core heaters" to
>keep the memory temperature constant).

yes. I think there were some late first generation that also used
drum memory. The SS-90 had 5000 words of 10 digits each. There
were some tracks that had multiple read heads spaced around them for
higher speed access for code that needed to run as fast as possible.

What version of the 1620 did you work on...Mod. I or Mod. II?

--
Hal Heydt
Albany, CA

My dime, my opinions.
.

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