2 Feb
2007
2 Feb
'07
1:41 p.m.
No, it was a 7070, "IBM seven oh seventy", and it used hundreds if not
thousands of 12au7s or 12ax7s don't remember which it was. And it was
definitely NOT solid state. The first solid state addition to it was a
memory matrix unit that used germanium or silicon junctions in a plane of
12x12 giving 144 bits of permanent memory sitting behind a plastic window so
we could look at it and marvel at the wonders of science ( I dont think it
was really permanent memory as I seem to remember it required a voltage
input to keep it from fading) . It was a frame about 12 inches square and
looked like a course window screen with small dots of junction at every
intersection of the wires. I remember the questions like "I wonder if I
stuck a screw driver in there and twisted it around will the computer
scream?" All in jest of course.
Maybe IBM used some numbers over? But I am absolutely sure of the number
because we called it by that name when referring to it. This was in 1959
and 1960
On 2/2/07, William Donzelli <wdonzelli at gmail.com> wrote:
--
Jim Isbell
"If you are not living on the edge, well then,
you are just taking up too much space."
I used the 7070 because that was all that was
available. Don't know the
7090. But at the time the 7070 was the best available. The US gov paid
dearly for it even though it had only 9K of memory, 10 bit words and no
hard
drives, just a bank of big Ampex tape drives.
For the record, the 7070 was a solid state machine, as were all the
7000 series processors. Perhaps you were using an older 700 series
machine? They were tube based.
When it shut down it took 2
days to get all the blown tubes replaced so it was back up again.
During the first six months or so, yes, probably, but if tubes kept
going bad like this past this point, something was seriously wrong
with the machine.
Once a tube machine was installed and all the weak tubes weeded out -
generally it took about six months - reliability shot straight up.
Often a tube machine was scrapped with many of the tubes original to
the installation. Remember, these were well made tubes, low power, and
not pushed to their limits.
--
Will