28 Jun
2007
28 Jun
'07
3:52 p.m.
On 28 Jun 2007 at 14:52, Jules Richardson wrote:
Yet another oddity discovered today: it would seem
that the rotating magnetic
fixed-head disk in the Burroughs L-2000/3000/4000/5000 machines wasn't for
secondary storage (as I'd assumed), it was the primary store in place of the
core typically found in systems of the time. I bet there can't be many
machines around which had rotating store as the primary memory.
Not at all uncommon during the 1950's. (e.g. LGP-30)
In fact, the Univac SS-80 that I mentioned not only has a drum as
main memory, but it's synchronized to the card reader. There were
two machines in the Univac "Solid State" series; the SS-80 for
conventional 80-column Hollerith cards and the SS-90 for Univac 90-
column cards. The layout on the drum was different for each.
The "solid state" refers not to transistors (which were used mostly
to drive indicator lamps), but rather to the magnetic cores used not
for memory, but for logical operations; one clock cycle per core.
The master clock was driven with 6 4X150 power tetrodes.
Very unusual--and very reliable for its day.
Cheers,
Chuck