2 Feb
2004
2 Feb
'04
6:39 p.m.
On Mon, 2 Feb 2004, William Donzelli wrote:
I'll give this list a shot a something meat I have
had for a while -
maybe I can get a nice trade.
I have a big logic trainer that I would like to move on. It is pretty
neat and unique for three reasons:
1) It is based on vacuum tubes. Inside are a number of 12AX7oids that do
the work. I think this dates to the very late 1950s.
2) The logic is really odd. It is binary, but the logic levels are not
voltage levels, but phases. Hell of a way to run a railroad, in my book.
3) Its Japanese. Yes, Japanese. Apparently part of an early minicomputer
project that came out of Japan called Parametron.
So what I have is a really odd duck - a Parametron LT-2E, with power
supply, spares kit (with spare tubes!), and the reamins of a manual. It
is a pretty big desktop unit, but I think I can ship it FedEx ground in a
couple of boxes (from 10512).
As of now it is untested, but tomorrow I think I might look into powering
it up. There is some paint flakage and a little corrosion in the aluminum
body, but nothing to scream about.
So I am fishing for a trade. A good trade, as I know this thing is worth
some real money. What do I like? Big is good, old is good, IBM or Univac is
good, but I am open to ideas. I can trade up or down with cash, if we can
not quite equal things out.
Try me.
I'll try to get some pictures shot tomorrow.
William Donzelli
aw288(a)osfn.org
"Digital Computer Design Fundamentals" - Chu - 1962
Has a full section (about 4 pages) on Parametron logic, here are a couple
little excerpts:
"The Parametron, developed by Goto of Japan, is a parametric phase-locked
subharmonic oscillator (PLO). As described in chapter 6, a PLO is a
resonant circuit with a reactive element varying periodically at a pump
frequency fp; the resonant circuit produces a parametric oscillation with a
frequency fo which is the second subharmonic of the pump frequency (or fp =
2fo). The parametric subharmonic oscillation has a remarkable property in that
the oscillation has two stable phases which differ by 180 degrees as shown in
figure 6-35. These two stable modes of oscillation represent the binary
states; hence a PLO is a binary storage element..."
"The parametric oscillation is not a new phenomenom. Its application to the
digital computer was independently conceived by both the late Von Neumann ant
Goto of Japan at nearly the same time (1954) . The Parametron has been used in
several digital computers in Japan.
"
Peter Wallace