Jan Rajchman Oral History
This
interview is part of the RCA
Engineers Collection.
Rajchman,
a computer pioneer, was born in England and educated
in Zurich, Switzerland. He graduated with a
degree in electrical engineering from the
Swiss Federal Institute of Technology in 1935.
Rajchman began working for RCA in 1935, and in
1936 began his work on the electron multiplier
with Vladimir Zworykin. In 1939, Rajchman began
working on the possibilities of computation,
developing the idea of the selective storage
electrostatic tube and magnetic core memories.
Rajchman was involved in Project Lightning and
held the position of director of RCA's
computer research laboratory from 1957 to 1967.
The
interview covers Rajchman's work with electron
multipliers and his involvement with the first
computation developments in the late 1930s.
There is an extended discussion of ENIAC and
Rajchman's activities with various people
involved in the project, including John von Neumann
and Herman Goldstein. Rajchman also discusses
his involvement with Project Lightning. The
interview continues with a discussion of Rajchman's
extensive work on computer memory, including the
Selectron, magnetic cores, and transflexers.
The development of timesharing software and
RCA's pioneering work in superconductive memory is
also covered. The interview concludes with
Rajchman's remarks concerning what he sees to be
the fundamental problem to be resolved in computer
technology--the development of an inexpensive,
purely electronic memory. He includes a
discussion of possible approaches to this problem,
including holographic and magnetic bubble
memory.
See aslo Interview #002, Jan Rajchman &
Albert Hoagland (March 21, 1971)
Table of Contents
- Early life in Europe
- Education at Swiss Federal Institute of
Technology
Attracted by industrial
research opportunities in U.S.
Had
heard of Vladimir Zworykin
Summer
session at MIT
Began work with RCA,
transferred to Zworykin's lab in 1936
Electron multiplier was first assignment with
Zworykin
- Electron optics the forte of Zworykin's
lab
Rajchman simplifies electron
multiplier by making them electrostatic
Used rubber model analogy as design tool
- Solves problem of ion feedback
Multipliers today use same design, production
line is completely computerized
- RCA one of best suppliers of
multipliers
Begins work on the
possibilities of computation in 1939
RCA approached by Franklin Arsenal to make
computers to direct anti-aircraft
guns
Work on analog devices and
digital devices
- Involvement with the Moore School of
Engineering Origins of ENIAC
RCA
declines offer to build ENIAC
- Zworykin's reasons for declining
offer
Beginnings of ideas for other
uses for ENIAC
- Concept of the total program computer
as a gradual invention
Work on a
computing tube, the "computron"
- Work on microwaves
Builds
a small betatron
Just miss the
concept of strong focusing
- Discusses the general concept of strong
focusing
Gave up on the idea
because of the tough mathematics
Cristopholus does calculations
- Development of stored-program machine
Institute and RCA in joint project to
develop machine and memory Idea of the selective
storage electrostatic tube, the
"selectron"
- Discussion of the selectron as a
positive digital device von Neumann used
an electron beam tube
Rajchman
considers the magnetic core
- Issues with magnetic core for memory
- Task of assembling cores turns out to
be simple
First cores made from
magnetic ribbons
Asks Leverenz for
a ferrite material to replace expensive, fragile
ribbons
- Adapt aspirin tablet machine to produce
ferrite cores
Learn of MIT's
parallel efforts RCA reluctant to manufacture
cores
- Attempts at integrated production of
cores leads to concept of transflexer
- Transflexer non-destructive and
analog
Discussion of the
transflexer and flatscreen TV display
- Reliability of transflexers Industrial
use of transflexers
Reliability and
cheapness of transflexers limit market
- Transflexers versus transistors
- Position as director of research from
1957 to 1967 Project Lightning
- Project Lightning focused industry
towards high speed
RCA responds
quickly to Esaki's tunnel diode
- Sees Project Lightning as a positive
project
Rajchman director of the
computer research laboratory
- Recognizes need to focus on computer
technology
Creates software
research group
Develops timesharing
software MIT pioneer in timesharing area
- Anecdote about Sarnoff's visit to the
lab and discussion of timesharing
- RCA using timesharing for their company
system still
- Inexpensiveness of microprocessors
revising concept of timesharing
Pioneering work in development of computer
circuits with MOS RCA strength in
practical combination of semiconductor
technology and circuit and system work
- Advances in core memory Begin work on
superconductive memory
- Advantages of the superconducting
devices
- Difficulties with superconductive
memory Continuing need to improve
computer memory
- Magnetic storage disk as mainstay of
IBM
Compares cheapness of logic to
expense of memory
- Sees development of inexpensive,
electronic method of storing information
as outstanding problem of electronics
Proposes as an intellectual challenge for
civilization
- Attempts at developing holographic
memory
- Predicts gradual improvements in
semiconductor memories
- Limits to inexpensiveness of
semiconductor memory
Possibilities
of holographic memory
- Advantages of holgrams in principle
- Limitations of holographic memory
Magnetic bubble memories
- Problems with combination of bubble
serial memory and semiconductor
- Continued applications of timesharing
