The S-C 5000 High Speed Electronic Printer, with cabinet open, to
show interior assembly. Reference to the accompanying schematic drawing
will identify the various components of the equipment.
There are very few computer users left who still can recall
the frustration of having to wait for a printout. For instance, around
1953-1954, at the Lawrence Livermore National Laboratory (LLNL), the
first printers used in conjunction with the UNIVAC I--our first computer--were
nothing more than typewriters with print rates of perhaps 6 characters
per second. Since the typical output from a design calculation involved
50,000 to 100,000 characters, printing would take an inordinately
long time. The quest for speedy printing at LLNL led us through a
succession of interesting machines, one of which we relied on for
about 10 years, starting in 1964. This was the so-called "Radiation
Printer", an eccentric and demanding invention that met our computer
printing needs for speed despite its own oddities.
To better appreciate what the Radiation Printer represented, it
will be useful to consider first, the few printers that preceded
it. I've already mentioned the use of suitably modified typewriters
on the UNIVAC I. The IBM computers that arrived next had modified
407 accounting machines serving as printers. They were rated at
150 lines per minute, a line being up to 132 characters wide. They
were also far too slow to meet our needs. As I recall things now,
IBM never included faster printers for its initial computers. If
you dealt with IBM, these 407s were what you got; a Hobson's choice.
ON THE JOB HEARING LOSS
One of our first attempts to get something faster than these printers
arrived from Remington Rand around 1957. This was a 600-line-per-minute
impact printer, where a line included any number of characters from
0 to 120; each page held about 50 lines. As fast as this was, it
was still too slow to serve the needs of dozens of people who spent
too much of their valuable time waiting for results. Also, when
these so-called impact printers ran, the noise level was dangerously
high A few intense users lost some of their hearing from standing
in front of the printer, anxiously trying to read their output as
it was being printed. In addition to being very noisy, impact printers
were not sufficiently reliable, so we sought other solutions.
THE GIRL WITH A CURL
We tried a marriage of cathode ray tubes and xerography: The SC5000
built by Stromberg Carlson in 1959. This device formed characters
by projecting an electron bean [sic] through a character mask, creating
a spatial distribution of electrons then formed the selected character
when plotted on the screen of the CRT. The SC5000 further selected
where to position the character along the print line. The light
thus generated was projected onto a selenium-coated drum that is
fundamental in the xerographic printing procedure. In this process,
after the image was formed on the selenium drum, it was dusted with
xerographic powder ("toner"), which adhered only where
the light had suitably charged the surface. By bringing paper in
contact with the drum, the image was transferred. The paper then
moved through an oven where the powder was fused to the paper. Input
to the printing system was via magnetic tape.
Editor's note: This is an expansion of an article that appeared
in CORE 1.4,
a Computer Museum History Center publication, in November, 2000.
Used here with the permission of the Computer History Museum.