Three tonnes of PCs – 40 years of computers serving the University
In just a few decades, the computer has become such a key part of our society that it is hard to imagine life without it. In 2012, an exhibition about computers in the service of the University documented some significant steps in computer development.
Early computers used punched hole cards and punched strips for input and output of programs and data. They also had a so-called primary memory large enough to temporarily store data during processing. Later, a secondary memory developed to store large amounts of information that the computer itself could process without the need for repeated input and output. Through technical development, the storage density and speed of secondary memories have increased.
The first experimental computers of the 1930s and 40s were built with electromechanical relays. These were replaced by electron tubes (also known as valves), but they generated a lot of heat and were unreliable. The solution came around 1950 with the transistor. Since the integrated circuit came in the early 1960s computers have become ever smaller and more compact. By the beginning of the 1970s it had become possible to make a computer's entire processor as a single microchip. Soon, usable computers could be made small enough to set up on a desk. With falling component prices, the computer entered the home and the microcomputer revolution was a fact.
Data processing with IBM 026 hole cards punched at the Astronomy Department
Today we communicate with the computer via the keyboard and the screen, but until the middle of the 1970s, computer communication took place mainly with punched hole cards. A mechanical hole card machine punched programs and data in the form of holes in the cards. The holes were determined by the keys the operator pressed down. In 1949, the IBM 026 hole card punch was introduced, and was used for a long time by astronomers at Uppsala University to record observations. The principal use was for photometric observations, i.e. measurements of radiation intensity from different sky objects. Unused cards were fed one at a time into the punching station from the card holder. The punching station was located at the right hand side of the machine, above the keyboard. When a card was punched, it was automatically moved to the reading position at the centre and from there to the card stacker at the left hand side of the machine. The completed cards were then read into a card reader. It was a time-consuming process that sometimes went wrong because of the human factor. The University's punched cards were processed by UDAC (Uppsala Data Centre) on Sysslomansgatan in Uppsala.
LINC-8 at the Psychology Department
During the 1960s, Professor Gunnar Johansson and his colleagues at the Psychology Department performed experiments on patterns of movement and human perception. They were interested, among other things, in the factors that influence how an observer perceives depth. These experiments often entailed complicated preparations and required several assistants as well as a range of paraphernalia. The equipment limited the possible number of experimental variables and thus the results. Johansson therefore bought a LINC-8 mini-computer that allowed a great increase in the number of variables in the experiments. Preparation time decreased when the need for assistants and supplies decreased. It was the first computer to be installed at a psychological institution in Europe and one of only three LINC-8 computers then existing in Sweden.
The first LINC computer was specialized for laboratory environments and was designed in 1962 at the Massachusetts Institute of Technology (MIT). The Digital Equipment Corporation (DEC) later took over the production, which was made to order. A total of 50 computers were produced. The desk-top computer industry began in 1959 when DEC introduced PDP-1 for 840,000 SEK, an extremely low price for a computer at the time. It had the same components as the room-sized computers but was no bigger than a refrigerator. In 1965, the first mass-produced small computer, PDP-8, was introduced. DEC also chose to design a hybrid between PDP-8 and LINC, which in 1966 resulted in LINC-8. The relatively low price and the machine's many features made it popular in the research community.
PDP-12, Elsa – Ulleråker Hospital
PDP-12 was introduced in 1969 and cost about 200,000 SEK. Less than 1,000 of these computers were made. PDP-12 was designed as an easy-to-use tool for laboratories and other types of research units. It could be used to collect and analyze data from different types of peripherals such as a programmable laboratory clock, card reader or PC12 High Speed Tape Reader and Punch as well as other types of laboratory equipment. The computer Elsa, which is in the care of Update, was used in research at Ulleråker hospital in Uppsala. With its help, several important studies were carried out with patients as subjects, including studies of reaction times. The name Elsa came from the fact that the few computers that were connected to the network were given a name for them to be distinguished on the network. It can be compared to today's IP addresses that identify the computer on the internet.
One of the main purposes of the exhibition was to highlight Update’s extensive collection of older computers and stimulate interest in them. It became a very much appreciated exhibition. Many older people who worked at the University came to re-experience the machines from their working days, but children and young people also constituted a large part of the audience.