3 Wegematic 1000

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3.2 Wegematic 1000

According to Pär Rittsel [Rittsel www] Axel Wenner-Gren's company Logistics Research, Inc in California was building the following computers: AP-2, Aslap 2 and Float I (before 1953), Alwac II, III, III-E, 800, 880 (1953, 1954, 1955, 1957, 1957). The name Alwac comes from Axel Leonard Wenner-Gren Automatic Computer. The computers were to be used in his Alweg project aiming at the construction of a monorail system, that required advanced computations. Manuals for all of these except Alwac II, 800, 880 can be found in Box 39.A.2.B at Computer Product Manuals Collection (CBI 60), Charles Babbage Institute, University of Minnesota, Minneapolis [Babbage www]. Logistics Research, Inc was formed in 1952, changed its name to ALWAC in 1957, and was subsequently bought by El-Tronics in 1958.

The price for Alvac III-E was $76 950 as compared to $55 000 for IBM 610, and $182 000 for an IBM 650 (tapes) [Ordnance Corps www]. Alwac III-E is in [Macmillan www] mentioned as an early minicomputer that in 1955 was first in time-sharing remote terminals. University of British Columbia in Canada bought an Alwac III-E which was installed in March 1957 and remained in operation until October 1961, when an IBM 1620 was installed [UBC www]. A compatible installation of Alwac III-E was maintained at Oregon State College.

Alwac III-E was a first generation computer (1950-1960) used in the academia and the military. These were characterized by the use of vacuum tubes as their switching technology. The most popular memory technique was the rotating drum, an electromechanical device, which was slow, but its reliability and low cost made it suitable for small-scale machines like IBM 650 and Alwac III-E. These machines became outdated because of the introduction of the transistor and the ferrite core memory in the late 1950's.

Wegematic 1000 was similar to Alwac III-E and was manufactured by Bo Nyman AB in Bollmora, Sweden. The Wegematic 1000 processing unit comprised of a an operating unit and some six meters of racks holding a vertically oriented magnetic drum memory (3 600 rev/min) with 261 channels (tracks), about 10 000 diodes and about 500 electron tubes on laminate circuit boards, se picture below. Wegematic 1000 module (Part of the Helsinki Wegematic at display in Jyväskylä at a computer show in 1995) The energy consumption was about 15 kW.

Magnetic tape stations were available but were never installed. Mainly paper tape was used for input (150 char/s) and output (50 char/s). Also cards were used in the administrative applications.

The magnetic drum held registers (part of one channel), the working (prime) memory (four channels) and the main (secondary) memory (256 channels). Each track could store 32 words plus a check word, each word consisting of 32 bits plus a sign bit. The prime memory consisted of four channels with a multiple of read/write heads. The 4 x 32 words in the prime memory were addressable half-word wise in hexadecimal from 00 to FF.

There were four arithmetic registers A, B, and D of word size. A and B could be combined to a single register AB of double word size. There was an index register E of half word size mainly used for address modification. The drum speed was approximately 2 words/ms, an addition (subtraction) took 1 ms, a multiplication (division) 16 ms, excluding fetch times. A comparison took 0.5 ms. Fetch times for data and instructions in prime memory were on the average 4 ms and 2 ms respectively, for secondary memory 8 ms. Copying from secondary memory to a prime memory channel and execution of code in another prime memory channel could take place in parallel.

The operating unit consisted of an auto writer, for entering data and writing results and channel content, paper tape units for reading and writing, and the console containing some arrays of led lights and switches making it possible to view and change the content of a word in the prime memory or in the registers. As an alternative to the normal processing mode a one-step processing mode could be chosen, which made it possible to check the execution step by step.