Electrologica X1
The Electro Logica X1 (or simply EL X1 ) was a digital computer, which was constructed in the Netherlands and produced from 1958 to 1965. About 30 plants were built and sold abroad.
The X1 was designed in the Mathematisch Centrum Amsterdam by Carel Scholten and Bram Loopstra. Produced the X1 from the Electro Logica NV, a company that was established specifically to the Mathematisch Centrum and the insurance company Nillmij 1958.
An asset is sold at a coffee company in Germany, from where they later came as a used machine to the TU Braunschweig, where she was until 1975 in use ( the machines remained until the end a certain smell of coffee ). There was a slightly larger plant, which could be fed by punched tape, punched card or magnetic tape and was operated by professional operators or by trained users, as well as a smaller one that was only equipped with paper tape (input and output ) and electrical typewriter and ran in self-service mode by the students. They were almost exclusively programmed in Algol 60.
The X1 was a fully transistorized Binärcomputer with toroidal memory. The circuits were designed as plug-in modules in metal cups of about cigarette box size. A module contained in a discrete transistor logic, a single logic gate, so usually one or two transistors. The CPU was a cube-shaped cabinet of about one cubic meter volume.
The word length was 27 bits of memory. A smaller machine which had about 7 K words which filled a second cabinet of the same size as the CPU. Maximum was 32,768 memory locations are addressed as 15 address bits were available.
The "small X1" could directly use about 3 Kbytes memory, "split- Compiler" 8 Kbytes; the "great X1" could use 16 kByte memory.
As peripheral punched tape, punched cards, magnetic tape, line printer, DIN A1 plotter and electric typewriters were available. The X1 was one of the first European computer with an interrupt system. Could be carried out to peripheral devices much more efficient Building on the interfaces so that they mainly offered some buffer between faster and slower CPU peripherals, like a discharge channel later mainframe.
As with competitive models Zuse Z22 and ZEBRA could all commands not only the branches conditionally ( conditional ) are carried out. This enabled very compact programs written. The following example shows the loading of the absolute value of the stored value from memory location n into the accumulator A.
2A n P / / [ n] to A Copy N3A n / / if A is negative, copy - [ n] to A A remarkable peculiarity of the X1, or at least the people who worked with her, was the use of 32- Bittiger notation in its own base -32 number format for the addresses.
The X1 has been the subject of Edsger W. Dijkstra's thesis and the target machine for the first fully implemented Algol -60 compiler, completed by Dijkstra and Jaap Zonneveld. The X1 in 1965 was replaced by the X8. Electro Logica was acquired the following year by Philips.
Pictures
The following pictures ( except the last ) were taken just before and after 1975, the X1 TU Braunschweig was demolished.
X1 backplane wiring after demolition
X1 modules after demolition, re-plugged
X1 modules after the demolition, the color indicates the type of logic gate in the module
Interior of an X1 module
IBM typewriter, as they could be connected in a similar version (without keys ) as the output unit to the X1
Credentials
- CACM 2 (9 ): 24 (1959). 1, EE, Edsger W. Dijkstra: Communication with to Automatic Computer, University of Amsterdam 1959.