Electrologica X1
Encyclopedia
The Electrologica X1 was a digital computer
designed and manufactured in the Netherlands from 1958 to 1965. About thirty were produced and sold in the Netherlands and abroad.
The X1 was designed by the Mathematical Centre in Amsterdam
, an academic organization that had been involved in computer design since 1947, and manufactured by Electrologica NV, a company formed expressly for the purpose of producing the machine.
The X1 was a solid-state binary computer ("completely transistorized") with magnetic core memory. Word-length was 27 bits and peripherals included punched and magnetic tape. It was one of the first European computers to have an interrupt
facility.
Like its counterparts the Zuse Z22 and the ZEBRA
, (and the much later ARM architecture
), all instructions, not just branches, could be made conditional. This allowed for compact expression of programs. The following example demonstrates the loading of the absolute value of memory at n into the accumulator A:
2A n P // copy [n] to A
N 3A n // if A is negative, copy -[n] to A
The X1 arithmetic operators used binary fixed-point arithmetic
.
A notable peculiarity of the X1, or at least of the people who worked with it, was the use of base-32
notation when writing addresses.
The X1 was the subject of Edsger Dijkstra's
Ph.D. dissertation, and the target of the first complete working ALGOL 60
compiler, completed by Dijkstra and Jaap Zonneveld. In 1965, the X1 was superseded by the X8
. Electrologica was taken over by Philips
a few years later.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
designed and manufactured in the Netherlands from 1958 to 1965. About thirty were produced and sold in the Netherlands and abroad.
The X1 was designed by the Mathematical Centre in Amsterdam
Amsterdam
Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...
, an academic organization that had been involved in computer design since 1947, and manufactured by Electrologica NV, a company formed expressly for the purpose of producing the machine.
The X1 was a solid-state binary computer ("completely transistorized") with magnetic core memory. Word-length was 27 bits and peripherals included punched and magnetic tape. It was one of the first European computers to have an interrupt
Interrupt
In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
facility.
Like its counterparts the Zuse Z22 and the ZEBRA
ZEBRA (computer)
The ZEBRA was one of the first computers to be designed in the Netherlands, and one of the first Dutch computers to be commercially available...
, (and the much later ARM architecture
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
), all instructions, not just branches, could be made conditional. This allowed for compact expression of programs. The following example demonstrates the loading of the absolute value of memory at n into the accumulator A:
2A n P // copy [n] to A
N 3A n // if A is negative, copy -[n] to A
The X1 arithmetic operators used binary fixed-point arithmetic
Fixed-point arithmetic
In computing, a fixed-point number representation is a real data type for a number that has a fixed number of digits after the radix point...
.
A notable peculiarity of the X1, or at least of the people who worked with it, was the use of base-32
32 (number)
32 is the natural number following 31 and preceding 33.-In mathematics:32 is the smallest number n with exactly 7 solutions to the equation φ = n...
notation when writing addresses.
The X1 was the subject of Edsger Dijkstra's
Edsger Dijkstra
Edsger Wybe Dijkstra ; ) was a Dutch computer scientist. He received the 1972 Turing Award for fundamental contributions to developing programming languages, and was the Schlumberger Centennial Chair of Computer Sciences at The University of Texas at Austin from 1984 until 2000.Shortly before his...
Ph.D. dissertation, and the target of the first complete working ALGOL 60
ALGOL
ALGOL is a family of imperative computer programming languages originally developed in the mid 1950s which greatly influenced many other languages and became the de facto way algorithms were described in textbooks and academic works for almost the next 30 years...
compiler, completed by Dijkstra and Jaap Zonneveld. In 1965, the X1 was superseded by the X8
Electrologica X8
The Electrologica X8 was a digital computer designed as a successor to the Electrologica X1 and manufactured in the Netherlands by Electrologica NV from 1965 onwards....
. Electrologica was taken over by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
a few years later.
External links
- The Electrologica X1 and X8 computers
- "Communication with an Automatic Computer", Dijkstra's Ph.D. thesis (PDF)
- The Dijkstra-Zonneveld ALGOL 60 compiler for the Electrologica X1 (PDF) includes a good description of the X1 instruction set.