TX-0
Encyclopedia
The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo , was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic core memory. The TX-0 was built in 1955 and went online in 1956 and was used continually through the 1960s
at MIT. The TX-0 and its direct descendant, the original PDP-1
, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture.
largely as an experiment in transistor
ized design and the construction of very large core memory systems, the TX-0 was essentially a transistorized version of the equally famous Whirlwind
, also built at Lincoln Lab. While the Whirlwind filled an entire floor of a large building, TX-0 fit in a single reasonably sized room and yet was somewhat faster. Like the Whirlwind, the TX-0 was equipped with a display system, in this case a 12" oscilloscope
hooked to output pins of the processor allowing it to display 512×512 points
in a 7" by 7" array.
The TX-0 was a fully 16-bit computer with a 16-bit address range and 16-bit operations. Its word size was 18 bits; this allowed for 16 bits of data and 2 bits of instructions. These 2 bits could create 4 possible instructions, which included store, add, and conditional branch instructions as a basic set. The fourth instruction, "operate", took additional operands and allowed access to a number of "micro-orders" which could be used separately or together to provide many other useful instructions. An "add" instruction took 10 microseconds.
in 1958. Since core memory was very expensive at the time, several parts of the TX-0 memory were cannibalized for the TX-2 project. After a time, the TX-0 was no longer considered worth keeping at Lincoln Lab, and was "loaned" (semi-permanently) to the MIT Research Laboratory of Electronics
(RLE) in July 1958, where it became a centerpiece of research that would eventually evolve into the MIT Artificial Intelligence Lab and the original computer "hacker" culture.
Delivered from Lincoln Laboratory with only 4K of core, the machine no longer needed 16 bits to represent a storage address. After about a year and a half, the number of instruction bits was doubled to 4, allowing a total of 16 instructions, and an index register
was added. This dramatically improved programmability of the machine, but still left room for a later memory expansion to 8K (the four instruction bits and one-bit indexing flag left 13 bits for addressing). This newly-modified TX-0 was used to develop a huge number of advances in computing, including speech
and handwriting recognition
, as well as the tools needed to work on such projects, including text editor
s and debugger
s.
Meanwhile the TX-2 project was running into difficulties of its own, and several team members decided to leave the project at Lincoln Lab and start their own company. After a short time selling "lab modules" in the form of simple logic elements from the TX-2 design, the newly-formed Digital Equipment Corporation
(DEC) decided to produce a "cleaned up" TX-0 design, and delivered it in 1961 as the PDP-1
. A year later, DEC donated the engineering prototype PDP-1 machine to MIT. It was installed in the room next to TX-0, and the two machines would run side-by-side for almost a decade.
Significant pieces of the TX-0 are currently on display in the Library at Lincoln Laboratory. The library is only accessible to Lincoln Lab employees.
1960s
The 1960s was the decade that started on January 1, 1960, and ended on December 31, 1969. It was the seventh decade of the 20th century.The 1960s term also refers to an era more often called The Sixties, denoting the complex of inter-related cultural and political trends across the globe...
at MIT. The TX-0 and its direct descendant, the original PDP-1
PDP-1
The PDP-1 was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1960. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere...
, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture.
Background
Designed at the MIT Lincoln LaboratoryLincoln Laboratory
MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense research and development center chartered to apply advanced technology to problems of national security. Research and development activities focus on long-term technology development as well as...
largely as an experiment in transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
ized design and the construction of very large core memory systems, the TX-0 was essentially a transistorized version of the equally famous Whirlwind
Whirlwind (computer)
The Whirlwind computer was developed at the Massachusetts Institute of Technology. It is the first computer that operated in real time, used video displays for output, and the first that was not simply an electronic replacement of older mechanical systems...
, also built at Lincoln Lab. While the Whirlwind filled an entire floor of a large building, TX-0 fit in a single reasonably sized room and yet was somewhat faster. Like the Whirlwind, the TX-0 was equipped with a display system, in this case a 12" oscilloscope
Oscilloscope
An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or 'Y' axis, plotted as a function of time,...
hooked to output pins of the processor allowing it to display 512×512 points
Pixel
In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....
in a 7" by 7" array.
The TX-0 was a fully 16-bit computer with a 16-bit address range and 16-bit operations. Its word size was 18 bits; this allowed for 16 bits of data and 2 bits of instructions. These 2 bits could create 4 possible instructions, which included store, add, and conditional branch instructions as a basic set. The fourth instruction, "operate", took additional operands and allowed access to a number of "micro-orders" which could be used separately or together to provide many other useful instructions. An "add" instruction took 10 microseconds.
Development
With the successful completion of the TX-0, work turned immediately to the much larger and far more complex TX-1. However this project soon ran into difficulties due to its complexity, and was redesigned into a smaller form that would eventually be delivered as the TX-2TX-2
The MIT Lincoln Laboratory TX-2 computer was the successor to the Lincoln TX-0 and was known for its role in advancing both artificial intelligence and human-computer interaction.- Specifications :...
in 1958. Since core memory was very expensive at the time, several parts of the TX-0 memory were cannibalized for the TX-2 project. After a time, the TX-0 was no longer considered worth keeping at Lincoln Lab, and was "loaned" (semi-permanently) to the MIT Research Laboratory of Electronics
Research Laboratory of Electronics at MIT
The Research Laboratory of Electronics at the Massachusetts Institute of Technology was founded in 1946 as the successor to the famed MIT Radiation Laboratory of World War II....
(RLE) in July 1958, where it became a centerpiece of research that would eventually evolve into the MIT Artificial Intelligence Lab and the original computer "hacker" culture.
Delivered from Lincoln Laboratory with only 4K of core, the machine no longer needed 16 bits to represent a storage address. After about a year and a half, the number of instruction bits was doubled to 4, allowing a total of 16 instructions, and an index register
Index register
An index registerCommonly known as a B-line in early British computers. in a computer's CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations...
was added. This dramatically improved programmability of the machine, but still left room for a later memory expansion to 8K (the four instruction bits and one-bit indexing flag left 13 bits for addressing). This newly-modified TX-0 was used to develop a huge number of advances in computing, including speech
Speech recognition
Speech recognition converts spoken words to text. The term "voice recognition" is sometimes used to refer to recognition systems that must be trained to a particular speaker—as is the case for most desktop recognition software...
and handwriting recognition
Handwriting recognition
Handwriting recognition is the ability of a computer to receive and interpret intelligible handwritten input from sources such as paper documents, photographs, touch-screens and other devices. The image of the written text may be sensed "off line" from a piece of paper by optical scanning or...
, as well as the tools needed to work on such projects, including text editor
Text editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
s and debugger
Debugger
A debugger or debugging tool is a computer program that is used to test and debug other programs . The code to be examined might alternatively be running on an instruction set simulator , a technique that allows great power in its ability to halt when specific conditions are encountered but which...
s.
Meanwhile the TX-2 project was running into difficulties of its own, and several team members decided to leave the project at Lincoln Lab and start their own company. After a short time selling "lab modules" in the form of simple logic elements from the TX-2 design, the newly-formed Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
(DEC) decided to produce a "cleaned up" TX-0 design, and delivered it in 1961 as the PDP-1
PDP-1
The PDP-1 was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1960. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere...
. A year later, DEC donated the engineering prototype PDP-1 machine to MIT. It was installed in the room next to TX-0, and the two machines would run side-by-side for almost a decade.
Significant pieces of the TX-0 are currently on display in the Library at Lincoln Laboratory. The library is only accessible to Lincoln Lab employees.
See also
- Expensive Desk CalculatorExpensive Desk CalculatorExpensive Desk Calculator by Robert A. Wagner is thought to be computing's first interactive calculation program.The software first ran on the TX-0 computer loaned to the Massachusetts Institute of Technology by Lincoln Laboratory...
- Expensive Tape RecorderExpensive Tape RecorderExpensive Tape Recorder is a digital audio program written by David Gross while a student at the Massachusetts Institute of Technology. Gross developed the idea with Alan Kotok, a fellow member of the Tech Model Railroad Club...
- First video game#1959: Mouse in the Maze, Tic-Tac-Toe — early video games invented on the TX-0
External links
- RLE Technical Report 627 TX-0 Computer History (Oct 1974)
- Oral history interview with Jack B. Dennis, Charles Babbage InstituteCharles Babbage InstituteThe Charles Babbage Institute is a research center at the University of Minnesota specializing in the history of information technology, particularly the history since 1935 of digital computing, programming/software, and computer networking....
, University of Minnesota. — Dennis describes his educational background and work in time-sharing computer systems at the Massachusetts Institute of Technology (MIT), including the TX-0 computer, the work of John McCarthyJohn McCarthy (computer scientist)John McCarthy was an American computer scientist and cognitive scientist. He coined the term "artificial intelligence" , invented the Lisp programming language and was highly influential in the early development of AI.McCarthy also influenced other areas of computing such as time sharing systems...
on time-sharing, and the development of MULTICSMulticsMultics was an influential early time-sharing operating system. The project was started in 1964 in Cambridge, Massachusetts...
at General Electric. - The TX-0: Its Past and Present
- TX-0 documentation
- TX-0 programs
- Steven LevySteven LevySteven Levy is an American journalist who has written several books on computers, technology, cryptography, the Internet, cybersecurity, and privacy.-Career:...
, Hackers: Heroes of the Computer RevolutionHackers: Heroes of the Computer RevolutionHackers: Heroes of the Computer Revolution is a book by Steven Levy about hacker culture. It was published in 1984 in Garden City, New York by Anchor Press/Doubleday...
— Website dedicated to information about the TX-0 computer. [Website partially working when checked]