computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...

, the Blit was a programmable

bitmap In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array A bit array (also known as bitmask, bit map, bit set, bit string, or bit vector) is an array data structure that c ...

graphics Graphics () are visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of data, as in design and manufacture ...

terminal Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output devic ...

Rob Pike Robert "Rob" Pike (born 1956) is a Canadian programmer and author. He is best known for his work on the Go programming language and at Bell Labs, where he was a member of the Unix team and was involved in the creation of the Plan 9 from Bell La ...

and Bart Locanthi Jr. of

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

in 1982.

History

The Blit programmable

was designed by

and Bart Locanthi Jr. of

in 1982. The Blit technology was commercialized by

AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile tel ...

and

Teletype A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initia ...

. In 1984, the DMD (dot-mapped display) 5620 was released, followed by models 630 MTG (multi-tasking graphics) in 1987 and 730 MTG in 1989. The 5620 used a

Western Electric The Western Electric Company was an American electrical engineering and manufacturing company officially founded in 1869. A wholly owned subsidiary of American Telephone & Telegraph for most of its lifespan, it served as the primary equipment ma ...

32100 processor (aka

Bellmac 32 The Bellmac 32 is a microprocessor developed by Bell Labs' processor division in 1980, implemented using CMOS technology and was the first microprocessor that could move 32 bits in one clock cycle. The microprocessor contains 150,000 transistors ...

) and had a 15" green phosphor display with 800×1024×1 resolution (66×88 characters in the initial text mode) interlaced at 30 Hz. The 630 and 730 had

Motorola 68000 The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector ...

processors and a 1024×1024×1 monochrome display at 60 Hz (most had amber displays, but some had white or green displays). The

folk etymology Folk etymology (also known as popular etymology, analogical reformation, reanalysis, morphological reanalysis or etymological reinterpretation) is a change in a word or phrase resulting from the replacement of an unfamiliar form by a more famili ...

for the ''Blit'' name is that it stands for ''Bell Labs Intelligent Terminal'', and its creators have also joked that it actually stood for ''Bacon, Lettuce, and Interactive Tomato''. However, Rob Pike's paper on the Blit explains that it was named after the second syllable of ''

bit blit Bit blit (also written BITBLT, BIT BLT, BitBLT, Bit BLT, Bit Blt etc., which stands for ''bit block transfer'') is a data operation commonly used in computer graphics in which several bitmaps are combined into one using a ''boolean function''. The ...

'', a common name for the bit-block transfer operation that is fundamental to the terminal's graphics. Its original nickname was ''Jerq'', inspired by a joke used during a demo of a Three Rivers'

PERQ The PERQ, also referred to as the Three Rivers PERQ or ICL PERQ, was a pioneering workstation computer produced in the late 1970s through the early 1980s. In June 1979, the company took its very first order from the UK's Rutherford Appleton La ...

graphic workstation and used with permission.

Functionality

When initially switched on, the Blit looked like an ordinary textual "dumb" terminal, although taller than usual. However, after logging into a

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

host (connected to the terminal through a

serial port In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. ...

), the host could (via special escape sequences) load software to be executed by the processor of the terminal. This software could make use of the terminal's full graphics capabilities and attached peripherals such as a

computer mouse A computer mouse (plural mice, sometimes mouses) is a hand-held pointing device that detects two-dimensional motion relative to a surface. This motion is typically translated into the motion of a pointer on a display, which allows a smooth c ...

. Normally, users would load the window systems ''mpx'' (or its successor ''mux''), which replaced the terminal's

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...

by a mouse-driven windowing interface, with multiple terminal windows all multiplexed over the single available serial-line connection to the host. Each window initially ran a simple

terminal emulator A terminal emulator, or terminal application, is a computer program that emulates a video terminal within some other display architecture. Though typically synonymous with a shell or text terminal, the term ''terminal'' covers all remote termin ...

, which could be replaced by a downloaded interactive graphical application, for example a more advanced terminal emulator, an editor, or a clock application. The resulting properties were similar to those of a modern Unix windowing system; however, to avoid having user interaction slowed by the serial connection, the interactive interface and the host application ran on separate systems—an early implementation of

distributed computing A distributed system is a system whose components are located on different computer network, networked computers, which communicate and coordinate their actions by message passing, passing messages to one another from any system. Distributed com ...

Window systems

Pike wrote two window systems for the Blit, ''mpx'' for 8th Edition Unix and ''mux'' for 9th Edition, both sporting a minimalistic design. The design of these influenced the later Plan 9 window systems

8½ ' (Italian title: , ) is a 1963 surrealist comedy-drama film directed and co-written (with Tullio Pinelli, Ennio Flaiano and Brunello Rondi) by Italian filmmaker Federico Fellini. The metafictional narrative centers on Guido Anselmi, played by Ma ...

and

rio Rio or Río is the Portuguese, Spanish, Italian, and Maltese word for "river". When spoken on its own, the word often means Rio de Janeiro, a major city in Brazil. Rio or Río may also refer to: Geography Brazil * Rio de Janeiro * Rio do Sul, a ...

. When the Blit was commercialized as the DMD 5620, a variant of mpx called "layers" was added to

SVR3 Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, an ...

. 9front (a Plan 9 fork) contains a Blit emulator that runs its original firmware, which can be used with mux (available in recently released

Research Unix The term "Research Unix" refers to early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC). History The term ''Research ...

v8).

References

;Notes : *

External links

* Bart Locanthi, Rob Pike
Blit (MPEG)(YouTube)
the classic animated short about the windowing terminal project (it was necessary to explain how mice worked back then; this was 1982, two years before the Mac) (

MPEG The Moving Picture Experts Group (MPEG) is an alliance of working groups established jointly by International Organization for Standardization, ISO and International Electrotechnical Commission, IEC that sets standards for media coding, includ ...

) * Source code (contains proprietary code
5620
{{DEFAULTSORT:Blit (Computer Terminal) AT&T computers Computer terminals History of computing hardware Thin clients User interfaces

History

Functionality

Window systems

See also

References

External links