ASCII character set (rather than, say, EBCDIC or anything specific to one company), but early/economy models often supported only capital letters (such as the original ADM-3, the Data General model 6052 – which could be upgraded to a 6053 with a lower-case character ROM – and the Heathkit H9).This made them inexpensive and they quickly became extremely popular Input-Output devices on many different types of computer system, often replacing earlier and more expensive printing terminals.Īfter 1970 several suppliers gravitated to a set of common standards: These devices used no CPU, instead relying on individual logic gates or very primitive LSI chips. Important early products were the ADM-3A, VT52, and VT100. The classic era of the VDU began in the early 1970s and was closely intertwined with the rise of time sharing computers. ![]() Despite this, early devices of this type were often called "Glass TTYs". The next generation of VDUs went beyond teletype emulation with an addressable cursor that gave them the ability to paint two-dimensional displays on the screen. CRT displays in that time frame were used in, e.g., experimental computers at MIT Commercial computer from, e.g., DEC, ERA, IBM, UNIVAC military computers for, e.g., BMEWS, BUIC, SAGE. VDUs in the 1950s were typically designed for displaying graphical data rather than just text. Due to that technology these devices were often called "CRTs". It faded away after 1980 under pressure from video display units (VDUs), with the last revision (the DECwriter IV of 1982) abandoning the classic teletypewriter form for one more resembling a desktop printer.Ī video display unit (VDU) displays information on a screen rather than printing text to paper and typically uses a cathode-ray tube (CRT). The DECwriter was the last major printing-terminal product. Although at that time "paper was king" the speed of interaction was relatively limited. Respective top speeds of teletypes, IBM 2741 and the LA30 (an early DECwriter) were 10, 15 and 30Ĭharacters per second. This led to the use of the current loop interface that was already used in telegraphy, as well as a thriving market in surplus machines for computer use.Ĭustom-designs keyboard/printer terminals that came later included the IBM 2741 (1965) and the DECwriter (1970). The device was a Friden Flexowriter, which would continue to serve this purpose on many other early computers well into the 1960s.Ĭategories Hard-copy terminals Ĭloseup of an IBM 2741 printing terminal, which used a changeable Selectric "golfball" typing element and was faster than the earlier teletype machinesĮarly user terminals connected to computers were, like the Flexowriter, electromechanical teleprinters/teletypewriters (TeleTYpewriter, TTY), such as the Teletype Model 33, originally used for telegraphy early Teletypes were typically configured as Keyboard Send-Receive (KSR) or Automatic Send-Receive (ASR), the latter including a paper tape reader and punch. In 1955, the Whirlwind Mark I computer was the first computer equipped with a keyboard-printer combination with which to support direct input of data and commands and output of results. Both machines had a row of display lamps for results. But these consoles could only be used to enter numeric inputs and were thus analogous to those of calculating machines programs, commands, and other data were entered via paper tape. The console of Konrad Zuse's Z3 had a keyboard in 1941, as did the Z4 in 1942–1945. A personal computer can run terminal emulator software that replicates functions of a real-world terminal, sometimes allowing concurrent use of local programs and access to a distant terminal host system, either over a direct serial connection or over a network using, e.g., SSH. A terminal that depends on the host computer for its processing power is called a " dumb terminal" or a thin client. The function of a terminal is typically confined to transcription and input of data a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. ![]() The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades.Įarly terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. IBM 2741, a widely emulated computer terminal in the 1960s and 1970sĪ computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system.
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