In computing, multitasking is the concurrent execution of multiple tasks over a certain period of time. New tasks can interrupt already started ones before they finish, instead of waiting for them to end. As a result, a computer executes segments of multiple tasks in an interleaved manner, while the tasks share common processing resources such as central processing units (CPUs) and main memory. Multitasking automatically interrupts the running program, saving its state and loading the saved state of another program and transferring control to it. This "context switch" may be initiated at fixed time intervals, or the running program may be coded to signal to the supervisory software when it can be interrupted.
The Motorola 68060 ("sixty-eight-oh-sixty") is a 32-bit microprocessor from Motorola released in 1994. It is the successor to the Motorola 68040 and is the highest performing member of the 68000 series. Two derivatives were produced, the 68LC060 and the 68EC060.
The Sinclair QL microcomputer is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the Sinclair ZX Spectrum. The QL was aimed at the serious home user and professional and executive users markets from small to medium-sized businesses and higher educational establishments, but failed to achieve commercial success.
The ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research.
Psion was a designer and manufacturer of mobile handheld computers for commercial and industrial applications. The company was headquartered in London, England with major operations in Mississauga, Ontario, Canada and additional company offices in Europe, the United States, Asia, Latin America, and the Middle East. It was a public company listed on the London Stock Exchange and was once a constituent of the FTSE 100 Index.
QDOS is the multitasking operating system found on the Sinclair QL personal computer and its clones. It was designed by Tony Tebby whilst working at Sinclair Research, as an in-house alternative to 68K/OS, which was later cancelled by Sinclair, but released by original authors GST Computer Systems. Its name is not regarded as an acronym and sometimes written as Qdos in official literature.
SMSQ/E is a computer operating system originally developed in France by Tony Tebby, the designer of the original QDOS operating system for the Sinclair QL personal computer. It began life as SMSQ, a QDOS-compatible version of SMS2 intended for the Miracle Systems QXL emulator card for PCs. This was later developed into an extended version, SMSQ/E, for the Atari ST. It consists of a QDOS compatible SMS kernel, a rewritten SuperBASIC interpreter called SBasic, a complete set of SuperBASIC procedures and functions and a set of extended device drivers originally written for the QL emulator for the Atari ST.
SuperBASIC is an advanced variant of the BASIC programming language with many structured programming additions. It was developed at Sinclair Research by Jan Jones during the early 1980s. Originally SuperBASIC was intended as the BASIC interpreter for a home computer code-named SuperSpectrum, then under development. This project was later cancelled; however, SuperBASIC was subsequently included in the ROM firmware of the Sinclair QL microcomputer, also serving as the command line interpreter for the QL's QDOS operating system. It was one of the first second-generation BASICs to be integrated into a microcomputer's operating system, making the OS user-extendable—as done by Linus Torvalds in his formative years.
Sinclair Research Ltd is a British consumer electronics company founded by Clive Sinclair in Cambridge. It was originally incorporated in 1973 as Westminster Mail Order Ltd, renamed Sinclair Instrument Ltd, then Science of Cambridge Ltd, then Sinclair Computers Ltd, and finally Sinclair Research Ltd. It remained dormant until 1976, when it was activated with the intention of continuing Sinclair's commercial work from his earlier company Sinclair Radionics, and adopted the name Sinclair Research in 1981.
Written by Laurence Reeves in England, Minerva was a reimplementation of Sinclair QDOS, the built-in operating system of the Sinclair QL line of personal computers. Minerva incorporated many bug fixes and enhancements to both QDOS and the SuperBASIC programming language. Later versions also provided the ability to multi-task several instances of the SuperBASIC interpreter, something not supported by QDOS.
In computing, preemption is the act of temporarily interrupting a task being carried out by a computer system, without requiring its cooperation, and with the intention of resuming the task at a later time. Such changes of the executed task are known as context switches. They are normally carried out by a privileged task or part of the system known as a preemptive scheduler, which has the power to preempt, or interrupt, and later resume, other tasks in the system.
Miracle Systems Ltd. were a manufacturer of personal computer peripherals and upgrades, specializing in the Sinclair QL, in the 1980s and early 1990s.
The One Per Desk, or OPD, was an innovative hybrid personal computer/telecommunications terminal based on the hardware of the Sinclair QL. The One Per Desk was built by International Computers Limited (ICL) and launched in the UK in 1984. It was the result of a collaborative project between ICL, Sinclair Research and British Telecom begun in 1981, originally intended to incorporate Sinclair's flat-screen CRT technology.
Tony Tebby is probably most famous for designing Qdos, the computer operating system used in the Sinclair QL personal computer, whilst working as an engineer at Sinclair Research in the early 1980s. He left Sinclair Research in 1984 in protest at the premature launch of the QL, and formed QJUMP Ltd., a software house specializing in system software and utilities for the QL, based in Rampton, Cambridgeshire, England.
The CST Thor series of personal computers were Sinclair QL-compatible systems designed and produced by Cambridge Systems Technology during the late 1980s.
GST was a group of computer companies based in Cambridge, England, founded by Jeff Fenton in June 1979. The company worked with Sinclair Research, Torch Computers, Acorn Computers, Monotype Corporation and Kwik-Fit, amongst others.
The Q40 and Q60 are computer motherboards designed in the late 1990s, based on the Motorola 68040 and 68060 microprocessors respectively and intended to be partially compatible with the Sinclair QL microcomputer.
