QDOS is the multitasking

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

found on the

Sinclair QL The Sinclair QL (for ''Quantum Leap'') is a personal computer launched by Sinclair Research in 1984, as an upper-end counterpart to the ZX Spectrum. The QL was aimed at the serious home user and professional and executive users markets from small ...

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

and its clones. It was designed by

Tony Tebby Tony Tebby is a computer programmer and the designer of Qdos, the computer operating system used in the Sinclair QL personal computer, while working as an engineer at Sinclair Research in the early 1980s. He left Sinclair Research in 1984 in prot ...

whilst working at

Sinclair Research 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, the ...

, as an in-house alternative to

68K/OS 68K/OS was a computer operating system developed by GST Computer Systems for the Sinclair QL microcomputer. It was commissioned by Sinclair Research in February 1983. However, after the official launch of the QL in January 1984, 68K/OS was rejec ...

, which was later cancelled by Sinclair, but released by original authors

GST Computer Systems GST was a group of computer companies based in Cambridge, England, founded by Jeff Fenton in June 1979. The company worked with Atari, Sinclair Research, Torch Computers, Acorn Computers, Monotype Corporation and Kwik-Fit, amongst others. Th ...

. Its name is not regarded as an

acronym An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...

and sometimes written as Qdos in official literature (see also the identically-pronounced word

kudos Kudos may refer to: Arts and media * ''Kudos'' (computer game), a life simulation game produced by Positech Games * Kudos (production company), a UK-based film and television production company * Kudos, a fictional currency used by the Dwellers ...

). QDOS was implemented in

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 ...

assembly language In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...

, and on the QL, resided in 48 KB of

ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...

, consisting of either three 16 KB EPROM chips or one 32 KB and one 16 KB ROM chip. These ROMs also held the

SuperBASIC 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 interprete ...

interpreter, an advanced variant of

BASIC BASIC (Beginners' All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages designed for ease of use. The original version was created by John G. Kemeny and Thomas E. Kurtz at Dartmouth College ...

programming language A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming ...

with structured programming additions. This also acted as the QDOS

command-line interpreter A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invoking executables and pro ...

.1 KB = 1024 bytes Facilities provided by QDOS included management of processes (or "jobs" in QDOS terminology), memory allocation, and an extensible "redirectable I/O system", providing a generic framework for

filesystem In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

s and

device driver In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...

s. Very basic screen

window A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent materia ...

functionality was also provided. This, and several other features, were never fully implemented in the released versions of QDOS, but were improved in later extensions to the operating system produced by Tebby's own company, QJUMP. Rewritten, enhanced versions of QDOS were also developed, including Laurence Reeves'

Minerva Minerva (; ett, Menrva) is the Roman goddess of wisdom, justice, law, victory, and the sponsor of arts, trade, and strategy. Minerva is not a patron of violence such as Mars, but of strategic war. From the second century BC onward, the Roma ...

and Tebby's SMS2 and

SMSQ/E 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 last is the most modern variant and is still being improved.

Versions

QDOS versions were identified by numerical version numbers. However, the QL firmware ROMs as a whole (including SuperBASIC) were given two- or three-letter alphabetic identifiers (returned by the SuperBASIC function ''VER$''). The following version of QDOS were released (dates are estimated first customer shipments): * 0.08: the last pre-production version. * 1.00: corresponded to the ''FB'' version QL ROMs, released in April 1984. * 1.01: corresponded to the ''PM'' version ROMs. This was faster and had improved

Microdrive The Microdrive is a registered trademark for miniature, 1-inch hard disks produced by IBM and Hitachi. These rotational media storage devices were designed to fit in CompactFlash (CF) Type II slots. The release of similar drives by other ...

support. * 1.02: corresponded to the ''AH'' ROM version released in June 1984. This fixed many bugs and was the first ROM version to be produced in quantity. * 1.03: included in ROM versions ''JM'' and ''TB''; a minor bug-fix release issued in late 1984. * 1.10: corresponded to the ''JS'' and ''JSU'' ( US export version) ROMs, released in early 1985. This was the last version used in QLs manufactured for the UK market. * 1.13: corresponding to the ''MG''x series of ROM versions for European export markets. Included a significant number of bug fixes. The following localised versions of the ''MG'' firmware are known to exist: ** ''MGE:''

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

** ''MGF:'' French ** ''MGG:''

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

** ''MGI:''

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

** ''MGS:''

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

The localised versions of QDOS were identified by the "." in the version number being replaced by the ROM version suffix letter used to identify the territory, e.g. the ''MGE'' ROMs contained QDOS version 1E13. All ''MG'' firmware versions shared the same bottom 32 KB ROM chip. Qdos 1.13 was also reported to be included in a

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

localised ROM version, known as ''ΣFP'' (marked on the ROMs as ''EFP'').

Notes

References

* Andrew Pennell (1985). ''The Sinclair QDOS Companion: a guide to the QL operating system''. London: Sunshine Books. * Simon Goodwin. "Bugging the ROM", ''Sinclair QL World'', August 1987
QL History FAQ: Firmware

External links

The official SMSQ/E site Source Code, binaries and documentation

QDOS Internals Dokuwiki established by Norman Dunbar

Amiga implementation
{{Disk operating systems Disk operating systems Discontinued operating systems Sinclair Research Assembly language software 68k-based computers 1984 software