Sinclair QDOS
Encyclopedia
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
.
QDOS was implemented in Motorola 68000
assembly language
, and on the QL, resided in 48 kB
of ROM
, consisting of either three 16 kB EPROM chips or one 32 kB and one 16 kB ROM chip. These ROMs also held the SuperBASIC
interpreter, an advanced variant of BASIC with structured programming additions. This also acted as the QDOS command line interpreter.
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 filesystems and device driver
s. Very basic screen window
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
, and Tebby's SMS2
and SMSQ/E
. The latter is the most modern variant and is still being improved.
The following version of QDOS were released (dates are estimated first customer shipments):
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, eg. 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
localised ROM version, known as ΣFP (marked on the ROMs as EFP).
Computer multitasking
In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
found on the Sinclair QL
Sinclair QL
The Sinclair QL , was a personal computer launched by Sinclair Research in 1984, as the successor to the Sinclair ZX Spectrum...
personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
and its clones. It was designed by Tony Tebby
Tony Tebby
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...
whilst working at Sinclair Research, as an in-house alternative to 68K/OS
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...
, which was later cancelled by Sinclair, but released by original authors GST Computer Systems
GST Computer Systems
GST was a group of computer companies based in Cambridge, England, founded by Dr Jeff Fenton in June 1979. The company worked with Sinclair Research, Torch Computers, Acorn Computers, Monotype Corporation and Kwik-Fit, amongst others.The group included:...
.
QDOS was implemented in Motorola 68000
Motorola 68000
The Motorola 68000 is a 16/32-bit CISC microprocessor core designed and marketed by Freescale Semiconductor...
assembly language
Assembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
, and on the QL, resided in 48 kB
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
of ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...
, 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
SuperBASIC was 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 for a home computer, code-named SuperSpectrum, then under development...
interpreter, an advanced variant of BASIC with structured programming additions. This also acted as the QDOS command line interpreter.
Facilities provided by QDOS included management of processes
Process (computing)
In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system , a process may be made up of multiple threads of execution that execute instructions concurrently.A computer program is a...
(or "jobs" in QDOS terminology), memory allocation, and an extensible "redirectable I/O system", providing a generic framework for filesystems and device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
s. Very basic screen window
Window (computing)
In computing, a window is a visual area containing some kind of user interface. It usually has a rectangular shape that can overlap with the area of other windows...
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 (QDOS reimplementation)
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...
, and Tebby's SMS2
SMS2
SMS2 was a computer operating system developed for the Atari ST by Tony Tebby, the designer of the Qdos operating system for the Sinclair QL personal computer...
and SMSQ/E
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 Miracle Systems QXL emulator card for PCs. This was...
. The latter 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 MicrodriveZX MicrodriveThe ZX Microdrive is a magnetic tape data storage system launched in July 1983 by Sinclair Research for their ZX Spectrum home computer. The Microdrive technology was later also used in the Sinclair QL and ICL One Per Desk personal computers.-Development:...
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 (USUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
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 MGx 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: SpanishSpanish languageSpanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
- MGF: FrenchFrench languageFrench is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
- MGG: GermanGerman languageGerman is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
- MGI: ItalianItalian languageItalian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...
- MGS: SwedishSwedish languageSwedish is a North Germanic language, spoken by approximately 10 million people, predominantly in Sweden and parts of Finland, especially along its coast and on the Åland islands. It is largely mutually intelligible with Norwegian and Danish...
- MGE: Spanish
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, eg. 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 language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
localised ROM version, known as ΣFP (marked on the ROMs as EFP).