Editing Sinclair QDOS

{{about|the Sinclair QL operating system|the predecessor of MS-DOS|86-DOS}}
{{Infobox OS
| name                   = QDOS<!-- Name of program or distribution -->
| logo                   = <!-- filename only (no wikilink, no Image:/File:) -->
| logo caption           = 
| logo size              = 
| logo alt               = 
| screenshot             = <!-- filename only (no wikilink, no Image:/File:) -->
| caption                = 
| screenshot_size        = 
| screenshot_alt         = 
| collapsible            = 
| version of             = <!-- For articles about releases of operating systems ONLY -->
| developer              = [[Tony Tebby]] whilst working at [[Sinclair Research]]<!-- Name of main developer or sponsor-->
| family                 = <!-- "Unix-like" or "Microsoft Windows" -->
| working state          = <!-- "Current", "Discontinued" (operating systems), or "No longer supported" (releases) -->
| source model           = <!-- "Open source", "Closed source", or "Shared source" -->
| released               = {{Start date and age|1984|4}}
| discontinued           = <!-- DON'T use this for articles about releases of operating systems -->
| RTM date               = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} ONLY for articles about OS releases -->
| GA date                = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} ONLY for articles about OS releases -->
| latest release version = 1.13
| latest release date    = 
| latest preview version = 
| latest preview date    = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| marketing target       = 
| programmed in          = [[Motorola 68000]] [[assembly language]]
| language               = [[Spanish language|Spanish]], [[French language|French]], [[German language|German]], [[Italian language|Italian]], [[Swedish language|Swedish]]<!-- Supported human languages (English, French, Italian, Arabic, ...) -->
| update model           = <!-- APT, Windows Update, etc. -->
| package manager        = <!-- dpkg, rpm, Windows installer, etc. -->
| supported platforms    = [[Motorola 68008]]<!-- IA-32, x64, Itanium, ARM, etc. -->
| kernel type            = <!-- Hybrid, Monolithic, Microkernel, Exokernel, Nanokernel, etc. -->
| userland               = 
| ui                     = 
| license                = [[Proprietary software|proprietary]]
| preceded by            = [[68K/OS]]
| succeeded by           = 
| website                = <!-- {{URL|www.example.org}} -->
| support status         = <!-- For articles about releases of operating systems ONLY -->
| other articles         = 
| prog_language          = 
}}
'''QDOS''' is the [[computer multitasking|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.

QDOS was implemented in [[Motorola 68000]] [[assembly language]], and on the QL, resided in 48&nbsp;[[kibibyte|KB]] of [[read-only memory|ROM]], consisting of either three 16&nbsp;KB EPROM chips or one 32&nbsp;KB and one 16&nbsp;KB ROM chip. These ROMs also held the [[SuperBASIC]] interpreter, an advanced variant of [[BASIC]] [[programming language]] with structured programming additions. This also acted as the QDOS [[command-line interpreter]].<ref>1&nbsp;KB = 1024 bytes</ref>

Facilities provided by QDOS included management of [[process (computing)|processes]] (or "jobs" in QDOS terminology), memory allocation, and an extensible "redirectable I/O system", providing a generic framework for [[filesystem]]s and [[device driver]]s. Very basic screen [[window (computing)|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 (QDOS reimplementation)|Minerva]] and Tebby's [[Small Multitasking System 2|SMS2]] and [[SMSQ/E]]. 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 [[ZX Microdrive|Microdrive]] 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'' ([[United States|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 language|Spanish]]
** ''MGF:'' [[French language|French]]
** ''MGG:'' [[German language|German]]
** ''MGI:'' [[Italian language|Italian]]
** ''MGS:'' [[Swedish language|Swedish]]

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&nbsp;KB ROM chip. Qdos 1.13 was also reported to be included in a [[Greek language|Greek]] localised ROM version, known as ''ΣFP'' (marked on the ROMs as ''EFP'').

== Notes==
{{Reflist}}

== References ==
* Andrew Pennell (1985). ''The Sinclair QDOS Companion: a guide to the QL operating system''. London: Sunshine Books. {{ISBN|0-946408-69-6}}
* Simon Goodwin. "Bugging the ROM", ''Sinclair QL World'', August 1987
* [http://www.staff.uni-mainz.de/roklein/ql/Firmware QL History FAQ: Firmware]

== External links ==
* [http://www.wlenerz.com/smsqe/ The official SMSQ/E site Source Code, binaries and documentation]
* [http://www.qdosmsq.dunbar-it.co.uk/doku.php QDOS Internals Dokuwiki established by Norman Dunbar]
* {{usurped|1=[https://archive.today/20130114043221/http://www.dilwyn.me.uk/qlrom/index.html QL ROM versions list by Dilwyn Jones]}}
* [http://sinclairql.net/repository.html#QLE QL/E The QL runtime Environment]
* [http://aminet.net/search?query=qdos Amiga implementation]

{{Disk operating systems}}

[[Category:Disk operating systems]]
[[Category:Discontinued operating systems]]
[[Category:Sinclair Research]]
[[Category:Assembly language software]]
[[Category:1984 software]]