Editing Sinclair QL

{{Short description|Personal computer by Sinclair Research}}

{{Infobox information appliance
| name = Sinclair QL
| title = 
| aka = 
| logo = 
| image = Sinclair QL Top.jpg
| caption = 
| developer = 
| manufacturer = 
| family = 
| type = [[Personal computer]]
| generation = 
| releasedate = {{Start date and age|1984|1|12|df=y}}
| lifespan = 
| price = £399 ({{Inflation|UK|399|1984|fmt=eq|cursign=£}})
| discontinued = {{End date|1986|04}}
| unitssold = 150,000<ref>{{cite web |title=QL, what? Never heard of the QL... |url=http://sinclairql.net/what.html |access-date=2020-12-11}}</ref>
| unitsshipped = 
| media = 
| os = [[Sinclair QDOS]], [[SuperBASIC]]
| power = 
| soc = 
| cpu = [[Motorola 68008|68008]]
| memory = 128 [[kilobyte|KB]]<ref>1 KB = 1024 [[byte|B]]</ref> (896 KB max.)
| storage = 2× [[ZX Microdrive|Microdrive]]
| memory card = 
| display = [[PAL]] TV or RGB Monitor<br />{{resx|256×256}} (8 colours)<br />{{resx|512×256}} (4 colours)
| graphics = [[ZX8301]]
| sound = [[Intel 8049]]
| input = 
| controllers = 
| camera = 
| touchpad = 
| connectivity = expansion slot, ROM cartridge socket, dual [[RS-232]] ports, proprietary QLAN [[local area network]] ports, dual [[joystick]] ports, external [[ZX Microdrive|Microdrive]] bus
| platform = 
| service = 
| dimensions = 
| weight = 
| topgame = 
| compatibility = 
| predecessor = [[ZX Spectrum]]
| successor = [[Sinclair PC200]]
| related = 
| website = <!--{{URL|example.org}}-->
| CPUspeed = 7.5 MHz
}}

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]].<ref>{{Cite web |title=Sinclair QL - Computer |url=http://www.computinghistory.org.uk/det/655/Sinclair-QL/ |access-date=2022-11-22 |website=The Centre for Computing History}}</ref><ref>{{Cite web |last=Smith |first=Tony |title=Sinclair’s 1984 big shot at business: The QL is 30 years old |url=https://www.theregister.com/2014/01/12/archaeologic_sinclair_ql/ |access-date=2023-08-02 |website=www.theregister.com |language=en}}</ref><ref name=":0">{{Cite web |last=Claaßen |first=André |date=2015-04-18 |title=Sinclair QL — The first real Computer |url=https://medium.com/@AndreClaassen/sinclair-ql-the-first-real-computer-2bff6046ea28 |access-date=2023-08-02 |website=Medium |language=en}}</ref> 

The QL was the last desktop [[microcomputer]] 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.<ref>{{Cite web |last=Smith |first=Tony |date=2014 |title=Sinclair's 1984 big shot at business: The QL is 30 years old |url=https://www.theregister.com/2014/01/12/archaeologic_sinclair_ql/ |access-date=2022-11-22 |website=www.theregister.com |language=en}}</ref> 

While the ZX Spectrum has an 8-bit [[Zilog Z80]] as the CPU, the QL uses a [[Motorola 68008]].<ref>{{Cite web |title=Sinclair QL microcomputer |url=https://www.computerhistory.org/revolution/personal-computers/17/298/1180 |access-date=2022-11-22 |website=Computer History Museum}}</ref> The 68008 is a member of the [[Motorola 68000]] family with [[32-bit computing|32-bit]] internal data registers, but an [[8-bit computing|8-bit]] external [[Bus (computing)|data bus]] characteristic of microcomputers.<ref name=":0" />

== History ==

=== Development ===
The QL was conceived in 1981 under the code name ''ZX83'', as a [[portable computer]] for business users, with a built-in ultra-thin flat-screen [[CRT display]] similar to the later [[TV80]] pocket TV, printer and [[modem]]. As development progressed it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration.<ref name="sunrise">{{cite web|url=http://www.nvg.ntnu.no/sinclair/computers/ql/ql_sst.htm|title=The Quantum Leap - to where?|work=Sinclair and the 'Sunrise' Technology|first1=Ian|last1=Adamson|first2=Richard |last2=Kennedy |access-date=2006-12-15}}</ref><ref name="dickinson-ql">{{ cite web | url = https://www.flickr.com/photos/9574086@N02/sets/72157600854938578/ | title = QL and Beyond | work = Flickr | first = Rick | last = Dickinson | date = 2007-07-16 | access-date = 2008-04-21 }}</ref> 

The electronics were primarily designed by David Karlin, who joined Sinclair Research in summer 1982. The [[industrial design]] was done by [[Rick Dickinson]], who already designed the [[ZX81]] and ZX Spectrum range of products.

The QL was designed to be more powerful than the [[IBM Personal Computer]], and comparable to Apple's [[Macintosh 128K|Macintosh]];<ref name="nytimes British race">{{cite news |author=Feder, Barnaby J. |date=February 27, 1984 |title=British race is on in microcomputers |work=[[The New York Times]] |location=New York |url=https://www.nytimes.com/1984/02/27/business/british-race-is-on-in-microcomputers.html |url-access=limited |access-date=December 12, 2011 |quote=The QL is designed to be more powerful than the current bestseller, the International Business Machines Corporation's Personal Computer - comparable, in fact, to Apple Computer's new Macintosh.}}</ref> observers thought that Sinclair announced it a week before Macintosh to divert attention away from the new Apple product.{{r|pountain198409}} While the CPU [[clock speed]] is comparable to that of the Macintosh, and the later [[Atari ST]] and [[Amiga]], the 8-bit [[Bus (computing)|databus]] and [[cycle stealing]] of the [[ZX8301]] [[gate array]] limit the QL's performance.

Sinclair had commissioned [[GST Computer Systems]] to produce the [[operating system]] for the machine, but switched to [[Domesdos]], developed by [[Tony Tebby]] as an in-house alternative, before launch. GST's OS, designed by Tim Ward, was later made available as [[68K/OS]], in the form of an add-on ROM card.<ref>{{cite journal | url = http://www.users.globalnet.co.uk/~jg27paw4/yr07/yr07_05.htm | title = QL Affairs | first = Leon | last = Heller | journal = [[Your Spectrum]] | issue = 7 | date = September 1984 | access-date = 2008-04-21 }}</ref><ref>{{cite web |last=Graham |first=Adrian |title=Sinclair QL |url=http://www.binarydinosaurs.co.uk/Museum/Sinclair/ql/ |access-date=2008-04-21 |work=Binary Dinosaurs}}</ref> The tools developed by GST for the QL would later be used on the Atari ST, where GST object format became standard.

=== Launch ===
[[file:Ql dongle.png|thumb|Sinclair QL ROM "dongle" – needed to expand the internal 32&nbsp;KB ROM to 48&nbsp;KB in early QLs]]

At the time of the rushed launch, on 12 January 1984, the QL was far from being ready for production, with no complete [[Prototype|working prototype]]. Although Sinclair started taking orders immediately, promising delivery within 28 days, first customer deliveries only started, slowly, in April. This provoked criticism of the company and the attention of the [[Advertising Standards Authority (United Kingdom)|Advertising Standards Authority]].<ref name="sunrise" />

Because of its premature launch, the QL was plagued by a number of problems from the start. Early production QLs were shipped with preliminary versions of [[firmware]] containing numerous [[computer bug|bugs]], mainly in [[SuperBASIC]]. Part of the firmware was held on an external 16&nbsp;KiB ROM cartridge also known as the "[[kludge]]" or "[[dongle]]", until the QL was redesigned to accommodate the necessary 48&nbsp;KiB of ROM internally, instead of the 32&nbsp;KiB initially specified.<ref name="sunrise" />

The QL also suffered from reliability problems of its [[ZX Microdrive|Microdrives]]. These problems were later rectified, by Sinclair engineers, especially on [[Samsung]] produced models, as well as by [[Aftermarket (merchandise)|aftermarket]] firms such as Adman Services and TF Services, to the point where several QL users report the Samsung Microdrives in particular working perfectly even after almost 17 years of service; but in any case too late to redeem the negative image they had already created.{{citation needed | date=January 2024 | reason=Sounds like a very specific report, presumably appearing in a specific publication.}}

=== Reception ===
''[[BYTE]]'' in September 1984 described QL as a "premature baby", noting the incomplete operating system, "dead and unresponsive" keyboard, fragile microdrive tapes, and lack of sprites. The magazine approved of the bundled applications, and SuperBASIC's improvement over [[Sinclair BASIC]], but criticized the language's "very, very slow" speed. ''BYTE'' concluded that QL was superior to the "wildly overpriced" [[BBC Model B]] for hobbyists, but expected that the computer's "extremely disappointing performance figures achieved so far" from the "emasculated" CPU, unreliable microdrive, and keyboard would make it unsuitable for businesses. "A rival to Macintosh this is not, but then, you get what you pay for", the magazine said, hoping that third-party developers would increase QL's appeal.<ref name="pountain198409">{{Cite magazine |last=Pountain |first=Dick |date=September 1984 |title=The Sinclair QL |url=https://archive.org/details/BYTE_Vol_09-10_1984-09_Computer_Graphics/page/n416/mode/1up?view=theater |access-date=2025-04-10 |magazine=BYTE |pages=415-419}}</ref>

Although the computer was hyped as being advanced for its time, and relatively cheap, it failed to sell well, and UK production was suspended in 1985, due to lack of demand. After [[Amstrad]] acquired Sinclair's computer product lines in April 1986, the QL was officially discontinued.

Apart from its reliability issues, the target business market was becoming wedded to the [[IBM PC]] platform, whilst the majority of ZX Spectrum owners were uninterested in upgrading to a machine which had a minimal library of games (with only about 70 titles,<ref>{{Cite web |title=Sinclair QL |url=https://www.uvlist.net/platforms/detail/51-QL |access-date=2023-01-03 |website=Universal Videogame List |language=en}}</ref> compared to the Spectrum's more than 4700<ref>{{Cite web |title=ZX Spectrum |url=https://www.uvlist.net/platforms/detail/25-ZX+Spectrum |access-date=2023-01-03 |website=Universal Videogame List |language=en}}</ref>). Sinclair's persistence with the non-standard Microdrive and uncomfortable keyboard did not endear it to the business market. Clive Sinclair later maintained that the Microdrive was "a marvellous approach", also claiming that he had really wanted to base the QL on the Z80, that others in the company had persuaded him to use the 68000, and that "there was nothing you could do on the 68000 that you couldn't do on the Z80".<ref name="sinclairuser198608_sinclair">{{ cite magazine | url=https://archive.org/details/Sinclair_User_053/page/54/mode/2up | title=Sir Clive Life After Death? | magazine=Sinclair User | date=August 1986 | access-date=16 January 2024 | last1=Taylor | first1=Graham | pages=54–56 }}</ref> Software publishers were also reluctant to support the QL because Microdrive cartridges were the only available distribution medium for the QL, and the unfavourable pricing of the medium (production costs being given as over six times that of compact cassette) impacted profitability and made QL-based products uncompetitive.<ref name="qluser198503_resolution">{{ cite magazine | url=https://archive.org/details/ql-user/QL%20User%201985-03/page/n3/mode/1up | title=Resolution Resolved | magazine=QL User | date=March 1985 | access-date=18 January 2024 | pages=6 }}</ref>

Dedicated magazines were published for the system, such as ''QL World'' (published from 1985 to 1994),<ref>{{Cite web |title=QLWorld |url=https://microhobby.speccy.cz/150504/scannerwebs/QLWorld/qlworld.htm |access-date=2023-06-05 |website=microhobby.speccy.cz}}</ref> ''QL User'' (published from 1984 to 1985),<ref>{{Cite book |url=http://archive.org/details/ql-user |title=QL User |date=1984}}</ref> or ''QL Today'' (published from 1996 to 2013).<ref>{{Cite web |title=QL Today |url=https://sinclairql.net/qlt/index_english.htm |access-date=2023-06-05 |website=sinclairql.net}}</ref>

== Design ==
[[file:Sincalir-QL-68008-Processor.jpg|thumb|Motorola 68008 and ZX8301 on the QL's PCB]]

Based on a Motorola 68008 processor clocked at 7.5&nbsp;MHz, the QL included 128 [[kilobyte|KiB]] of [[random-access memory|RAM]], which is officially expandable to 640&nbsp;KiB and in practice, 896&nbsp;KB.<ref name="Nostalgia Nerd">{{Cite web |last=Leigh |first=Peter |date=2016-03-17 |title=Sinclair QL (Quantum Leap) System Review |url=https://www.nostalgianerd.com/sinclair-ql/ |access-date=2022-11-22 |website=Nostalgia Nerd |language=en-US}}</ref>

It can be connected to a [[Computer monitor|monitor]] or TV for display. Sinclair recommended the "''SINCLAIR VISION-QL''" [[RGB monitor]] for usage with the QL.<ref>{{Cite book |url=https://ia600804.us.archive.org/9/items/SinclairQLHomepage/docs/manuals/visionql.pdf |title=SINCLAIR VISION-QL OWNER'S GUIDE |publisher=MBS Data Efficiency Ltd}}</ref> When connected to a normally-adjusted TV or monitor, the QL's video output [[overscan|overscans]] horizontally. This is reputed to have been due to the timing constants in the ZX8301 chip being optimised for the flat-screen CRT display originally intended for the QL.<ref>{{cite newsgroup |url=http://groups.google.com/group/comp.sys.sinclair/msg/6bdb4bd808bdb3d6 |newsgroup=comp.sys.sinclair |first=Rupert |last=Goodwins |title=Sinclair Loki Superspectrum |message-id=3cde626f.45085128@news-text.blueyonder.co.uk |access-date=2008-04-22}}</ref>

{| class="infobox sidebar"
|+ Sinclair QL color palette
|-
! {{Resx|256x256}}
! {{Resx|512x256}}
|-
| style="color: white; background-color: #000000" | black
| style="color: white; background-color: #000000" rowspan=2 | black
|-
| style="color: white; background-color: #0000ff" | blue
|-
| style="color: white; background-color: #ff0000" | red
| style="color: white; background-color: #ff0000" rowspan=2 | red
|-
| style="background-color: #ff00ff"| magenta
|-
| style="background-color: #00ff00" | green
| style="background-color: #00ff00" rowspan="2"| green
|-
| style="background-color: #00ffff" | cyan
|-
| style="background-color: #ffff00" | yellow
| style="background-color: #ffffff" rowspan=2| white
|-
| style="background-color: #ffffff" | white
|}
Two video modes are available, {{Resx|256x256}} pixels with 8 primary [[RGB color model|RGB]] colours and per-pixel flashing, or {{Resx|512x256}} pixels with four colours: black, red, green and white.<ref name="Nostalgia Nerd" /> Both [[Commodore 64]] and [[MSX]] computers can display more colours, but at lower resolutions.{{r|pountain198409}} Both screen modes use a 32&nbsp;KiB [[framebuffer]] in main memory. The hardware is capable of switching between two different areas of memory for the frame buffer, thus allowing [[Multiple buffering#Double buffering in computer graphics|double buffering]]. However, this would use 64&nbsp;KB of the standard machine's 128&nbsp;KiB of RAM and there is no support for this feature in the QL's original firmware. The alternative and improved operating system [[Minerva (QDOS reimplementation)|Minerva]] provides full support for the second frame buffer. [[file:QL-inside.jpeg|thumb|QL internals (with Minerva ROM fitted)]]Internally, the QL comprises the CPU, two ULAs (ZX8301 "Master Chip" and ZX8302 "Peripheral Chip") and an [[Intel MCS-48|Intel 8049]]<ref name="Nostalgia Nerd" /> [[microcontroller]] known as the IPC, or "Intelligent Peripheral Controller". [[file:Sinclair QL rear view (brighter)(filtered).jpg|thumb|QL rear view]]The ZX8301 implements the video display generator and also provides [[DRAM]] refresh. The ZX8302  interfaces to the [[RS-232]] ports (transmit only), Microdrives, QLAN ports, [[real-time clock]] and the 8049 via a synchronous serial link. The 8049 runs at 11&nbsp;MHz and provides a keyboard/joystick interface, RS-232 serial receivers and an audio generator.<ref name="faq-hardware" /><ref name="Nostalgia Nerd" /> The 8049 was added at a late stage in the QL's design, as the ZX8302 was originally intended to include its functions.<ref name="sunrise" /> 

[[file:Sinclair QL mp3h0654.jpg|thumb|Bundled Psion application software on Microdrive cartridges]]

Two built-in Microdrive tape-loop cartridge drives provide mass storage, in place of the more expensive [[floppy disk]] drives found on similar systems of the era. Microdrives had been introduced for the ZX Spectrum in July 1983, although the QL uses a different logical tape format.

Interfaces include an expansion slot, ROM cartridge socket, dual RS-232 ports, proprietary QLAN [[local area network]] ports, dual [[joystick]] ports and an external Microdrive bus. The QL uses British Telecom type 631W plugs of similar design to [[British telephone sockets]] for serial cables except for QLs built by Samsung for export markets, which have [[D-subminiature|DE-9]] sockets. Joysticks connect to the QL with similar type 630W plugs.

While the keyboard improves on ZX Spectrum's, it is a rubber [[membrane keyboard]] under the keycaps.{{r|pountain198409}} Physically, the QL is the same black colour as the preceding ZX81 and Spectrum, but introduced a new angular styling theme and keyboard design which would later be seen in the ZX Spectrum+.

[[Sinclair QDOS|QDOS]], [[Computer multitasking#Preemptive multitasking|a pre-emptive multitasking]] operating system primarily designed by Tony Tebby, is included on [[read-only memory|ROM]], as is an advanced [[BASIC#Structured BASIC|structured BASIC]] [[Interpreter (computing)|interpreter]], named SuperBASIC designed by [[Jan Jones (novelist)|Jan Jones]], which is also used as the [[Command-line interface#Command-line interpreter|command-line interpreter]].<ref>{{Cite web |title=SBASIC/SuperBASIC Reference Manual Online — SBASIC/SuperBASIC Reference Manual Online 4.0.1 documentation |url=https://superbasic-manual.readthedocs.io/en/latest/ |access-date=2023-04-03 |website=superbasic-manual.readthedocs.io}}</ref> The QL is bundled with an [[Productivity software#Office suite|office suite]], consisting of a [[Word processor program|word processor]], [[spreadsheet]], [[database]], and business graphics written by [[Psion (company)|Psion]].{{r|pountain198409}}

According to Sinclair Research, it was the first mass-market computer with an [[Operating System|OS]] featuring pre-emptive multitasking and a [[Windows]]-style operating system, predating Microsoft [[Windows 95]] by 11 years, and [[Apple Computer]] Macintosh launch by a month.<ref>{{cite web |title=Sinclair QL |url=http://www.sinclairzx.com/about-us.html#15 |archive-url=https://web.archive.org/web/20101220003729/http://www.sinclairzx.com/about-us.html#15 |archive-date=2010-12-20}}</ref>

== Legacy ==

=== ICL One Per Desk ===
{{Main|One Per Desk}}
[[File:Merlin Tonto.jpg|thumb|Merlin Tonto at [[The National Museum of Computing]]]]
The QL's [[Central processing unit|CPU]], ZX8301 and ZX8302 [[Application-specific integrated circuit|ASICs]] and Microdrives form the basis of [[One Per Desk]] (OPD). Built by [[International Computers Limited]] (ICL), it was also marketed by [[BT Group|British Telecom]] as the [[One Per Desk#Merlin Tonto|Merlin Tonto]] and by [[Telstra|Telecom Australia]] as the [[Computerphone]].

The result of a three-year collaboration between Sinclair Research, ICL and British Telecom, the One Per Desk adds a [[telephone handset]] at one end of the keyboard, and rudimentary [[Computer-Telephony Integration]] (CTI) software.<ref>{{cite web|url=http://www.old-computers.com/museum/computer.asp?c=275|title=ICL OPD One Per Desk|work=OLD-COMPUTERS.COM|access-date=2008-04-21}}</ref> This machine interested a number of high-profile business customers, including certain divisions of the former [[HM Customs & Excise|UK Customs and Excise Department]], but its success was generally limited. In the late 1980s they were used in bingo halls to allow a country-wide networked bingo game.<ref>{{cite web|url=http://www.binarydinosaurs.co.uk/Museum/icl/opd.php|title=ICL OPD|work=Binary Dinosaurs|access-date=2008-04-21}}</ref>

=== Linux ===

[[Linus Torvalds]] has attributed his eventually developing the [[Linux kernel]], likewise having [[Preemption (computing)|pre-emptive multitasking]], in part to having owned a Sinclair QL in the 1980s. Because of the lack of support, particularly in his native [[Finland]], Torvalds became used to writing his own software rather than relying on programs written by others.<ref>{{cite AV media | people = Torvalds, Linus (speaker) |title = Presentation: "The Origins of Linux," |date = 19 September 2001 | via = [[YouTube]] |url= https://www.youtube.com/watch?v=WVTWCPoUt8w&t=9m13s  |archive-url=https://ghostarchive.org/varchive/youtube/20211211/WVTWCPoUt8w| archive-date=2021-12-11 |url-status=live|time = 9:13}}{{cbignore}}</ref> In part, his frustration with [[Minix]] on the Sinclair<ref>{{Cite book |last=Moody |first=Glyn |url=https://books.google.com/books?id=kIU1scm4w6QC |title=Rebel Code: Linux and the Open Source Revolution |date=2009-02-18 |publisher=Basic Books |isbn=978-0-7867-4520-3 |pages=90 |language=en}}</ref> led years later to his purchase of a more standard [[IBM PC compatible]] on which he would develop Linux. In ''[[Just for Fun (book)|Just for Fun]]'', Torvalds wrote, "Back in 1987, one of the selling points of the QL was that it ''looked'' cool", because it was "entirely matte black, with a black keyboard" and was "fairly angular". He also wrote he bought a floppy controller so he could stop using microdrives, but the floppy controller driver was bad, so he wrote his own. Bugs in the operating system, or discrepancies with the documentation, that made his software not work properly, got him interested in operating systems. "Like any good computer purist raised on a 68008 chip," Torvalds "despised PCs", but decided in autumn 1990 to purchase a [[I386|386]] custom-made IBM PC compatible, which he did in January 1991.<ref>{{Cite book |last1=Torvalds |first1=Linus |url=http://archive.org/details/justforfun00linu |title=Just for fun : the story of an accidental revolutionary |last2=Diamond |first2=David |date=2001 |publisher=New York : HarperBusiness |others=Internet Archive |isbn=978-0-06-662072-5 |pages=43–60}}</ref>

=== Clones ===
{{Main articles|List of Sinclair QL clones}}

After Amstrad abandoned the QL in 1986, several companies previously involved in the QL peripherals market stepped in to fill the void. These included [[Cambridge Systems Technology|CST]] and DanSoft, creators of the [[CST Thor|Thor]] line of compatible systems; [[Miracle Systems]], creator of the Gold Card and Super Gold Card processor/memory upgrade cards and the QXL PC-based hardware emulator; and Qubbesoft, with the Aurora, the first replacement QL mainboard, with enhanced graphics modes.<ref name="faq-hardware">{{ cite web | url = http://www.staff.uni-mainz.de/roklein/ql/Hardware | title = QL History FAQ: Hardware | first = Robert | last = Klein | access-date = 2008-04-21 | url-status = dead | archive-url = https://web.archive.org/web/20060504000555/http://www.staff.uni-mainz.de/roklein/ql/Hardware | archive-date = 2006-05-04 }}</ref>

In the late 1990s, two partly QL-compatible [[motherboard]]s named Q40 and Q60 (collectively referred to as [[Qx0]]) were designed by Peter Graf and marketed by D&D Systems. The Q40 and Q60, based on the [[Motorola 68040]] and [[68060]] [[CPU]]s respectively, are much more powerful than the original QL and have the ability among other things (such as multimedia, high resolution graphics, [[Ethernet]] networking etc.) to run the [[Linux]] operating system.<ref>{{cite web | url = http://www.q40.de/ | title = Q40.de | access-date = 2008-04-21 }}</ref>

In 2013 Peter Graf announced that he was working on the Q68, a FPGA based QL compatible single board computer. The Q68 was first presented to the public in April 2014 and became available in autumn 2017. It is produced and marketed by Derek Stewart (of former D&D Systems).<ref>{{ cite web | url = https://qlforum.co.uk/viewtopic.php?f=2&t=2203 | title = Q68 Order Process | first = Derek | last = Stewart | access-date = 2020-01-16 }}</ref>

Hardware add-ons such as new developments like the QL-SD (designed by Peter Graf)<ref>{{ cite web | url = https://qlforum.co.uk/viewtopic.php?f=2&t=385 | title = QL-SD card project | first = Dilwyn | last = Jones | access-date = 2020-01-16 }}</ref> and reengineered or even expanded 1990s designs such as QubIDE interfaces (by José Leandro Novellón).<ref>{{ cite web | url = https://qlforum.co.uk/viewtopic.php?f=2&t=566 | title = QubIDE clone | author = José Leandro Novellón | access-date = 2020-01-16 }}</ref> Trump, Gold & Super Gold Cards (by Tetroid) are still being produced for the original QL.<ref>{{ cite web | url = https://qlforum.co.uk/viewtopic.php?f=2&t=1670 | title = Announcement - new QL Interface | author = RWAP | access-date = 2020-01-16 }}</ref>

RWAP Software supplies various hardware and software upgrades and spare parts.

=== Operating systems ===

Patched or reengineered versions of QDOS were produced, most notably Minerva which gradually evolved into a completely rewritten operating system, offering improved speed, with multitasking SuperBASIC interpreters. Tony Tebby went on to produce another updated operating system, [[SMSQ/E]], which has continued to be developed for the Sinclair QL and emulators, offering many more features.<ref>{{ cite web | url = http://www.staff.uni-mainz.de/roklein/ql/Firmware | title = QL History FAQ: Firmware | first = Robert | last = Klein | access-date = 2008-04-21 }}</ref>

=== Emulators, virtual QLs and distributions ===

Several [[Emulator|emulators]] and virtual QLs became available over time, of which Q-emuLator (Windows/Mac),<ref>{{Cite web |title=Q-emuLator Sinclair QL |url=http://www.terdina.net/ql/q-emulator.html |access-date=2023-01-05 |website=www.terdina.net}}</ref> QPC2 (Windows),<ref>{{Cite web |title=QPC {{!}} Kilgus.net |url=https://www.kilgus.net/qpc/ |access-date=2023-01-05 |language=en-US}}</ref> SMSQmulator (Java),<ref>{{Cite web |title=The official SMSQmulator Site |url=https://wlenerz.com/smsqmulator/index.html |access-date=2023-01-05 |website=wlenerz.com}}</ref> ZEsarUX (Windows/Mac/Linux)<ref>{{Citation |last=Hernandez |first=Cesar |title=chernandezba/zesarux |date=2023-01-03 |url=https://github.com/chernandezba/zesarux |access-date=2023-01-05}}</ref> and sQLux (Windows/Mac/Linux)<ref>{{Citation |title=sQLux (or QL Sux according to DaveP) |date=2022-11-28 |url=https://github.com/SinclairQL/sQLux |publisher=Sinclair QL Home Computer Development |access-date=2023-01-05}}</ref> are actively maintained. 

Several distributions of emulators, applications and information have been produced, of which Black Phoenix<ref>{{Cite web |title=Black Phoenix – Quantum Technology |url=http://www.hunggartorino.it/ql/black-phoenix-en/ |access-date=2023-01-05 |language=en-GB}}</ref> and QL/E<ref>{{Cite web |title=THE REPOSITORY - Sinclair QL Preservation Project (SQPP) - sinclairql.net site |url=https://www.sinclairql.net/repository.html#QLE |access-date=2023-01-05 |website=www.sinclairql.net}}</ref> are the most actively maintained.

== See also ==

* [[Sinclair QL Software]]
* [[Sinclair QL character set]]
* [[One Per Desk]]
* [[CST Thor]]
* [[Q40 (motherboard)|Q40/Q60]]
* [[SMSQ/E]]
* [[Sinclair QDOS]]
* [[List of Sinclair QL clones]]

== References ==

{{refs}}

== External links ==
{{commonscat}}

* [https://dilwyn.qlforum.co.uk/ Dilwyn Jones's QL pages] – Well maintained site with comprehensive QL related information and a huge software download library.
* [http://sinclairql.net/repository.html THE REPOSITORY of the Sinclair QL Preservation Project] – Well maintained project with valuable Sinclair QL related information and software.
* {{cite web |url=https://www.theregister.co.uk/2014/01/12/archaeologic_sinclair_ql/?page=1 |work=The Register |title=Sinclair's 1984 big shot at business: The QL is 30 years old}}

{{Sinclair computers and clones}}
{{Authority control}}

[[Category:Computer-related introductions in 1984]]
[[Category:Home computers]]
[[Category:68000-based home computers]]
[[Category:Computers designed in the United Kingdom]]
[[Category:Personal computers]]
[[Category:Sinclair QL]]