 | |
| Type | Personal computer |
|---|---|
| Release date | 12 January 1984; 41 years ago (1984-01-12) |
| Introductory price | £399 (equivalent to £1,620 in 2023) |
| Discontinued | April 1986 (1986-04) |
| Units sold | 150,000[1] |
| Operating system | Sinclair QDOS,SuperBASIC |
| CPU | 68008 @ 7.5 MHz |
| Memory | 128KB[2] (896 KB max.) |
| Storage | 2×Microdrive |
| Display | PAL TV or RGB Monitor 256 × 256 (8 colours) 512 × 256 (4 colours) |
| Graphics | ZX8301 |
| Sound | Intel 8049 |
| Connectivity | expansion slot, ROM cartridge socket, dualRS-232 ports, proprietary QLANlocal area network ports, dualjoystick ports, externalMicrodrive bus |
| Predecessor | ZX Spectrum |
| Successor | Sinclair PC200 |
TheSinclair QL (forQuantum Leap) is apersonal computer launched bySinclair Research in 1984, as an upper-end counterpart to theZX Spectrum.[3][4][5]
The QL was the last desktopmicrocomputer 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.[6]
While the ZX Spectrum has an 8-bitZilog Z80 as the CPU, the QL uses aMotorola 68008.[7] The 68008 is a member of theMotorola 68000 family with32-bit internal data registers, but an8-bit externaldata bus characteristic of microcomputers.[5]
The QL was conceived in 1981 under the code nameZX83, as aportable computer for business users, with a built-in ultra-thin flat-screenCRT display similar to the laterTV80 pocket TV, printer andmodem. As development progressed it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration.[8][9]
The electronics were primarily designed by David Karlin, who joined Sinclair Research in summer 1982. Theindustrial design was done byRick Dickinson, who already designed theZX81 and ZX Spectrum range of products.
The QL was designed to be more powerful than theIBM Personal Computer, and comparable to Apple'sMacintosh;[10] observes thought that Sinclair announced it a week before Macintosh to divert attention away from the new Apple product.[11] While the CPUclock speed is comparable to that of the Macintosh, and the laterAtari ST andAmiga, the 8-bitdatabus andcycle stealing of theZX8301gate array limit the QL's performance.
Sinclair had commissionedGST Computer Systems to produce theoperating system for the machine, but switched toDomesdos, developed byTony Tebby as an in-house alternative, before launch. GST's OS, designed by Tim Ward, was later made available as68K/OS, in the form of an add-on ROM card.[12][13] The tools developed by GST for the QL would later be used on the Atari ST, where GST object format became standard.
At the time of the rushed launch, on 12 January 1984, the QL was far from being ready for production, with no completeworking 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 theAdvertising Standards Authority.[8]
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 offirmware containing numerousbugs, mainly inSuperBASIC. Part of the firmware was held on an external 16 KiB ROM cartridge also known as the "kludge" or "dongle", until the QL was redesigned to accommodate the necessary 48 KiB of ROM internally, instead of the 32 KiB initially specified.[8]
The QL also suffered from reliability problems of itsMicrodrives. These problems were later rectified, by Sinclair engineers, especially onSamsung produced models, as well as byaftermarket 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]
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 overSinclair 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.[11]
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. AfterAmstrad 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 theIBM 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,[14] compared to the Spectrum's more than 4700[15]). 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".[16] 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.[17]
Dedicated magazines were published for the system, such asQL World (published from 1985 to 1994),[18]QL User (published from 1984 to 1985),[19] orQL Today (published from 1996 to 2013).[20]
Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128KiB ofRAM, which is officially expandable to 640 KiB and in practice, 896 KB.[21]
It can be connected to amonitor or TV for display. Sinclair recommended the "SINCLAIR VISION-QL"RGB monitor for usage with the QL.[22] When connected to a normally-adjusted TV or monitor, the QL's video outputoverscans 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.[23]
| 256 × 256 | 512 × 256 |
|---|---|
| black | black |
| blue | |
| red | red |
| magenta | |
| green | green |
| cyan | |
| yellow | white |
| white |
Two video modes are available,256 × 256 pixels with 8 primaryRGB colours and per-pixel flashing, or512 × 256 pixels with four colours: black, red, green and white.[21] BothCommodore 64 andMSX computers can display more colours, but at lower resolutions.[11] Both screen modes use a 32 KiBframebuffer in main memory. The hardware is capable of switching between two different areas of memory for the frame buffer, thus allowingdouble buffering. However, this would use 64 KB of the standard machine's 128 KiB of RAM and there is no support for this feature in the QL's original firmware. The alternative and improved operating systemMinerva provides full support for the second frame buffer.
Internally, the QL comprises the CPU, two ULAs (ZX8301 "Master Chip" and ZX8302 "Peripheral Chip") and anIntel 8049[21]microcontroller known as the IPC, or "Intelligent Peripheral Controller".
(filtered).jpg)
The ZX8301 implements the video display generator and also providesDRAM refresh. The ZX8302 interfaces to theRS-232 ports (transmit only), Microdrives, QLAN ports,real-time clock and the 8049 via a synchronous serial link. The 8049 runs at 11 MHz and provides a keyboard/joystick interface, RS-232 serial receivers and an audio generator.[24][21] The 8049 was added at a late stage in the QL's design, as the ZX8302 was originally intended to include its functions.[8]
Two built-in Microdrive tape-loop cartridge drives provide mass storage, in place of the more expensivefloppy 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 QLANlocal area network ports, dualjoystick ports and an external Microdrive bus. The QL uses British Telecom type 631W plugs of similar design toBritish telephone sockets for serial cables except for QLs built by Samsung for export markets, which haveDE-9 sockets. Joysticks connect to the QL with similar type 630W plugs.
While the keyboard improves on ZX Spectrum's, it is a rubbermembrane keyboard under the keycaps.[11] 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+.
QDOS,a pre-emptive multitasking operating system primarily designed by Tony Tebby, is included onROM, as is an advancedstructured BASICinterpreter, named SuperBASIC designed byJan Jones, which is also used as thecommand-line interpreter.[25] The QL is bundled with anoffice suite, consisting of aword processor,spreadsheet,database, and business graphics written byPsion.[11]
According to Sinclair Research, it was the first mass-market computer with anOS featuring pre-emptive multitasking and aWindows-style operating system, predating MicrosoftWindows 95 by 11 years, andApple Computer Macintosh launch by a month.[26]
The QL'sCPU, ZX8301 and ZX8302ASICs and Microdrives form the basis ofOne Per Desk (OPD). Built byInternational Computers Limited (ICL), it was also marketed byBritish Telecom as theMerlin Tonto and byTelecom Australia as theComputerphone.
The result of a three-year collaboration between Sinclair Research, ICL and British Telecom, the One Per Desk adds atelephone handset at one end of the keyboard, and rudimentaryComputer-Telephony Integration (CTI) software.[27] This machine interested a number of high-profile business customers, including certain divisions of the formerUK 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.[28]
Linus Torvalds has attributed his eventually developing theLinux kernel, likewise havingpre-emptive multitasking, in part to having owned a Sinclair QL in the 1980s. Because of the lack of support, particularly in his nativeFinland, Torvalds became used to writing his own software rather than relying on programs written by others.[29] In part, his frustration withMinix on the Sinclair[30] led years later to his purchase of a more standardIBM PC compatible on which he would develop Linux. InJust for Fun, Torvalds wrote, "Back in 1987, one of the selling points of the QL was that itlooked 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 a386 custom-made IBM PC compatible, which he did in January 1991.[31]
After Amstrad abandoned the QL in 1986, several companies previously involved in the QL peripherals market stepped in to fill the void. These includedCST and DanSoft, creators of theThor 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.[24]
In the late 1990s, two partly QL-compatiblemotherboards named Q40 and Q60 (collectively referred to asQx0) were designed by Peter Graf and marketed by D&D Systems. The Q40 and Q60, based on theMotorola 68040 and68060CPUs 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 theLinux operating system.[32]
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).[33]
Hardware add-ons such as new developments like the QL-SD (designed by Peter Graf)[34] and reengineered or even expanded 1990s designs such as QubIDE interfaces (by José Leandro Novellón).[35] Trump, Gold & Super Gold Cards (by Tetroid) are still being produced for the original QL.[36]
RWAP Software supplies various hardware and software upgrades and spare parts.
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.[37]
Severalemulators and virtual QLs became available over time, of which Q-emuLator (Windows/Mac),[38] QPC2 (Windows),[39] SMSQmulator (Java),[40] ZEsarUX (Windows/Mac/Linux)[41] and sQLux (Windows/Mac/Linux)[42] are actively maintained.
Several distributions of emulators, applications and information have been produced, of which Black Phoenix[43] and QL/E[44] are the most actively maintained.
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.
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Compatible or related systems |
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