The Sinclair QL (for ''Quantum Leap'') is a

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 te ...

launched by

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, then ...

in 1984, as an upper-end counterpart to the

ZX Spectrum The ZX Spectrum () is an 8-bit home computer that was developed by Sinclair Research. It was released in the United Kingdom on 23 April 1982, and became Britain's best-selling microcomputer. Referred to during development as the ''ZX81 Colou ...

. The QL was 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. While the ZX Spectrum has an 8-bit

Zilog Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...

as the CPU, the QL uses a

Motorola 68008 The Motorola 68008 is an 8/32-bit microprocessor introduced by Motorola in 1982. It is a version of 1979's Motorola 68000 with an 8-bit external data bus, as well as a smaller address bus. The 68008 was available with 20 or 22 address lines (r ...

. The 68008 is a member of the

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 Secto ...

family with 32-bit internal data registers, but an 8-bit external data bus.

History

left, Sinclair QL ROM "dongle" – needed to expand the internal 32 KB ROM to 48 KB in early QLs The QL was originally conceived in 1981 under the code-name ''ZX83'', as a

portable computer A portable computer is a computer designed to be easily moved from one place to another and included a display and keyboard together, with a single plug, much like later desktop computers called '' all-in-ones'' (AIO), that integrate the s ...

for business users, with a built-in ultra-thin flat-screen CRT display similar to the later TV80 pocket TV, printer and

modem A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more c ...

. As development progressed it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration. The electronics were primarily designed by David Karlin, who joined

in summer 1982. The

industrial design Industrial design is a process of design applied to physical products that are to be manufactured by mass production. It is the creative act of determining and defining a product's form and features, which takes place in advance of the manufactu ...

was done by

Rick Dickinson Rick Dickinson (c. 1957 – 24 April 2018) was a British industrial designer who developed pioneering computer designs in the 1980s. Notable examples of his design work include the ZX81 case and touch-sensitive keyboard and the ZX Spectrum' ...

, who already designed the ZX81 and ZX Spectrum range of products. 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. The tools developed by GST for the QL would later be used on the

Atari ST The Atari ST is a line of personal computers from Atari Corporation and the successor to the Atari 8-bit family. The initial model, the Atari 520ST, had limited release in April–June 1985 and was widely available in July. It was the first per ...

, where GST object format became standard. The QL was designed to be more powerful than the

IBM Personal Computer The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a tea ...

, and comparable to Apple's

Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc., Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and ...

. While the CPU

clock speed In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pro ...

is comparable to that of the Macintosh, and the later Atari ST and Amiga, the 8-bit databus and

cycle stealing In computing, traditionally cycle stealing is a method of accessing computer memory (RAM) or bus without interfering with the CPU. It is similar to direct memory access (DMA) for allowing I/O controllers to read or write RAM without CPU interve ...

of the

ZX8301 The ZX8301 is an Uncommitted Logic Array (ULA) integrated circuit designed for the Sinclair QL microcomputer. Also known as the "Master Chip", it provides a Video Display Generator, the division of a 15 MHz crystal to provide the 7.5 MHz system clo ...

gate array A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according ...

limit the QL's performance. At the time of the rushed launch, on 12 January 1984, the QL was far from being ready for production—there being no complete working prototype in existence. 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. 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 In computing, firmware is a specific class of computer software that provides the low-level control for a device's specific hardware. Firmware, such as the BIOS of a personal computer, may contain basic functions of a device, and may provide h ...

containing numerous bugs, mainly in SuperBASIC. Part of the firmware is held on an external 16 KiB ROM cartridge also known as the "

kludge A kludge or kluge () is a workaround or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to extend and hard to maintain. This term is used in diverse fields such as computer science, aerospace engineering, Internet sla ...

" or "

dongle A dongle is a small piece of computer hardware that connects to a port on another device to provide it with additional functionality, or enable a pass-through to such a device that adds functionality. In computing, the term was initially synonym ...

", until the QL was redesigned to accommodate the necessary 48 KiB of ROM internally, instead of the 32 KiB initially specified. The QL also suffers from reliability problems of its Microdrives. These problems were later rectified, by Sinclair engineers, especially on

Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...

produced models, as well as by 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. 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 Amstrad was a British electronics company, founded in 1968 by Alan Sugar at the age of 21. The name is a contraction of Alan Michael Sugar Trading. It was first listed on the London Stock Exchange in April 1980. During the late 1980s, Amstra ...

acquired Sinclair's computer products 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 The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible de facto standard. Released on August 12, 1981, it was created by a team ...

platform, whilst the majority of ZX Spectrum owners were uninterested in upgrading to a machine which had a minimal library of games. Sinclair's persistence with the non-standard Microdrive and uncomfortable keyboard did not endear it to the business market; coupled with the machine's resemblance to a ZX Spectrum+, they led many to perceive the QL as something akin to a toy. Software publishers were also reluctant to support the QL because Microdrive cartridges were the only available distribution medium for QL.

Design

left, QL internals (with Minerva ROM fitted) left, QL rear view left, Motorola 68008 and ZX8301 on the QL's PCB Based on a

processor clocked at 7.5 MHz, the QL included 128

KiB The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit ...

RAM Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...

, which is officially expandable to 640 KiB and in practice, 896 KB. It can be connected to a

monitor Monitor or monitor may refer to: Places * Monitor, Alberta * Monitor, Indiana, town in the United States * Monitor, Kentucky * Monitor, Oregon, unincorporated community in the United States * Monitor, Washington * Monitor, Logan County, West ...

or TV for display. Two built-in

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 ma ...

tape-loop cartridge drives provide mass storage, in place of the more expensive

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined ...

drives found on similar systems of the era. Microdrives had been introduced for the Sinclair 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 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' ('' data terminal equipment'') suc ...

ports, proprietary QLAN

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a large ...

ports, dual

joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...

ports and an external

bus. Two video modes are available, 256×256 pixels with 8

RGB The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three addi ...

colours and per-pixel flashing, or 512×256 pixels with four colours: black, red, green and white. The supported colours can be stippled in 2×2 blocks to simulate up to 256 colours, an effect which does not copy reliably on a TV, especially over an RF connection. Both screen modes use a 32 KiB

framebuffer A framebuffer (frame buffer, or sometimes framestore) is a portion of random-access memory (RAM) containing a bitmap that drives a video display. It is a memory buffer containing data representing all the pixels in a complete video frame. Mode ...

in main memory. The hardware is capable of switching between two different areas of memory for the frame buffer, thus allowing double 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 system

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 R ...

provides full support for the second frame buffer. When connected to a normally-adjusted TV or monitor, the QL's video output overscans horizontally. This is reputed to have been due to the timing constants in the

chip being optimised for the flat-screen CRT display originally intended for the QL. Internally, the QL comprises the CPU, two ULAs (ZX8301 and ZX8302) and an Intel 8049

microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs ( processor cores) along with memory and programmabl ...

known as the IPC, or "Intelligent Peripheral Controller", responsible for keyboard, joystick ports, RS-232 inputs and sound output. The ZX8301 or "Master Chip" implements the video display generator and also provides

DRAM Dynamic random-access memory (dynamic RAM or DRAM) is a type of random-access semiconductor memory that stores each bit of data in a memory cell, usually consisting of a tiny capacitor and a transistor, both typically based on metal-oxid ...

refresh. The ZX8302, or "Peripheral Chip", interfaces to the RS-232 ports (transmit only) Microdrives, QLAN ports, real-time clock and the 8049 via a synchronous serial link. The 8049 included at a late stage in the QL's design (the ZX8302 originally being intended to perform its functions) runs at 7.5 MHz and acts as a keyboard/joystick interface, RS-232 receive buffer and audio generator. When comparing technical specifications among

microcomputer A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PC ...

s in the traditional sense of the term, the QL qualifies as the fastest for having a 15 MHz clock that alternates between Motorola's 68008 & Intel's 8049. Bundled Psion application software on Microdrive cartridges QDOS, a pre-emptive multitasking

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

primarily designed by Tony Tebby, is included on ROM, as is an advanced structured BASIC interpreter, named SuperBASIC designed by Jan Jones, which is also used as the

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 ...

. The QL is bundled with an

office suite Productivity software (also called personal productivity software or office productivity software) is application software used for producing information (such as documents, presentations, worksheets, databases, charts, graphs, digital painting ...

, consisting of a word processor, spreadsheet, database, and business graphics written by Psion. It is the first OS to feature a

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for se ...

-style

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

, predating

Apple Computer Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...

by a month. Physically, the QL is the same black colour as the preceding ZX81 and Sinclair ZX Spectrum models, but introduced a new angular styling theme and keyboard design which would later be seen in the ZX Spectrum+. 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

DE-9 The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems. Description, no ...

sockets. Joysticks connect to the QL with similar type 630W plugs.

Legacy

ICL One Per Desk

The QL's

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, a ...

and ZX8302 ASICs and Microdrives form the basis of

International Computers Limited International Computers Limited (ICL) was a British computer hardware, computer software and computer services company that operated from 1968 until 2002. It was formed through a merger of International Computers and Tabulators (ICT), English E ...

's (ICL's)

One Per Desk The One Per Desk, or OPD, was an innovative hybrid personal computer/telecommunications terminal based on the hardware of the Sinclair QL. The One Per Desk was built by International Computers Limited (ICL) and launched in the UK in 1984. It wa ...

(OPD) - also marketed by

British Telecom BT Group plc (trading as BT and formerly British Telecom) is a British multinational telecommunications holding company headquartered in London, England. It has operations in around 180 countries and is the largest provider of fixed-line, b ...

as the Merlin Tonto and by Telecom Australia as the Computerphone. The result of a three-year collaboration between

, ICL and British Telecom, the OPD has the addition of a telephone handset at one end of the keyboard, and rudimentary Computer-Telephony Integration (CTI) software. This machine interested a number of high-profile business customers, including certain divisions of the former 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.

Linux

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also ...

has attributed his eventually developing the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...

, likewise having pre-emptive multitasking, in part to having owned a Sinclair QL in the 1980s. Because of the lack of support, particularly in

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bot ...

, Torvalds became used to writing his own software rather than relying on programs written by others. His frustration with the Sinclair led, years later, to his purchase of a more standard

IBM PC compatible IBM PC compatible computers are similar to the original IBM PC, XT, and AT, all from computer giant IBM, that are able to use the same software and expansion cards. Such computers were referred to as PC clones, IBM clones or IBM PC clones ...

on which he would develop Linux.

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 CST and DanSoft, creators of the

Thor Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding god associated with lightning, thunder, storms, sacred groves and trees, strength, the protection of humankind, hallowing, ...

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. In the late 1990s, two partly QL-compatible

motherboard A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...

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 The Motorola 68040 ("''sixty-eight-oh-forty''") is a 32-bit microprocessor in the Motorola 68000 series, released in 1990. It is the successor to the 68030 and is followed by the 68060, skipping the 68050. In keeping with general Motorola na ...

and

68060 The Motorola 68060 ("''sixty-eight-oh-sixty''") is a 32-bit microprocessor from Motorola released in 1994. It is the successor to the Motorola 68040 and is the highest performing member of the 68000 series. Two derivatives were produced, the 68L ...

s respectively, are much more powerful than the original QL and have the ability among other things (such as multimedia, high resolution graphics,

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

networking etc.) to run the

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...

operating system. 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). Hardware add-ons such as new developments like the QL-SD (designed by Peter Graf) and reengineered or even expanded 1990s designs such as QubIDE interfaces (by José Leandro Novellón). Trump, Gold & Super Gold Cards (by Tetroid) are still being produced for the original QL. RWAP Software supplies various hardware and software upgrades and spare parts.

Operating systems

Patched or reengineered versions of QDOS were produced, most notably

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.

Emulators, virtual QLs and distributions

Quite a few emulators and virtual QLs became available over time of which Q-emuLator (Windows/Mac), QPC2 (Windows), SMSQmulator (Java), ZEsarUX (Windows/Mac/Linux) and sQLux (Windows/Mac/Linux) are actively maintained. Several distributions of emulators, applications and information have been produced, of which Black Phoenix and QL/E are the most actively maintained.

References

External links

Dilwyn Jones's QL pages
– Well maintained site with comprehensive QL related information and a huge software download library.

– Well maintained project with valuable Sinclair QL related information and software. * {{Authority control Computer-related introductions in 1984 Home computers 68000-based home computers Computers designed in the United Kingdom Personal computers QL