How Sinclair's QL computer outshined Apple's Macintosh against all odds

Compatible hardware and peripherals are still on sale, four decades after its launch

Retro Tech Week Two weeks before Apple launched the Macintosh, Sir Clive Sinclair launched his unprecedentedly powerful yet affordable Motorola-powered SOHO computer – starting a line of hardware and software that, remarkably, is still going.

The QL remains a much-misunderstood computer. For its time, it was just as radical as the closely related machine that launched days later. Although it wasn't a smash hit, it wasn't the failure it's often deemed. A multinational licensed Sinclair's hardware, and several big-name companies sold versions of it around the world. The QL also inspired a dozen software-compatible successors, at least one of which is still manufactured today ... and not one but two versions of its unique operating system are still around as open source.

A Quantum Leap … to where?

Sinclair Research launched the QL on January 12, 1984, nearly two weeks before Apple Computer launched its new Macintosh computer on the 24th. Both machines had Motorola 68000-family processors, a mere 128 kB of memory, and just a pair of serial ports for I/O. Both launched with powerful bundled applications. Both had brutally cut-down specifications to make them price competitive, and both were big technological gambles on unproven technology, previously only available in vastly more expensive computers.

Sinclair's bet was that multitasking would be the key differentiator. It was the first affordable personal computer to offer this. Today it's clear that Sinclair backed the wrong horse, but four decades ago, its mistake was understandable. Before the Macintosh, it was not at all clear that GUIs were the future. The Macintosh wasn't the first GUI-driven PC – one year earlier, Apple launched the Lisa, and that really was a flop. A few years later, 2,500 Lisas went to landfill, and there never were any Lisa compatibles.

When the QL turned 30, The Reg published a detailed history, but a decade on, we thought it would be more interesting to look at the legacy of this pioneering machine – the many models of QL-compatible machines that appeared after Sinclair Research moved on to other things, and the descendants of its remarkable OS and their continued existence in the 21st century.

The QL's original operating system was called QDOS, a pun on kudos – and no, not that QDOS. QDOS took the ideas of the early 1980s, but did them better. Like all Sinclair's earlier computers and their competitors, QDOS came in ROM, so the machine was immediately usable. It ran direct from ROM too, so bootup was almost instant and all the machine's RAM was available. Sinclair QDOS used a second generation BASIC as its shell – also standard practice for the time – and SuperBASIC was a good one too. You can read the current version of the SuperBASIC manual [PDF] online, thanks to Reg Retro Tech Week 2023 guest Rich Mellor.

At launch, the QL cost £399, equivalent to £1,600 ($2,000) today. A bargain compared to the $2,495 Macintosh, which would be $7,600 (£6,000) today. For four hundred quid, you got two ZX Microdrives and an expansion bus. The Mac had just one single-sided floppy drive, from which it also had to boot, eating more precious memory – and little expansion potential.

What's more, four years before Redmond thought up Microsoft Office, the QL came with an entire application suite for free: Psion Xchange, including the Quill word processor, Abacus spreadsheet, Archive database, and Easel graphics program. There was also a version of this for IBM compatibles, called Psion PC Four.

For 1984, this was a lot of computer for a good price. In comparison, on the Macintosh, 128 kB was so inadequate that the "Fat Mac" followed just eight months later. The Fat Mac had 512 kB and cost $2,795 – half the price of the 512 kB IBM PC/AT at a whopping $5,295 ($16,150 or £12,666 today). Without a screen or keyboard, obviously: they cost extra.

Send in the clones

The QL's value proposition looked pretty compelling in 1984, and other computer vendors wanted to get in on the action. British "hardware and services giant ICL" as we called it licensed the hardware to create the ICL One Per Desk. The OPD had an integrated telephone handset, and could work as an office phone and answering machine as well as a desktop computer, complete with a modem for email and online access. It came with a cut-down OS and SuperBASIC, a version of the Xchange suite, and Microdrives re-engineered for greater reliability. Other companies in turn sub-licensed the OPD. BT sold it as the Merlin Tonto, and down under, it was the Telecom Australia ComputerPhone. They sold well enough that various peripherals and expansions followed, including faster modems, IBM mainframe connectivity, floppy drives, and more.

After Sinclair stopped making new QLs, a supplier of QL add-ons called CST stepped in, bought the remaining motherboards and launched the Thor range, as reviewed by Reg co-founder John Lettice in Personal Computer Weekly in May 1986. The original Thor had a QL motherboard, its RAM maxed out at 640 kB, in a metal desktop case with a parallel port, one or two 3.5-inch floppies and an optional 20 MB SCSI hard disk, plus a PC-style keyboard. For 1986, this was a professional workstation-level specification, rather than Sinclair's budget version – although that meant it cost £599. Another similar machine was the Sandy QXT-640.

In 1987, CST launched the Thor 20, as reviewed on page 12 of QL World [PDF] in July that year. It was twice the price, but with a CPU upgrade: a daughterboard containing a full 32-bit 68020 that ran at 12.5 MHz. The Thor 21 added a matching 68881 math co-processor, and there was a faster 16.66 MHz 68030 option, taking it up to a formidable £2,300. They were considerably faster, even though limited by the eight-bit data bus of the original 68008 CPU. This was resolved in 1988 with the final CST machine, the CST Thor XVI, with a new, fully 16-bit motherboard holding an 8MHz 68000.

Alongside the standalone computers, there was also a variety of go-faster boards which either supplemented the original QL or replaced it completely. Miracle Systems offered the Gold Card, with a 16 MHz 68000 and 2 MB of RAM, and later the Super Gold Card, with a 68020 and 4 MB. Remarkably, you can still buy modern clones of both: Tetroid's Gold Card and Super Gold Card.

Ron Dunnett's Qubbesoft sold the Aurora motherboard, designed by Željko "Nasta" Nastasić. Although it was designed to go into an AT-style PC case, it was possible to fit an Aurora board into an original QL case. Either way, you needed a donor QL as the Aurora needed some of the chips from the original machine.

As supplies of original QL motherboards dwindled, Miracle Systems invented an ingenious alternative, the QXL Card, and later, the faster QXL 2 card. The QXL cards put the core logic of a QL-compatible computer – a 68EC040 CPU, from one to four megabytes of RAM, and two QL network ports – onto a 16-bit ISA card to fit into a PC. A DOS application called QXL.EXE transferred control to the Motorola chip, with the PC providing disk storage, I/O, and display. These devices even made it around the world. The Reg FOSS desk last saw one installed into an Amstrad ALT-386 at the ByteFest retro computing show in Prague, and for Sinclair users stateside, Update magazine carried the news in its April 1993 issue.

Fast forward to 1999, and an entirely new family of QL-compatible motherboards appeared: the Q40 and Q60, designed by Peter Graf. The devices are standalone mini AT-form factor motherboards, with two SIMM slots and two ISA slots. The Q40 motherboard has a 40 MHz 68040 and maxes out at 32 MB, while the latter Q60 board offered a 66 MHz or 80 MHz 68060 and up to 128 MB of RAM. The Q40 and Q60 homepage is still alive and has more info, although no new boards have been made in some years.

This is because Herr Graf moved on to a new project, the FPGA-based Q68 computer, a simulated 68000 core running at 40 MHz, with 32 MB of RAM, QL-compatible graphics from 256 x 256 up to 1,024 x 768 in 16-bit color, serial, Ethernet and I2C interfaces, and twin SD card slots. It may not sound much by 2024 PC standards, but for a QL-compatible, this is formidable stuff, and it's only £150 ($190) plus shipping. The QL user group Quanta – itself 40 years old as well – has more info. The Q68 board is tiny and capable, however, the best news is that you can still order new units today from long-term builder of QL-compatibles Derek Stewart.

By our reckoning, that's some 14 different models of QL-compatible hardware from the CST Thor in 1986 to the Q68 today – and that's excluding accelerator boards for the original machine. We reckon that is an impressive tally, and more than most 1980s computers can boast.

Youtube Video

Minerva, SMSQ/E and other offspring

As The Reg history of the QL at 30 covered, initial shipping suffered repeated delays and the early machines shipped with an add-on ROM cartridge in the rear to hold the OS. The official stated reason, although disputed, was that the machine contained 32 kB of ROM, but the OS needed 48 kB. What is a matter of record is that QDOS went through multiple revisions in the QL's first year or so, which is commonplace today, but in the 1980s meant replacing ROM chips.

Some of the early QL-compatibles were built around original motherboards, which meant that they inherited the 48 kB limitation. That led to the existence of one of the forks of QDOS that's still around: Laurence Reeve's Minerva. As his partial release history shows, there were many versions of this, but he made his final version, release 1.98, open source under the GPL – although since then there have been a couple of bug fixes.

The other continuing fork of QDOS started out from its original developer, Tony Tebby. With no more new QL hardware available, he ported the OS to the next cheapest 68000 box available, the Atari ST. He called the result SMS2, Small Multitasking System 2. This had a different interface from QDOS because the proprietary SMS2 OS didn't include the SuperBASIC interpreter written by Jan Jones which formed the main UI for QDOS.

In time, QDOS compatibility was added back, along with a multitasking version of SuperBASIC called SBASIC, to make SMSQ, and this was then gradually enhanced to create SMSQ/E, which also runs on later QL-compatible hardware. Tebby wrote an excellent brief history of the evolution of the system for its Wikipedia page, but in their finite wisdom, the site administrators deleted it. Fortunately, you can still read it in the page's history. The SMSQ/E source code is still available, which is sadly more than we can say of Tebby's planned successor, which he called Stella, although there is a historical introduction.

After Tebby retired, Marcel Kilgus – developer of one of the leading QL emulators for Windows, the now-freeware QPC2 – took over development. There is also a Java-based emulator called SMSQmulator for non-Windows types.

Closing words

For a machine widely derided as a failure, the QL platform survived in the form of well over a dozen clones, at least one of which is still on sale today. There are two forks of its OS that ended up becoming open source. One was for systems built around the original motherboard with its 48 kB of ROM space. The other runs on much less-constrained environments, and continued to evolve well into the 21st century. It can be run on Atari hardware, as well as QL-compatible hardware – and emulators of both, of course.

SMSQ/E's Pointer Environment, as found in the Distribution, is quite unlike anything else – a glimpse of an alternate universe

SMSQ/E's Pointer Environment, as found in The Distribution, is quite unlike anything else – a glimpse of an alternate universe

If you want to explore this unique OS and its software today, Urs König curates a free 4 GB archive of software, emulators, magazines, videos, and more called The Distribution. If you just want a compilation of the software, that exists as a subset called the QL Environment. Both are available from There's an active community on the QL Forum, which also hosts the comprehensive Dilwyn Jones Sinclair QL Pages. ®

More about


Send us news

Other stories you might like