Sinclair QL | Code Like It's 198x

On 12 January 1984, Clive Sinclair launched a business computer at the Inter-Continental Hotel on London’s Hyde Park Corner. It had a Motorola 68008 processor, the chip family Apple would put in the Macintosh twelve days later, along with 128K of memory, two built-in tape drives, a multitasking operating system and four office programs in the box, for £399. He called it the QL, for Quantum Leap.

Your Computer could hardly believe the list: 128K of RAM, a 32-bit processor, two built-in Microdrives “and all the interfaces — cartridge, RS-232, joystick and RGB — that Sinclair usually leaves out, for just £399.” The same report noted that “even customers used to waiting 28 days and more for Sinclair products are wondering if it really stands for Quite Late.”

They were right to wonder. The machine shown to the press was not finished, the operating system on display was not the one that shipped, and the first QLs reached customers months late with part of their ROM in a box plugged into the back.

Fast facts

Launched: 12 January 1984 · Price: £399, by mail order
CPU: Motorola 68008 at 7.5 MHz, clocked by the ZX8301 chip
Second processor: Intel 8049, the “Intelligent Peripheral Controller”, which reads the keyboard and joysticks, drives the loudspeaker and receives serial data
Custom chips: ZX8301 (display, clock, memory) and ZX8302 (Microdrives, network, serial output, real-time clock)
Memory: 128K RAM, about 90K of it free for programs; 48K ROM
Display: 512 × 256 in four colours, or 256 × 256 in eight
Storage: two built-in Microdrives, each cartridge holding “at least 100 Kbytes”
Software: QDOS operating system and SuperBASIC in ROM; Psion’s Quill, Abacus, Archive and Easel on cartridge
Industrial design: Rick Dickinson

A 32-bit machine on an 8-bit bus

Sinclair sold the QL as a 32-bit computer, and its own service manual describes the 68008 the same way: “a 32-bit microprocessor with an 8-bit data bus”. Motorola’s reference manual is more modest and calls the MC68008 a “16-Bit Microprocessor with 8-Bit Data Bus”. Both are fair descriptions of the same part. Inside, it has the 68000’s 32-bit registers and instruction set. Outside, every byte travels over eight data lines, so a 32-bit value takes four trips to memory.

The choice was about money. David Karlin, the QL’s project manager, persuaded Sinclair to use the 68008 because a 68000 with a 16-bit bus would have cost far more, according to the author Tim Danton, who interviewed him. Your Computer, looking back in January 1986, said that when Sinclair chose it a 68000 cost five times as much as a 68008.

The rest of the machine was built just as tightly. The CPU does not scan the keyboard or make sounds. An Intel 8049 microcontroller does those jobs and passes the results to the main processor over a serial link. Two semi-custom chips handle everything else. The ZX8301 builds the television picture from main memory and has priority whenever it needs a byte, so the processor has to wait its turn. The ZX8302 runs the Microdrives, the network, the real-time clock and the sending half of the serial ports. Karlin told Danton he was allowed only two custom chips, with 40 pins each, and spent “more time than anything else counting pins”.

QDOS and SuperBASIC

The software was the most advanced thing about the QL. QDOS, written by Tony Tebby, was a multitasking operating system: the user guide explains that each job gets “a share of the CPU in line with their priority”. Tebby wrote the QL Software Developer’s Guide with Karlin. SuperBASIC, written by Jan Jones, was a structured BASIC with named procedures and functions. Jones told Danton that “nothing looked as if it had been added on later as an afterthought or patch”.

Neither was ready at the launch, and the accounts of why differ. Nigel Searle, Sinclair Research’s managing director, told Danton that Tebby would not commit to deadlines, so he commissioned a second operating system from the Cambridge firm GST as insurance. Your Computer, in January 1986, told it the other way round: the operating system had originally been contracted to GST, and QDOS was the back-up. Either way, the QL shown to journalists in January ran GST’s system, and Sinclair User later said the launch machine “was hardly a QL at all”. Your Computer also reported that up to a month before the launch the QL was to have no BASIC.

The kludge

Then came the thing on the back of the computer. Tim Hartnell described the first machines in Your Computer in June 1984:

“We can’t get all of the operating system in,” a spokesman confided. So sticking out of the ROM socket at the back of the QL is a blob of metal, slightly larger than a matchbox, which contains the bits of the computer which Sinclair could not squeeze into the case.

Sinclair User explained the same month that the code would not fit into the planned 32K, “so the designers had to include an extra 16K ROM”. Until owners sent their machines back for an on-board upgrade, that ROM lived in an EPROM in the external socket, and the socket could not be used for anything else. Your Computer later traced the problem to the rush: GST’s operating system had been written for two 16K ROM sockets, Tebby’s QDOS “would fit along with SuperBasic into a total of 48K”, and the result was “the infamous kludge, pending 32K Roms”. Hartnell was clear about why it shipped that way:

Sinclair felt it was more important to quiet the clamour over protracted delivery delays — even if it meant sending out cobbled together machines — than it was to delay the whole thing until they got it right.

The machine inside the case was changing too. Sinclair User reported in June 1984 that the QL “bears little resemblance to the machine launched in January”. The battery-backed clock had been dropped from every model, and SuperBASIC had changed enough that the manuals at the printer were already wrong. Asked whether the machine shown to journalists would be the same in six months, “a spokesman for Sinclair declined to comment.”

Quite late

Sinclair sold the QL by mail order, promising delivery within 28 days, so customers paid first. Your Computer reported in 1986 that an early draft of the press release had promised machines by “end-April”, and that this was changed to “end-February” because the advertisements said 28 days. By May, on Sinclair User’s figures, the company was holding £5 million against 13,000 orders and had delivered only a few hundred machines. Machines arrived four months after the launch, and Sinclair User dated the first reliable working QL to late summer 1984. By then the Advertising Standards Authority had criticised Sinclair.

To make amends, Sinclair sent a free RS-232 lead, normally £14.95, with every QL that took longer than 28 days to arrive. Hartnell reported that the lead was meant to make up for the delays and for the interest customers had lost on the money they had sent. Owners who had already bought a lead got £14.95 back.

FB and AH

Owners learned to type PRINT VER$ to find out which ROM they had. The first production version was FB; the fix was AH. Kathleen Peel’s second review in Your Computer, in July 1984, is the fullest list of what FB was like to own:

The QL as released initially was not really suitable for business or pleasure as it had far too many faults and kept crashing.

She listed the faults. The QL was slow and its editor unfriendly. The Microdrives were “prone to lose files and data”. There was no documentation except for the Psion programs, the network would not work with Spectrums, the RS-232 interface had bugs, and the keyboard was clattery, with a sticking Enter key. The AH ROM fixed some of this but, in her words, “does not present a cure for all the QL’s troubles and cannot make any difference to the hardware faults”.

Two months later, after weeks with an AH machine, she reported that the lost files had stopped, “which means it must have been a software problem in the old ROM”. The cost of cartridges had not changed, and she thought “£5 is still daylight robbery”.

What it was like to use

The Microdrive was a loop of tape about 200 inches long, running at 28 inches per second. According to the user guide it “completes one circuit every 7½ seconds”, so finding a block could mean waiting for the whole loop to come round. Hartnell timed Quill at 70 seconds to load. Peel found that programs seemed to load more slowly from the QL’s Microdrives than from the Spectrum’s.

The multitasking did not reach the programs people used every day. Peel found that Quill tied up the machine while it printed: “despite the fact that it is a multitasking machine the QL does not provide spooling of printing with input operations”. Her document took over six minutes to print, then left her back at the start of the file. Saving a 750-word document and carrying on took three minutes and eighteen seconds. If she did not press ENTER at an ambiguous prompt after saving, “the data file is dumped and the user ends up with a blank page”. She also noted that the literature did not explain that multitasking was available only from machine code.

Her verdict still ended with praise:

In hardware terms the QL currently represents the ultimate in technical achievement in computers priced at £400.

Readers answered back. In September 1984 Your Computer printed a letter headed “Quelling the QL bashers”, which argued that QL machine code ran “some two to three times faster” than Spectrum code, and that comparing BASIC benchmarks was “as meaningless as comparing cars by their performence in first gear”. The writer asked for “less cataloguing of bugs and more hard connector and interface layouts, interrupts, and documentation”, and had little time for the bundle: “The Psion software should be seen for what it is, a plastic toy in the cornflake packet.”

The keyboard had a problem of its own. Rick Dickinson later recalled pressing all the keys into the first sample case at the toolmaker’s and turning it upside down, “and four or five fell out”. Fixing the mould would have delayed production by a week, and the delay was refused.

Sales, price cuts and ICL

By October 1985 the price had fallen to £199. Your Computer reported the previous month that only 50,000 QLs had been sold in the fifteen months since bug-free machines reached the shops. In the same period, Amstrad’s CPC 464 had become one of the three best-selling home computers in Britain.

The QL design had one large customer. ICL built its One Per Desk executive workstation on the same hardware, adding a telephone handset and a monitor with the power supply built in, and later histories report that ICL invested £1 million in Sinclair during the QL’s development. An improved, integrated version of Psion’s programs, Xchange, was first bundled with One Per Desk and the other QL derivatives sold by ICL and BT.

After Sinclair

Amstrad bought Sinclair’s computer business on 7 April 1986 and soon announced that it was not interested in the QL. It tried to raise a quarter of a million pounds by selling the remaining 19,000 machines, with the manufacturing rights thrown in free. Timex and the QL user group Quanta were among the interested parties.

The machine carried on without its maker:

CST’s Thor put a QL board in a larger case with 640K, disk drives and an AT-style keyboard. Your Sinclair listed it at £600 plus VAT for one drive, up to £1,400 with a 20Mb hard disk, with an £80 trade-in on your own QL. CRASH, reporting from the May 1986 Microfair, noted that “last month’s tales of the QL’s death were rather premature”. In January 1988 it described the Thor as still in production.
Sandy (Farmintel) offered a similar package, the Q-XT640, with 640K, a disk drive and an AT-style keyboard for £599. By 1988 CRASH called the Sandy Futura “now defunct”.
Blackberry, a 512K “super QL designed by Sinclair escapees Tony Tebby and Jan Jones”, was announced for the same Microfair. Its prototype failed to arrive, and the non-arrival was blamed on a power cut during development.

Tebby went on writing for the QL, including the Super Toolkit and, later, SMS/Q, a QDOS successor for Atari, PC and expanded QL hardware. In 1996 Amiga Format’s Simon Goodwin wrote that many Amiga developers had met the 68000 through the QL, including HiSoft, RealTime Games and the Bitmap Brothers, and that HiSoft BASIC and the Devpac assembler began as QDOS products.

One Finnish teenager learned to program on a QL. Linus Torvalds, who went on to write Linux, recalled in a 2010 interview for Google’s open-source blog that “you had to play all these insane tricks” on it: the Microdrives were so speed-critical that modified operating-system code running from RAM was too slow to drive them. The interviewer, Jeremy Allison, wrote that because software was hard to get in Finland, Torvalds wrote his own assembler and editor.

Sources

Your Computer, February 1984, p. 46: the launch report (“Quite Late”, the specification, the Psion packages, “90K RAM free for programs”).
Your Computer, June 1984, p. 64: Tim Hartnell’s review (the blob, “cobbled together machines”, the RS-232 lead compensation, Psion without the final QDOS, the 70-second Quill load).
Sinclair User issue 27, June 1984, p. 13, “QL Mark Two”: the 32K and extra 16K ROM, the external EPROM and ROM socket, the dropped battery clock, SuperBASIC changes and the spokesman’s refusal to comment.
Sinclair User issue 29, August 1984, p. 15: the EPROM incorporated in the main casing; the first 13,000 customers due by August.
Your Computer, July 1984, pp. 52–54: Kathleen Peel, “Second Look” (the FB and AH ROMs, the faults, loading and printing times, multitasking only from machine code, the conclusions).
Your Computer, September 1984, p. 32: letter, “Quelling the QL bashers”; pp. 131–133: Kathleen Peel on the Microdrives after eight months.
Your Computer, September 1985, p. 40: 50,000 QLs sold; October 1985, p. 48: the price of £199.
Your Computer, January 1986, pp. 51–53: the choice of the 68008 and its price, GST, the late decision to include SuperBASIC, the ROM sockets and the “infamous kludge”, the press-release dates.
Sinclair User issue 51, June 1986, p. 47: “in a desperate hurry to beat the launch of Apple’s Macintosh”, the GST operating system at the launch, £5 million against 13,000 orders by May, the four-month delay, late summer 1984, the Advertising Standards Authority; pp. 7–8: Amstrad, the 19,000 machines and the interested parties.
CRASH issue 29, June 1986, p. 11: Simon Goodwin at the May 1986 Microfair (Thor, Blackberry); CRASH issue 48, January 1988, p. 143: Sandy Futura “now defunct”, CST Thor “still in production”.
Your Sinclair issue 8, August 1986, p. 82, and issue 11, November 1986, p. 84: the Thor’s specification, prices and trade-in; the Sandy Q-XT640.
Amiga Format issue 90, November 1996, pp. 23–24: Simon Goodwin on QDOS, SuperBASIC “as designed by Jan Jones”, QDOS software on the Amiga, Tebby’s SMS/Q, One Per Desk and Xchange.
Sinclair Research, Sinclair QL Service Manual, issue 3, October 1985, section 1: the processors, clock, ROM and custom chips.
Sinclair Research, Sinclair QL User Guide (1984): screen modes (Beginner’s Guide, chapter 3); Microdrives and multitasking (Concepts section).
Tony Tebby and David Karlin, QL Software Developer’s Guide (Sinclair Research, 1984), title page.
Motorola, M68000 Family Programmer’s Reference Manual, p. 1-1: “MC68008 — 16-Bit Microprocessor with 8-Bit Data Bus”.
Alessandro Grussu, Spectrumpedia, volume 1 (English edition, CC BY-NC-ND 4.0), p. 41: the launch date.
Tim Danton, The Computers That Made Britain (Raspberry Pi Press, 2021), chapter “Sinclair QL”, with sidebars “The SuperBASIC story” and “One Per Desk”: interviews with David Karlin, Jan Jones and Nigel Searle; the launch venue; GST; the 68008 decision; the pin count; One Per Desk and ICL’s £1 million; the date of the Macintosh launch (24 January 1984) from the book’s Macintosh chapter.
Edge issue 137, June 2004, p. 81: Rick Dickinson on the keys that fell out.
Jeremy Allison, “Geek Time with Linus Torvalds”, Google Open Source Blog, 27 September 2010 (web, secondary): the assembler and editor. Torvalds’s “insane tricks” remark is quoted from the same interview by Danton. https://opensource.googleblog.com/2010/09/geek-time-with-linus-torvalds.html