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Remembering the Sinclair QL

Looking back at Sinclair's Quantum Leap, with its 68008 processor and microdrives.

Sinclair QL Computer
Sinclair QL (Photo by Telecarlos licensed under CC BY 3.0)

Leaping Ahead

Standing for ‘Quantum Leap’, this was Sinclair’s attempt to move upmarket. The QL was released in 1984, and featured more advanced hardware than the ZX Spectrum. Unfortunately, it seems that many compromises were made in the design, in order to keep costs down.

Programmer's Mug 68000 Chip

Technical Limitations

The QL had a 68008 microprocessor, clocked at 7.5 MHz. The 68008 was a sort of cut-down version of the 68000 chip, which was found in 16-bit machines such as the Mac, as well as slightly later machines like the Amiga and Atari ST.

The chip used in the QL only had an 8-bit wide data bus, which made it much slower.

Despite the 8-bit external data bus, Sinclair tended to refer to the QL as being a 32-bit machine, because of its internal registers. Even at the time, I don’t think many people took Sinclair’s claims very seriously.

Memory was 128 KB as standard, and could be upgraded to 896 KB. Compared to a ZX Spectrum, that sounded like quite a lot. But when compared to a 68000-based machine like the Amiga, which could be expanded to 8.5 MB, it wasn’t quite so impressive.

Sinclair Microdrive Opened vs Audio Cassette
The inside of a microdrive cartridge, next to an audio cassette (Photo by Mumiemonstret licensed under CC0 1.0)

Cheap Keyboard

Sinclair also insisted on using an inferior type of keyboard. The key caps looked promising, compared to the rubber keys found on the original Spectrum.

Unfortunately, it was still a membrane keyboard underneath. Sinclair went on to use the same design with the Spectrum+, later in 1984.

Microdrive Storage

Most computers aimed at the higher end of the market used floppy disks. In another attempt to control costs, Sinclair chose to use a slightly updated version of their own microdrive storage system, which they had first released in 1983 for the ZX Spectrum.

Unfortunately, being based on a loop of tape, microdrives were slower and less reliable than floppy disks.

Video Modes

When it came to video modes, the QL had to make do with just two. Although somewhat limited, they were adequate for the intended market.

One mode had eight colours at a resolution of 256 x 256, and the other had four colours at 512 x 256.

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Sounds of the ZX Spectrum

As for sound, the QL lacked a proper sound generator chip, and it was only really intended to produce simple beeps. That made it no better than the original ZX Spectrum.


Built-in networking allowed up to 64 QL computers to be connected together.

The network was fairly slow at 100 kbit/s, although the Mac’s AppleTalk network was not tremendously fast either, at around 230 kbit/s for up to 32 devices.


The QL had a much more advanced BASIC than the ZX Spectrum. It also had a multi-tasking operating system called QDOS.

An office suite was supplied with the machine, in an attempt to appeal to business users and serious home users alike.

Third-party software vendors didn’t exactly rush to write software for the QL. Perhaps they expected it to fail in the market. But the need to ship software on Microdrive cardridges didn’t help either.

Market Performance

Physically, the QL looked rather like a Spectrum+. That made it hard for people to think of the QL as a serious business machine.

Most Spectrum owners didn’t want to make the switch, due to a lack of games software for the QL. Also, there were bugs in QL’s the firmware, and the use of microdrives didn’t make the machine any more appealing.

In the end, the QL did not perform well in the market. Sadly, after Amstrad took over Sinclair, it was discontinued in 1986.


Back in the 80s, when I was a Spectrum / Commodore 64 owner, I was somewhat curious about the QL. Even though it didn’t quite offer the right blend of features for me, I still wanted to try one out.

The same is true today — perhaps it’s time to head over to eBay…

Do you have memories of using the Sinclair QL?
Share your thoughts in the comments section below.

Related Articles

Memorable 1980s Home and Personal Computers

Remembering the Sinclair ZX Spectrum
Remembering the Commodore 64
Remembering the Commodore Amiga
Remembering the Atari ST
Remembering the Original Apple Macintosh

External Links

Sinclair QL (Wikipedia)
Sinclair QL (Old Computers)
Sinclair QL (Nostalgia Nerd)
ZX Microdrive (Wikipedia)

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