Sinclair QL (Quantum Leap) Computer 1984

The QL was the first mass-market personal computer based on the
Motorola 68000-series processor family.

Sir Clive Sinclair 1983

Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128 kB of RAM (officially expandable to 640 kB; in practice, 896 kB) and could be connected to a monitor or TV for display. Two built-in Microdrive tape-loop cartridge drives provided mass storage, in place of the more expensive floppy disk drives found on similar systems of the era. (Microdrives had been introduced for the Sinclair ZX Spectrum in July 1983, although the QL used a different logical tape format.) Interfaces included an expansion slot, ROM cartridge socket, dual RS-232 ports, proprietary QLAN local area network ports, dual joystick ports and an external Microdrive bus. Two video modes were available, 256×256 pixels with 8 out of 256 RGB colours and per-pixel flashing, or 512×256 pixels with four colours (black, red, green and white). Both screen modes used a 32 kB framebuffer in main memory. The hardware is capable of switching between two different areas of memory for the framebuffer, thus allowing double buffering. However, this would have used 64 KB of the standard machine's 128 kB of RAM and there is no support for this feature in the QL's original firmware..

History

The QL was originally conceived in 1981 under the code-name ZX83, as a portable computer for business users, with a built-in ultra-thin flat-screen CRT display (similar to the later TV80 pocket TV), printer and modem. As development progressed it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration.[3][5] The electronics were primarily designed by David Karlin, who joined Sinclair Research in summer 1982. The industrial design was done by Rick Dickinson, 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.

The QL was designed to be more powerful than the IBM Personal Computer, and comparable to Apple's Macintosh. The QL was the first mass-market personal computer based on the Motorola 68000-series processor family. Rushed into production, the QL beat the Apple Macintosh by a month, the Atari ST by a year and the Commodore Amiga by a year and 2 months. While clock speeds were comparable, the 8-bit databus and cycle stealing of the ZX8301 gate array limited the QL's performance. However, at the time of launch, on January 12, 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 much criticism of the company and the attention of the Advertising Standards Authority