The Sinclair QL
(QL standing for Quantum Leap
), was a personal computer launched by in 1984, it was lauched as a successor to the ZX Spectrum
. The QL was aimed at the hobbyist and small business users and markets, but failed to achieve commercial success.
The QL was originally conceived in 1981 under the code-name ZX83, as a portable computer for business users, with a built-in flat-screen CRT display and internal modem. As development progressed, and ZX83 became ZX84, it eventually became clear that the portability features were over-ambitious and the specification was reduced to a conventional desktop configuration.
Based on a Motorola 68008 processor clocked at 7.5 MHz, the QL included 128 KB of RAM (officially expandable to 640 KB) and could be connected to a monitor or TV for display. Two built-in Microdrive tape-loop cartridge drives (first seen as a peripheral for the ZX Spectrum) provided mass storage, in place of the more expensive floppy disk drives found on similar systems of the era. 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 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.