A computer system launched by Sinclair Research in 1984. QL stood for "Quantum Leap". A successor to the ZX Spectrum, the QL was designed with the hobbiest and small business market in mind. It used a Motorola M68008 processor and came with 128 kB of RAM as standard, and could be connected to a monitor or TV for display. It used a multitasking operating system, QDOS, and was bundled with a suite of productivity software (wordprocessor, spreadsheet, database and graphics) written by Psion. It had a built-in advanced BASIC interpreter.
The QL was plagued by a number of problems from release, particularly bugs in the QDOS operating system on ROM, which lead to multiple releases of the firmware. The machine also suffered from reliability problems of its built-in "microdrive" tape-loop storage systems (first seen as add-ons for the ZX Spectrum). Although the computer was rather advanced for its time, and relatively cheap, it failed to sell well and was eventually discontinued.
The QL was also available for a short period of time in the guise of ICL's 'One Per Desk' (OPD). Based around the same platform as the QL, but with a different case and keyboard, the OPD had the intruiging addition of a telephone handset on one end of the keyboard, and rudimentary Computer-Telephony Integration. The OPD was in turn marketed by British Telecom as the BT Merlin, with limited success.