Crummy Computers Wiki
First article on the wiki!

The QL (short for Quantum Leap) was a personal computer produced by Sinclair Research Ltd. as a higher-end version of their popular ZX Spectrum. It was aimed at serious home users, as well as professional and executive users.

Why it both Failed and was Crummy[]

  1. The QL was rushed into production to beat the original Macintosh to the market by a month, the Atari ST line by a year, and the Commodore Amiga by 14 months. They didn't think this one through now did they?
    • Because of this, it was far from ready for production that there wasn't even a prototype in existence by the time that its release date had rolled around.
    • Sinclair immediately took orders for the system, promising to deliver them within 28 days, with the first customer deliveries having started at a slow pace in April. This had landed Sinclair with negative criticism, as well as the attention of the Advertising Standards Authority. Talk about consequences!
  2. Its premature launch meant that the system had some major problems from the start.
    • The early production models that came off of the assembly line were shipped with bugged, preliminary versions of the firmware, mainly in SuperBASIC. Not helping is that part of the firmware is contained in an external 16 KB ROM cartridge referred to as a "kludge" or a "dongle". The system was redesigned to accommodate the necessary 48 KB of ROM internally, instead of the 32 KB initially specified.
    • The QL's Microdrives had reliability problems, which were later recitified by Sinclair engineers, especially on the Samsung produced drives, in addition to aftermarket firms such as Adman Services and TF Services to the point where several QL users report the Samsung Microdrives in particular working perfectly even after almost 17 years of service. However, it was too little too late to redeem the negative image that the QL had already gained.
  3. The target business market that the QL was aimed for was getting increasingly invested in the IBM PC platform, along with ZX Spectrum owners being uninterested to upgrading to a machine that had a minimal library of games.
  4. Sinclair's insistence of using the non-standard Microdrive format and the system's uncomfortable keyboard didn't exactly endear it to the business market.
  5. The QL had something of a resemblance to a ZX Spectrum+, leading people to perceive it to something that is akin to a toy.

Redeeming Qualities[]

  • Linus Torvalds developing the Linux kernel was owed in part to him having owned a QL.


  • Sir Clive Sinclair himself had appeared in the TV advertisement of the QL.
  • The QL's CPU, ASICs, and Microdrives had formed the basis for One Per Desk (OPD), the innovative hybrid PC/telecommunications terminal developed by International Computers Limited (ICL).

External Link(s)[]