QDOS is the multitasking operating system found on the Sinclair QL personal computer and its clones. It was designed by Tony Tebby while working at Sinclair Research as an in house alternative to 68K/OS, later cancelled by Sinclair but released by its original authors, GST Computer Systems. The name is not regarded as an acronym and is sometimes written Qdos; during early development it was referred to internally as Domesdos. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/
Facts
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LicenseProprietary (Closed Source) 2 FAQs
What does the name QDOS stand for?
The origin of the name is uncertain; several readings have been suggested but none is settled.
The origin of the name is uncertain. The Free On-line Dictionary of Computing suggests it may be a weak pun on kudos, in the way Unix was a pun on Multics. It also notes that an unrelated operating system called Q.D.O.S., short for Quick And Dirty Operating System, existed from the early days of personal computers, and that QDOS might alternatively stand for QL Data, Disk, Drive or Device Operating System. None of these is settled as the official meaning.
How did QDOS handle devices such as the screen and disk drives?
QDOS treated every device uniformly and let programs redirect logical channels to different physical devices.
QDOS treated all devices, including serial ports, mouse ports, the screen, microdrives, disk drives and the keyboard, in the same uniform way. Because of this, a text file could be printed directly to disk or a binary could be saved to the screen. Logical channels could also be assigned to particular physical devices, so output sent to a channel went to whichever device it was assigned to, and channels could be redirected without changing how a process sent or received its data.
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Source Wikipedia: Sinclair QDOS
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Sources
1. Wikipedia: Sinclair QDOS
Lead section
QDOS is the multitasking operating system found on the Sinclair QL personal computer and its clones.
In Field: Operating Systems, Lead sentence
QDOS is the multitasking operating system found on the Sinclair QL personal computer and its clones.
View the Source2. Wikidata: Sinclair QDOS
- Wikidata Q2712090, class allow-list match (w-wdresolver-0926)
- Wikidata Q2712090 P275 (license)
- Wikidata Q2712090 P577 (publication/release date) claim -> 1984; checked 2026-09-28
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