For the Microsoft operating system, see Hebrew MS-DOS. For the fast food company, see Hot Dog on a Stick.
Operating system
HDOS
Developer
Heath Company / Gordon Letwin, Richard Musgrave
Working state
Discontinued
Source model
Open source
Initial release
1978; 46 years ago (1978)
Latest release
3.02
Available in
English
Platforms
Heathkit H8, Heathkit H89, Zenith Z-89
License
Public domain
HDOS is an early microcomputer operating system, originally written for the Heathkit H8 computer system and later also available for the Heathkit H89 and Zenith Z-89 computers. The author was Heath Company employee Gordon Letwin, who later was an early employee of Microsoft and lead architect of OS/2.
HDOS originally came with a limited set of system software tools, including an assembler, but many commercial and large set of freeware programs from HUG (Heath User Group) became available for it eventually.
HDOS 2.0 is notable because it was one of the first microcomputer operating systems to use loadable device drivers to achieve a degree of device independence and extensibility. Device names followed the RSX-11-style convention of DKn: where the first two letters were the device driver file name and n was a number (DK0:, DK1:, and so on would all be handled by DK.SYS). Other similarities to RSX included the use of PIP for file transfer, and the use of EOT for file termination.
Similar to how Heath/Zenith published complete schematics and part lists for its computers, the company sold to users the source code for HDOS.[1][2] Item references (Heathkit part number) are HOS-1-SL part number 595–2466.
^"Untitled". InfoWorld. 1980-09-01. p. 17. Retrieved 16 February 2015.
^Needle, David (1982-09-13). "Personal touch: Zenith inherits do-it-yourself Heath fans". InfoWorld. pp. 24–25. Retrieved 29 June 2014.
code for HDOS. Item references (Heathkit part number) are HOS-1-SL part number 595–2466. The following list of commands are supported by HDOS. BOOT BYE...
HDOS Enterprises Trade name Hot Dog on a Stick Company type Subsidiary Industry Restaurants Genre Fast food Founded June 1946; 78 years ago (1946-06) Santa...
HDO may refer to: Hispanic Democratic Organization, United States, a PAC Hydrodeoxygenation, removing oxygen from compounds Semiheavy water, replacing...
Heathkit, porting Colossal Cave Adventure to the computer and working on HDOS and Benton Harbor BASIC. Letwin's first project at Microsoft was writing...
in Venus' cryosphere and high-altitude measurements of HF, HCl, H2O and HDO" (PDF). Nature. 450 (7170): 646–649. Bibcode:2007Natur.450..646B. doi:10...
original on May 22, 2008. Retrieved April 28, 2012. "Hot Dog On A Stick". HDOS Enterprises. Archived from the original on January 26, 2011. Retrieved April...
contains deuterium atoms and is used in nuclear reactors. Semiheavy water (HDO) is more common than pure heavy water, while heavy-oxygen water is denser...
small hardware modification and an updated ROM to do so. Heath also offered HDOS, which was written by Gordon Letwin. Letwin later went to Microsoft and was...
and punched tape (with the H10 puncher–reader). The H8's operating system, HDOS (Heath Disk Operating System), could only read hard-sectored 5.25-inch floppy...
Hydrodeoxygenation (HDO) is a hydrogenolysis process for removing oxygen from oxygen-containing compounds. Typical HDO catalysts commonly are sulfided...
he was doing and decided to hire him directly. Letwin's first project was HDOS, an operating system for the platform. With this completed, he began work...
8859-8. As non-localized issues of DOS (except for Hebrew MS-DOS a.k.a. HDOS) had no inherent bidirectionality support, Hebrew text encoded using code...
HD 156768 is a double star in the southern constellation of Ara, with a combined apparent magnitude of 5.86. The brighter component is a sixth magnitude...
natural water contains deuterated molecules, almost all as semiheavy water HDO with only one deuterium atom. The existence of deuterium on Earth, elsewhere...
Hindon Airport (IATA: HDO, ICAO: VIDX), also spelled Hindan Airport, is a commercial domestic airport and an Indian Air Force base in Ghaziabad, Uttar...
hydrogen contains about 50% HDO and 25% each of H2O and D2O, in dynamic equilibrium. In regular water, about 1 molecule in 3,200 is HDO (one hydrogen in 6,400...
1960s; 63 years ago (1960s) Operating system BATCH-11/DOS-11, RT-11, RSTS/E, RSX-11, OS/8, TOPS-10, TOPS-20, CP/M, MP/M, DOS Plus, HDOS, VMS Type Command...
South Texas Regional Airport at Hondo (ICAO: KHDO, FAA LID: HDO) is a public use airport located two nautical miles (4 km) northwest of the central business...
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