HDOS is an early
microcomputer
A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (P ...
operating system
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs.
Time-sharing operating systems scheduler (computing), schedule tasks for ...
, 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
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...
and lead architect of
OS/2
OS/2 is a Proprietary software, proprietary computer operating system for x86 and PowerPC based personal computers. It was created and initially developed jointly by IBM and Microsoft, under the leadership of IBM software designer Ed Iacobucci, ...
.
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 driver
In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabli ...
s to achieve a degree of device independence and extensibility. Device names followed the
RSX-11
RSX-11 is a discontinued family of multi-user real-time operating systems for PDP-11 computers created by Digital Equipment Corporation. In widespread use through the late 1970s and early 1980s, RSX-11 was influential in the development of later ...
-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
In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer.
Since a computer, at base, only ...
for HDOS.
Item references (Heathkit part number) are HOS-1-SL part number 595–2466.
Heath/Zenith also offered the widely used
CP/M
CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/Intel 8085, 85-based microcomputers by Gary Kildall of Digital Research, Dig ...
as an alternative operating system. Although differing in design and internals, CP/M and HDOS are technical comparable and sold for the same price; from 1981 CP/M became the company's preferred operating system.
Commands
The following list of
command
Command may refer to:
Computing
* Command (computing), a statement in a computer language
* command (Unix), a Unix command
* COMMAND.COM, the default operating system shell and command-line interpreter for DOS
* Command key, a modifier key on A ...
s are supported by HDOS.
* BOOT
* BYE
*
CAT
The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have shown that the ...
*
COPY
*
DATE
*
DELETE
* DISMOUNT
* FLAGS
*
HELP
Help may refer to:
Arts, entertainment, and media
Films
* Help (2010 film), ''Help'' (2010 film), a Bollywood horror film
* Help (2021 theatrical film), ''Help'' (2021 theatrical film), a British psychological thriller film
* Help (2021 TV ...
*
MOUNT
Mount is often used as part of the name of specific mountains, e.g. Mount Everest.
Mount or Mounts may also refer to:
Places
* Mount, Cornwall, a village in Warleggan parish, England
* Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, ...
* ONECOPY
*
PIP
*
RENAME
* RUN
* SET
* STAT
* STATUS
*
TYPE
Type may refer to:
Science and technology Computing
* Typing, producing text via a keyboard, typewriter, etc.
* Data type, collection of values used for computations.
* File type
* TYPE (DOS command), a command to display contents of a file.
* ...
*
VER
Versions
*HDOS 1.0 – written in 1978 by J. Gordon Letwin
*HDOS 1.5 – Gregg Chandler
*HDOS 1.6 – Gregg Chandler
*HDOS 2.0 – released in 1980, written by Gregg Chandler, released into the public domain in April 1988
*HDOS 3.0 – released into the public domain in August 1986
*HDOS 3.02 – enhanced version by Richard Musgrave
HeathDOS
See also
*Heathkit
Heathkit is the brand name of kits and other electronic products produced and marketed by the Heath Company. The products over the decades have included electronic test equipment, high fidelity home audio equipment, television receivers, amateu ...
*Zenith Data Systems
Zenith Data Systems Corporation (ZDS) was an American computer systems manufacturing company active from 1979 to 1996. It was originally a division of the Zenith Radio Company (later Zenith Electronics), after they had purchased the Heath Com ...
* List of operating systems
References
External links
HeathDOSMichael A. Pechuria, Comparing Two Microcomputer Operating Systems: CP/M and HDOS. Communications of the ACM, March 1983, vol. 26, no. 3.
A web site dedicated to preserving the Heathkit 8-bit computers, source listing in PDF form
{{Operating system
Free software operating systems
Public-domain software with source code
1978 software
Zenith Data Systems