Multi-user software is computer software that allows access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term "multitasking" is more common in this context.
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined.
Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and eventually replaced it with SCO UNIX.
Digital Research, Inc. was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and GEM. It was the first large software company in the microcomputer world. Digital Research was originally based in Pacific Grove, California, later in Monterey, California.
This article presents a timeline of events in the history of computer operating systems from 1951 to the current day. For a narrative explaining the overall developments, see the History of operating systems.
Coherent is a clone of the Unix operating system for IBM PC compatibles and other microcomputers, developed and sold by the now-defunct Mark Williams Company (MWC). Historically, the operating system was a proprietary product, but it became open source in 2015, released under the BSD-3-Clause license.
The Zilog Z8000 is a 16-bit microprocessor designed by Zilog in early 1979.
The Santa Cruz Operation, Inc. was an American software company, based in Santa Cruz, California, that was best known for selling three Unix operating system variants for Intel x86 processors: Xenix, SCO UNIX, and UnixWare.
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.
The Acorn Business Computer (ABC) was a series of microcomputers announced at the end of 1983 by the British company Acorn Computers. The series of eight computers was aimed at the business, research and further education markets. Demonstrated at the Personal Computer World Show in September 1984, having been under development for "about a year" and having been undergoing field trials from May 1984, the range "understandably attracted a great deal of attention" and was favourably received by some commentators. The official launch of the range was scheduled for January 1985.
The history of Unix dates back to the mid-1960s, when the Massachusetts Institute of Technology, Bell Labs, and General Electric were jointly developing an experimental time-sharing operating system called Multics for the GE-645 mainframe. Multics introduced many innovations, but also had many problems. Bell Labs, frustrated by the size and complexity of Multics but not its aims, slowly pulled out of the project. Their last researchers to leave Multics – among them Ken Thompson, Dennis Ritchie, Doug McIlroy, and Joe Ossanna – decided to redo the work, but on a much smaller scale.
A BBC Micro expansion unit, for the BBC Micro is one of a number of peripherals in a box with the same profile and styling as the main computer.
The TRS-80 Model II is a computer system launched by Tandy in October 1979, and targeted at the small-business market. It is not an upgrade of the original TRS-80 Model I, but a new system.
DOS is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of IBM PC DOS and a rebranded version, Microsoft's MS-DOS, both of which were introduced in 1981. Later compatible systems from other manufacturers include DR-DOS (1988), ROM-DOS (1989), PTS-DOS (1993), and FreeDOS (1998). MS-DOS dominated the IBM PC compatible market between 1981 and 1995.
A Unix-like operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell. Although there are general philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like.
Altos Computer Systems was founded in 1977 by David G. Jackson and Roger William Vass Sr. It focused on small multi-user computers, starting with multi-user derivatives of CP/M, and later including Unix and Xenix-based machines. In its 1982 initial public offering on NASDAQ, the company raised $59M. Thereafter the company's stock was traded under the symbol ALTO.
Onyx Systems, Inc. was a computer hardware and software company founded in Cupertino, California in 1979 by Bob Marsh and Kip Myers, former managers in Zilog's systems group. It was one of the earliest vendors of microprocessor-based Unix systems.
The Altos 586 is a multi-user microcomputer that was intended for the business market. It was introduced by Altos Computer Systems in 1983. A configuration with 512 KB of RAM, an Intel 8086 processor, Microsoft Xenix, and 10 MB hard drive cost about US$8,000. 3Com offered this Altos 586 product as a file server for their IBM PC networking solution in spring 1983. The network was 10BASE2 (thin-net) based, with an Ethernet AUI port on the Altos 586.
