An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
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 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 Pick operating system is a demand-paged, multiuser, virtual memory, time-sharing computer operating system based around a MultiValue database. Pick is used primarily for business data processing. It is named after one of its developers, Richard A. (Dick) Pick.
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.
Unix System V is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, and 4. System V Release 4 (SVR4) was commercially the most successful version, being the result of an effort, marketed as Unix System Unification, which solicited the collaboration of the major Unix vendors. It was the source of several common commercial Unix features. System V is sometimes abbreviated to SysV.
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.
Xinuos OpenServer, previously SCO UNIX and SCO Open Desktop, is a closed source computer operating system developed by Santa Cruz Operation (SCO), later acquired by SCO Group, and now owned by Xinuos. Early versions of OpenServer were based on UNIX System V, while the later OpenServer 10 is based on FreeBSD 10.
The history of Unix dates back to the mid-1960s. when the Massachusetts Institute of Technology, AT&T 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.
Windows Vista—a major release of the Microsoft Windows operating system—was available in six different product editions: Starter, Home Basic, Home Premium, Business, Enterprise, and Ultimate. On September 5, 2006, Microsoft announced the USD pricing for editions available through retail channels; the operating system was later made available to retail on January 30, 2007. Microsoft also made Windows Vista available for purchase and download from Windows Marketplace; it is the first version of Windows to be distributed through a digital distribution platform. Editions sold at retail were available in both Full and Upgrade versions and later included Service Pack 1 (SP1).
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.
MS-DOS is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and few operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS". MS-DOS was the main operating system for IBM PC compatibles during the 1980s, from which point it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system.
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.
The Altos 586 was a multi-user microcomputer 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 10Base-2 (thin-net) based, with an Ethernet AUI port on the Altos 586.
