Multi-user software is
computer software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
that allows access by multiple
users of a
computer.
Time-sharing
In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1
Its emergence ...
systems are multi-user systems. Most
batch processing
Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...
systems for
mainframe computer
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...
s may also be considered "multi-user", to avoid leaving the
CPU
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...
idle while it waits for
I/O operations to complete. However, the term "
multitasking" is more common in this context.

An example is a
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
or
Unix-like
A Unix-like (sometimes referred to as UN*X or *nix) 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-li ...
system where multiple remote users have access (such as via a
serial port
In computing, a serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in paralle ...
or
Secure Shell
The Secure Shell Protocol (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution.
SSH applications are based ...
) to the
Unix shell
A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system t ...
prompt at the same time. Another example uses multiple
X Window
The X Window System (X11, or simply X) is a windowing system for bitmap displays, common on Unix-like operating systems.
X provides the basic framework for a GUI environment: drawing and moving windows on the display device and interacting wit ...
sessions spread across multiple terminals powered by a single machine - this is an example of the use of
thin client
In computer networking, a thin client is a simple (low-performance) computer that has been optimized for establishing a remote connection with a server-based computing environment. They are sometimes known as ''network computers'', or in ...
. Similar functions were also available in a variety of non-Unix-like operating systems, such as
Multics
Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
,
VM/CMS
VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers.
The following versions ...
,
OpenVMS
OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Ope ...
,
MP/M
MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each u ...
,
Concurrent CP/M
MP/M (Multi-Programming Monitor Control Program) is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each u ...
,
Concurrent DOS
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.
An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed b ...
,
FlexOS
FlexOS is a discontinued modular real-time multiuser multitasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. Developed by Digital Research's Flexible Automation Business U ...
,
Multiuser DOS
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.
An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...
,
REAL/32
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.
An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by ...
,
OASIS
In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment[THEOS
THEOS, which translates from Greek as "God", is an operating system which started out as OASIS, a microcomputer operating system for small computers that use the Z80 processor. When the operating system was launched for the IBM Personal Comp ...]
,
PC-MOS
PC-MOS/386 is a multi-user, multitasking computer operating system produced by The Software Link (TSL), announced at COMDEX in November 1986 for February 1987 release. PC-MOS/386, a successor to PC-MOS, can run many MS-DOS programs on the host ...
,
TSX-32
TSX-32 has been a general purpose 32-bit multi-user multitasking operating system for x86 architecture platform, with a command line user interface. It is compatible with some 16-bit DOS applications and supports file systems FAT16 and FAT32. It ...
and
VM/386
VM/386 is a multitasking operating system or 'control program' that took early advantage of the capabilities of Intel's 386 processor. By utilizing Virtual 8086 mode, users were able to run their existing text-based and graphical DOS software i ...
.
Some multi-user operating systems such as
Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ...
versions from the
Windows NT
Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system.
The first version of Wi ...
family support simultaneous access by multiple users (for example, via
Remote Desktop Connection
Remote Desktop Services (RDS), known as Terminal Services in Windows Server 2008 and earlier, is one of the components of Microsoft Windows that allow a user to initiate and control an interactive session on a remote computer or virtual machin ...
) as well as the ability for a user to disconnect from a local session while leaving processes running (doing work on their behalf) while another user logs into and uses the system. The operating system provides isolation of each user's processes from other users, while enabling them to execute concurrently.
Management systems
A management system is a set of policies, processes and procedures used by an organization to ensure that it can fulfill the tasks required to achieve its objectives. These objectives cover many aspects of the organization's operations (including ...
are implicitly designed to be used by multiple users, typically one
system administrator
A system administrator, or sysadmin, or admin is a person who is responsible for the upkeep, configuration, and reliable operation of computer systems, especially multi-user computers, such as servers. The system administrator seeks to en ...
or more and an
end-user
In product development, an end user (sometimes end-user) is a person who ultimately uses or is intended to ultimately use a product. The end user stands in contrast to users who support or maintain the product, such as sysops, system administrato ...
community.
The complementary term, single-user, is most commonly used when talking about an operating system being usable only by one person at a time, or in reference to a single-user
software license agreement
An end-user license agreement or EULA () is a legal contract between a software supplier and a customer or end-user, generally made available to the customer via a retailer acting as an intermediary. A EULA specifies in detail the rights and restr ...
. Multi-user operating systems such as Unix sometimes have a
single user mode
Single-user mode is a mode in which a multiuser computer operating system boots into a single superuser. It is mainly used for maintenance of multi-user environments such as network servers. Some tasks may require exclusive access to shared resour ...
or
runlevel
A runlevel is a mode of operation in the computer operating systems that implements Unix System V-style initialization. Conventionally, seven runlevels exist, numbered from zero to six. ''S'' is sometimes used as a synonym for one of the levels. ...
available for emergency maintenance. Examples of single-user operating systems include
MS-DOS
MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few oper ...
,
OS/2
OS/2 (Operating System/2) is a series of computer operating systems, initially created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 ...
and
Classic Mac OS
Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Macintosh family of personal computers by Apple Computer from 1984 to 2001, starting with System 1 and ending with Mac OS 9. Th ...
.
See also
*
AT Multiuser System
The IBM Personal Computer/AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel ...
*
Multiseat
*
Multiuser DOS Federation (MDOS)
References
External links
Interix in a Multi-User Windows TSE Environmentpaper about the
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...
multi-user model and
MS-Windows
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...
NT
TSE
Operating system technology
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