Multi-user is a term that defines an operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 or application software

Application software

Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...

 that allows concurrent access by multiple user

User (computing)

A user is an agent, either a human agent or software agent, who uses a computer or network service. A user often has a user account and is identified by a username , screen name , nickname , or handle, which is derived from the identical Citizen's Band radio term.Users are...

s of a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

. Time-sharing

Time-sharing

Time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major technological shift in the history of computing.By allowing a large...

 systems are multi-user systems. Most batch processing

Batch processing

Batch processing is execution of a series of programs on a computer without manual intervention.Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters...

 systems for mainframe computer

Mainframe computer

Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s may also be considered "multi-user", to avoid leaving the CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 idle while it waits for I/O

Input/output

In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

 operations to complete. However, the term "multitasking

Computer multitasking

In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...

" is more common in this context.

An example is a Unix server where multiple remote users have access (such as via Secure Shell

Secure Shell

Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...

) to the Unix shell

Unix shell

A Unix shell is a command-line interpreter or shell that provides a traditional user interface for the Unix operating system and for Unix-like systems...

 prompt at the same time. Another example uses multiple X Window

X Window System

The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...

 sessions spread across multiple terminals powered by a single machine - this is an example of the use of thin client

Thin client

A thin client is a computer or a computer program which depends heavily on some other computer to fulfill its traditional computational roles. This stands in contrast to the traditional fat client, a computer designed to take on these roles by itself...

. Similar functions were also available under MP/M

MP/M

MP/M was a 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 using a separate terminal....

, Concurrent DOS, Multiuser DOS

Multiuser DOS

Multiuser DOS is a soft real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.An evolution of the older Concurrent CP/M-86 and Concurrent DOS operating systems, it was originally developed by Digital Research and later further developed by Novell...

 and FlexOS

FlexOS

FlexOS was a modular real-time multi-user multi-tasking operating system designed for computer-integrated manufacturing, laboratory, retail and financial markets...

.

Management systems are implicitly designed to be used by multiple users, typically one system administrator

System administrator

A system administrator, IT systems administrator, systems administrator, or sysadmin is a person employed to maintain and operate a computer system and/or network...

 or more and an end-user 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

Software license agreement

A software license agreement is a contract between the "licensor" and purchaser of the right to use software. The license may define ways under which the copy can be used, in addition to the automatic rights of the buyer including the first sale doctrine and .Many form contracts are only contained...

. Multi-user operating systems such as Unix sometimes have a single user state or runlevel

Runlevel

The term runlevel refers to a mode of operation in one of the computer operating systems that implement Unix System V-style initialization. Conventionally, seven runlevels exist, numbered from zero to six; though up to ten, from zero to nine, may be used. S is sometimes used as a synonym for one...

 available for emergency maintenance.

External links

• Interix in a Multi-User Windows TSE Environment paper about the Unix
  Unix
  Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
  
   multi-user model and MS-Windows NT TSE
  Terminal Services
  Remote Desktop Services in Windows Server 2008 R2, formerly known as Terminal Services in Windows Server 2008 and previous versions, is one of the components of Microsoft Windows that allows a user to access applications and data on a remote computer over a network, using the Remote Desktop...