<P> An example is a Unix server where multiple remote users have access (such as via a serial port or Secure Shell) to the Unix shell prompt at the same time . Another example uses multiple X Window sessions spread across multiple terminals powered by a single machine - this is an example of the use of thin client . Similar functions were also available under MP / M, Concurrent DOS, Multiuser DOS and FlexOS . </P> <P> Some multi-user operating systems such as Windows versions from the Windows NT family support simultaneous access by multiple users (for example, via Remote Desktop Connection) 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 . </P> <P> Management systems are implicitly designed to be used by multiple users, typically one system administrator or more and an end - user community . </P> <P> 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 . Multi-user operating systems such as Unix sometimes have a single user mode or runlevel available for emergency maintenance . </P>

Advantage and disadvantage of multi user operating system