Published on Feb 12, 2016


An operating system is a collection of programs and procedures that help the user to work with the computer efficiently. To enable an efficient and productive use with the system of any sort, the prorating system used must be so designed such that it gives all the necessary facilities to work for the users.

Description of Plan 9 Operating System

Many operating systems have been designed over the years for different classes of users. But most of them were designed for single user workstations. By the mid 1980's, the trend in computing was away from large centralized time-shared computers towards networks of smaller, personal machines, typically UNIX `workstations'. People had grown weary of overloaded, bureaucratic timesharing machines and were eager to move to small, self-maintained systems, even if that meant a net loss in computing power. As microcomputers became faster, even that loss was recovered, and this style of computing remains popular today.

In the rush to personal workstations, though, some of their weaknesses were overlooked. First, the operating system they run, UNIX, is itself an old timesharing system and has had trouble adapting to ideas born after it. Graphics and networking were added to UNIX well into its lifetime and remain poorly integrated and difficult to administer.

Plan 9 began in the late 1980's as an attempt to have it both ways: to build a system that was centrally administered and cost-effective using cheap modern microcomputers as its computing elements. The idea was to build a time-sharing system out of workstations, but in a novel way. Different computers would handle different tasks: small, cheap machines in people's offices would serve as terminals providing access to large, central, shared resources such as computing servers and file servers.

For the central machines, the coming wave of shared-memory multiprocessors seemed obvious candidates.The problems with UNIX were too deep to fix, but some of its ideas could be brought along. The best was its use of the file system to coordinate naming of and access to resources, even those, such as devices, not traditionally treated as files. Plan 9 is designed around this basic principle that all resources appear as files in a hierarchial file system, which is unique to each process.