24-02-2009, 12:00 AM
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. 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. Plan 9 is designed around this basic principle that all resources appear as files in a hierarchical file system, which is unique to each process. As for the design of any operating system various things such as the design of the file and directory system implementation and the various interfaces are important. Plan 9 has all these well-designed features. All these help to provide a strong base for the operating system that could be well suited in a distributed and networked environment. The different features of Plan 9 operating system are: The dump file system makes a daily snapshot of the file store available to the users. Unicode character set supported throughout the system. Advanced kernel synchronization facilities for parallel processing. Security- there is no super-user or root user and the passwords are never sent over the network.