18-09-2012, 04:53 PM
PLAN9
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INTRODUCTION
Plan 9 from Bell Labs is a free software distributed operating system. It was developed primarily for research purposes as the successor to Unix by the Computing Sciences Research Center at Bell Labs between the mid-1980s and 2002. Plan 9 continues to be used and developed by operating system researchers and hobbyists.
Plan 9 has novel features such as the 9P protocol for accessing local and remote resources as files, union mounts, an improved proc file system, and native unicode support throughout the system. In Plan 9, all system interfaces, including those required for networking and the user interface, are represented through the file system rather than specialized interfaces.
The name Plan 9 from Bell Labs is a reference to the Ed Wood 1959 cult science fiction Z-movie Plan 9 from Outer Space.[3] Also, Glenda, the Plan 9 Bunny, is presumably a reference to Wood's film Glen or Glenda.
What is Plan 9?
Plan 9 is a new computer operating system and associated utilities. It was built by the Computing Science Research Center of Lucent Technologies Bell Laboratories, the same group that developed Unix, C, and C++.
Plan 9 is a distributed system. In the most general configuration, it uses three kinds of components: terminals that sit on users' desks, file servers that store permanent data, and other servers that provide faster CPUs, user authentication, and network gateways. These components are connected by various kinds of networks, including Ethernet, specially-built fiber networks, ordinary modem connections, and ISDN. In typical use, users interact with applications that run either on their terminals or on CPU servers, and the applications get their data from the file servers. The design, however, is highly configurable; it escapes from specific models of networked workstations and central machine service.
Subject: What is in the latest Plan9 release?
The press release for the third edition of Plan9 is at http://www.bell-labsnews/2000/june/7/2.html
Among the changes in this release of Plan 9 are a revised kernel, which now has the means to resolve ambiguous file names; an improved graphics environment; an updated command set; and expanded libraries. The system's creators also have installed "plumbing," a new mechanism for passing messages between interactive programs, as part of the user interface.
The new release is available for free download under an open source agreement. This is a significant step over previous releases.
If you'd like to browse the distribution packages before actually installing
Relation to other operating systems?
Plan 9 is itself an operating system; it doesn't run as an application under another system. It was written from the ground up and doesn't include other people's code. Although the OS's interface to applications is strongly influenced by the approach of Unix, it's not a replacement for Unix; it is a new design.
Advantages
Plan 9's approach improves generality and modularity of application design by encouraging servers that make any kind of information appear to users and to applications just like collections of ordinary files. Here are a few examples.
The Plan 9 window system is small and clean in part because its design is centered on providing a virtual keyboard, mouse, and screen to each of the applications running under it, while using the real keyboard, mouse, and screen supplied by the operating system. That is - besides creating, deleting, and arranging the windows themselves - its job is be a server for certain resources used by its clients. As a side benefit, this approach means that the window system can run recursively in one of its windows, or even on another machine.
Plan 9 users do Internet FTP by starting a local program that makes all the files on any FTP server (anywhere on the Internet) appear to be local files. Plan 9 PC users with a DOS/Windows partition on their disk can use the files stored there. ISO 9660 CD-ROMs and tar and cpio tapes all behave as if they were native file systems. The complete I/O behavior and performance of any application can be monitored by running it under a server that sees all its interactions. The debugger can examine a program on another machine even if it is running on a different hardware architecture.
History
Plan 9 was a Bell Labs internal project from its start during the mid 1980s. It replaced Unix as Bell Labs's primary platform for operating systems research. It explored several changes to the original Unix model that facilitate the use and programming of the system, notably in distributed multi-user environments. In 1992, Bell Labs provided the first public release to universities, and three years later a commercial second release version became available to the general public. In the late 1990s, Lucent Technologies, having inherited Bell Labs, dropped commercial support for the project. In 2000, a non-commercial third release was distributed under an open source license. A fourth release under a new free software license occurred in 2002.
A user and development community, including current and former Bell Labs members and Massachusetts Institute of Technology personnel, continues to produce minor daily releases in form of ISO images. Bell Labs still hosts the development.The development source tree is accessible over the 9P and HTTP protocols and is used to update existing installations.[6] In addition to the official components of the OS included in the ISOs, Bell Labs also hosts a repository of externally developed applications and tools.
9P protocol
To reduce the number of custom APIs and system calls, Plan 9 makes heavy use of the 9P protocol. 9P is a generic medium-agnostic byte-oriented protocol that provides for messages delivered between a server and a client.[13] The protocol is used to refer to and communicate with processes, programs, and data, including both the user interface and the network.[14] With the release of the 4th edition, it was modified and renamed 9P2000.[4]
Unlike most other operating systems, Plan 9 does not provide special application programming interfaces (such as Berkeley sockets, X resources or ioctl system calls) to access devices.[13] Instead, Plan 9 device drivers implement their control interface as a file system, so that the hardware can be accessed by the ordinary file input/output operations read and write. Consequently, sharing the device across the network can be accomplished by mounting the corresponding directory tree to the target machine
Why use Plan 9?
Plan 9 offers only a few advantages to single workstation users running in isolation. Its advantages grow rapidly as the number of networked Plan 9 workstations increase. If you are developing a large distributed computing application, using Plan 9 makes a lot of sense. If, for instance, you are performing large-scale scientific computing that needs to run across a large number of computers you are faced with a variety of difficult challenges. A particular problem in large node computing is that the failure of a single node can bring your whole computing cluster to a halt. This problem is increasingly likely as the number of processors increase. Consider that a computer node with a mean time between failure of 10,000 hours (or about 1.15 years), when used in a cluster of 10,000 nodes will fail on average of once an hour. In other words, your large, expensive super-computer will crash once an hour. Plan 9 provides the basis for writing processes that can be mirrored or replicated in more efficient ways and can become fault tolerant. Without increased fault tolerance, large scale computing just doesn't scale well
How is Plan 9 Better?
It was designed as a faster, cleaner, more-lightweight multi-processor operating system with better security in all aspects of operation. It uses lightweight processes that were designed for fine-grained resource control across forks. The thread library uses no kernel support and this makes it very quick. Plan 9's system libraries were built with multi-processing and Unicode character support from day 1. In fact, UTF-8 was invented for Plan 9. These libraries, in conjunction with a new generation of high performance Plan 9 compilers, make application development very fast and very reliable.
The Plan 9 security model is quite different from other mainstream operating systems. It has no root, administrator, or super user. Instead, local host owners have privileges over their own machines and can join various network groups that extend more privileges and access to resources such as printers or the CPU. Authentication is done using the Secstore client application. The Secstore server exchanges encrypted passwords or hardware passkeys, and stores sensitive information in memory.