preliminary version of the FAQ

preliminary version of the FAQ

[Steve]

                  PLAN 9 (TM) FROM AT&T BELL LABORATORIES FAQ
                                       
   Here is a preliminary version of the FAQ I'm working on.
   
   Much of it was taken (with permission) from Dennis Ritchie's Plan 9
   Q&A press release. If you've already seen that, you can skip straight
   to the How can I help? section.
   
   A hypertext version of this FAQ is available on the Plan 9 web page,
   URL http://www.ecf.toronto.edu/plan9/
   
   Please forward any comments or suggestions on this FAQ to 
    steve@ecf.toronto.edu.
    
   
   
  INTRODUCTION:
     * What is Plan 9?
     * What is its relation to other operating systems?
     * What are its key ideas?
     * What are the advantages to this approach?
       
  HARDWARE AND SOFTWARE:
     * What platforms does it run on?
     * What about applications and tools?
     * What about application portability?
     * What resources does it need?
     * What GUIs does it support?
     * What character set does it use?
     * What about security and user authentication?
     * How does it communicate with other systems?
       
  GENERAL INFORMATION
     * Who is using Plan 9?
     * Where did the name come from?
     * What are the plans for Plan 9?
     * How can I help?
     * How can I get more detailed technical information?
       
  INTRODUCTION:
  
   
   
  SUBJECT: WHAT IS PLAN 9?
  
   Plan 9 is a new computer operating system and associated utilities.
   It has been built over the past several years by the Computing Science
   Research Center of AT&T 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, Datakit, 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 ITS 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. 
   
  SUBJECT: WHAT ARE ITS KEY IDEAS?
  
   Plan 9 exploits, as far as possible, three basic technical ideas:
   first, all the system objects present themselves as named files that
   are manipulated by read/write operations; second, all these files may
   exist either locally or remotely, and respond to a standard protocol;
   third, the file system name space the set of objects visible to a
   program is dynamically and individually adjustable for each of the
   programs running on a particular machine. The first two of these ideas
   were foreshadowed in Unix and to a lesser extent in other systems,
   while the third is new: it allows a new engineering solution to the
   problems of distributed computing and graphics. Plan 9's approach
   means that application programs don't need to know where they are
   running; where, and on what kind of machine, to run a Plan 9 program
   is an economic decision that doesn't affect the construction of the
   application itself.
   
   
   
  SUBJECT: WHAT ARE THE ADVANTAGES TO THIS APPROACH?
  
   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 (called 8 1/2) 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. .As Another example is the approach
   to networks. In Plan 9, each network presents itself as a set of files
   for connection creation, I/O, and control. A common semantic core for
   the operations is agreed upon, together with a general server for
   translating human-readable addresses to network-specific ones. As a
   result, applications don't care which kind of network (TCP/IP, ISDN,
   modem, Datakit) they are using. In fact, applications don't even know
   whether the network they are using is physically attached to the
   machine the application is running on: the network interface files can
   be imported from another machine.
   
  HARDWARE AND SOFTWARE:
  
   
   
  SUBJECT: WHAT PLATFORMS DOES IT RUN ON?
  
   The Plan 9 kernel and applications are highly portable. Plan 9 runs
   on four major machine architectures: Intel 386/486/Pentium, MIPS,
   SPARC, and Motorola 68020. Data structures and protocols are designed
   for distributed computing on machines of diverse design. Except for
   necessarily machine-dependent parts of the kernel, the compilers, and
   a few libraries, there is a single source representation for
   everything. 
   
  SUBJECT: WHAT ABOUT APPLICATIONS AND TOOLS?
  
   Plan 9 comes with its own compilers for C and other languages,
   together with all the commands and program-development tools
   originally pioneered in the Unix environment. It also provides newly
   designed software. Alef is a new language that provides threads,
   inter-process and inter-machine communication through typed channels,
   and abstract data types. Acid is a programmable debugger that
   understands multiple-process programs, and the programs it is
   debugging may be running on a hardware plaform different from its own.
   Acme is a new user interface in which any word on the screen can be
   interpreted as a command by clicking on it, and any string can specify
   a file to be displayed. 
   
  SUBJECT: WHAT ABOUT APPLICATION PORTABILITY?
  
   Plan 9 comes with a library that makes it easy to import
   POSIX-conforming applications. There is also a library that emulates
   the Berkeley socket interface. 
   
  SUBJECT: WHAT RESOURCES DOES IT NEED?
  
   As might be expected, the answer depends on what you want to do. The
   kernel, the window system, and the basic applications will run
   comfortably on a laptop PC with 4MB of memory. A single, self-booting
   demo diskette will hold the kernel, window system, editor, and basic
   Ethernet/Internet interface. A 4-diskette set will hold a system
   sufficient for simple program development (compiler, loader, debugger,
   more utilities).
   
   On the other hand, the system can grow. The installation at AT&T Bell
   Laboratories includes multiprocessor SGI Power Series and Challenge
   machines as CPU servers, and a 350GB Sony WORM disk jukebox for the
   file server. 
   
  SUBJECT: WHAT GUIS DOES IT SUPPORT?
  
   A: The standard interface doesn't use icons; Plan 9 people tend to be
   text-oriented. But the window system, the editor, and the general feel
   are very mousy, very point-and-click: Plan 9 windows are much more
   than a bunch of glass TTYs. The system supports the graphics
   primitives and libraries of basic software for building GUIs, and if
   need arises, the X window system has been ported to Plan 9. 
   
  SUBJECT: WHAT CHARACTER SET DOES IT USE?
  
   The character set is Unicode, the 16-bit set unified with the ISO
   10646 standard for representing languages used throughout the world.
   The system and its utilities support Unicode using a byte-stream
   representation (called UTF-8) that is compatible with ASCII. On Plan
   9, one may .I grep for Cyrillic strings in a file with a Japanese name
   and see the results appear correctly on the terminal. 
   
  SUBJECT: WHAT ABOUT SECURITY AND USER AUTHENTICATION?
  
   Plan 9's authentication design is akin to that of MIT's Kerberos.
   Passwords are never sent over networks; instead encrypted tickets are
   obtained from an authentication server. It doesn't have the concept of
   set UID programs. The file server doesn't run user programs, and
   except at its own console, it doesn't allow access to protected files
   except by authenticated owners. The concept of a special root user is
   gone. 
   
  SUBJECT: HOW DOES IT COMMUNICATE WITH OTHER SYSTEMS?
  
   The distribution includes a server that runs on Unix-compatible
   systems and understands the native Plan 9 remote file protocol, so
   that file systems of Unix machines may be imported into Plan 9. It
   also includes an NFS-compatible server that runs on Plan 9, so that
   Plan 9 file systems may be accessed from other systems that support
   NFS. It includes the full suite of Internet protocols.
   
  GENERAL INFORMATION
  
   
   
  SUBJECT: WHO IS USING PLAN 9?
  
   At the moment, mostly our own group. There are a few hundred
   educational licensees within universities, and there is exploratory
   use in commercial companies, both within AT&T and outside. Most
   visibly, the Netlib service that supplies mathematical and other
   software and documents to the public via FTP, mail, and WWW uses a
   Plan 9 server. This service includes the AT&T 800-number directory by
   which WWW users can find the toll-free numbers of AT&T 800-number
   advertisers. 
   
  SUBJECT: WHERE DID THE NAME COME FROM?
  
   It was chosen in the Bell Labs tradition of selecting names that make
   marketeers wince. They also wished to pay homage to the famous film,
   `Plan 9 From Outer Space.' 
   
  SUBJECT: WHAT ARE THE PLANS FOR PLAN 9?
  
   Plan 9 was developed within the research organization of AT&T Bell
   Laboratories as an exercise in understanding the principles and
   mechanisms useful in designing operating systems, and not as a product
   as such. In this way it is analogous to the Unix efforts of the past.
   Nevertheless, to succeed, it must be used, both within our company and
   outside. We believe that making it more generally available under
   reasonable terms will enhance its impact, and have been working with
   the AT&T Software Solutions group to find the best ways of doing this.
   Although not all the details have been determined, the intent is to
   make available a general distribution of the technology for
   non-commercial purposes, and also to be ready to license it for
   commercial purposes on terms to be negotiated. Just as in the early
   stages of deployment of Unix, these arrangements will be `as-is,' with
   no support promised.
   
   Current plans call for this distribution to consist of a CD-ROM
   containing the entire source and binary for all platforms, a
   two-volume manual set, and four diskettes. The diskettes contain a
   binary-only version of the system that can be installed on a PC to
   demonstrate the window system, many of the applications including
   Internet communications, and the Intel-architecture C and Alef
   compilers. 
   
  SUBJECT: HOW CAN I HELP?
  
   The best way to help is to write something that other people in the
   Plan 9 user community could use, or to port the system to new
   platforms. Several people have already made their applications
   available, such as an http server, fileserver port to the PC, etc. The
   current list of user-community projects includes:

	Dave Letterman is re-writing the fortune program in Alef.
	George Bush is porting the system to the CM-5.
	Steven Spielberg is porting DOOM to Plan 9.

	etc. you get the idea ...

	If anyone would like their projects listed here, let me know.
	This could help prevent duplication of effort,
	and increase involvment from the 'net community.

   Other items on the todo list include getting the moderated newsgroup
   comp.os.plan9 created, etc. 
   
  SUBJECT: HOW CAN I GET MORE DETAILED TECHNICAL INFORMATION?
  
   The Internet site plan9.att.com stores a collection of papers about
   the system in the plan9 directory; they are available for anonymous
   FTP. Currently they are somewhat old; within a month a newer
   collection, including the current manual, will appear. Also,
   volunteers at the University of Toronto maintain a World Wide Web
   page, at URL http://www.ecf.toronto.edu/plan9/.