FACTOID # 15: A mere 0.8% of West Virginians were born in a foreign country.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Named pipe

In computing, a named pipe (also FIFO for its behaviour) is an extension to the traditional pipe concept on Unix and Unix-like systems, and is one of the methods of inter-process communication. The concept is also found in Microsoft Windows, although the semantics differ substantially. A traditional pipe is "unnamed" because it exists anonymously and persists only for as long as the process is running. A named pipe is system-persistent and exists beyond the life of the process and must be "unlinked" or deleted once it is no longer being used. Processes generally attach to the named pipe (usually a file) to perform IPC (inter-process communication). Memory (Random Access Memory) Look up computing in Wiktionary, the free dictionary. ... FIFO is an acronym for First In, First Out. ... A pipeline of three programs run on a text terminal In Unix-like computer operating systems, a pipeline is the original software pipeline: a set of processes chained by their standard streams, so that the output of each process (stdout) feeds directly as input (stdin) of the next one. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ... Microsoft Windows is the name of several families of proprietary software operating systems by Microsoft. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ...

Contents

Named pipes in Unix

Instead of a conventional, unnamed, shell pipeline, a named pipeline is explicitly created using mknod or mkfifo, and two separate processes can access the pipeline by name.


For example, one can create a pipe and set up gzip to compress things piped to it

 mkfifo pipe gzip -9 -c < pipe > out 

in a separate process shell, independently, one could perform

 cat file > pipe 

which would then perform the compression by gzip.


Named pipes in Windows

In Windows, the design of named pipes is biased towards client-server communication, and they work much like sockets, other than the usual read and write operations. Windows named pipes also support an explicit "passive" mode for server applications (compare: Unix domain sockets). Windows 95 supports named pipe clients, Windows NT based systems can also be servers. Client/Server is a network application architecture which separates the client (usually the graphical user interface) from the server. ... It has been suggested that Ip socket be merged into this article or section. ... A Unix domain socket or IPC socket (inter-procedure call socket) is a virtual socket, similar to an internet socket that is used in POSIX operating systems for inter-process communication. ... Windows 95 is a consumer-oriented graphical user interface-based operating system. ... Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ...


The named pipe can be accessed much like a file. Win32 SDK functions such as CreateFile, ReadFile, WriteFile and CloseHandle can be used to open, read from, write to, and close a pipe. C library functions such as fopen, fread, fwrite, and fclose can also be used, unlike Windows Sockets, which does not implement network use of standard file i/o operations. There is no command line interface like Unix. The title given to this article is incorrect due to technical limitations. ... In computing, Winsock (also Windows Sockets) is a specification that defines how Windows network software should access network services, especially TCP/IP. Winsock intends to provide a single API to which both application developers and network software vendors should conform. ...


Named pipes aren't permanent and can't be created as special files on any writable filesystem, unlike in Unix, but are volatile names (freed after the last reference to them is closed) allocated in the root directory of the named pipe filesystem (NPFS), mounted under the special path .pipe (that is, a pipe named "foo" would have a full path name of .pipefoo). Anonymous pipes used in pipelining are actually named pipes with a random name. Foo is a metasyntactic variable used heavily in computer science to represent concepts abstractly and can be used to represent any part of a complicated system or idea including the data, variables, functions, and commands just to name a few. ...


They are very rarely seen by users, but there are notable exceptions. The VMware Workstation PC hardware virtualization tool, for instance, can expose emulated serial ports to the host system as named pipes, and the kd kernel mode debugger from Microsoft supports named pipes as a transport for debugging sessions (in fact, VMware and kd can be coupled together - since kd normally requires a serial connection to the target computer - letting driver developers do their development and testing on a single computer). Both programs require the user to enter names in the .pipename form. VMware Inc. ... The Altair 8800 was among the first microcomputers to be affordable by an individual, although it initially lacked peripherals and memory. ... A male DE-9 connector used for a serial port on a PC style computer. ... KD abbreviates Kraft Dinner. ... A debugger is a computer program that is used to test and debug other programs. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... Windows XP loading drivers during a Safe Mode bootup A device driver, or a software driver is a specific type of computer software, typically developed to allow interaction with hardware devices. ... A software developer is a person who is concerned with one or more facets of the software development process, a somewhat broader scope of computer programming or a specialty of project managing. ... A BlueGene supercomputer cabinet. ...


Windows NT Named Pipes can inherit a security context.


Summary of named pipes on Microsoft Windows:

  • Intermachine and Intramachine IPC
  • Full-Duplex
  • Byte-oriented and Message-oriented (choosable)
  • Reliable
  • Blocking or Nonblocking read and write (choosable)
  • Standard device IO handles (FileRead, FileWrite)
  • Namespace used to create handles
  • Inefficient WAN traffic (explicit data transfer request, unlike e.g. TCP/IP sliding window etc.)
  • Peekable reads (read without removing from pipe's input buffer)

Duplex is the having of two principal elements or parts. ... A communication is byte oriented or character oriented when the transmitted information is grouped into bytes. ... In general, a namespace is an abstract container, which is or could be filled by names, or technical terms, or words, and these represent (stand for) real-world things. ...

Named pipes in Windows networking

Named Pipes is also a networking protocol in the Server Message Block (SMB) suite, based on the use of a special Inter-process communication (IPC) share. SMB's IPC can seamlessly and transparently pass the authentication context of the user across to Named Pipes. Windows NT's entire NT Domain protocol suite of services are implemented as DCE/RPC services over Named Pipes, as are the Exchange 5.5 Administrative applications. Server Message Block (SMB) is an application-level network protocol mainly applied to shared access to files, printers, serial ports, and miscellaneous communications between nodes on a network. ... Inter-Process Communication (IPC) is a set of techniques for the exchange of data between two or more threads in one or more processes. ... DCE/RPC stands for Distributed Computing Environment / Remote Procedure Calls. Note that DCE/RPC should not be confused with just DCE which is a suite of DCE/RPC services that provide, amongst other things, CDS and DFS. DCE/RPC was commissioned by the Open Software Foundation in a Request for...


Windows NT Named Pipe authentication inheritance is sufficiently opaque and seamless to the user and developer perspective as to be nearly invisible, and consequently it is frequently misunderstood.


See also

In computer science, an anonymous pipe is a simplex FIFO communication channel that may be used for one-way interprocess communication. ... // Unix file types For normal files in the file system, Unix does not impose or provide any internal file structure. ...

External links


  Results from FactBites:
 
Introduction to Interprocess Communication Using Named Pipes (2005 words)
Named pipes are identified by their access point, which is basically in a file kept on the file system.
Because named pipes have the pathname of a file associated with them, it is possible for unrelated processes to communicate with each other; in other words, two unrelated processes can open the file associated with the named pipe and begin communication.
A named pipe supports blocked read and write operations by default: if a process opens the file for reading, it is blocked until another process opens the file for writing, and vice versa.
Named pipe - Wikipedia, the free encyclopedia (514 words)
In computing, a named pipe (also FIFO for its behaviour) is an extension to the traditional pipe concept on Unix and Unix-like systems, and is one of the methods of inter-process communication.
A named pipe is system-persistent and exists beyond the life of the process and must be "unlinked" or deleted once it is no longer being used.
Windows NT Named Pipe authentication inheritance is sufficiently opaque and seamless to the user and developer perspective as to be nearly invisible, and consequently it is frequently misunderstood.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m