FACTOID # 10: The total number of state executions in 2005 was 60: 19 in Texas and 41 elsewhere. The racial split was 19 Black and 41 White.
 
 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 > Virtual file system

A virtual file system (VFS) or virtual filesystem switch is an abstraction layer on top of a more concrete file system. The purpose of a VFS is to allow for client applications to access different types of concrete file systems in a uniform way. A VFS can for example be used to access local and network storage devices transparently without the client application noticing the difference. Or it can be used to bridge the differences in Windows, Mac OS and Unix filesystems, so that applications could access files on local file systems of those types without having to know what type of file system they're accessing. In computing, a file system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ... Microsoft Windows is the name of several families of operating systems by Microsoft. ... This article or section does not cite its references or sources. ... 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. ...


A VFS specifies an interface (or a contract) between the kernel and a concrete file system. Therefore, it is easy to add new file systems to the kernel simply by fulfilling the contract. The terms of the contract might change incompatibly from release to release, which would require that concrete file systems be recompiled, and possibly modified before recompilation, to allow it to work with a new release of the operating system; or the supplier of the operating system might make only backward-compatible changes to the contract, so that a concrete file system built for a given release of the operating system would work with future versions of the operating system. An interface defines the communication boundary between separate computer components. ... A kernel connects the software and hardware of a computer. ...

Contents

Implementations

One of the first virtual file system mechanisms in Unix-like systems was the one introduced by Sun Microsystems in SunOS 2.0 in 1985. It allowed UNIX system calls to access local UFS file systems and remote NFS file systems transparently. For this reason, UNIX vendors who licensed the NFS code from Sun often copied the design of Sun's VFS. Other file systems could be plugged into it as well: there was an implementation of the MS-DOS FAT file system developed at Sun that plugged into the SunOS VFS, although it wasn't shipped as a product until SunOS 4.1. The SunOS implementation was the basis of the VFS mechanism in System V Release 4. 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. ... Sun Microsystems, Inc. ... SunOS was the version of the UNIX operating system developed by Sun Microsystems for their workstations and server systems until the early 1990s. ... The UNIX file system (UFS) is a file system used by many Unix and Unix-like operating systems. ... Need for Speed (NFS) is a series of video games by EA Games released on platforms including personal computers, Nintendo, Xbox and PlayStation 2 consoles. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... File Allocation Table (FAT) is a partially patented file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ... System V, previously known as AT&T System V, was one of the versions of the Unix computer operating system. ...


John Heidemann developed a stacking VFS under SunOS 4.0 for the experimental Ficus file system. This design provided for code reuse among file system types with differing but similar semantics (e.g., an encrypting file system could reuse all of the naming and storage-management code of a non-encrypting file system). Heidemann adapted this work for use in 4.4BSD as a part of his thesis research; descendants of this code underpin the file system implementations in modern BSD derivatives including Mac OS X. A computer programming paradigm in which one writes small bits of code to accomplish a common task. ... BSD redirects here; for other uses see BSD (disambiguation). ... Look up thesis in Wiktionary, the free dictionary. ... Mac OS X (official IPA pronunciation: ) is a line of proprietary, graphical operating systems developed, marketed, and sold by Apple Computer, the latest of which is pre-loaded on all currently shipping Macintosh computers. ...


Other virtual file system mechanisms in UNIX-like systems include the File System Switch in System V Release 3, the Generic File System in Ultrix, and the VFS in Linux. In OS/2 and Microsoft Windows, the virtual file system mechanism is called the Installable File System. In Microsoft Windows, virtual filesystems can also be implemented through Shell namespace extensions. Unix history tree Unix System V commonly abbreviated SysV and rarely called System 5, was one of the versions of the Unix operating system. ... Ultrix (officially all-caps ULTRIX) was the brand name of Digital Equipment Corporations (DEC) native Unix systems. ... Linux (also known as GNU/Linux) is a Unix-like computer operating system. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Microsoft Windows is the name of several families of operating systems by Microsoft. ... The Installable File System (IFS) is a Filesystem API in IBM OS/2 and Microsoft Windows NT that enables the operating system to recognize and load drivers for filesystems. ... In Microsoft Windows, a shell extension is a computer programme that integrates itself into Windows Explorer (the shell. ...


References

  • Put virtual filesystems to work
  • Vnodes: An Architecture for Multiple File System Types in Sun UNIX
  • The Linux Virtual File-system Layer
  • Linux kernel's Virtual File System
  • Rodriguez, R.; M. Koehler; R. Hyde (June 1986). "The Generic File System". Proceedings of the USENIX Summer Technical Conference, 260–269, Atlanta, Georgia: USENIX Association.
  • Karels, M.; M. K. McKusick (September 1986). "Towards a Compatible File System Interface". Proceedings of the European UNIX Users Group Meeting, 481–496, Manchester, England: EUUG.
  • Heidemann, John (1995). Stackable Design of File Systems. Technical Report UCLA CSD-950032.
  • The Linux VFS, Chapter 4 of Linux File Systems by Moshe Bar (McGraw-Hill, 2001). ISBN 0-07-212955-7
  • Chapter 12 of Understanding the Linux Kernel by Daniel P. Bovet, Marco Cesati (O'Reilly Media, 2005). ISBN 0-596-00565-2

The USENIX Association is the Advanced Computing Technical Association. ... Marshall Kirk McKusick (normally called Kirk) is a computer scientist, famous for his extensive work on BSD, from the 1980s to FreeBSD in the present day. ... The University of California, Los Angeles, generally known as UCLA, is a public university whose main campus is located in the affluent Westwood neighborhood of Los Angeles, California, United States. ... Moshe Bar is the founder, main developer and project manager of openMosix. ... The McGraw-Hill Companies logo. ... Programming Perl is a classic OReilly book. ...

See also

  • 9P - Distributed file system protocol that maps directly to the Plan 9 from Bell Labs VFS layer making all file system access network transparent.
  • Gnome VFS
  • FUSE (Linux)
  • Installable File System, a filesystem API for IBM OS/2 and Microsoft Windows NT.
  • Toronto Virtual File System, a VFS for OS/2 developed by IBM Toronto that allows mounting diverse filesystems under a common structure.

9P, or the Plan 9 Filesystem Protocol, is a network protocol developed for the Plan 9 distributed operating system as the means of connecting the components of a Plan 9 system (site). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... GNOME VFS is short for GNOME Virtual File System. ... Filesystem in Userspace (FUSE) is a Free (GPL and LGPLed) Unix kernel module that allows non-privileged users to create their own file systems without the need to write any kernel code. ... The Installable File System (IFS) is a Filesystem API in IBM OS/2 and Microsoft Windows NT that enables the operating system to recognize and load drivers for filesystems. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

External links


  Results from FactBites:
 
File system - Wikipedia, the free encyclopedia (2606 words)
File systems may use a storage device such as a hard disk or CD-ROM and involve maintaining the physical location of the files, or they may be virtual and exist only as an access method for virtual data or for data over a network (e.g.
The file system software is responsible for organizing these sectors into files and directories, and keeping track of which sectors belong to which file and which are not being used.
A disk file system is a file system designed for the storage of files on a data storage device, most commonly a disk drive, which might be directly or indirectly connected to the computer.
Virtual file system - Wikipedia, the free encyclopedia (558 words)
A VFS specifies an interface (or a contract) between the kernel and a concrete file system.
One of the first virtual file system mechanisms in Unix-like systems was the one introduced by Sun Microsystems in SunOS 2.0.
Other virtual file system mechanisms in UNIX-like systems include the File System Switch in System V Release 3, the Generic File System in Ultrix, and the VFS in Linux.
  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