Reiser4

Reiser4
Reiser4
Developer Namesys
Full name Reiser4
Introduced 2004 (Linux)
Partition identifier

Apple_UNIX_SVR2 (Apple Partition Map)
0x83 (MBR)

Basic data partition (GPT)
Structures
Directory contents Dancing B*-tree
Limits
Max file size 8 TiB on x86
Max filename length 3976 bytes
Allowed characters in filenames All bytes except NUL and '/'
Features
Dates recorded modification (mtime), metadata change (ctime), access (atime)
Date range 64-bit timestamps[1]
Forks Extended attributes
File system permissions Unix permissions, ACLs and arbitrary security attributes
Transparent compression Yes
Transparent encryption No
Data deduplication No
Supported operating systems Linux

Reiser4 is a computer file system, successor to the ReiserFS file system, developed from scratch by Namesys and sponsored by DARPA as well as Linspire. Named after its former lead developer Hans Reiser, Reiser4's continued development is uncertain following his conviction for murder.

Contents

Features

Some of the goals of the Reiser4 file system are:

Some of the more advanced Reiser4 features (such as user-defined transactions) are also not available because of a lack of a VFS API for them.

At present Reiser4 lacks a few standard file system features, such as an online repacker (similar to the defragmentation utilities provided with other file systems). The creators of Reiser4 say they will implement these later, or sooner if someone pays them to do so.[2]

Performance

Reiser4 uses B*-trees in conjunction with the dancing tree balancing approach, in which underpopulated nodes will not be merged until a flush to disk except under memory pressure or when a transaction completes. Such a system also allows Reiser4 to create files and directories without having to waste time and space through fixed blocks.

As of 2004, synthetic benchmarks performed by Namesys show that Reiser4 is 10 to 15 times faster than its most serious competitor ext3 working on files smaller than 1 KiB. Namesys's benchmarks suggest it is typically twice the performance of ext3 for general-purpose filesystem usage patterns.[3]

Integration with Linux

As of 2011, Reiser4 has not yet been merged into the mainline Linux kernel and consequently is still not supported on many Linux distributions; however, its predecessor ReiserFS v3 has been widely adopted. Reiser4 is also available from Andrew Morton's -mm kernel sources, and from Zen patch set. Linux kernel developers claim that Reiser4 does not follow Linux coding standards,[4] but Hans Reiser suggested political reasons.[5]

History of Reiser4

Hans Reiser was convicted of murder on April 28, 2008, leaving the future of Reiser4 uncertain. After his arrest, employees of Namesys assured they would continue to work and that the events would not slow down the software development in the immediate future. In order to afford increasing legal fees, Hans Reiser announced on December 21, 2006 that he was going to sell Namesys;[6] as of March 26, 2008, it had not been sold, although the website was unavailable. In January 2008, Edward Shishkin, an employee of and programmer for Namesys, was quoted in a CNET interview saying that "Commercial activity of Namesys has stopped." Shishkin and others continued the development of Reiser4,[7] making source code available from Shishkin's web site,[8] later relocated to kernel.org.[9] Since 2008, Namesys employees have received 100% of their sponsored funding from DARPA which is why Edward said 'commercial funding has stopped'.[10][11][12]

Future of Reiser4

Reiser4 development still continues,[13] delivering patches via kernel.org.[14]

In a mailing list post from July 2009, Edward Shishkin wrote that in the coming autumn, they would start exploring the opportunity of getting Reiser4 into the main Linux kernel.[15] In a November 2009 interview[16] with Phoronix he said he was going to publish a plug-in design document for independent expert review. He aimed for January 2011,[17] but as of June 2011, and with the 3.0 Branch of kernel in full development, Reiser4 has not yet been integrated into the mainline kernel.

See also

References

  1. ^ Documentation/filesystems/reiser4.txt from a reiser4-patched kernel source, "By default file in reiser4 have 64-bit timestamps."
  2. ^ Reiser, Hans (2004-09-16). "Re: Benchmark: ext3 vs reiser4 and effects of fragmentation.". Namesys, ReiserFS mailing list. http://marc.info/?l=reiserfs-devel&m=109535506122706&w=2. Retrieved 2009-10-03. 
  3. ^ Hans Reiser (November 20, 2003). "Benchmarks Of ReiserFS Version 4". Namesys. http://www.namesys.com/benchmarks.html. Retrieved 2006-11-28. 
  4. ^ "Linux: Why Reiser4 Is Not in the Kernel". Kerneltrap. September 19, 2005. http://kerneltrap.org/node/6844. 
  5. ^ Reiser, Hans (21 July 2006). "The "'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion". http://lkml.org/lkml/2006/7/21/109. Retrieved 2008-03-01. 
  6. ^ "Murder Suspect Selling Namesys". Wired News. 2006-12-21. http://www.wired.com/news/technology/0,72342-0.html?tw=wn_technology_1. Retrieved 2006-12-30. 
  7. ^ Namesys vanishes, but ReiserFS project lives on. http://www.news.com/8301-13580_3-9851703-39.html CNet (January 16, 2008). Retrieved on 2008-01-26.
  8. ^ "Namesys things". Chichkin_i.zelnet.ru. http://chichkin_i.zelnet.ru/namesys/. Retrieved 2010-02-08. 
  9. ^ New location of Namesys software Linux Kernel Mailing List post, 2008-08-04
  10. ^ "Re: we got the DARPA grant to add views to Reiser4". Mail-archive.com. 2004-04-10. http://www.mail-archive.com/reiserfs-list@namesys.com/msg11961.html. Retrieved 2010-02-08. 
  11. ^ https://bugzilla.redhat.com/show_bug.cgi?id=114785
  12. ^ "Reports - ext3 or ReiserFS? Hans Reiser Says Red Hat's Move Is Understandable - Red Hat's Decision is Conservative, Not Radical". LinuxPlanet. http://www.linuxplanet.com/linuxplanet/reports/3726/1/. Retrieved 2010-02-08. 
  13. ^ ReiserFS Development Mailing List. Retrieved on 2009-04-11.
  14. ^ "Edward Shishkin's Kernel Space". Kernel.org. http://kernel.org/pub/linux/kernel/people/edward/reiser4/. Retrieved 2010-02-08. 
  15. ^ "Edward Shishkin on Reiser4's status". Spinics.net. 2009-07-31. http://www.spinics.net/lists/reiserfs-devel/msg01800.html. Retrieved 2010-02-08. 
  16. ^ "Reiser4 May Go For Mainline Inclusion In 2010". Phoronix.com. 2009-11-10. http://www.phoronix.com/scan.php?page=news_item&px=NzY4OQ. Retrieved 2010-02-08. 
  17. ^ Shishkin, Edward (17 Oct 2010). "Re: Mainline inclusion". http://marc.info/?l=reiserfs-devel&m=128735194402215. Retrieved 2010-10-17. 

External links


Wikimedia Foundation. 2010.

Поможем написать курсовую

Look at other dictionaries:

  • Reiser4 — Saltar a navegación, búsqueda Reiser4 Desarrollador Namesys Nombre completo Reiser4 Introducido 2004 (Linux) Identificador de la partición Apple UNIX SVR2 (Apple Partition Map) 0x83 (MBR) EBD0A0A2 B9E5 …   Wikipedia Español

  • Reiser4 — Reiser4  4 я версия журналируемой файловой системы ReiserFS, разработанной специально для Linux (хотя может использоваться и в других ОС) компанией Namesys под руководством Ганса Райзера (англ. Hans Reiser). Система представлена в… …   Википедия

  • Reiser4 — est la version 4 du système de fichiers ReiserFS. Sortie en août 2004, cette version apporte comme nouveautés essentielles : des transactions atomiques : une modification est toujours complètement effectuée, ou pas du tout effectuée.… …   Wikipédia en Français

  • Reiser4 — es un sistema de archivos para computadoras. Se trata de la versión más reciente del sistema de archivos ReiserFS, implementada desde cero. Entre sus ventajas se encuentran: ● Soporte eficiente de gran cantidad de archivos pequeño. ● Manejo de… …   Enciclopedia Universal

  • Reiser4 — ReiserFS Hersteller Namesys (Hans Reiser) Vollständige Bezeichnung Reiser File System Technische Umsetzung Verzeichnisse B⁺ Baum (ReiserFS 1 3) B* Baum (Reiser4) Dateien Bitm …   Deutsch Wikipedia

  • ReiserFS — Infobox Filesystem name = ReiserFS full name = ReiserFS developer = Namesys introduction os = Linux 2.4.1 introduction date = 2001 OS = Linux partition id = Apple UNIX SVR2 (Apple Partition Map) 0x83 (MBR) EBD0A0A2 B9E5 4433 87C0 68B6B72699C7… …   Wikipedia

  • Hans Reiser — Hans Thomas Reiser Hans Reiser mug shot Born December 19, 1963 (1963 12 19) (age 47) California …   Wikipedia

  • Comparison of file systems — The following tables compare general and technical information for a number of file systems. Contents 1 General information 2 Limits 3 Metadata 4 Features …   Wikipedia

  • ReiserFS — Hersteller Namesys (Hans Reiser) Vollständige Bezeichnung Reiser File System Technische Umsetzung Verzeichnisse B⁺ Baum (ReiserFS 1 3) B* Baum (Reiser4) Dateien Bitm …   Deutsch Wikipedia

  • Reiser File System — ReiserFS Hersteller Namesys (Hans Reiser) Vollständige Bezeichnung Reiser File System Technische Umsetzung Verzeichnisse B⁺ Baum (ReiserFS 1 3) B* Baum (Reiser4) Dateien Bitmap …   Deutsch Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”