Ext3cow
Encyclopedia
Ext3cow or third extended filesystem with copy-on-write is an open source
, versioning file system
based on the ext3
file system. Versioning is implemented through block-level copy-on-write
. It shares many of its performance characteristics with ext3
.
Ext3cow provides a time-shifting interface that permits a real-time and continuous view of data in the past. Time-shifting is a novel interface, introduced in ext3cow, allowing users to navigate through and access past namespaces by adding a time component to their commands.
Ext3cow was designed to be a platform for compliance with the versioning and auditability requirements
of recent US electronic record retention legislation, such as Sarbanes-Oxley and HIPAA.
A version of ext3cow for the Linux
2.6 kernel was released on March 30, 2007.
Details on ext3cow's implementation can be found in a 2005 paper.
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
, versioning file system
Versioning file system
A versioning file system is any computer file system which allows a computer file to exist in several versions at the same time. Thus it is a form of revision control. Most common versioning file systems keep a number of old copies of the file. Some limit the number of changes per minute or per...
based on the ext3
Ext3
The ext3 or third extended filesystem is a journaled file system that is commonly used by the Linux kernel. It is the default file system for many popular Linux distributions, including Debian...
file system. Versioning is implemented through block-level copy-on-write
Copy-on-write
Copy-on-write is an optimization strategy used in computer programming. The fundamental idea is that if multiple callers ask for resources which are initially indistinguishable, they can all be given pointers to the same resource...
. It shares many of its performance characteristics with ext3
Ext3
The ext3 or third extended filesystem is a journaled file system that is commonly used by the Linux kernel. It is the default file system for many popular Linux distributions, including Debian...
.
Ext3cow provides a time-shifting interface that permits a real-time and continuous view of data in the past. Time-shifting is a novel interface, introduced in ext3cow, allowing users to navigate through and access past namespaces by adding a time component to their commands.
Ext3cow was designed to be a platform for compliance with the versioning and auditability requirements
of recent US electronic record retention legislation, such as Sarbanes-Oxley and HIPAA.
A version of ext3cow for the Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
2.6 kernel was released on March 30, 2007.
Details on ext3cow's implementation can be found in a 2005 paper.
See also
- ext3Ext3The ext3 or third extended filesystem is a journaled file system that is commonly used by the Linux kernel. It is the default file system for many popular Linux distributions, including Debian...
- Next3Next3Next3 is a journaled file system for Linux based on ext3 which adds snapshots support, yet retains compatibility to the ext3 on-disk format. Next3 is implemented as open-source software, licensed under the GPL license.-Background:...
- List of file systems
- Comparison of file systemsComparison of file systems-General information:-Limits:-Metadata:-Features:-Allocation and layout policies:-Supporting operating systems:-See also:* Comparison of archive formats* Comparison of file archivers* List of archive formats* List of file archivers...
- HtreeHtreeAn HTree is a specialized tree data structure for directory indexing, similar to a B-tree. They are constant depth of either one or two levels, have a high fanout factor, use a hash of the filename, and do not require balancing...