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__NOTOC__ Write Ahead Physical Block Logging (WAPBL) provides meta data journaling for file systems in conjunction with Fast File System (FFS) to accomplish rapid filesystem consistency after an unclean shutdown of the filesystem and better general use performance over regular FFS. With the journal,
fsck The system utility fsck (''file system consistency check'') is a tool for checking the consistency of a file system in Unix and Unix-like operating systems, such as Linux, macOS, and FreeBSD. A similar command, CHKDSK, exists in Microsoft Windows ...
is no longer required at system boot; instead, the system can replay the journal in order to correct any inconsistencies in the filesystem if the system has been shut down in an unclean fashion.


History

WAPBL was initially committed into NetBSD in 2008, and first appeared with NetBSD 5.0 (2009). With NetBSD 6.0 (2012), '' soft updates'' (known as ''soft dependencies'' in NetBSD) was removed in favour of ''WAPBL''.


See also

*
Log-structured file system A log-structured filesystem is a file system in which data and metadata are written sequentially to a circular buffer, called a log. The design was first proposed in 1988 by John K. Ousterhout and Fred Douglis and first implemented in 1992 by ...
* Soft updates *
Unix File System The Unix file system (UFS) is a family of file systems supported by many Unix and Unix-like operating systems. It is a distant descendant of the original filesystem used by Version 7 Unix. Design A UFS volume is composed of the following ...
(UFS/FFS)


References


External links

* * * Computer file systems Disk file systems NetBSD Unix file system technology {{compu-storage-stub