NetWare File System: Difference between revisions

Revision as of 04:30, 8 June 2010

Revision as of 04:31, 8 June 2010

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'''NetWare File System''' ('''NWFS''') is a [[file system]], based on a heavily-modified version of [[File Allocation Table|FAT]]. It was used in the [[Novell NetWare]] [[operating system]]. It is the default and only file system for all volumes in versions 2.x through 4.x, and the default and only file system for the SYS volume continuing through version 5.x. There were two varieties of NWFS: 16-bit NWFS 286, used in NetWare 2.x; and 32-bit NWFS 386, used in NetWare 3.x through NetWare 6.x. It was superseded by the release of [[Novell Storage Services]] (NSS) in 1998.

The Netware File System uses a 32 bit File Allocation Table scheme similiarsimilar to the MSDOS file system with several improvements including block suballocation, sparse files by the use of block indexes in the fat tables, and mirrored fat and directory files. The NetWare file system also employed a 4 way cylinder aligned segment table to record volume disk segments should a drive spindle fail allowing recovery. NSS subsequently integrated many of the robust features of the NetWare File system into its design including mirroring and hotfixing. The Open Source NetWare File System was designed by Jeff Merkey and Darren Major.

The NetWare file system was the first storage architecture to employ sector remapping for failed drive sectors called drive hotfixing which would redirect sector mapping to a reserved area of the device. Later Disk Drive manufactuters employed the same technique internally within the drive logic to perform a similiarsimilar function transparently to the host operating system.

The NWFS on-disk format for NetWare 3.x, 4,x, and 5.x was publically released on Linux in 1998 and 1999 by former Novell Chief Scientist Jeff Merkey and Darren Major from the Timpanogas Research Group. The specifications for 32-bit NWFS are: