Topic: examples of file systems

topics > computer science > operating system > Group: file system

log-structured file system
read-only and write-once file systems


A file system stores persistant files of data. There are many kinds of file systems. Examples include Cedar's immutable files, Google's huge files, backing stores, Elephant's versioned files, Unix inodes, Multic's virtual memory, Amoeba's distributed system, and Inferno's hierarchical resources. (cbb 12/07)

Subtopic: immutable, atomic files up

Quote: Cedar files designed for simplicity and performance; only from file servers, immutable, atomic updates, send & cache whole files [»giffDK3_1988]
Quote: in Cedar, all remote files are immutable; replaces cache consistency problem with version control [»giffDK3_1988]
Quote: Cedar atomically adds a file to a file server (transfer, new version id, and directory update); implemented with mutual exclusion [»giffDK3_1988]
Quote: Cedar can retrieve a file with a specified creation time; searches all versions [»giffDK3_1988]
Quote: with Cedar, can attach local names to remote files that are cached on disk; allows a large set of locally named files [»giffDK3_1988]
Quote: Modeler uses immutable objects with unique names; allows name to be used in place of text [»lampBW6_1983]

Subtopic: huge files up

Quote: Google uses BigFiles with 64-bit offsets, multiple file systems, compression, and allocation/deallocation [»brinS4_1998]
Quote: a GFS file consists of fixed-size chunks identified by a globally unique 64-bit handle; a chunk is a Linux file [»gherS10_2003]

Subtopic: idempotent blocks up

Quote: V reads and writes blocks without a file position; idempotent transactions allows kernel to ignore reply messages [»cherDR4_1984]

Subtopic: transactional store up

Quote: ZFS provides a transactional store of objects with 2^64 sets of 2^64 objects, each 2^64 bytes; not designed for 32-bit architectures [»browD9_2007]

Subtopic: backing store up

Quote: a backing store server manages persistent objects with internal names; allocates and frees storage space [»birrAD9_1980]
Quote: a file server stores and retrieves bulk data for a local area network [»birrAD9_1980]
Quote: a filing system is a client of the backing store server; applications have access to either [»birrAD9_1980]
Quote: objects in a backing store server are either publicly accessible segments or private indices [»birrAD9_1980]

Subtopic: versioned files up

Quote: the Elephant file system saves all important versions; easy undo of recent changes [»santDS12_1999]
Quote: the Elephant file system uses Keep-One for unimportant and easily recreated files; like standard file system [»santDS12_1999]
Quote: Keep-Safe guarantees that a file version is retained for an interval; deleted after a younger version or permanent deletion [»santDS12_1999]
Quote: versioned file system does not affect write disk caching; little data rewritten to versioned files [»santDS12_1999]

Subtopic: Unix file system up

Quote: file system implemented in Multics [»daleRC_1965]
Quote: UNIX file system described by a replicated, immutable superblock [»mckuMK8_1984]
Quote: UNIX uses at least 4K file blocks; allows 4 gigabyte files with two levels of indirection [»mckuMK8_1984]
Quote: description of new file system for UNIX 4.2bsd [»mckuMK8_1984]
Quote: a Unix file exists independently of its directory entries; deleted when last entry is deleted [»ritcDM7_1978a]
Quote: Unix files accessed by their i-number which indexes their i-node in the devices i-list [»ritcDM7_1978a]
Quote: except for Inames of mounted volumes, Inames are only preserved in indices of the same volume [»birrAD9_1980]
Quote: the Unix i-list gives each file a short, unique name; is reliable and simple, with easy access to file information [»ritcDM7_1978a]
Quote: forked, Unix process share the same open file table entry; multiple opens of a file share the same i-node table entry [»thomK7_1978]
Quote: disk fragmentation slows down the BSD Fast File System by 5-15%; segment cleaner overhead slows down a log-structured system by 33% [»seltM1_1995]
Quote: the BSD Fast File System takes up to six distinct I/O operations to create a new one-kilobyte file [»seltM1_1995]
Quote: the BSD Fast File System does not attempt to preserve large free extents

Subtopic: virtual memory up

Quote: Multics treats files as segments in virtual memory; avoids file copies and overlay management, needs 'attach' mechanism [»dennPJ_1980]
Quote: an Oberon writer initially creates an anonymous file; extension of memory since the disk space is reclaimed on system boot [»wirtN9_1989]
Quote: Pilot's managers implement file management and complex virtual memory operations
Quote: Pilot's kernel manages virtual memory access to special files and to preexisting, fixed-size normal files [»redeDD2_1980]

Subtopic: Amoeba -- distributed up

Quote: Amoeba files are replicated on two disks; the create-file operation can return when 0, 1 or 2 copies written to disk [»vanrR10_1988]
Quote: Amoeba's bullet server keeps the i-node table in memory; records the file's cache address if any [»taneAS12_1990]
Quote: Amoeba's bullet file server reads 2-3 times faster than SUN NFS; large write bandwidth is 4 times higher; small file create is slower [»vanrR10_1988]
Quote: Amoeba file reads are 2-3 times faster than Sun NFS; large file writes are faster; capability overhead is constant [»taneAS12_1990]
Quote: Amoeba has separate file and directory servers; one handles storage, the other naming and protection; works well [»taneAS12_1990]
Quote: Amoeba's file server performs garbage collection by touching every file every k days and deleting a file if not accessed in n days (n>>k) [»taneAS12_1990]
Quote: a file's capability includes its i-node index; Amoeba's memory-resident i- node table gives the disk and cache address; at most 1 disk seek [»vanrR10_1988]

Subtopic: Inferno -- hierarchical resources up

Quote: Inferno applications use a fixed set of files for devices and system services [»dorwSM1_1997]
Quote: in Inferno and Plan 9, all resources have a hierarchical file name in a forest of file systems and in a private name space [»dorwSM1_1997]
Quote: represent device drivers with a data file and a control file

Related Topics up

Topic: log-structured file system (11 items)
Topic: read-only and write-once file systems
(8 items)

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