Topic: file cache

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

memory management

data caching
file input/output
I/O streams
log-structured file system
memory cache
memory management by paging
read-only and write-once file systems
replicated data
updating information in a distributed system


Cached files avoid the delays of retrieving files from disk. By storing the file in memory, access may start immediately on request. Data may be pre-fetched.

File cache may pass-through writes or record modifications in a recovery log. It may publish change notifications. (cbb 12/07)

Subtopic: cache file access up

Quote: segmented LRU: protected segment of cache hits; halves cache size; two disk accesses tend to indicate many disk accesses [»kareR3_1994]
Quote: for warm reboot of a file cache, protect a separate registry of file information [»chenPM9_1996]
Quote: Amoeba's bullet server keeps the i-node table in memory; records the file's cache address if any [»taneAS12_1990]
Quote: all Amoeba files are stored contiguously on disk and in memory [»taneAS12_1990]
Quote: OS6 implemented buffered, fast streams; 6x faster [»stoyJE3_1972]
Quote: all free pages kept in OS6's free storage file, in cache memory, and on backup disk [»stoyJE3_1972]
QuoteRef: cbb_1973 ;;7/27/79 Staged memory of small --frequently used segments and another of large-infrequently used. from disk to large memory than to small memory if high usage.

Subtopic: cache file writes up

Quote: file system for a WORM disk and a disk cache; read-only snapshots at any time by flushing the cache (a few seconds); assumes unbounded capacity [»quinS12_1991]
Quote: immediately write modified buffers to any location on disk; eventually write the buffer to its correct location; cheaper than a single random write [»orjiCU9_1994]
Quote: log-structured file system: all writes appended to end with indexing information for reads; since caches make writes predominate [»roseM10_1991]
Quote: caching partial files not worth it: server waits until all uses terminate, no disconnected operation, failures on read, inefficient [»satyM1_1992]
Quote: implement a safe file cache with battery-backed memory [»chenPM9_1996]
Quote: the EROS kernel cannot create or destroy resources; uses main memory as a cache [»shapJS1_2002]

Subtopic: pre-fetching up

Quote: performance analysis of prefetching; significant gains from disk caching, I/O amortization, seek time reduction, and overlapped computation and I/O [»shriE6_1999]
Quote: if a program accesses sequential blocks, Unix asynchronously pre-reads the next block; improves performance significantly [»ritcDM7_1978a]
Quote: INGRES typically knows exactly what block it will access next; often not the next sequential block [»stonM7_1981]

Subtopic: immutable files up

Quote: immutable files are easy to cache since no consistency requirement [»giffDK3_1988]

Subtopic: cache local names up

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: reliably cache names by defining an expiration time for each entry; can only move-and-relink unless expired [»lampBW8_1985]

Subtopic: concurrent file access up

Quote: allocate a disk cache segment for each concurrent process accessing a file [»shriE6_1999]

Subtopic: cached metadata up

Quote: direct access to 64MB chunks with cached metadata; few master communications, persistent TCB connection to chunkserver, all metadata in master's memory [»gherS10_2003]

Subtopic: cache compression up

Quote: use Huffman code to compress memory swap pages with many zeros; ten times faster than gzip or LZRW1 [»rizzL4_1997]

Subtopic: change notification up

Quote: use callbacks for change notification of cached files; must reestablish after notification and periodically confirm

Related Topics up

Group: memory management   (11 topics, 367 quotes)

Topic: data caching (35 items)
Topic: file input/output (21 items)
Topic: I/O streams (17 items)
Topic: efficiency (96 items)
Topic: log-structured file system (11 items)
Topic: memory cache (29 items)
Topic: memory management by paging (23 items)
Topic: read-only and write-once file systems (8 items)
Topic: replicated data (51 items)
Topic: updating information in a distributed system
(50 items)

Updated barberCB 1/06
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