Cache (computing): Difference between revisions

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review: thin unsourced. more than Page cache is covered here so {{Main}} is not appropriate.
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====Weather forecast====
In 2011, the use of smartphones with weather forecasting options was overly taxing [[AccuWeather]] servers; two requests from the same area would generate separate requests. An optimization by edge-servers to truncate the GPS coordinates to fewer decimal places meant that the cached results from a nearby query would be used. The number of to-the-server lookups per day dropped by half.<ref>{{cite magazine|author=Murphy|first=Chris|date=May 30, 2011|title=5 Lines Of Code In The Cloud|magazine=[[InformationWeek]]|page=28|quote=300 million to 500 million fewer requests a day handled by AccuWeather servers}}</ref><!--[[User:Kvng/RTH]]-->
 
==Software caches==
===Disk cache===
While CPU caches are generally managed entirely by hardware, a variety of software manages other caches. The [[page cache]] in main memory, which is an example of disk cache, is managed by the operating system [[Kernel (operating system)| kernel]].
{{Main|Page cache}}
While CPU caches are generally managed entirely by hardware, a variety of software manages other caches. The [[page cache]] in main memory, which is an example of disk cache, is managed by the operating system [[Kernel (operating system)|kernel]].
 
While the [[disk buffer]], which is an integrated part of the hard disk drive or solid state drive, is sometimes misleadingly referred to as "''disk cache"'', its main functions are write sequencing and read prefetching. Repeated cache hits are relatively rare, due to the small size of the buffer in comparison to the drive's capacity. However, highHigh-end [[disk controller]]s often have their own on-board cache offor the hard disk drive's data blocks.
 
Finally, a fast local hard disk drive can also cache information held on even slower data storage devices, such as remote servers ([[web cache]]) or local [[tape drive]]s or [[optical jukebox]]es; such a scheme is the main concept of [[hierarchical storage management]]. Also, fast flash-based solid-state drives (SSDs) can be used as caches for slower rotational-media hard disk drives, working together as [[hybrid drive]]s or .<!--[[solid-state hybrid driveUser:Kvng/RTH]]s (SSHDs).-->
 
===Web cache===