Search results
Results from the WOW.Com Content Network
Initially, zram had only the latter function, hence the original name "compcache" ("compressed cache"). Unlike swap, zram only uses 0.1% of the maximum size of the disk when not in use. [1] After four years in the Linux kernel's driver staging area, zram was introduced into the mainline Linux kernel in version 3.14, released on March 30, 2014. [2]
Linux tmpfs (previously known as shm fs) [6] is based on the ramfs code used during bootup and also uses the page cache, but, unlike ramfs, it supports swapping out less-used pages to swap space, as well as filesystem size and inode limits to prevent out-of-memory situations (defaulting to half of physical RAM and half the number of RAM pages ...
Cache hierarchy, or multi-level cache, is a memory architecture that uses a hierarchy of memory stores based on varying access speeds to cache data. Highly requested data is cached in high-speed access memory stores, allowing swifter access by central processing unit (CPU) cores.
A memory-mapped file is a segment of virtual memory [1] that has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource. This resource is typically a file that is physically present on disk, but can also be a device, shared memory object, or other resource that an operating system can reference through a file descriptor.
The Intel 8080 used by these computers was an 8-bit processor, with 16-bit address space, which allowed it access up to 64 KB of memory; .COM executables used with CP/M have a maximum size of 64 KB due to this, as do those used by DOS operating systems for 16-bit microprocessors.
The page cache in main memory, which is an example of disk cache, is managed by the 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.
Unlike the case of exclusive cache, where the unique memory capacity is the combined capacity of all caches in the hierarchy. [4] If the size of lower level cache is small and comparable with the size of higher level cache, there is more wasted cache capacity in inclusive caches.
The hit ratio of a cache describes how often a searched-for item is found. More efficient replacement policies track more usage information to improve the hit rate for a given cache size. The latency of a cache describes how long after requesting a desired item the cache can return that item when there is a hit.