Computer storage

From ArticleWorld

Computer storage is the place where data is held in an electromagnetic or optical form to be accessed by a computer processor. Following are the two major usages 1) Storage is frequently used to mean the devices and data connected to the computer by input/output operations - they are hard disk, tape systems and other forms of storage that don't include computer memory and other in-computer storage. For the enterprise, the options for this kind of storage are of much greater variety and expense than that related to memory.

2) In a more formal usage, storage has been divided into: (a) primary storage, which holds data in memory (sometimes called random access memory or RAM) and other "built-in" devices such as the processor's L1 cache, and (b) secondary storage, which holds data on hard disks, tapes, and other devices requiring input/output operations.

Primary storage is much faster to access than secondary storage because of the proximity of the storage to the processor or because of the nature of the storage devices. On the other hand, secondary storage can hold much more data than primary storage.

In addition to RAM, primary storage includes read-only memory (ROM) and L1 and L2 cache memory. In addition to hard disks, secondary storage includes a range of device types and technologies, including diskettes, Zip drives, redundant array of independent disks (RAID) systems, and holographic storage. Devices that hold storage are collectively known as storage media.

A somewhat antiquated term for primary storage is the main storage and a somewhat antiquated term for secondary storage is auxiliary storage.

Computer Storage can be broadly classified into following categories 1. Primary/Secondary - basically to be accessed by CPU for its processing. 2. Random/Sequential Access - basically its based on the way in which the memory is accessed for retrieving or storing data. 3. Read Only Memory / Read Only Memory / Write Once and Read Many Memory.

Various Technologies involved in Memory Storage are :- 1. Compact disc, recordable ( CD-R ) or rewritable ( CD-RW ) and DVD 2. Diskettes. 3. Hard drive, external 4. Hard drive, internal 5. Removable storage (ZIP disks, JAZ disks, etc.) 6. Solid-state storage (USB devices, flash memory, smart cards, etc.) 7. Direct-attached storage (DAS) 8. Disk library 9. Disk-to-disk-to-tape ( D2D2T ) 10. Fibre Channel 11. iSCSI 12. Magnetic tape 13. Network-attached storage 14. Redundant array of independent disks 15. Storage area network

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