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Encyclopedia > Hierarchical storage management

Hierarchical Storage Management (HSM) is a data storage technique that automatically moves data between high-cost and low-cost storage media. HSM systems exist because high-speed storage devices, such as hard disk drives, are more expensive (per byte stored) than slower devices, such as optical discs and magnetic tape drives. While it would be ideal to have all data available on high-speed devices all the time, this is prohibitively expensive for many organizations. Instead, HSM systems store the bulk of the enterprise's data on slower devices, and then copy data to faster disk drives when needed. In effect, HSM turns the fast disk drives into caches for the slower mass storage devices. The HSM system monitors the way data is used and makes best guesses as to which data can safely be moved to slower devices and which data should stay on the hard disks. The terms storage (U.K.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ... Typical hard drives of the mid-1990s. ... A byte is commonly used as a unit of storage measurement in computers, regardless of the type of data being stored. ... Look up cache in Wiktionary, the free dictionary. ...

HSM was first implemented by IBM on their mainframe computers to reduce the cost of data storage, and to simplify the retrieval of data from slower media. The user would not need to know where the data was stored and how to get it back, the computer would retrieve the data automatically. The only difference to the user was the speed at which data is returned.

Later, IBM ported HSM to its AIX operating system, and then to other unix-like operating systems such as Solaris, HP-UX and Linux.

Software implementing HSM:

This category is for articles having to do with the slower forms of storage like disk storage. IBM Tivoli Framework is a systems management platform from IBM (previously Tivoli Systems, acquired by IBM in 1995 and moved into IBMs Software Group division). ... QFS is a filesystem sold by Sun Microsystems. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Disk storage is a group of data storage mechanisms for computers; data are transferred to planar surfaces or disks for temporary or permanent storage. ...

For articles about faster forms of memory (like DRAM), use the Category:Computer memory. Dram can mean several things: For the imperial unit of volume see dram (unit), commonly used to describe a measure of Scotch whisky For the imperial unit of weight or mass see avoirdupois and apothecaries system (of mass) For the Armenian monetary unit see dram (currency) DRAM is a type...

  Results from FactBites:
HSM for NetWare: A Guide to Hierarchical Storage Management (HSM) (3169 words)
HSM is one of the most important developments in storage management today.
The HSM name signifies that the software has the intelligence to move files along a hierarchy of storage devices that are ranked in terms of cost per megabyte of storage, speed of storage and retrieval, and overall capacity limits.
HSM is highly cost effective because it optimizes the use of the hard drive and utilizes less-expensive media in its place.
  More results at FactBites »



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