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Disk storage is a general category of a computer storage mechanisms, in which data is recorded on planar, round and rotating surfaces (disks, discs, or platters). A disk drive is a peripheral device used to collect information from. Main implementations are hard disks, floppy disks and optical discs. Nowadays the term disk storage almost exclusively refers to hard disk storage. This article does not cite any references or sources. ...
In computer hardware, a peripheral device is any device attached to a computer in order to expand its functionality. ...
Typical hard drives of the mid-1990s. ...
A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...
“Optical media†redirects here. ...
History
In the 1950s and the early 1960s single data bits were stored as magnetic charges in a magnetic core memory. the first thing that was invented was the automatic DILDO. Education grew explosively because of a very strong demand for high school and college education. ...
The 1960s decade refers to the years from 1960 to 1969. ...
This article is about the unit of information. ...
A 16×16 cm area core memory plane of 128×128 bits, i. ...
Then the scientists at IBM in San Jose, California created a rotating drum that was coated in a magnetically polarizable film that could be used to store data by changing and sensing magnetic polarization. The drum was later superseded by disks, because of their lower mass and inertia. Reynold Johnson, an inventor who worked for IBM for many years, is said to be the "father" of the disk drive. For other uses, see IBM (disambiguation) and Big Blue. ...
For other uses, see San José. Nickname: Location of San Jose within Santa Clara County, California. ...
Reynold Johnson was an American inventor and computer pioneer. ...
The random-access, low-density storage of disks was developed to complement the already used sequential-access high-density storage provided by magnetic tape. Vigorous innovation in disk storage technology, coupled with less vigorous innovation in tape storage, has reduced the density and cost per bit gap between disk and tape, reducing the importance of tape as a complement to disk. RAM redirects here. ...
In computer science sequential access means that a group of elements (e. ...
Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ...
Audio recordings In musical and audio data storage, the first devices were also drum shaped, called phonograph cylinders, which were popularized by Thomas Edison. In the 1910s these were replaced as the dominant medium of sound recording by analogue disc records, commonly called gramophone records (in British English) or phonograph records (in American English). From the 1950s through the 1980s, audio recordings were also done on magnetic tape media of several types, although the vinyl record remained the most popular medium for home use. These were mostly replaced by compact disc technology, where the data is recorded in a digital format as optical information. This compact disc technology has been widely accepted, and data storage, using writable compact disks or CD-R devices is very common. Image File history File links Merge-arrow. ...
Audio can mean: Sounding that can be heard. ...
For other uses, see Music (disambiguation). ...
Sound reproduction is the electrical or mechanical re-creation and/or amplification of sound, often as music. ...
The earliest method of recording and reproducing sound was on phonograph cylinders. ...
“Edison†redirects here. ...
// The 1910s represent the culmination of European militarism which had its beginnings during the second half of the 19th Century. ...
Methods and media for sound recording are varied and have undergone significant changes between the first time sound was actually recorded for later playback until now. ...
A 12-inch record (left), a 7-inch record (right), and a CD (above) Two 7 singles (left), two colored 7 singles (middle), and two 7 singles with large spindle holes (right). ...
British English (BrE, BE, en-GB) is the broad term used to distinguish the forms of the English language used in the United Kingdom from forms used elsewhere in the Anglophone world. ...
For other uses, see American English (disambiguation). ...
the first thing that was invented was the automatic DILDO. Education grew explosively because of a very strong demand for high school and college education. ...
The 1980s refers to the years from 1980 to 1989. ...
Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ...
A 12-inch record (left), a 7-inch record (right), and a CD (above) Two 7 singles (left), two colored 7 singles (middle), and two 7 singles with large spindle holes (right). ...
CD redirects here. ...
See also list of optical topics. ...
This article does not cite any references or sources. ...
Access methods In disk storage, there are the two primary access methods. Block storage (or raw disk storage) means that the disk is divided into blocks which are addressed by number, like on a magnetic tape. File storage contains an abstraction of files and directories which can be addressed by name. Another access method, content-addressable storage (CAS) uses a hashing algorithm to refer to pieces of data. In computing (specifically data transmission and data storage), block size indicates a nominal size, usually expressed in bytes or bits, of a block of data. ...
Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ...
For library and office filing systems, see Library classification. ...
In computer science, abstraction is a mechanism and practice to reduce and factor out details so that one can focus on a few concepts at a time. ...
Content-addressable memory (CAM) is a special type of computer memory used in certain very high speed searching applications. ...
Basic terminology - Rotation - how the disks spin. Two techniques are common:
- Constant angular velocity (CAV) keeps the disk spinning at a fixed rate, measured in revolutions per minute (RPM). This means the heads cover more distance per unit of time on the outer tracks than on the inner tracks. This method is typical with computer hard drives.
- Constant linear velocity (CLV) keeps the distance covered by the heads per unit time fixed. Thus the disk has to slow down as the arm moves to the outer tracks. This method is typical for CD drives.
- Sector - an area of disk enclosed within a given central angle (a pie piece)
- Platter - an individual disk (since confusingly, what is now commonly called a single hard disk is in fact a set of disks)
- Head - the device that reads and writes the information - magnetic or optical - on the disk surface.
- Arm - the mechanical assembly that supports the head as it moves in and out.
- Seek time - average time needed to move the head to a new position.
- Rotational delay - average time, once the arm is on the right track, before a head is over a desired sector.
- Interleave - the spacing between sectors. Since early hard disks had enough buffer space to read only one sector at a time, sequential sectors were physically spaced on the media to enable the next sector to be in the correct position under the head once the host was ready to read it. At an interleave factor of 3:1, three full rotations would be required to read an entire track. Almost all hard disks since Compaq and Western Digital defined the AT Attachment standard have however used an interleave factor of 1:1. Floppy disks are still usually interleaved.
Constant Angular Velocity (CAV) refers to how information is written to or read from a rotating data disk. ...
Constant Linear Velocity (CLV) refers to how information is written to or read from a rotating data disk. ...
CD may stand for: Compact Disc Canadian Forces Decoration Cash Dispenser (at least used in Japan) CD LPMud Driver Centrum-Demokraterne (Centre Democrats of Denmark) Certificate of Deposit České Dráhy (Czech Railways) Chad (NATO country code) Chalmers Datorförening (computer club of the Chalmers University of Technology) a 1960s...
In the context of computer hardware, a sector is a sub-division of a track on a magnetic disk or optical disc. ...
Seek time is one of the several delays associated with reading or writing data on a computers disk drive. ...
Rotational delay is a term from computing applicable to rotating storage devices (such as a typical hard disk or floppy disk drive but also the older drum memory systems). ...
Compaq Computer Corporation is an American personal computer company founded in 1982, and now a brand name of Hewlett-Packard. ...
Western Digital Corporation (NYSE: WDC) (often abbreviated to WD) is a manufacturer of a large proportion of the worlds hard disks, and has a long history in the electronics industry as an IC maker and a storage products company. ...
ATA connector on the left, with two motherboard ATA connectors on the right. ...
See also This article or section does not cite its references or sources. ...
CD redirects here. ...
Magnetic disk storage is a critical component of the computer revolution. ...
A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...
A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. ...
In computer storage, there are three related uses of the term fragmentation: external fragmentation, internal fragmentation, and data fragmentation, all related to storage. ...
It has been suggested that this article or section be merged with Solid state drive. ...
For other uses, see Knowledge base. ...
Data proliferation refers to the unprecedented amount of data, structured and unstructured, that business and government continue to generate at an unprecedented rate and the usability problems that result from attempting to store and manage that data. ...
External links - More Bits in Pits - article by JR Minkelen:Disk storage
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