Mass storage
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In
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, e ...
, mass storage refers to the storage of large amounts of
data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted ...
in a persisting and machine-readable fashion. In general, the term is used as large in relation to contemporaneous hard disk drives, but it has been used large in relation to
primary memory Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer ...
as for example with
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...
s on
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s. Devices and/or systems that have been described as mass storage include
tape libraries In computer storage, a tape library, sometimes called a tape silo, tape robot or tape jukebox, is a storage device that contains one or more tape drives, a number of slots to hold tape cartridges, a barcode reader to identify tape cartridges ...
,
RAID Raid, RAID or Raids may refer to: Attack * Raid (military), a sudden attack behind the enemy's lines without the intention of holding ground * Corporate raid, a type of hostile takeover in business * Panty raid, a prankish raid by male college ...
systems, and a variety of computer drives such as
hard disk drive A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
s,
magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...
drives,
magneto-optical disc A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc. Both 130 mm (5.25 in) and 90 mm (3.5 in) form factors exist. In 1983, just a year after the introduc ...
drives,
optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...
drives,
memory card A memory card is an electronic data storage device used for storing digital information, typically using flash memory. These are commonly used in digital portable electronic devices. They allow adding memory to such devices using a card in a so ...
s, and
solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is ...
s. It also includes experimental forms like
holographic memory Holographic data storage is a potential technology in the area of high-capacity data storage. While magnetic and optical data storage devices rely on individual bits being stored as distinct magnetic or optical changes on the surface of the recor ...
. Mass storage includes devices with removable and non-removable media. It does not include
random access memory Random-access memory (RAM; ) is a form of computer memory that can be read and changed in any order, typically used to store working Data (computing), data and machine code. A Random access, random-access memory device allows data items to b ...
(RAM). There are two broad classes of mass storage: local data in devices such as
smartphones A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, which ...
or
computers A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs ...
, and enterprise servers and data centers for the cloud. For local storage, SSDs are on the way to replacing HDDs. Considering the mobile segment from phones to notebooks, the majority of systems today is based on
NAND Flash Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...
. As for Enterprise and
data centers A data center (American English) or data centre (British English)See spelling differences. is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunic ...
, storage tiers have established using a mix of SSD and HDD.


Definition

The notion of "large" amounts of data is of course highly dependent on the time frame and the market segment, as storage device capacity has increased by many orders of magnitude since the beginnings of computer technology in the late 1940s and continues to grow; however, in any time frame, common mass storage devices have tended to be much larger and at the same time much slower than common realizations of contemporaneous
primary storage Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a compute ...
technology. Papers at the 1966
Fall Joint Computer Conference The Joint Computer Conferences were a series of computer conferences in the United States held under various names between 1951 and 1987. The conferences were the venue for presentations and papers representing "cumulative work in the omputerfield ...
(FJCC) used the term ''mass storage'' for devices substantially larger than contemporaneous hard disk drives. Similarly, a 1972 analysis identified mass storage systems from
Ampex Ampex is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name AMPEX is a portmanteau, created by its founder, which stands for Alexander M. Poniatoff Excellence.AbramsoThe History ...
(Terabit Memory) using video tape, Precision Industries (Unicon 690-212) using lasers and International Video (IVC-1000) using video tape and states "In the literature, the most common definition of mass storage capacity is a trillion bits.". The first IEEE conference on mass storage was held in 1974 and at that time identified mass storage as "capacity on the order of 1012 bits" (1 gigabyte). In the mid-1970s IBM used the term to in the name of the
IBM 3850 The IBM 3850 Mass Storage System was an online tape library used to hold large amounts of infrequently accessed data. It was one of the earliest examples of nearline storage. History Starting in the late-1960s IBM's lab in Boulder, Colorado be ...
Mass Storage System, which provided virtual disks backed up by
Helical scan Helical scan is a method of recording high-frequency signals on magnetic tape. It is used in open-reel video tape recorders, video cassette recorders, digital audio tape recorders, and some computer tape drives. History Earl E Masterson from ...
magnetic tape cartridges, slower than disk drives but with a capacity larger than was affordable with disks. The term ''mass storage'' was used in the PC marketplace for devices, such as floppy disk drives, far smaller than devices that were not considered mass storage in the mainframe marketplace. Mass storage devices are characterized by: * Sustainable transfer speed *
Seek time Higher performance in hard disk drives comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories: access time and data transfer time (or rate). Access time The ''access ...
* Cost * Capacity


Storage media

Magnetic disks are the predominant storage media in
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s. Optical discs, however, are almost exclusively used in the large-scale distribution of retail software, music and movies because of the cost and manufacturing efficiency of the molding process used to produce
DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...
and
compact disc The compact disc (CD) is a Digital media, digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then rele ...
s and the nearly-universal presence of reader drives in personal computers and consumer appliances.
Flash memory Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both us ...
(in particular,
NAND flash Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...
) has an established and growing niche as a replacement for magnetic
hard disk A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magnet ...
s in high performance enterprise computing installations due to its robustness stemming from its lack of moving parts, and its inherently much lower latency when compared to conventional magnetic hard drive solutions. Flash memory has also long been popular as removable storage such as
USB stick A USB flash drive (also called a thumb drive) is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, rewritable and much smaller than an optical disc. Most weigh less than . Since first ...
s, where it de facto makes up the market. This is because it scales better cost-wise in lower capacity ranges, as well as its durability. It has also made its way onto
laptops A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...
in the form of
SSDs A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is a ...
, sharing similar reasons with enterprise computing: Namely, markedly high degrees of resistance to physical impact, which is again, due to the lack of moving parts, as well as a performance increase over conventional magnetic hard disks and markedly reduced weight and power consumption. Flash has also made its way onto
cell phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...
s.. The design of
computer architecture In computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, t ...
s and
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
s are often dictated by the mass storage and
bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
technology of their time.. (A discussion of recent trends in mass storage.)


Usage

Mass storage devices used in desktop and most server computers typically have their data organized in a
file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...
. The choice of file system is often important in maximizing the performance of the device: general purpose file systems (such as
NTFS New Technology File System (NTFS) is a proprietary journaling file system developed by Microsoft. Starting with Windows NT 3.1, it is the default file system of the Windows NT family. It superseded File Allocation Table (FAT) as the preferred fil ...
and HFS, for example) tend to do poorly on slow-seeking optical storage such as compact discs. Some
relational database A relational database is a (most commonly digital) database based on the relational model of data, as proposed by E. F. Codd in 1970. A system used to maintain relational databases is a relational database management system (RDBMS). Many relatio ...
s can also be deployed on mass storage devices without an intermediate file system or storage manager.
Oracle An oracle is a person or agency considered to provide wise and insightful counsel or prophetic predictions, most notably including precognition of the future, inspired by deities. As such, it is a form of divination. Description The word '' ...
and
MySQL MySQL () is an open-source relational database management system (RDBMS). Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, and "SQL", the acronym for Structured Query Language. A relational database o ...
, for example, can store table data directly on raw
block device In Unix-like operating systems, a device file or special file is an interface to a device driver that appears in a file system as if it were an ordinary file. There are also special files in DOS, OS/2, and Windows. These special files allow an ...
s. On
removable media Expandable storage is a form of computer storage that is designed to be inserted and removed from a system. Some forms of removable media, such as optical discs, require a reader to be installed in the computer, while others, such as USB flash dr ...
, archive formats (such as
tar archive In computing, tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for Software distribution, distribution or backup purposes. The name is derived from "tape archive", as it was ...
s on
magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...
, which pack file data end-to-end) are sometimes used instead of file systems because they are more
portable Portable may refer to: General * Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work * Portable classroom, a temporary building installed on the grounds of a school to provide a ...
and simpler to
stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...
. On embedded computers, it is common to
memory map In computer science, a memory map is a structure of data (which usually resides in memory itself) that indicates how memory is laid out. The term "memory map" can have different meanings in different contexts. *It is the fastest and most flexible ...
the contents of a mass storage device (usually
ROM Rom, or ROM may refer to: Biomechanics and medicine * Risk of mortality, a medical classification to estimate the likelihood of death for a patient * Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac * ...
or flash memory) so that its contents can be traversed as in-memory data structures or executed directly by programs.


See also

*
Data storage Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are conside ...
for general overview of storage methods **
Computer data storage Computer data storage is a technology consisting of computer components and Data storage, recording media that are used to retain digital data (computing), data. It is a core function and fundamental component of computers. The central pro ...
for storage methods specific to computing field ***
Disk storage Disk storage (also sometimes called drive storage) is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is ...
for both magnetic and optical recording of disks ***
Magnetic tape data storage Magnetic-tape data storage is a system for storing digital information on magnetic tape using digital recording. Tape was an important medium for primary data storage in early computers, typically using large open reels of IBM 7 track, 7-track, ...
***
Computer storage density Density is a measure of the quantity of information bits that can be stored on a given length (''linear density'') of track, area of surface (''areal density''), or in a given volume (''volumetric density'') of a computer storage medium. Generall ...
***
List of device bandwidths This is a list of interface bit rates, is a measure of information transfer rates, or digital bandwidth capacity, at which digital interfaces in a computer or network can communicate over various kinds of buses and channels. The distinction can ...
***
Solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is ...
***
RAM disk Ram, ram, or RAM may refer to: Animals * A male sheep * Ram cichlid, a freshwater tropical fish People * Ram (given name) * Ram (surname) * Ram (director) (Ramsubramaniam), an Indian Tamil film director * RAM (musician) (born 1974), Dutch * ...
***
RAID Raid, RAID or Raids may refer to: Attack * Raid (military), a sudden attack behind the enemy's lines without the intention of holding ground * Corporate raid, a type of hostile takeover in business * Panty raid, a prankish raid by male college ...


Notes


References

{{Authority control Computer storage devices