Mass storage

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In computing, mass storage refers to the storage of large amounts of data 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 as for example with floppy disks on personal computers.

Contents

Devices and/or systems that have been described as mass storage include tape libraries, RAID systems, and a variety of computer drives such as hard disk drives, magnetic tape drives, magneto-optical disc drives, optical disc drives, memory cards, and solid-state drives. It also includes experimental forms like holographic memory. Mass storage includes devices with removable and non-removable media. [1] [2] It does not include random access memory (RAM).

There are two broad classes of mass storage: local data in devices such as smartphones or computers, 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. As for Enterprise and data centers, storage tiers have established using a mix of SSD and HDD. [3]

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 technology.

Papers [4] [5] [6] at the 1966 Fall Joint Computer Conference [7] (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 (Terabit Memory) using video tape, Precision Industries (Unicon 690-212) using lasers and International Video (IVC-1000) using video tape [8] and states "In the literature, the most common definition of mass storage capacity is a trillion bits.". [9] The first IEEE conference on mass storage was held in 1974 [10] and at that time identified mass storage as "capacity on the order of 1012 bits" (1 gigabyte). [11] In the mid-1970s IBM used the term to in the name of the IBM 3850 Mass Storage System, which provided virtual disks backed up by Helical scan magnetic tape cartridges, slower than disk drives but with a capacity larger than was affordable with disks. [12] The term mass storage was used in the PC marketplace for devices, such as floppy disk drives, far smaller than devices that were not [lower-alpha 1] considered mass storage in the mainframe marketplace.

Mass storage devices are characterized by:

Storage media

Magnetic disks are the predominant storage media in personal computers. 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 and compact discs and the nearly-universal presence of reader drives in personal computers and consumer appliances. [13] Flash memory (in particular, NAND flash) has an established and growing niche as a replacement for magnetic hard disks 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 sticks, 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 in the form of SSDs, 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 phones. [14] [15]

The design of computer architectures and operating systems are often dictated by the mass storage and bus technology of their time. [16]

Usage

Mass storage devices used in desktop and most server computers typically have their data organized in a file system. The choice of file system is often important in maximizing the performance of the device: general purpose file systems (such as NTFS and HFS, for example) tend to do poorly on slow-seeking optical storage such as compact discs.

Some relational databases can also be deployed on mass storage devices without an intermediate file system or storage manager. Oracle and MySQL, for example, can store table data directly on raw block devices.

On removable media, archive formats (such as tar archives on magnetic tape, which pack file data end-to-end) are sometimes used instead of file systems because they are more portable and simpler to stream.

On embedded computers, it is common to memory map the contents of a mass storage device (usually ROM or flash memory) so that its contents can be traversed as in-memory data structures or executed directly by programs.

See also

Notes

  1. ↑ E.g., the obsolete 1956 IBM 350 stored 5 million six-bit characters, larger than contemporary 1.44 and 2.88 MB floppies.

Related Research Articles

<span class="mw-page-title-main">Computer data storage</span> Storage of digital data readable by computers

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.

<span class="mw-page-title-main">Disk storage</span> General category of storage mechanisms

Disk 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 a device implementing such a storage mechanism. Notable types are hard disk drives (HDD) containing one or more non-removable rigid platters, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives (ODD) and associated optical disc media.

A disk operating system (DOS) is a computer operating system that resides on and can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc. A disk operating system provides a file system for organizing, reading, and writing files on the storage disk, and a means for loading and running programs stored on that disk. Strictly speaking, this definition does not include any other functionality, so it does not apply to more complex OSes, such as Microsoft Windows, and is more appropriately used only for older generations of operating systems.

<span class="mw-page-title-main">Floppy disk</span> Removable disk storage medium

A floppy disk or floppy diskette is a 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 with a fabric that removes dust particles from the spinning disk. Floppy disks store digital data which can be read and written when the disk is inserted into a floppy disk drive (FDD) connected to or inside a computer or other device.

<span class="mw-page-title-main">Hard disk drive</span> Electro-mechanical data storage device

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 magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small rectangular box.

In computing, a removable media is a data storage media that is designed to be readily inserted and removed from a system. Most early removable media, such as floppy disks and optical discs, require a dedicated read/write device to be installed in the computer, while others, such as USB flash drives, are plug-and-play with all the hardware required to read them built into the device, so only need a driver software to be installed in order to communicate with the device. Some removable media readers/drives are integrated into the computer case, while others are standalone devices that need to be additionally installed or connected.

Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. It is also referred to as data decay, data rot or bit rot. This results in a decline in data quality over time, even when the data is not being utilized.

<span class="mw-page-title-main">USB flash drive</span> Data storage device

A flash drive is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz). Since first offered for sale in late 2000, the storage capacities of USB drives range from 8 to 256 gigabytes (GB), 512 GB and 1 terabyte (TB). As of 2023, 2 TB flash drives were the largest currently in production. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances.

Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data.

<span class="mw-page-title-main">Magnetic storage</span> Recording of data on a magnetizable medium

Magnetic storage or magnetic recording is the storage of data on a magnetized medium. Magnetic storage uses different patterns of magnetisation in a magnetizable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads.

Reading is an action performed by computers, to acquire data from a source and place it into their volatile memory for processing. Computers may read information from a variety of sources, such as magnetic storage, the Internet, or audio and video input ports. Reading is one of the core functions of a Turing machine.

Density is a measure of the quantity of information bits that can be stored on a given length of track, area of the surface, or in a given volume of a computer storage medium. Generally, higher density is more desirable, for it allows more data to be stored in the same physical space. Density therefore has a direct relationship to storage capacity of a given medium. Density also generally affects the performance within a particular medium, as well as price.

Hierarchical storage management (HSM), also known as Tiered storage, is a data storage and Data management technique that automatically moves data between high-cost and low-cost storage media. HSM systems exist because high-speed storage devices, such as solid state drive arrays, are more expensive than slower devices, such as hard disk drives, 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. 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 fast devices.

Write once read many (WORM) describes a data storage device in which information, once written, cannot be modified. This write protection affords the assurance that the data cannot be tampered with once it is written to the device, excluding the possibility of data loss from human error, computer bugs, or malware.

<span class="mw-page-title-main">Optical storage</span> Method to store and retrieve computer data using optics

Optical storage refers to a class of data storage systems that use light to read or write data to an underlying optical media. Although a number of optical formats have been used over time, the most common examples are optical disks like the compact disc (CD) and DVD. Reading and writing methods have also varied over time, but most modern systems as of 2023 use lasers as the light source and use it both for reading and writing to the discs. Britannica notes that it "uses low-power laser beams to record and retrieve digital (binary) data."

In computing, a hybrid drive is a logical or physical storage device that combines a faster storage medium such as solid-state drive (SSD) with a higher-capacity hard disk drive (HDD). The intent is adding some of the speed of SSDs to the cost-effective storage capacity of traditional HDDs. The purpose of the SSD in a hybrid drive is to act as a cache for the data stored on the HDD, improving the overall performance by keeping copies of the most frequently used data on the faster SSD drive.

In computing, external storage refers to non-volatile (secondary) data storage outside a computer's own internal hardware, and thus can be readily disconnected and accessed elsewhere. Such storage devices may refer to removable media, compact flash drives, portable storage devices, or network-attached storage. Web-based cloud storage is the latest technology for external storage.

<span class="mw-page-title-main">Solid-state drive</span> Computer storage device with no moving parts

A solid-state drive (SSD) is a solid-state storage device. It provides persistent data storage using no moving parts.

This glossary of computer hardware terms is a list of definitions of terms and concepts related to computer hardware, i.e. the physical and structural components of computers, architectural issues, and peripheral devices.

Solid-state storage (SSS) is non-volatile computer storage that has no moving parts – uses only electronic circuits. This solid-state design dramatically differs from the commonly-used competing technology of electromechanical magnetic storage which uses moving media coated with magnetic material. Generally, SSS is much faster, but is more expensive.

References

  1. ↑ "Definition of: mass storage". PC Magazine . Ziff Davis. Archived from the original on 2016-07-05. Retrieved 2019-10-10.
  2. ↑ Sterling, Thomas; Anderson, Matthew; Brodowicz, Maciej (2018). "17 – Mass storage". High performance computing. Morgan Kaufmann (Elsevier). ISBN   978-0-12-420158-3.
  3. ↑ https://www.hyperstone.com/en/NAND-Flash-is-displacing-hard-disk-drives-1249,12728.html, NAND Flash is displacing Hard Disk Drives, Retrieved 29. May 2018
  4. ↑ 1966FJCC, pp. 711–742, TECHNOLOGIES AND SYSTEMS FOR ULTRA-HIGH CAPACITY STORAGE.
  5. ↑ 1966FJCC, pp. 711–716, UNICON Computer Mass Memory System, C.H.BECKER.
  6. ↑ 1966FJCC, pp. 735–742, A Photo-Digital Mass Storage System, J. D. KUEHLER, H. R. KERBY.
  7. ↑ Unknown (1966). 1966 Fall Joint Computer Conference. AFIPS Conference Proceedings. Vol. 29. Spartan Books. doi:10.1145/1464291. ISBN   978-1-4503-7893-2. 1966FJCC.
  8. ↑ Norman F. Schneidewind; Gordon H. Syms; Thomas L. Grainger; Robert J. Carden (July 1972). A SURVEY AND ANALYSIS OF HIGH DENSITY MASS STORAGE DEVICES AND SYSTEMS (Report). US Navy Postgraduate School, Monterey CA. CiteSeerX   10.1.1.859.1517 . NPS-55SS72071A.
  9. ↑ NPS-55SS72071A, p. 6, A. Definition and Uses of Mass Storage.
  10. ↑ The 35th conference was held in 2019.
  11. ↑ Bacon, G. C. (October 1974). "Mass Storage Workshop Report". Computer. 7 (10). IEEE: 64–65. doi:10.1109/MC.1974.6323336. S2CID   29301138 . Retrieved December 3, 2020.
  12. ↑ Introduction to the IBM 3850 Mass Storage System (MSS) (PDF) (Second ed.). IBM. November 1974. GA32-0028-1.
  13. ↑ Taylor, Jim. "DVD FAQ". Archived from the original on 2009-08-22. Retrieved 2007-07-08. In 2003, six years after introduction, there were over 250 million DVD playback devices worldwide, counting DVD players, DVD PCs, and DVD game consoles.
  14. ↑ Gonsalves, Antone (23 May 2007). "Micron predicts flash memory will replace disk drives". EETimes ..
  15. ↑ Heingartner, Douglas (2005-02-17). "Flash Drives: Always on the Go, Without Moving Parts". New York Times . Retrieved 2008-02-24..
  16. ↑ Patterson, Dave (June 2003). "A Conversation With Jim Gray". ACM Queue . 1 (4). Archived from the original on April 21, 2005.. (A discussion of recent trends in mass storage.)
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