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Shingled Recording
Shingled magnetic recording (SMR) is a magnetic storage data recording technology used in hard disk drives (HDDs) to increase storage density and overall per-drive storage capacity. Conventional hard disk drives record data by writing non-overlapping magnetic tracks parallel to each other (perpendicular magnetic recording, PMR), while shingled recording writes new tracks that overlap part of the previously written magnetic track, leaving the previous track narrower and allowing for higher track density. Thus, the tracks partially overlap similar to roof shingles. This approach was selected because, if the writing head is made too narrow, it cannot provide the very high fields required in the recording layer of the disk. The overlapping-tracks architecture complicates the writing process since writing to one track also overwrites an adjacent track. If adjacent tracks contain valid data, they must be rewritten as well. As a result, SMR drives are divided into many append-only (seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMR HDD Rewrite
SMR may refer to: Organisations * Seattle Mountain Rescue, American non-profit * Solomon Mahlangu Regiment of the South African Army * Swedish Resistance Movement, a neo-Nazi political party Places * San Marino (by ISO 3166-1, IOC and FIFA country code) * Rimba Secondary School (), Brunei * Simón Bolívar International Airport (Colombia) (by IATA code) * Tell Kazel (Ancient Egyptian: ''Smr''), archaeological site in Syria Railways * Snowdon Mountain Railway, Gwynedd, Wales * South Maitland Railway, NSW, Australia * Stapleford Miniature Railway, Melton Mowbray, England Science and technology Biology and medicine * Sensorimotor rhythm, a brain wave rhythm * Standardized mortality ratio, in epidemiology * Suppressed mite reproduction, a trait in honey bees, see varroa sensitive hygiene Computing * Shingled magnetic recording, a hard disk storage method * State machine replication in distributed computing * Symbolic Music Representation in MPEG-4 Part 3 Other uses i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toshiba
, commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors, hard disk drives (HDD), printers, batteries, lighting, as well as IT solutions such as quantum cryptography which has been in development at Cambridge Research Laboratory, Toshiba Europe, located in the United Kingdom, now being commercialised. It was one of the biggest manufacturers of personal computers, consumer electronics, home appliances, and medical equipment. As a semiconductor company and the inventor of flash memory, Toshiba had been one of the top 10 in the chip industry until its flash memory unit was spun off as Toshiba Memory, later Kioxia, in the late 2010s. The Toshiba name is derived from its former name, Tokyo Shibaura Denki K.K. (Tokyo Shibaura Electri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resilvering
In data storage, disk mirroring is the replication of logical disk volumes onto separate physical hard disks in real time to ensure continuous availability. It is most commonly used in RAID 1. A mirrored volume is a complete logical representation of separate volume copies. In a disaster recovery context, mirroring data over long distance is referred to as storage replication. Depending on the technologies used, replication can be performed synchronously, asynchronously, semi-synchronously, or point-in-time. Replication is enabled via microcode on the disk array controller or via server software. It is typically a proprietary solution, not compatible between various data storage device vendors. Mirroring is typically only synchronous. Synchronous writing typically achieves a recovery point objective (RPO) of zero lost data. Asynchronous replication can achieve an RPO of just a few seconds while the remaining methodologies provide an RPO of a few minutes to perhaps sever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 also sometimes called a semiconductor storage device, a solid-state device or a solid-state disk, even though SSDs lack the physical spinning disks and movable read–write heads used in hard disk drives (HDDs) and floppy disks. SSD also has rich internal parallelism for data processing. In comparison to hard disk drives and similar electromechanical media which use moving parts, SSDs are typically more resistant to physical shock, run silently, and have higher input/output rates and lower latency. SSDs store data in semiconductor cells. cells can contain between 1 and 4 bits of data. SSD storage devices vary in their properties according to the number of bits stored in each cell, with single-bit cells ("Single Level Cells" or "SLC") ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flash Memory Controller
A flash memory controller (or flash controller) manages data stored on flash memory (usually NAND flash) and communicates with a computer or electronic device. Flash memory controllers can be designed for operating in low duty-cycle environments like memory cards, or other similar media for use in PDAs, mobile phones, etc. USB flash drives use flash memory controllers designed to communicate with personal computers through the USB port at a low duty-cycle. Flash controllers can also be designed for higher duty-cycle environments like solid-state drives (SSD) used as data storage for laptop computer systems up to mission-critical enterprise storage arrays. Initial setup After a flash storage device is initially manufactured, the flash controller is first used to format the flash memory. This ensures the device is operating properly, it maps out bad flash memory cells, and it allocates spare cells to be substituted for future failed cells. Some part of the spare cells is also used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disk Controller
{{unreferenced, date=May 2010 The disk controller is the controller circuit which enables the CPU to communicate with a hard disk, floppy disk or other kind of disk drive. It also provides an interface between the disk drive and the bus connecting it to the rest of the system. Early disk controllers were identified by their storage methods and data encoding. They were typically implemented on a separate controller card. Modified frequency modulation (MFM) controllers were the most common type in small computers, used for both floppy disk and hard disk drives. Run length limited (RLL) controllers used data compression to increase storage capacity by about 50%. Priam created a proprietary storage algorithm that could double the disk storage. Shugart Associates Systems Interface ( SASI) was a predecessor to SCSI. Modern disk controllers are integrated into the disk drive as peripheral controllers. For example, disks called "SCSI disks" have built-in SCSI controllers. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azimuth Recording
Azimuth recording is the use of a variation in angle between two recording heads that are recording data so close together on magnetic tape that crosstalk would otherwise likely occur. Normally, the head is perpendicular to the movement of the tape, and this is considered zero degrees. However, if the heads are mounted at slightly different angles (such as ±7 degrees in VHS), destructive interference will occur at high frequencies when reading data recorded in the cross-talking channel but not in the channel that is intended to be read. At low frequencies relative to the maximum allowed by the head gap, however, this technique is ineffective. Thus one head is slanted slightly leftwards and the magnetic gap of the other head slanted slightly rightwards. To look at it another way, channel A sees the channel B data stretched out in time, hence the technique has a low-pass effect on noise intruding from another channel. Every videotape system was designed to put as much video as pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betamax
Betamax (also known as Beta, as in its logo) is a consumer-level analog recording and cassette format of magnetic tape for video, commonly known as a video cassette recorder. It was developed by Sony and was released in Japan on May 10, 1975, followed by the US in November of the same year. Betamax is widely considered to be obsolete, having lost the videotape format war which saw its closest rival, VHS, dominate most markets. Despite this, Betamax recorders continued to be manufactured and sold until August 2002, when Sony announced that they were discontinuing production of all remaining Betamax models. Sony continued to sell Betamax cassettes until March 2016. Original version Launch and early models The first Betamax device introduced in the United States was the LV-1901 console, which included a color monitor, and appeared in stores in early November 1975. The cassettes contain videotape in a design similar to that of the earlier, professional , U-matic format. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Cassette Recorders
A videocassette recorder (VCR) or video recorder is an electromechanical device that records analog audio and analog video from broadcast television or other source on a removable, magnetic tape videocassette, and can play back the recording. Use of a VCR to record a television program to play back at a more convenient time is commonly referred to as '' timeshifting''. VCRs can also play back prerecorded tapes. In the 1980s and 1990s, prerecorded videotapes were widely available for purchase and rental, and blank tapes were sold to make recordings. VCRs declined in popularity during the early 2000s and in July 2016, Funai Electric, the last manufacturer of them ceased production. History Early machines and formats The history of the videocassette recorder follows the history of videotape recording in general. Ampex introduced the quadruplex videotape professional broadcast standard format with its Ampex VRX-1000 in 1956. It became the world's first commercially suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 RCA patented the first helical scan method in 1950 after stealing it from German engineer Eduard Schüller. Eduard Schüller developed an actually working helical scan method of recording in 1953 while working at AEG. With the advent of television broadcasting in Japan in the early 1950s, they saw the need for magnetic television signal recording. Dr. Kenichi Sawazaki developed a prototype helical scan recorder in 1954. Gallery Bcn-scanner-head.jpg, Type B videotape video scanner head Vxa1-drive-nocover-nobezel-front.jpg, rotary head visible in a VXA computer tape drive Vxa1-drive-nocover-top-front.jpg, VXA tape drive, alternate view of rotary head and loading mechanism See also * Type A videotape *1 inch type B videotape *1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Action
A class action, also known as a class-action lawsuit, class suit, or representative action, is a type of lawsuit where one of the parties is a group of people who are represented collectively by a member or members of that group. The class action originated in the United States and is still predominantly a US phenomenon, but Canada, as well as several European countries with civil law, have made changes in recent years to allow consumer organizations to bring claims on behalf of consumers. Description In a typical class action, a plaintiff sues a defendant or a number of defendants on behalf of a group, or class, of absent parties. This differs from a traditional lawsuit, where one party sues another party, and all of the parties are present in court. Although standards differ between states and countries, class actions are most common where the allegations usually involve at least 40 people who the same defendant has injured in the same way. Instead of each damaged person brin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Data
In computer storage, cold data refers to data that is rarely accessed, therefore considered "cold". Cold data is the opposite of hot data, which is data that is frequently accessed. To optimize storage costs, cold data can be stored on lower performing and less expensive storage media. For example, solid state disks may be used for storing hot data, while cold data can be moved to hard drives, optical discs, tapes or migrated to cloud storage. Enterprise Storage Forum See also * Hierarchical storage management * |
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