1.
Linear Tape-Open
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Hewlett Packard Enterprise, IBM and Quantum control the LTO Consortium, which directs development and manages licensing and certification of media and mechanism manufacturers. The standard form-factor of LTO technology goes by the name Ultrium, the seventh generation of LTO Ultrium was released in 2015 and can hold 6.0 TB in a cartridge of the same size. Upon introduction, LTO Ultrium rapidly defined the super tape market segment and has consistently been the best-selling super tape format, LTO is widely used with small and large computer systems, especially for backup. Half-inch magnetic tape has been used for storage for more than 60 years. In the mid 1980s, IBM and DEC put this kind of tape into a single reel, although the physical tape was nominally the same size, the technologies and intended markets were significantly different and there was no compatibility between them. IBM called its format 3480 and designed it to meet the requirements of its mainframe products. DEC originally called theirs CompacTape, but later it was renamed DLT, in the late 1980s, Exabytes Data8 format, derived from Sonys dual-reel cartridge 8 mm video format, saw some popularity, especially with UNIX systems. Sony followed this success with their own now-discontinued 8 mm data format, by the late 1990s, Quantums DLT and Sonys AIT were the leading options for high-capacity tape storage for PC servers and UNIX systems. These technologies were tightly controlled by their owners, consequently, there was little competition between vendors and the prices were relatively high. To counter this, IBM, HP and Seagate formed the LTO Consortium, much of the technology is an extension of the work done by IBM at its Tucson lab during the previous 20 years. Around the time of the release of LTO-1, Seagates magnetic tape division was spun off as Seagate Removable Storage Solutions, later renamed Certance, despite the initial plans for two form-factors of LTO technology, only Ultrium was ever produced. In common usage, LTO generally refers to the Ultrium form factor, as of 2015, seven generations of LTO Ultrium technology have been made available and three more are planned. Between generations, there are strict compatibility rules that describe how, notes Data capacity and speed figures above are for uncompressed data. Most manufacturers list compressed capacities on their marketing material, capacities are often stated on tapes as double the actual value, they assume that data will be compressed with a 2,1 ratio. See Compression below and the table above, the units for data capacity and data transfer rates generally follow the decimal SI prefix convention and not the binary prefix convention. Minimum and maximum reading and writing speeds are drive-dependent, in contrast to other tape technologies, an Ultrium cartridge is rigidly defined by a particular generation of LTO technology and cannot be used in any other way. While Ultrium drives are also defined by a generation, they are required to have some level of compatibility with older generations of cartridges. The rules for compatibility between generations of drives and cartridges is as follows, An Ultrium drive can read data from a cartridge in its own generation and the two prior generations
2.
Computer data storage
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Computer data storage, often called storage or memory, is a technology consisting of computer components and recording media used to retain digital data. It is a function and fundamental component of computers. The central processing unit of a computer is what manipulates data by performing computations, in practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU and slower but larger and cheaper options farther away. In the Von Neumann architecture, the CPU consists of two parts, The control unit and the arithmetic logic unit. The former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data, without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output the result. It would have to be reconfigured to change its behavior and this is acceptable for devices such as desk calculators, digital signal processors, and other specialized devices. Von Neumann machines differ in having a memory in which they store their operating instructions, most modern computers are von Neumann machines. A modern digital computer represents data using the numeral system. Text, numbers, pictures, audio, and nearly any form of information can be converted into a string of bits, or binary digits. The most common unit of storage is the byte, equal to 8 bits, a piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information, or simply data. For example, the works of Shakespeare, about 1250 pages in print. Data is encoded by assigning a bit pattern to each character, digit, by adding bits to each encoded unit, redundancy allows the computer to both detect errors in coded data and correct them based on mathematical algorithms. A random bit flip is typically corrected upon detection, the cyclic redundancy check method is typically used in communications and storage for error detection. A detected error is then retried, data compression methods allow in many cases to represent a string of bits by a shorter bit string and reconstruct the original string when needed. This utilizes substantially less storage for many types of data at the cost of more computation, analysis of trade-off between storage cost saving and costs of related computations and possible delays in data availability is done before deciding whether to keep certain data compressed or not. For security reasons certain types of data may be encrypted in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and this traditional division of storage to primary, secondary, tertiary and off-line storage is also guided by cost per bit. In contemporary usage, memory is usually semiconductor storage read-write random-access memory, typically DRAM or other forms of fast but temporary storage
3.
Jukebox
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A jukebox is a partially automated music-playing device, usually a coin-operated machine, that will play a patrons selection from self-contained media. The classic jukebox has buttons with letters and numbers on them that, coin-operated music boxes and player pianos were the first forms of automated coin-operated musical devices. These instruments used paper rolls, metal disks, or metal cylinders to play a selection on the instrument, or instruments. In the 1890s these devices were joined by machines which used actual recordings instead of physical instruments, in 1890, Louis Glass and William S. The music was heard via one of four listening tubes, Some machines even contained carousels and other mechanisms for playing multiple records. Most machines were capable of holding only one selection, the automation coming from the ability to play that one selection at will. In 1928, Justus P. Seeburg, who was manufacturing player pianos, combined an electrostatic loudspeaker with a player that was coin-operated. This Audiophone machine was wide and bulky, and had eight separate turntables mounted on a rotating Ferris wheel-like device, later versions of the jukebox included Seeburgs Selectophone, with 10 turntables mounted vertically on a spindle. By maneuvering the tone arm up and down, the customer could select from 10 different records, greater levels of automation were gradually introduced. As electrical recording and amplification improved there was increased demand for coin-operated phonographs, as it applies to the use of a jukebox, the terms juking and juker are the correct expressions. Song-popularity counters told the owner of the machine the number of each record was played, with the result that popular records remained. Wallboxes were an important, and profitable, part of any jukebox installation, serving as a remote control, they enabled patrons to select tunes from their table or booth. One example is the Seeburg 3W1, introduced in 1949 as companion to the 100-selection Model M100A jukebox, stereo sound became popular in the early 1960s, and wallboxes of the era were designed with built-in speakers to provide patrons a sample of this latest technology. Initially playing music recorded on wax cylinders, the shellac 78 rpm record dominated jukeboxes in the part of the 20th century. C. D. s, and videos on DVDs were all introduced and used in the last decades of the century, MP3 downloads, and Internet-connected media players came in at the start of the 21st century. The jukeboxs history has followed the wave of technological improvements in music reproduction and distribution, Jukeboxes were most popular from the 1940s through the mid-1960s, particularly during the 1950s. By the middle of the 1940s, three-quarters of the records produced in America went into jukeboxes, while often associated with early rock and roll music, their popularity extends back much earlier, including classical music, opera and the swing music era. In 1977, The Kinks recorded a song called Jukebox Music for their album Sleepwalker, styling progressed from the plain wooden boxes in the early thirties to beautiful light shows with marbelized plastic and color animation in the Wurlitzer 850 Peacock of 1941
4.
Magnetic tape data storage
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Magnetic tape data storage is a system for storing digital information on magnetic tape using digital recording. Modern magnetic tape is most commonly packaged in cartridges and cassettes, the device that performs writing or reading of data is a tape drive. Autoloaders and tape libraries automate cartridge handling, for example, a common cassette-based format is Linear Tape-Open, which comes in a variety of densities and is manufactured by several companies. Sony announced in 2014 that they had developed a storage technology with the highest reported magnetic tape data density,148 Gbit/in². Initially, magnetic tape for storage was wound on 10. 5-inch reels. This de facto standard for computer systems persisted through the late 1980s. Tape cartridges and cassettes were available as early as the mid-1970s and were used with small computer systems. With the introduction of the IBM3480 cartridge in 1984, large computer systems started to move away from open reel tapes, magnetic tape was first used to record computer data in 1951 on the Eckert-Mauchly UNIVAC I. The UNISERVO drive recording medium was a metal strip of 0. 5-inch wide nickel-plated phosphor bronze. Recording density was 128 characters per inch on eight tracks at a speed of 100 in/s. Of the eight tracks, six were data, one was a parity track, making allowance for the empty space between tape blocks, the actual transfer rate was around 7,200 characters per second. A small reel of mylar tape provided separation from the metal tape, IBM computers from the 1950s used ferrous-oxide coated tape similar to that used in audio recording. IBMs technology soon became the de facto industry standard, magnetic tape dimensions were 0. 5-inch wide and wound on removable reels up to 10.5 inches in diameter. Different tape lengths were available with 1,200 feet and 2,400 feet on mil, during the 1980s, longer tape lengths such as 3,600 feet became available using a much thinner PET film. Most tape drives could support a maximum size of 10.5 inches. CDC used IBM compatible 1/2 inch magnetic tapes, but also offered a 1 inch wide variant, a so-called mini-reel was common for smaller data sets, such as for software distribution. These were 7-inch reels, often with no fixed length—the tape was sized to fit the amount of data recorded on it as a cost-saving measure. Early IBM tape drives, such as the IBM727 and IBM729, were mechanically sophisticated floor-standing drives that used vacuum columns to buffer long u-shaped loops of tape
5.
Hard disk drive
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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 manner, meaning that individual blocks of data can be stored or retrieved in any order. HDDs are a type of storage, retaining stored data even when powered off. Introduced by IBM in 1956, HDDs became the dominant secondary storage device for computers by the early 1960s. Continuously improved, HDDs have maintained this position into the era of servers. More than 200 companies have produced HDDs historically, though after extensive industry consolidation most current units are manufactured by Seagate, Toshiba, as of 2016, HDD production is growing, although unit shipments and sales revenues are declining. While SSDs have higher cost per bit, SSDs are replacing HDDs where speed, power consumption, small size, the primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1000, the two most common form factors for modern HDDs are 3. 5-inch, for desktop computers, and 2. 5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA, SATA, Hard disk drives were introduced in 1956, as data storage for an IBM real-time transaction processing computer and were developed for use with general-purpose mainframe and minicomputers. The first IBM drive, the 350 RAMAC in 1956, was approximately the size of two medium-sized refrigerators and stored five million six-bit characters on a stack of 50 disks. In 1962 the IBM350 RAMAC disk storage unit was superseded by the IBM1301 disk storage unit, cylinder-mode read/write operations were supported, and the heads flew about 250 micro-inches above the platter surface. Motion of the head array depended upon a binary system of hydraulic actuators which assured repeatable positioning. The 1301 cabinet was about the size of three home refrigerators placed side by side, storing the equivalent of about 21 million eight-bit bytes, access time was about a quarter of a second. Also in 1962, IBM introduced the model 1311 disk drive, users could buy additional packs and interchange them as needed, much like reels of magnetic tape. Later models of removable pack drives, from IBM and others, became the norm in most computer installations, non-removable HDDs were called fixed disk drives. Some high-performance HDDs were manufactured with one head per track so that no time was lost physically moving the heads to a track, known as fixed-head or head-per-track disk drives they were very expensive and are no longer in production. In 1973, IBM introduced a new type of HDD code-named Winchester and its primary distinguishing feature was that the disk heads were not withdrawn completely from the stack of disk platters when the drive was powered down. Instead, the heads were allowed to land on an area of the disk surface upon spin-down
6.
Optical disc
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The encoding material sits atop a thicker substrate which makes up the bulk of the disc and forms a dust defocusing layer. The encoding pattern follows a continuous, spiral path covering the disc surface. Most optical discs exhibit a characteristic iridescence as a result of the diffraction grating formed by its grooves and this side of the disc contains the actual data and is typically coated with a transparent material, usually lacquer. The reverse side of a disc usually has a printed label, sometimes made of paper. Optical discs are usually between 7.6 and 30 cm in diameter, with 12 cm being the most common size, a typical disc is about 1.2 mm thick, while the track pitch ranges from 1.6 µm to 320 nm. An optical disc is designed to support one of three recording types, read-only, recordable, or re-recordable, write-once optical discs commonly have an organic dye recording layer between the substrate and the reflective layer. Rewritable discs typically contain an alloy recording layer composed of a phase change material, most often AgInSbTe, an alloy of silver, indium, antimony, Optical discs are most commonly used for storing music, video, or data and programs for personal computers. The Optical Storage Technology Association promotes standardized optical storage formats, although optical discs are more durable than earlier audio-visual and data storage formats, they are susceptible to environmental and daily-use damage. Libraries and archives enact optical media preservation procedures to ensure continued usability in the optical disc drive or corresponding disc player. For computer data backup and physical data transfer, optical discs such as CDs and DVDs are gradually being replaced with faster, smaller solid-state devices and this trend is expected to continue as USB flash drives continue to increase in capacity and drop in price. Additionally, music purchased or shared over the Internet has significantly reduced the number of audio CDs sold annually. The first recorded use of an optical disc was in the 1884 when Alexander Graham Bell, Chichester Bell. An early optical disc system existed in 1935, named Lichttonorgel, an early analog optical disc used for video recording was invented by David Paul Gregg in 1958 and patented in the US in 1961 and 1969. This form of optical disc was an early form of the DVD. It is of special interest that U. S, patent 4,893,297, filed 1989, issued 1990, generated royalty income for Pioneer Corporations DVA until 2007 —then encompassing the CD, DVD, and Blu-ray systems. In the early 1960s, the Music Corporation of America bought Greggs patents and his company, american inventor James T. Russell has been credited with inventing the first system to record a digital signal on an optical transparent foil which is lit from behind by a high-power halogen lamp. Russells patent application was first filed in 1966 and he was granted a patent in 1970, following litigation, Sony and Philips licensed Russells patents in the 1980s. Both Greggs and Russells disc are floppy media read in transparent mode, in the Netherlands in 1969, Philips Research physicist, Pieter Kramer invented an optical videodisc in reflective mode with a protective layer read by a focused laser beam U. S
7.
Compact disc
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Compact disc is a digital optical disc data storage format released in 1982 and co-developed by Philips and Sony. The format was developed to store and play only sound recordings but was later adapted for storage of data. The first commercially available Audio CD player, the Sony CDP-101, was released October 1982 in Japan, standard CDs have a diameter of 120 millimetres and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data. The Mini CD has various diameters ranging from 60 to 80 millimetres, they are used for CD singles, storing up to 24 minutes of audio. At the time of the introduction in 1982, a CD could store much more data than a personal computer hard drive. By 2010, hard drives commonly offered as much space as a thousand CDs. In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs, by 2007,200 billion CDs had been sold worldwide. In 2014, revenues from digital music services matched those from physical format sales for the first time. American inventor James T. Russell has been credited with inventing the first system to record information on an optical transparent foil that is lit from behind by a high-power halogen lamp. Russells patent application was first filed in 1966, and he was granted a patent in 1970, following litigation, Sony and Philips licensed Russells patents in the 1980s. The compact disc is an evolution of LaserDisc technology, where a laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s, although originally dismissed by Philips Research management as a trivial pursuit, the CD became the primary focus for Philips as the LaserDisc format struggled. In 1979, Sony and Philips set up a joint task force of engineers to design a new audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980, after their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984, by 1988 CD sales in the United States surpassed those of vinyl LPs, and by 1992 CD sales surpassed those of prerecorded music cassette tapes. The success of the disc has been credited to the cooperation between Philips and Sony, who came together to agree upon and develop compatible hardware. The unified design of the disc allowed consumers to purchase any disc or player from any company. In 1974, L. However, due to the performance of the analog format
8.
DVD
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DVD is a digital optical disc storage format invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. The medium can store any kind of data and is widely used for software. DVDs offer higher capacity than compact discs while having the same dimensions. Pre-recorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD, such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs can be recorded using a DVD recorder. Rewritable DVDs can be recorded and erased many times, DVDs containing other types of information may be referred to as DVD data discs. The OED also states that in 1995, The companies said the name of the format will simply be DVD. Toshiba had been using the name ‘digital video disk’, but that was switched to ‘digital versatile disk’ after computer companies complained that it left out their applications, Digital versatile disc is the explanation provided in a DVD Forum Primer from 2000 and in the DVD Forums mission statement. There were several formats developed for recording video on optical discs before the DVD, Optical recording technology was invented by David Paul Gregg and James Russell in 1958 and first patented in 1961. A consumer optical disc data format known as LaserDisc was developed in the United States and it used much larger discs than the later formats. CD Video used analog video encoding on optical discs matching the established standard 120 mm size of audio CDs, Video CD became one of the first formats for distributing digitally encoded films in this format, in 1993. In the same year, two new optical disc formats were being developed. By the time of the launches for both formats in January 1995, the MMCD nomenclature had been dropped, and Philips and Sony were referring to their format as Digital Video Disc. Representatives from the SD camp asked IBM for advice on the system to use for their disc. Alan E. Bell, a researcher from IBMs Almaden Research Center, got that request and this group was referred to as the Technical Working Group, or TWG. On August 14,1995, an ad hoc group formed from five computer companies issued a release stating that they would only accept a single format. The TWG voted to both formats unless the two camps agreed on a single, converged standard. They recruited Lou Gerstner, president of IBM, to pressure the executives of the warring factions, as a result, the DVD specification provided a storage capacity of 4.7 GB for a single-layered, single-sided disc and 8.5 GB for a dual-layered, single-sided disc
9.
Floppy disk
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Floppy disks are read and written by a floppy disk drive. Floppy disks, initially as 8-inch media and later in 5¼-inch and 3½-inch sizes, were a form of data storage and exchange from the mid-1970s into the mid-2000s. These formats are usually handled by older equipment and these disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. The term floppy disk appeared in print as early as 1970, in 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs, there were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM and GCR. The 5¼-inch format displaced the 8-inch one for most applications, the most common capacity of the 5¼-inch format in DOS-based PCs was 360 kB and in 1984 IBM introduced the 1.2 MB dual-sided floppy disk along with its PC-AT model. IBM started using the 720 kB double-density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and these disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB DSED diskettes in its top-of-the-line PS/2 models, throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be practical than the 8-inch format, it was itself too large, as the quality of recording media grew. A number of solutions were developed, with drives at 2-, 2½-, 3-, 3½-, the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a number of manufacturers, was then rapidly adopted. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk. Floppy disks became ubiquitous during the 1980s and 1990s in their use with computers to distribute software, transfer data. Before hard disks became affordable to the population, floppy disks were often used to store a computers operating system. Most home computers from that period have a primary OS and BASIC stored as ROM, by the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were a five billion standard floppy disks in use. Then, distribution of packages was gradually replaced by CD-ROMs, DVDs. External USB-based floppy disk drives are available, many modern systems provide firmware support for booting from such drives
10.
Oracle Corporation
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Oracle Corporation is a multinational computer technology corporation, headquartered in Redwood Shores, California. In 2015 Oracle was the second-largest software maker by revenue, after Microsoft, larry Ellison co-founded Oracle Corporation in 1977 with Bob Miner and Ed Oates under the name Software Development Laboratories. Ellison took inspiration from the 1970 paper written by Edgar F. Codd on relational database management systems named A Relational Model of Data for Large Shared Data Banks and he heard about the IBM System R database from an article in the IBM Research Journal provided by Oates. Also derived from Codds theories, Ellison wanted to make Oracles product compatible with System R, SDL changed its name to Relational Software, Inc in 1979, then again to Oracle Systems Corporation in 1982, to align itself more closely with its flagship product Oracle Database. At this stage Bob Miner served as the senior programmer. In 1995, Oracle Systems Corporation changed its name to Oracle Corporation, officially named Oracle, but sometimes referred to as Oracle Corporation, part of Oracle Corporations early success arose from using the C programming language to implement its products. This eased porting to different operating systems, many of the products have been added to Oracles portfolio through acquisitions. Oracles E-delivery service provides generic downloadable Oracle software and documentation, Oracle Database Release 10, In 2004, Oracle Corporation shipped release 10g as the then latest version of Oracle Database. Release 11, Release 11g became the current Oracle Database version in 2007, Oracle Corporation released Oracle Database 11g Release 2 in September 2009. This version was available in four commercial editions—Enterprise Edition, Standard Edition, Standard Edition One, the licensing of these editions shows various restrictions and obligations that are considered complex. The Enterprise Edition, the most expensive of the Database Editions, has the fewest restrictions —, Oracle Corporation constrains the Standard Edition and Standard Edition One with more licensing restrictions, in accordance with their lower price. Release 12, Release 12c became available on July 1,2013, Oracle acquired Rdb in 1994 from Digital Equipment Corporation. Oracle has since made many enhancements to product and development continues as of 2008. Released in 2008, the Oracle Beehive collaboration software provides team workspaces, email, calendar, instant messaging, customers can use Beehive as licensed software or as software as a service. Oracle also sells a suite of business applications, users can access these facilities through a browser interface over the Internet or via a corporate intranet. The Social Engagement and Monitoring cloud provides the most effective and efficient responses across social, SEM is able to route correct responses to the right team, member, or customer-experience channel to ensure the best customer service. The analysis helps vendors to understand what is important to customers and it identifies trends, spikes, and anomalies to make real-time course corrections. It also can identify brand advocates, the SEM cloud identifies customer intention and interests by analyzing the common ways customers talk about a product or a service
11.
Barcode
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A barcode is an optical, machine-readable, representation of data, the data usually describes something about the object that carries the barcode. Originally barcodes systematically represented data by varying the widths and spacings of parallel lines, later two-dimensional codes were developed, using rectangles, dots, hexagons and other geometric patterns in two dimensions, usually called barcodes although they do not use bars as such. Barcodes originally were scanned by special optical scanners called barcode readers, later applications software became available for devices that could read images, such as smartphones with cameras. An early use of one type of barcode in a context was sponsored by the Association of American Railroads in the late 1960s. Two plates were used per car, one on side, with the arrangement of the colored stripes encoding information such as ownership, type of equipment. The plates were read by a scanner, located for instance, at the entrance to a classification yard. The project was abandoned after ten years because the system proved unreliable after long-term use. Barcodes became commercially successful when they were used to automate supermarket checkout systems and their use has spread to many other tasks that are generically referred to as automatic identification and data capture. The very first scanning of the now ubiquitous Universal Product Code barcode was on a pack of Wrigley Company chewing gum in June 1974, silver told his friend Norman Joseph Woodland about the request, and they started working on a variety of systems. Their first working system used ultraviolet ink, but the ink faded too easily and was expensive, convinced that the system was workable with further development, Woodland left Drexel, moved into his fathers apartment in Florida, and continued working on the system. His next inspiration came from Morse code, and he formed his first barcode from sand on the beach, I just extended the dots and dashes downwards and made narrow lines and wide lines out of them. To read them, he adapted technology from optical soundtracks in movies and he later decided that the system would work better if it were printed as a circle instead of a line, allowing it to be scanned in any direction. The patent was issued on 7 October 1952 as US Patent 2,612,994, in 1951, Woodland moved to IBM and continually tried to interest IBM in developing the system. IBM offered to buy the patent, but its offer was not high enough, philco purchased their patent in 1962 and then sold it to RCA sometime later. During his time as an undergraduate, David Collins worked at the Pennsylvania Railroad, immediately after receiving his masters degree from MIT in 1959, he started work at GTE Sylvania and began addressing the problem. He developed a system called KarTrak using blue and red reflective stripes attached to the side of the cars, encoding a six-digit company identifier, light reflected off the stripes was fed into one of two photomultipliers, filtered for blue or red. The Boston and Maine Railroad tested the KarTrak system on their cars in 1961. The tests continued until 1967, when the Association of American Railroads selected it as a standard, Automatic Car Identification, the installations began on 10 October 1967
12.
Tape drive
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A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is used for offline, archival data storage. Tape media generally has a unit cost and a long archival stability. A tape drive provides sequential access storage, unlike a hard disk drive, a disk drive can move to any position on the disk in a few milliseconds, but a tape drive must physically wind tape between reels to read any one particular piece of data. As a result, tape drives have very slow average seek times to data, however, tape drives can stream data very quickly off a tape when the required position has been reached. For example, as of 2010 Linear Tape-Open supported continuous data transfer rates of up to 140 MB/s, magnetic tape drives were first used for data storage on mainframe computers in the 1950s, with capacities less than one megabyte. As technology advanced, capacities increased to 10 terabytes or higher of uncompressed data per cartridge as of 2014, in early computer systems, magnetic tape might be the main storage medium, although the drives were expensive, the tapes were inexpensive. The true storage capacity is known as the native capacity or the raw capacity. IBM and Sony have also used higher compression ratios in their marketing materials, the compression ratio actually achievable depends on the data being compressed. Some data has little redundancy, large files, for example, already use compression technology. A sparse database, on the hand, may allow compression ratios better than 10,1. Tape drives can be connected to a computer with SCSI, Fibre Channel, SATA, USB, FireWire, FICON, or other interfaces. Tape drives are used with autoloaders and tape libraries which automatically load, unload, in the early days of home computing, floppy and hard disk drives were very expensive. Many computers had an interface to store data via a tape recorder. Simple dedicated tape drives, such as the professional DECtape and the home ZX Microdrive, however, the drop in disk drive prices made such alternatives obsolete. In this situation, the modern fast-running tape drive is unable to stop the tape instantly, instead, the drive must decelerate and stop the tape, rewind it a short distance, restart it, position back to the point at which streaming stopped and then resume the operation. If the condition repeats, the resulting back-and-forth tape motion resembles that of shining shoes with a cloth, shoe-shining decreases the attainable data transfer rate, drive and tape life, and tape capacity. In early tape drives, non-continuous data transfer was normal and unavoidable, computer processing power and amounts of available memory were usually insufficient to provide a constant stream, so tape drives were typically designed for so called start-stop operation
