 Page 2Page 2A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and a long archival stability.
A tape drive provides sequential access storage, unlike a hard disk drive, which provides direct access storage. 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 large average access times. However, tape drives can stream data very quickly off a tape when the required position has been reached. For example, as of 2017[update] Linear Tape-Open (LTO) supports continuous data transfer rates of up to 360 MB/s, a rate comparable to hard disk drives. An external QIC tape drive Magnetic tape drives with capacities of less than one megabyte were first used for data storage on mainframe computers in the 1950s. As of 2018[update], capacities of 20 terabytes or higher of uncompressed data per cartridge were available. In early computer systems, magnetic tape served as the main storage medium because although the drives were expensive, the tapes were inexpensive. Some computer systems ran the operating system on tape drives such as DECtape. DECtape had fixed-size indexed blocks that could be rewritten without disturbing other blocks, so DECtape could be used like a slow disk drive. Data tape drives may use advanced data integrity techniques such as multilevel forward error correction, shingling, and linear serpentine layout for writing data to tape. Tape drives can be connected to a computer with SCSI, Fibre Channel, SATA, USB, FireWire, FICON, or other interfaces.[a] Tape drives are used with autoloaders and tape libraries which automatically load, unload, and store multiple tapes, increasing the volume of data which can be stored without manual intervention. In the early days of home computing, floppy and hard disk drives were very expensive. Many computers had an interface to store data via an audio tape recorder, typically on Compact Cassettes. Simple dedicated tape drives, such as the professional DECtape and the home ZX Microdrive and Rotronics Wafadrive, were also designed for inexpensive data storage. However, the drop in disk drive prices made such alternatives obsolete. Data compressionAs some data can be compressed to a smaller size than the original files, it has become commonplace when marketing tape drives to state the capacity with the assumption of a 2:1 compression ratio; thus a tape with a capacity of 80 GB would be sold as "80/160". The true storage capacity is also known as the native capacity or the raw capacity. The compression ratio actually achievable depends on the data being compressed. Some data has little redundancy; large video files, for example, already use compression and cannot be compressed further. A database with repetitive entries, on the other hand, may allow compression ratios better than 10:1. Technical limitationsA disadvantageous effect termed shoe-shining occurs during read/write if the data transfer rate falls below the minimum threshold at which the tape drive heads were designed to transfer data to or from a continuously running tape. 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 available memory were usually insufficient to provide a constant stream, so tape drives were typically designed for start-stop operation. Early drives used very large spools, which necessarily had high inertia and did not start and stop moving easily. To provide high start, stop and seek performance, several feet of loose tape was played out and pulled by a suction fan down into two deep open channels on either side of the tape head and capstans. The long thin loops of tape hanging in these vacuum columns had far less inertia than the two reels and could be rapidly started, stopped and repositioned. The large reels would move as required to keep the slack tape in the vacuum columns. Later, most tape drives of the 1980s introduced the use of an internal data buffer to somewhat reduce start-stop situations.[b] These drives are often referred to as tape streamers. The tape was stopped only when the buffer contained no data to be written, or when it was full of data during reading. As faster tape drives became available, despite being buffered, the drives started to suffer from the shoe-shining sequence of stop, rewind, start. Some newer drives have several speeds and implement algorithms that dynamically match the tape speed level to the computer's data rate. Example speed levels could be 50 percent, 75 percent and 100 percent of full speed. A computer that streams data slower than the lowest speed level (e.g., at 49 percent) will still cause shoe-shining. Magnetic tape is commonly housed in a casing known as a cassette or cartridge—for example, the 4-track cartridge and the Compact Cassette. The cassette contains magnetic tape to provide different audio content using the same player. The outer shell, made of plastic, sometimes with metal plates and parts, permits ease of handling of the fragile tape, making it far more convenient and robust than having spools of exposed tape. Simple analog cassette audio tape recorders were commonly used for data storage and distribution on home computers at a time when floppy disk drives were very expensive. The Commodore Datasette was a dedicated data version using the same media.
Manufacturers often specify the capacity of tapes using data compression techniques; compressibility varies for different data (commonly 2:1 to 8:1), and the specified capacity may not be attained for some types of real data. As of 2014[update], tape drives capable of higher capacity were still being developed. In 2011, Fujifilm and IBM announced that they had been able to record 29.5 billion bits per square inch with magnetic tape media developed using the BaFe particles and nanotechnologies, allowing drives with true (uncompressed) tape capacity of 35 TB.[17][18] The technology was not expected to be commercially available for at least a decade. In 2014, Sony and IBM announced that they had been able to record 148 billion bits per square inch with magnetic tape media developed using a new vacuum thin-film forming technology able to form extremely fine crystal particles, allowing true tape capacity of 185 TB.[19][20]
Page 2The 3M Company (originally Minnesota Mining and Manufacturing Company) is an American multinational conglomerate corporation operating in the fields of industry, worker safety, U.S. health care, and consumer goods.[5] The company produces over 60,000 products under several brands,[6] including adhesives, abrasives, laminates, passive fire protection, personal protective equipment, window films, paint protection films, dental and orthodontic products, electrical and electronic connecting and insulating materials, medical products, car-care products,[7] electronic circuits, healthcare software and optical films.[8] It is based in Maplewood, a suburb of Saint Paul, Minnesota.[9] 3M headquarters in Maplewood, Minnesota FormerlyMinnesota Mining and Manufacturing Company (1902–2002)TypePublicTraded as
Two Harbors, Minnesota, U.S.[1]Founders
Maplewood, Minnesota ,U.S. Area served WorldwideKey people Mike Roman(Chairman, President, & CEO)[3]Revenue Operating income Net income Number of employees c. 95,000 (December 2021)[4]Websitewww.3m.com3M made $35.4 billion in total sales in 2021, and ranked number 102 in the Fortune 500 list of the largest United States corporations by total revenue.[10] As of 2021[update], the company had approximately 95,000 employees, and had operations in more than 70 countries.[4] Five businessmen founded the Minnesota Mining and Manufacturing Company as a mining venture in Two Harbors, Minnesota, making their first sale on June 13, 1902.[1][11] The goal was to mine corundum, but this failed because the mine's mineral holdings were anorthosite, which had no commercial value.[11] Co-founder John Dwan solicited funds in exchange for stock and Edgar Ober and Lucius Ordway took over the company in 1905.[11] The company moved to Duluth and began researching and producing sandpaper products.[11] William L. McKnight, later a key executive, joined the company in 1907, and A. G. Bush joined in 1909.[11] 3M finally became financially stable in 1916 and was able to pay dividends.[11] The company moved to St. Paul in 1910, where it remained for 52 years before outgrowing the campus and moving to its current headquarters at 3M Center in Maplewood, Minnesota, in 1962.[12] The John Dwan Office Building, where 3M was founded, now a museum Expansion and modern historyIn 1947, 3M began producing perfluorooctanoic acid (PFOA) by electrochemical fluorination.[13] In 1951, DuPont purchased PFOA from then-Minnesota Mining and Manufacturing Company for use in the manufacturing of teflon, a product that brought DuPont a billion-dollar-a-year profit by the 1990s.[14] DuPont referred to PFOA as C8.[15] The original formula for Scotchgard, a water repellent applied to fabrics, was discovered accidentally in 1952 by 3M chemists Patsy Sherman and Samuel Smith. Sales began in 1956, and in 1973 the two chemists received a patent for the formula.[16][17] In the late 1950s, 3M produced the first asthma inhaler,[18] but the company did not enter the pharmaceutical industry until the mid-1960s with the acquisition of Riker Laboratories, moving it from California to Minnesota.[19] 3M retained the Riker Laboratories name for the subsidiary until at least 1985.[20] In the mid-1990s, 3M Pharmaceuticals, as the division came to be called, produced the first CFC-free asthma inhaler in response to adoption of the Montreal Protocol by the United States.[21][22] In the 1980s and 1990s, the company spent fifteen years developing a topical cream delivery technology which led in 1997 to health authority approval and marketing of a symptomatic treatment for genital warts, Aldara.[23][24] 3M divested its pharmaceutical unit through three deals in 2006, netting more than US$2 billion.[25][26] At the time, 3M Pharmaceuticals comprised about 20% of 3M's health care business and employed just over a thousand people.[25]
3M traffic signals installed in Shelton, Washington. Standing off-axis from the intended viewing area, these signals are invisible to adjacent lanes of traffic in daylight. (A faint glow is visible at night.)
The same two signals above, taken in the signal's intended viewing area (a single lane of northbound traffic). Special light-diffusing optics and a colored fresnel lens create the indication. By the 1970s, 3M developed a theatrical blood formula based on red colorfast microbeads suspended in a carrier liquid.[27] This stage blood was sold as Nextel Simulated Blood,[27][28] and was used during the production of the 1978 film Dawn of the Dead.[29] It has since been discontinued.[28] 3M Mincom was involved in some of the first digital audio recordings of the late 1970s to see commercial release when a prototype machine was brought to the Sound 80 studios in Minneapolis. In 1979 3M introduced a digital audio recording system called "3M Digital Audio Mastering System".[30] In 1980, the company acquired Comtal, a manufacturer of digital image processors.[31] 3M launched "Press 'n Peel" in stores in four cities in 1977, but results were disappointing.[32][33] A year later 3M instead issued free samples directly to consumers in Boise, Idaho, with 95% of those who tried them indicating they would buy the product.[32] The product was sold as "Post-its" in 1979 when the rollout introduction began,[34] and was sold across the United States[34] from April 6, 1980.[35] The following year they were launched in Canada and Europe.[36] On its 100th anniversary, 3M changed its legal name to "3M Company" on April 8, 2002.[37][38] On September 8, 2008, 3M announced an agreement to acquire Meguiar's, a car-care products company that was family-owned for over a century.[39] In August 2010, 3M acquired Cogent Systems for $943 million[40] and on October 13, 2010, 3M completed acquisition of Arizant Inc.[41] In December 2011, 3M completed the acquisition of the Winterthur Technology Group, a bonded abrasives company. As of 2012, 3M was one of the 30 companies included in the Dow Jones Industrial Average, added on August 9, 1976, and was 97 on the 2011 Fortune 500 list.[42] On January 3, 2012, it was announced that the Office and Consumer Products Division of Avery Dennison was being bought by 3M for $550 million.[43] The transaction was canceled by 3M in September 2012 amid antitrust concerns.[44] In May 2013, 3M sold Scientific Anglers and Ross Reels to Orvis. Ross Reels had been acquired by 3M in 2010.[45] In March 2017, 3M purchased Johnson Controls International Plc's safety gear business, Scott Safety, for $2 billion.[46] In 2017, 3M had net sales for the year of $31.657 billion, up from $30.109 billion the year before.[47] In 2018, it was reported that the company would pay $850 million to end the Minnesota water pollution case concerning perfluorochemicals.[48] On May 25, 2018, Michael F. Roman was appointed CEO by the board of directors.[49] There are a few international subsidiaries such as 3M India, 3M Japan, and 3M Canada.[50] On December 19, 2018, 3M announced it had entered into a definitive agreement to acquire the technology business of M*Modal, for a total enterprise value of $1.0 billion.[51] In October 2019, 3M purchased Acelity and its KCI subsidiaries for $6.7 billion, including assumption of debt and other adjustments.[52] On May 1, 2020, 3M divested substantially all of its drug delivery business to an affiliate of Altaris Capital Partners, LLC., for approximately $650 million including a 17% interest in the new operating company, Kindeva Drug Delivery.[53] In December 2021, 3M announced that it would merge its food-safety business with food testing and animal healthcare products maker Neogen.[54] The deal, with an enterprise value of about $5.3 billion,[54] is expected to close by September 2022.[55] In July 2022, the company announced it would spin off its healthcare assets to form a new, independent firm, likely completing the transaction in 2023.[56] 3M will retain an ownership stake of 19.9% in the new, publicly-traded health care company and gradually divest the holdings.[56][55] 3M produces approximately 60,000 products, as of 2019,[57] and has four business groups focused on safety and industrial, transportation and electronics, health care, and consumer products.[58] 3M obtained its first patent in 1924, and acquires approximately 3,000 new patents annually. The company surpassed the 100,000-patent threshold in 2014.[59] The Target Light System, built by 3M at Target headquarters in Minneapolis.[60] 3M's Pollution Prevention Pays (3P) program was established in 1975. The program initially focused on pollution reduction at the plant level and was expanded to promote recycling and reduce waste across all divisions in 1989. By the early 1990s, approximately 2,500 3P projects decreased the company's total global pollutant generation by 50 percent and saved 3M $500–600 million by eliminating the production of waste requiring subsequent treatment.[61][62] In 1983, the Oakdale Dump in Oakdale, Minnesota, was listed as an EPA Superfund site after significant groundwater and soil contamination by VOCs and heavy metals was uncovered.[63] The Oakdale Dump was a 3M dumping site utilized through the 1940s and 1950s. During the 1990s and 2000s, 3M reduced releases of toxic pollutants by 99 percent and greenhouse gas emissions by 72 percent. The company earned the United States Environmental Protection Agency's Energy Star Award each year the honor was presented, as of 2012.[64] In 1999, the U.S. Environmental Protection Agency began investigating perfluorinated chemicals after receiving data on the global distribution and toxicity of perfluorooctanesulfonic acid (PFOS).[65] These materials are part of a broad group of perfluoroalkyl and polyfluoroalkyl substances often referred to as PFAS, each of which has different chemical properties.[66] 3M, the former primary producer of PFOS from the U.S., announced the phase-out of PFOS, perfluorooctanoic acid, and PFOS-related product production in May 2000.[67][68] Perfluorinated compounds produced by 3M have been used in non-stick cookware, stain-resistant fabrics, and other products. The Cottage Grove facility manufactured PFAS from the 1940s to 2002.[69] In response to PFAS contamination of the Mississippi River and surrounding area, 3M stated the area will be "cleaned through a combination of groundwater pump-out wells and soil sediment excavation". The restoration plan was based on an analysis of the company property and surrounding lands.[70] The on-site water treatment facility that handled the plant's post-production water was not capable of removing PFAS, which were released into the nearby Mississippi River.[69] The clean-up cost estimate, which included a granular activated carbon system to remove PFAS from the ground water was $50 to $56 million,[71] funded from a $147 million environmental reserve set aside in 2006.[72] In 2008, 3M created the Renewable Energy Division within 3M's Industrial and Transportation Business to focus on Energy Generation and Energy Management.[73][74] In late 2010, the state of Minnesota sued 3M for $5 billion in punitive damages, claiming they released PFCs—classified a toxic chemical by the EPA—into local waterways.[75] A settlement for $850 million was reached in February 2018,[76][68][77] although in 2019, 3M, along with the Chemours Company and DuPont, appeared before lawmakers to deny responsibility, with company Senior VP of Corporate Affairs Denise Rutherford arguing that the chemicals pose no human health threats at current levels and have no victims.[78] 3M's Zwijndrecht (Belgium) factory caused PFOS pollution that may be contaminating agricultural products within a 15 kilometer radius of the plant which includes Antwerp.[79][80] The Flemish Government has paid 63 million euros for cleanup costs so far with 3M contributing 75,000 euros.[81] Carbon footprint3M reported Total CO2e emissions (Direct + Indirect) for the twelve months ending 31 December 2020 at 5,280 Kt (-550 /-9.4% y-o-y)[82] and plans to reduce emissions 50% by 2030 from a 2019 base year.[83] The company also aims achieve carbon neutrality by 2050. [84]
The Combat Arms Earplugs, Version 2 (CAEv2), was developed by Aearo Technologies for U.S. military and civilian use. The CAEv2 was a double ended earplug that 3M claimed would offer users different levels of protection.[91] Between 2003 and 2015, these earplugs were standard issue to members of the U.S. military.[92] 3M acquired Aearo Technologies in 2008.[93] In May 2016, Moldex-Metric, Inc., a 3M competitor, filed a whistleblower complaint against 3M under the False Claims Act. Moldex-Metric claimed that 3M made false claims to the U.S. government about the safety of its earplugs, and that it knew the earplugs had an inherently defective design.[94] In 2018, 3M agreed to pay $9.1 million to the U.S government to resolve the allegations, without admitting liability.[95] Since 2018, more than 140,000 former users of the earplugs (primarily U.S. military veterans) have filed suit against 3M claiming they suffer from hearing loss, tinnitus, and other damage as a consequence of the defective design.[96] Internal emails showed that 3M officials boasted about charging $7.63 per piece for the earplugs which cost 85 cents to produce. The company's official response indicated that the cost to the government includes R&D costs.[97] The N95 respirator mask was developed by 3M and approved in 1972.[98] Being able to filter viral particulates, its use was recommended during the COVID-19 pandemic but supply soon became short.[98] Much of the company's supply had already been sold prior to the outbreak.[99] The shortages led to the U.S. government asking 3M to stop exporting US-made N95 respirator masks to Canada and to Latin American countries,[100] and President Donald Trump invoked the Defense Production Act to require 3M to prioritize orders from the federal government.[101] The dispute was resolved when 3M agreed to import more respirators, mostly from its factories in China.[101] 3M later struck a CA$70M deal with the federal government of Canada and the Ontario provincial government to produce N95 masks at their plant in Brockville, Ontario.[102] 3M facility in St. Paul, Minnesota 3M's general offices, corporate research laboratories, and some division laboratories in the U.S. are in St. Paul, Minnesota. In the United States, 3M operates 80 manufacturing facilities in 29 states, and 125 manufacturing and converting facilities in 37 countries outside the U.S. (in 2017).[103] In March 2016, 3M completed a 400,000-square-foot (37,000 m2) research-and-development building that cost $150 million on its Maplewood campus. Seven hundred scientists from various divisions occupy the building. They were previously scattered across the campus. 3M hopes concentrating its research and development in this manner will improve collaboration. 3M received $9.6 million in local tax increment financing and relief from state sales taxes in order to assist with development of the building.[104] Selected factory detail information:
3M wordmark used from 1961 to 1978 Board chairs have included: William L. McKnight (1949–1966),[133][134] Bert S. Cross (1966–1970),[135][136] Harry Heltzer (1970–1975),[137] Raymond H. Herzog (1975–1980),[138] Lewis W. Lehr (1980–1986), Allen F. Jacobson (1986–1991),[139] Livio DeSimone (1991–2001),[140] James McNerney (2001–2005),[141] George W. Buckley (2005–2012),[142][143] and Inge Thulin (2012–2018).[144] Thulin continued to serve as executive chairman until current chair Michael F. Roman was appointed in 2019.[145] 3M's CEOs have included: Cross (1966–1970),[146] Heltzer (1970–1975),[137] Herzog (1975–1979),[146][147] Lehr (1979–1986),[148] Jacobson (1986–1991),[139] DeSimone (1991–2001),[140] McNerney (2001–2005),[141] Robert S. Morrison (2005, interim),[149] Buckley (2005–2012),[142][143] Thulin (2012–2018), and Roman (2018–present).[144] 3M's presidents have included: Edgar B. Ober (1905–1929),[150] McKnight (1929–1949),[134][151] Richard P. Carlton (1949–1953),[152] Herbert P. Buetow (1953–1963),[153] Cross (1963–1966),[154] Heltzer (1966–1970),[135] and Herzog (1970–1975).[155] In the late 1970s, the position was separated into roles for U.S. and international operations. The position overseeing domestic operations was first held by Lehr,[147] followed by John Pitblado from 1979 to 1981,[156] then Jacobson from 1984 to 1991.[157] James A. Thwaits led international operations starting in 1979.[156] Buckley and Thulin were president during 2005–2012,[158] and 2012–2018, respectively.[144]
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Although older computers used tape cartridges, today’s computers use reel-to-reel tape drives.
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