of the disk and proceeding to the center of the disk, much like a gramophone record . The holes, when the disk rotates, trace circular ring surfaces, with inner and outer diameter depending on each hole s position on the disk and thickness equal to each hole s diameter. These surfaces may or may not partly overlap, depending on the exact construction of the disk. Process A lens projects an image of the scene in front of it directly onto the disk. ref cite web url http users.swing.be philippe.jadin nipkowdisk.htm title The Nipkowdisk publisher Users.swing.be date accessdate 2010 03 02 ref Each ... by a sensor. If a light is controlled behind a second Nipkowdisk rotating in synch at the same ... and observing an object through the small area. Here arises one of the drawbacks of the Nipkowdisk ... One of the few advantages of using a Nipkowdisk is that the image sensor that is, the device converting ... motor driving a Nipkowdisk, a small box containing a single light sensitive electric element .... Disadvantages The resolution along a Nipkowdisk s scanline is potentially very high, being ... of the transmission which was also accomplished with a Nipkowdisk. The images were typically very small ... of the disk, at least in the past. The Nipkow disks used in early TV receivers were roughly 30 ... television, which never took off for the practical reasons mentioned above, a Nipkowdisk ... Disks in 1888 London, at Skeptic Friends Network. DEFAULTSORT NipkowDisk Category Television ...Refimprove date March 2010 Image Nipkow disk.svg thumb 300px Schematic showing the circular paths traced by the holes in a Nipkowdisk A Nipkowdisk sometimes Anglicized as Nipkov disk , also known as scanning disk , is a mechanical, geometrically operating image scanning device, invented by Paul Gottlieb Nipkow . This scanning disk was a fundamental component in mechanical television through the 1920s. Design The device itself is nothing more than a mechanically spinning disk of any suitable material ... more details
Leslie Nipkow is an American essayist, television writer, playwright , and actress. Positions held Guarding Erica performer playwright published in Vintage Books anthology Talk to Me Monologue Plays As the World Turns hired by Jean Passanante Script Writer September 4, 2007 January 24, 2008 April 18, 2008 July 31, 2008 November 13, 2008 January 7, 2009 July 24, 2009 September 17, 2010, end of series One Life to Live hired by Gary Tomlin Script Writer 2000 September 19, 2005 Occasional Script Writer September 20, 2005 August 17, 2007 Script Editor September 20, 2005 October 3, 2007 Awards and nominations Daytime Emmy Award Winner, 2008, Best Writing, One Life to Live Nomination, 2011, Best Writing, As the World Turns Nomination, 2010, Best Writing, As the World Turns Nomination, 2006, Best Writing, One Life to Live Nomination, 2002, Best Writing, One Life to Live Writers Guild of America Award Winner, 2011, Best Writing, As the World Turns Winner, 2009, Best Writing, As the World Turns Nomination, 2010, Best Writing, As the World Turns Nomination, 2005, Best Writing, One Life to Live Nomination, 2003, Best Writing, One Life to Live External links http connotationpress.com creative nonfiction 1190 leslie nipkow creative nonfiction Reading Lolita in Hell s Kitchen from Connotation Press http www.salon.com life body wars ?story mwt feature 2011 08 04 this is why im fat This is Why I m Fat from Salon.com http www.oprah.com entertainment Summer Book Festivals Fun Ideas For Summer 1 ... Up on Mr. Beller s Neighborhood http www.freshyarn.com 53 essays nipkow mantooth1.htm Mantooth ... Leslie Nipkow s Blog Yogini Bikini http www.wgaeast.org fileadmin user upload files ... name nm1270730 Leslie Nipkow on IMDb http www.cencom.org programDetail.aspx?id 2458 CenCom http ... Nipkow, Leslie ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH PLACE OF BIRTH DATE OF DEATH PLACE OF DEATH DEFAULTSORT Nipkow, Leslie Category Living people Category American soap opera writers Category ... more details
children discipline institutions practice name significant projects Nipkowdisk significant design significant advance television significant awards Paul Julius Gottlieb Nipkow 22 August 1860 &ndash 24 August 1940 was a Germany German technician and inventor . Beginnings Nipkow was a German of born ... optics with Hermann von Helmholtz , and electro physics with Adolf Slaby . Nipkowdisk Image nipkow disc 1884.jpg thumb left Nipkow s disc from the patent application of 1884 While still a student he conceived the idea of using a spiral perforated diskNipkowdisk , to divide a picture into a mosaic ... images telegraphically in the 1840s but the Nipkowdisk improved the encoding process. He applied ... The first telecasts used an optical mechanical picture scanning method, the method that Nipkow had helped create with his disk he could claim some credit for the invention. Nipkow recounted his first ...Infobox engineer image paul nipkow.jpg caption Nipkow in about 1884 name Paul Gottlieb Nipkow nationality ... Neustadt Wejherowo , West Prussia , Nipkow experimented in telephony and the transmission of moving ... on 15 January 1885, retroactive to 6 January 1884. It is not known whether Nipkow ever attempted a practical realization of this disk but one may assume that he himself never constructed one. The patent lapsed after 15 years owing to lack of interest. Nipkow took up a position as a designer at an institute ... Television Company. Baird was the first inventor to use Nipkow s disc successfully, creating the first ... and Nipkow s invention was no longer essential to further development of television. Transmitter Paul Nipkow Germany s first public television channel, started in Berlin in 1935, was named Fernsehsender Paul Nipkow after Paul Nipkow the spiritual father of the core element of first generation ... Chamber . Nipkow died in Berlin. External links http inventors.about.com library inventors blnipkov.htm The Television System of Paul Nipkow http www.skepticfriends.org forum topic.asp?TOPIC ... more details
Image PaulNipkowTV.jpg thumb right Station identification card The Fernsehsender Paul Nipkow Berlin TV Station Paul Nipkow was the first television station in the world. It was on the air from March 22, 1935 until it was shut down in 1944. Its headquarters were in Berlin , Germany . It was named after Paul Nipkow , the inventor of the Nipkowdisk . Before 1935 there had been experimental television transmissions in Germany since 1928 from the transmitters D beritz , K nigs Wusterhausen and Witzleben , all around Berlin . The first test transmission was introduced to the public on April 18, 1934. The station was only receivable in and around Berlin. It became very popular when it covered the 1936 Summer Olympics in Berlin. About 160,000 viewers saw the Olympic games on a few private TV sets and in many public TV chambers. The Station was rarely used for propaganda issues, as Joseph Goebbels Goebbels preferred radio as a mass medium, but Nazi Indoctrination nevertheless was always present. The heavy and slow equipment made it difficult to report and almost all programming was broadcast live. From 1942 to 1944 the Germans also restarted the TV station in Paris to broadcast programs in German and French. In 1944 the station was shut down, as were most other cultural events, as a consequence of the approach of the Allied Armies in the Invasion of Normandy Normandy Campaign . After the collapse of East Germany in 1990 about 280 rolls of 35mm film was discovered that contained programming of Fernsehsender Paul Nipkow. In recent years much of that material has been aired on German and international channels, mostly by The History Channel . Citation needed date March 2008 See also Einheitsempf nger Einheits Fernseh Empf nger E1 External links de Fernsehsender Paul Nipkow Fernsehsender Paul Nipkow Detailed German Wikipedia about Fernsehsender Paul Nipkow http www.imdb.de title tt0256749 ... Nipkow ... more details
Notability Products date October 2009 Refimprove date November 2009 The term disk to disk , or D2D , generally refers to disk to disk backup. With D2D, a computer hard disk is backed up to another hard disk rather than to a tape or floppy. D2D is often confused with virtual tape , but differs in that it enables multiple backup and recovery operations to simultaneously access the disk directly by using a true file system. ref citebook title Backup and recovery first W. Curtis last Preston edition 2 publisher O Reilly Media year 2006 ISBN 0596102461 pages 219 ref Typical advantages of disk to disk Higher speed and higher capacity, relative to tape or floppy, resulting in shorter backup and recovery windows. Non linear recovery of data, enabling a specific file to be restored quicker and simpler than with tape. Lower total cost of ownership due to increased automation and lower hardware costs. Citation needed date August 2008 Remote backup services Remote backup service s are closely related to D2D backup as they are most often stored remotely on disk. The only major difference is that the data tends to be held at a remote location and these services are often provided by List of backup software Managed backup providers . References refs compu storage stub Category Computer backup Category Disk cloning ... more details
Unreferenced date October 2011 Infobox short story See Wikipedia WikiProject Novels or Wikipedia WikiProject Books name The Disk title orig El Disco translator author Jorge Luis Borges country Argentina language Spanish language Spanish series genre Fantasy , short story published in The Book of Sand book The Book of Sand publisher media type Print pub date 1975 english pub date 1977 The Disk is a 1975 in literature 1975 short story written by Argentina Argentinian writer Jorge Luis Borges . It appears in the collection The Book of Sand book The Book of Sand . Synopsis The story deals with a woodcutter who lives in the midst of a deep wood in old England and who has never seen the sea. He tells the reader that at one time a man, who asks lodging from him appears at his door. The woodcutter notes that the man was elderly, as he referred to England as Saxony , which, at the time, was a sign of age. The day after the man wishes to leave, but before he does, he says that he is a King and is descended from Odin . He tells the woodcutter that he is exiled, but that he shall always be a king, because he holds the Disk of Odin, the sole thing in the world that has but one side. He opens his hand and shows the disk the woodcutter sees only an empty palm, but thereafter touches it, feeling a chill in the fingers and seeing a flash. He makes a false claim that he has a full chest of gold and wants to trade it for the disk, because he knows the man will decline. And the man does, to which the woodcutter replies that the man may go. When he turns around, the woodcutter kills the man with an axe. He then drags the body and throws it into the river. He then comes back and searches for the disk, which he never finds. See also portal Novels Bibliography of Jorge Luis Borges Jorge Luis Borges DEFAULTSORT Disk, The Category 1975 short stories Category Short stories by Jorge Luis Borges story stub es El disco ... more details
Orphan date April 2012 Please leave this line alone Disk Expert Disk Expert is a shareware Disk space analyzer disk usage analysis , reporting and processing utility for Mac OS X . ref name Download Disk Expert 1.0.1 from Softpedia Functionality Disk Expert scans the volumes of hard drive ref name Video review of Disk Expert and visually displays the disk space usage as a sunburst diagram. ref name Disk Expert Key Features The utility discovers the bulkiest content ref name Download Disk Expert from ... Disk Expert from OneDayOneApp The user can manage the disk content by picking up files into the special list ref name Disk Expert review by LowEndMac from which he can copy or move them to other drives ..., as well as reveal file in Finder . History Disk Expert was developed by Nektony LLC. It is a software ... speed of the disk scanning process was critical for the utility developers. Also the big attention was paid to Usability interface usability . The application was released on Dec 24, 2011. ref name Disk Expert Release References Reflist refs ref name Disk Expert Release http www.macnews.com 2011 12 22 nektony disk expert new disk space manager mac Disk Expert 1.0 Released ref ref name Disk Expert Key Features http nektony.com disk expert Disk Expert Key Features ref ref name Download Disk Expert from MacUpdate http www.macupdate.com app mac 41199 disk expert Download Disk Expert for Mac. MacUpdate ref ref name Download Disk Expert from OneDayOneApp http mac.onedayoneapp.com ?s disk expert&submit Search Disk Expert featured as Today s Mac App. OneDayOneApp ref ref name Video review of Disk Expert http www.bestmacsoftware.net maintenance review of nektonys disk expert Video review of Disk Expert. Best Mac Software ref ref name Disk Expert review by LowEndMac http lowendmac.com practical 12sw disk expert.html Disk Expert review. LowEndMac ref ref name Download Disk Expert 1.0.1 from Softpedia http mac.softpedia.com get Utilities Disk Expert.shtml Download Disk Expert 1.0.1. Softpedia ... more details
Disk cache may refer to Disk buffer , the small amount of buffer memory present on a hard drive. Page cache , the cache of disk pages kept by the operating systems, stored in unused main memory. General application level cache computing caching of data stored on the disk. disambig ko zh ... more details
refimprove date March 2011 The Disk Fax was a machine that was used in combination with games for the Family Computer Disk System in Japan. One of the main features of the Disk System is the ability to save data, allowing players to save information such as high score s and other achievements on their game disk. Disk Fax machines could be found in certain stores in Japan during the late 80s early 90s. The Disk Fax machines read save data and send the scores to Nintendo for inclusion on a national scoreboard. Disk Fax machines were used by Nintendo to hold contests in Japan. References http www.atarihq.com tsr fds fds.html tsr s NES archive Family Computer Disk System Nintendo hardware NES Category Nintendo hardware Category Japan only video game hardware Nintendo stub ... more details
In computing , a disk failure usually refers to the failure of a disc based storage device. These are usually either A floppy disk See buzz of death A hard disk See hard disk failure See also Fault tolerant system RAID Data redundancy Disaster recovery Data recovery Data loss Not to be confused with Spinal disc herniation Slipped disk a medical condition of a spine. disambig ... more details
Disk aggregation is the process of combining more than one logical or physical disk drive into a larger logical disk drive. This is done for various reasons creating a single logical disk with a capacity larger than any of the available physical disks providing a simple way to increase disk performance a simple way to implement LUN level storage virtualization See also RAID Storage Virtualization Sources Unreferenced date February 2007 compu storage stub Category Storage virtualization ... more details
Orphan date December 2010 Unreferenced date December 2009 merge cartridge electronics date March 2012 Disk cartridge has several meanings related to computer storage . 1960s storage medium An early disk cartridge was a single hard disk platter encased in a protective plastic shell. When the removable cartridge was inserted into the cartridge drive peripheral device , the disk read and write head read write head s of the drive could access the magnetic data storage device data storage surface of the platter through holes in the shell. The disk cartridge was a direct evolution from the disk pack drive, or the early hard drive . As the computer storage density storage density improved, even a single platter would provide a useful amount of data storage space, with the benefit being easier to handle than a removable disk pack. An example of a cartridge drive is the IBM magnetic disk drives IBM 2310 IBM 2310 . Disk cartridges were made obsolete by floppy disk s. Expand section date June 2008 Modern storage medium Image Zip disc back.jpg thumb Zip disks are sometimes referred to as disk cartridges. Some more recent removable disk storage media are referred to as disk cartridges . This is most common with Zip drive Zip disk s. It is very rare, but not unheard of, to refer to the floppy disk 3 inch microfloppy as a disk cartridge. Protective casing Some types of optical disc s and magneto optical disc s were either permanently enclosed in a protective plastic sheath, or placed into a sheath before being inserted into the computer drive drive . This sheath was often called caddy , but sometimes also disk cartridge . See also Cartridge electronics Universal Media Disc DEFAULTSORT Disk Cartridge Category Rotating disc computer storage media ... more details
Infobox software name Disk Utility logo Image Diskutil.png 64px screenshot Image Disk Utility screenshot.png 220px Disk Utility screenshot caption author developer Apple Inc. released latest release version ... website Disk Utility is the name of a Utility software utility created by Apple Inc. Apple for performing Disk storage disk related tasks in Mac OS X . These tasks include ref http docs.info.apple.com article.html?path DiskUtility 10.5 en duh1008.html Disk Utility 10.5 Help Testing and repairing a disk or volume ref the creation, conversion, compression and encryption of disk image s from a wide range of formats read by Disk Utility to .dmg or for CD DVD images .cdr Mount computing mount ing, unmounting, and ejecting disks including both hard disk s, removable media and disk images enabling or disabling Journaling file system journaling verifying a disk s Data corruption integrity , and repairing it if the disk is damaged this will work for both Mac compatible format partitions, and FAT32 ... ref http support.apple.com kb HT1452 About Disk Utility s Repair Disk Permissions feature ref disk erasing, disk formatting formatting , disk partitioning partitioning ref http support.apple.com kb HT2374 Mac OS X 10.5 About resizing disk partitions ref and disk cloning cloning secure deletion of free space or disk using a zero out data, a 7 pass NISPOM DOD 5220 22 M standard, or a 35 pass Gutmann ... Mac OS X How to combine RAID sets in Disk Utility ref , and repairing RAID sets restoring volumes from Apple Software Restore ASR images Optical disc authoring burning disk images to CD ROM CD or DVD in HFS Plus HFS format ref http support.apple.com kb HT2087 Burning a disk image file on a CD or DVD ... Technology S.M.A.R.T status of a hard disk. Disk Utility functions may also be accessed from ... commands. Disk Utility was updated with Mac OS X v10.3 . Prior to v10.3, the functionality of Disk Utility was spread across two applications Disk Copy and Disk Utility. Disk Copy was used for creating ... more details
other uses2 Disc Unreferenced date December 2009 File CIRCLE 1.svg thumb A disk is the region bounded by a circle . An open disk is the interior topology interior of the disk excluding the bounding circle, while a closed disk see closed set is the open disk together with the bounding circle. In geometry , a disk also Spelling of disc spelled disc is the region in a plane geometry plane bounded by a circle . A disk is said to be closed or open according to whether or not it contains the circle that constitutes its boundary. In Cartesian coordinates , the open disk of center math a, b math and radius R is given by the formula math D x, y in mathbb R 2 x a 2 y b 2 R 2 math while the closed disk of the same center and radius is given by math overline D x, y in mathbb R 2 x a 2 y b 2 le R 2 . math The area geometry area of a closed or open disk of radius R is R sup 2 sup see pi . The Ball mathematics ball is the disk generalised to metric spaces . In context, the term ball may be used instead of disk . In theoretical physics a disk is a rigid body which is capable of participating in collisions in a two dimensional gas . Usually the disk is considered rigid so that collisions are deemed elastic collision elastic . Geometry The Euclidean disk is Circular symmetry circular symmetrical . Topological notions The open disk and the closed disk are not homeomorphic, since the latter is compact ... also that of a closed or open disk is 1. Every continuous map from the closed disk to itself ... disk consider for example math f x,y left frac x sqrt 1 y 2 2 ,y right math which maps every point of the open unit disk to another point of the open unit disk slightly to the right of the given one. See also Unit disk , a disk with radius one Annulus mathematics Ball mathematics , the usual term for the 3 dimensional diskDisk algebra Lentoid Moment of inertia of a uniform disc DEFAULTSORT Disk Mathematics Category Euclidean geometry Category Rigid bodies ar bs Krug ca Disc ... more details
Image Nashua diskpack.jpg thumb Disk pack manufactured by Nashua, USA, without its protective cover. A 3.5 modern hard drive is shown for comparison. A Disk pack is a layered grouping of hard disk platter s circular, rigid discs coated with a magnetic data storage device data storage surface . A disk pack is the core component of a hard disk drive. In modern hard disks, the disk pack is permanently sealed inside the drive. In many early hard disks, the disk pack was a removable unit, and would be supplied ... and a separate bottom that completed the sealed package. To remove the disk pack, the drive would ... shell inserted and twisted to unlock the disk platter from the drive and secure it to the top shell. The assembly would then be lifted out and the bottom cover attached. A different disk pack could then be inserted by removing the bottom and placing the disk pack with its top shell into the drive. Turning the handle would lock the disk pack in place and free the top shell for removal. The first removable disk pack was invented in 1965 by two IBM engineers, Thomas G. Leary and R. E. Pattison. The 14 ... vendors producing IBM compatible drives and disk packs. Examples of a hard disks with removable disk packs are the IBM magnetic disk drives IBM 1311 IBM 1311 , and the Digital Equipment Corporation Digital RP04. gallery File Fotothek df n 10 0000117.jpg Operator selects a disk pack File Fotothek df n 10 0000118.jpg Bottom cover is removed File Fotothek df n 10 0000119.jpg Disk pack is ready for insertion File IBM2314DiskDrivesAndIBM2540CardReaderPunch.jpg IBM 2314 s with removable disk packs and empty covers on top File Disk Pack.jpg A removable pack in place gallery References http www 03.ibm.com ... for Drum and Disk Records, U.S. Patent 3,206,214, 1965 R.E. Pattison, Portable Memory for Data Processing Machine, U.S. Patent 3,176,281, 1965 See also commons category Removable disk packs disk cartridge , History of hard disk drives DEFAULTSORT Disk Pack Category Rotating disc computer storage ... more details
An occulting disk is a small disk used in a telescope to block the view of a bright object in order to allow observation of a fainter one. The coronagraph , at its simplest, is an occulting disk in the focal plane of a telescope , or in front of the entrance aperture , that blocks out the image of the solar disk, so that the corona can be seen. Notes, References and Sources http www.daviddarling.info encyclopedia The Encyclopedia of Astrobiology, Astronomy, and Spaceflight astronomy stub Category Telescopes Category Optical devices de Kegelblende ... more details
Disk swapping refers to the practice of inserting and removing, or swapping, floppy disks in a floppy disk drive based computer system . In the early days of personal computer s, before hard drives became commonplace, most fully outfitted computer systems had 2 floppy drives addressed as A and B on CP M and MS DOS. Disk drives were expensive, however, and having two was seen as a luxury by many computer users who had to make to with a single drive. The purpose of 2 floppy drives was so that the disk containing the Application software application program could remain in the drive while the data disk containing the user s files could be accessed in the second drive. In order to use a function of the program not loaded into memory, the user would have to first remove the data disk, then insert the program disk. When the user then wanted to save their file, the reverse operation would have to be performed. On some less than user friendly systems, this could result in data loss when, for example, files were saved onto the program disk. Disk swapping was an infamous feature of early Macintosh 128k systems, which were extremely RAM starved. Category Floppy disk computer storage ... more details
In Sun Microsystems Solaris operating system Solaris computer operating system , disk partition s are sometimes known as slices . This is a conceptual reference to the slicing of a cake into several pieces. A slice is composed of a contiguous range of blocks on a disk. The term slice is also used in the FreeBSD operating system to refer to PC BIOS hard disk partitions, to avoid confusion with FreeBSD s own BSD disklabel disklabel based partitioning scheme. See also wikibooks Guide to Unix Explanations Partitioning Disks Partitioning Disks Disk partitioning BSD disklabel List of disk partitioning software References http docs.sun.com app docs doc 817 5093 disksconcepts 20068?l en&a view Solaris 10 System Administration Guide Devices and File Systems http www.freebsd.org doc en US.ISO8859 1 books handbook disks adding.html FreeBSD Handbook Compu stub Category Disk file systems Category Disk partitioning software Category Operating system technology Category Sun Microsystems software ... more details
Disk Manager was a popular 1980s and 1990s software and documentation package for MS DOS and PC DOS computers, useful for self installing personal computer Hard disk drive hard disk s. It was written by Ontrack, a company later acquired by Kroll Inc. Installation covered different aspects explaining personal computer hardware concepts documenting switches of many of the existing disks putting into place custom device driver s which circumvented Enhanced BIOS BIOS limitations , notably those related to maximum disk or partition size and logical block addressing providing testing and informational utilities Drivers could be either DOS type, or replacement master boot record code. Diskettes with Disk Manager were provided by some disk manufacturers e.g. IBM , in custom OEM versions, supporting all of their models. In recent years Kroll switched to the business of providing computer disk data recovery services as Kroll Ontrack Data Recovery . External links http www.ontrackdatarecovery.com Kroll Ontrack Data Recovery Category Windows software Category Utility software Windows software stub ... more details
unreferenced date May 2010 The disk controller is the Electronic circuit circuit which enables the Central processing unit CPU to communicate with a hard disk , floppy disk or other kind of disk drive . 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 Shugart Associates System Interface SASI was a predecessor to SCSI . Modern disk controllers are integrated into the disk drive. For example, disks called SCSI disks have built in SCSI controllers. In the past, before most SCSI controller functionality was implemented in a single chip, separate SCSI controllers interfaced disks to the SCSI bus. The most common types of interfaces provided nowadays by disk controllers are Parallel ATA PATA IDE and Serial ATA for home use. High end disks use SCSI , Fibre Channel or Serial Attached SCSI . Disk controller versus host adapter The correct term for the components that allows a computer to talk to a peripheral bus is host adapter or host bus adapter HBA . On the other hand, a disk controller allows a disk to talk to the same bus. Those two are often confused, especially in the Advanced Technology Attachment PC world . In fact signals read by a disk read and write head are converted by a disk controller, then transmitted over the peripheral ..., and then read by the CPU . Sometimes there may be yet another controller between a host adapter and a disk controller a disk array controller that allows RAID Hardware RAID hardware RAID to be formed ... also Disk array controller Floppy disk controller Forensic disk controller Controller computing ... more details
mergefrom Staging data discuss Talk Disk staging Merger proposal date October 2010 Unreferenced date December 2009 Disk staging is using hard disk disks as an additional, temporary stage of backup process before finally storing backup to magnetic tape data storage tape . Backups stay on disk typically for a day or a week, before being copied to tape in a background process and deleted afterwards. The process of disk staging is controlled by the same software that performs actual backups, which is different from virtual tape library where intermediate disk usage is hidden from main backup software. Both techniques are known as D2D2T disk to disk to tape . Restoring data Data is restored from disk if possible . But if the data exists only on tape it is restored directly no backward staging on restore . Reasons Reasons behind using D2D2T increase performance of small, random access restores disk has much faster random access than tape increase overall backup restore performance although disk and a tape have similar streaming throughput, you can easily scale disk throughput by the means of Data striping striping and tape striping is a much less established technique increase utilization of tape drive s tape shoe shining effect is eliminated when staging note that it may still happen on tape restores See also Backup Virtual tape library DEFAULTSORT Disk Staging Category Computer storage kk zh ... more details
Refimprove date May 2009 distinguish page cache File Fujitsu MPG3307AH ms avrs 110909.jpg thumb The disk buffer sits on the controller board of the hard drive. In computer storage , disk buffer often ambiguously Fact date September 2007 called disk cache or cache buffer Fact date September 2007 is the embedded ... and the physical hard disk platter that is used for storage. Modern hard disks come with 8 ... from the disk platter. The disk buffer is physically distinct from and is used differently than the page cache typically kept by the operating system in the computer s main memory . The disk buffer is controlled by the microcontroller in the hard disk drive , and the page cache is controlled by the computer to which that disk is attached. The disk buffer is usually quite small, from 8 ... cache is reused multiple times, the data in the disk buffer is rarely reused. Fact date September 2007 In this sense, the terms disk cache and cache buffer are misnomers the embedded controller s memory is more appropriately called the disk buffer. Note that disk array controller s, as opposed to disk controller s, usually have normal cache memory of around 0.5&ndash 8 GiB. Uses Read ahead read behind When executing a read from the disk, the disk arm moves the Disk read and write head read ... system. The disk s embedded computer typically saves these unrequested sectors in the disk buffer, in case the operating system requests them later. Speed matching The speed of the disk s I O interface ... the hard disk platter . The disk buffer is used so that both the I O interface and the disk read write head can operate at full speed. Write acceleration The disk s embedded microcontroller may signal the main computer that a disk write is complete immediately after receiving the write data, before ... from the disk buffer, and the file system on the disk may be left in an inconsistent state. On some ... of data is deemed more important than write performance. Another option is to send data to disk in a carefully ... more details
The term disk space is an amount of computer storage space on random access memory devices, such as on a hard drive , floppy or USB flash drive . Citation needed date September 2011 Disk space units are commonly measured in large numbers of bytes , such as kilobytes , megabytes , and gigabytes , with each unit 1024x times larger than the previous unit. The term originated in the 1950s, for the storage area on a hard disk drive , which internally had disk shaped platters to rotate quickly. As storage devices have been created in other shapes, the term disk space has still been used to refer to areas of permanent storage on various storage devices. The total disk space can span multiple devices, such as areas on an array of disk drives. ref NT Server and Disk Subsystem Performance , Microsoft.com, 2010, webpage http technet.microsoft.com en us library cc767920.aspx MS2 . ref The broader term storage space is so widely used that it can be mistaken for property storage, as with items stored in a closet or storage bin. Hence, the term disk space has remained in use, even when the storage devices are no longer shaped as disks. When storage of data is not permanent, then the common term memory space is often used instead. References Reflist Category Computer memory ... more details
Otheruses2 Disc Image Unit disk open.svg thumb right An open Euclidean unit disk In mathematics , the open unit disk or disc around P where P is a given point in the plane mathematics plane , is the set ... disk around P is the set of points whose distance from P is less than or equal to one math bar D 1 P Q P Q leq 1 . , math Unit disks are special cases of disk mathematics disks and unit ball s. Without further specifications, the term unit disk is used for the open unit disk about the origin mathematics ... plane C , the unit disk is often denoted math mathbb D math . The open unit disk, the plane, and the upper ... analytic and bijective function from the open unit disk to the plane its inverse function is also analytic. Considered as a real 2 dimensional analytic manifold , the open unit disk is therefore isomorphic to the whole plane. In particular, the open unit disk is homeomorphic to the whole plane. There is however no conformal map conformal bijective map between the open unit disk and the plane. Considered as a Riemann surface , the open unit disk is therefore different from the complex plane . There are conformal bijective maps between the open unit disk and the open upper half plane . So considered as a Riemann surface, the open unit disk is isomorphic biholomorphic , or conformally equivalent ... unit disk. One bijective conformal map from the open unit disk to the open upper half plane is the M bius ... so that the upper half plane becomes the disk s interior and the real axis forms the disk s circumference ... unit disk to the open upper half plane can also be constructed as the composition of two stereographic projection s first the unit disk is stereographically projected upward onto the unit upper half ... sphere opposite to the touching point as projection center. The unit disk and the upper half plane ... space The open unit disk is commonly used as a model for the Hyperbolic space hyperbolic plane ... the open unit disk and the upper half plane, this model can be turned into the Poincar half ... more details
A disk editor is a computer program that allows its user to read, edit, and write raw data at ASCII character or hexadecimal , byte byte levels on disk drives e.g., hard disk s, USB flash disk s or removable media such as a floppy disk s as such, they are sometimes called sector editors, since the read write routines built into the electronics of most disk drives require to read write data in chunks of disk sector sector s usually 512 bytes . Many disk editors can also be used to edit the contents of a running computer s computer memory memory or a disk image . Unlike hex editors, which are used to edit Computer file files , a disk editor allows access to the underlying disk structures, such as the master ... directories . Programmers can use disk editors to understand these structures and test whether ... disk editors include special functions which enable more comfortable ways to edit and fix file systems or other disk specific data structures. Furthermore some include simple file browsers that can present the disk contents for partially corrupted file systems or file systems unknown to the operating system. These features can be used for example for file recovery. History Disk editors for home ... resets, instead of having to be re loaded on the same disk drive that later would hold the floppy to be edited the majority of home computer users possessed only one floppy disk drive at that time . Having the disk editor on cartridge also helped the user avoid editing damaging the disk editor application disk by mistake. All disk editors strive to be better than code debug command DEBUG ... from a Floppy disk floppy or Hard disk drive hard disk based on the BIOS . This permits simple disk ... and is in essence useless as disk editor for the system drive. The Resource Kit and the support ... Technet accessdate 2011 07 05 ref as a very simple disk editor supporting the use and modification ... of some disk editors or products containing them This is a list of utility software utilities for performing ... more details
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