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Mir Quadeer's Questions & Answers

in Computers & Technology, Hyderabad& Electronics & Gadgets

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Total Points: 7569

Answers Given: 7655

Questions Asked: 189

Best Answers: 122

What does it mean when a hard disk has a "head crash"?

Asked by satya in Computers & Technology at 11:34 PM on August 22, 2007

Mir Quadeer's Answer

head crash is a specific type of hard disk failure, and occurs when the read-write head of a hard disk drive touches its rotating platter resulting in catastrophic damage to the magnetic media on the platter surface (see Hard disk platter). The head normally rides on a thin film of moving air entrapped at the surface of the platter (some drives of the mid-1990s used a thin fluid layer instead). The topmost layer of the platter is made of a Teflon-like material that acts like a lubricant. Underneath is a layer of sputtered carbon. These two layers protect the magnetic layer (data storage area) from most accidental touches of the read-write head. A head crash can be initiated by a tiny particle of dirt or other detritus which can cause the head to bounce against the disk, destroying the thin magnetic coating on the disk. The Disk read-and-write head is made using thin film techniques that include materials hard enough to scratch through the protective layers. Since most modern drives spin at rates between 5,000 and 15,000 rpm, the damage caused to the magnetic coating can be extensive. At 7,200 rpm the edge of the platter is traveling at over 74 miles per hour (120 km/h), as the crashed head drags over the platter surface the read-write head generally overheats, making the drive or at least parts of it unusable until the heads cool. Following a head crash, particles of material scraped free of the drive surface greatly increase the chances of further head crashes or damage to the platters. In large format printing the term head crash refers to the sudden jamming of the print heads on the scan axis. Typically the result of print media bunching up, a head crash can result in damage to the print head, requiring replacement.

Answered at 11:57 PM on August 22, 2007

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what is blurb? what is the use of it.

Asked by emarketer in Computers & Technology at 10:40 AM on August 21, 2007

Mir Quadeer's Answer

A blurb is a short summary or some words of praise accompanying a creative work, usually referring to the words on the back of the book but also commonly seen on DVD and video cases, web portals and news websites.

Answered at 11:36 AM on August 21, 2007

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Who Will win Battel of love if one is India and Other are world's?

Asked by Dan in Computers & Technology at 11:29 PM on August 17, 2007

Mir Quadeer's Answer

u.s

Answered at 12:06 AM on August 18, 2007

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What do you mean by SPROM?

Asked by nisha in Computers & Technology at 11:51 AM on August 20, 2007

Mir Quadeer's Answer

A short access time after the rising clock edge,. data appears on the SPROM DATA output pin that is con-. nected to the Spartan device DIN pin

Answered at 11:59 AM on August 20, 2007

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What is Fibre Optics? how it is used in Telephone cables or Cable TV Cables?

Asked by Sachin1988 in Computers & Technology at 11:41 AM on August 19, 2007

Mir Quadeer's Answer

An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length by confining as much light as possible in a propagating form. In fibers with large core diameter, the confinement is based on total internal reflection. In smaller diameter core fibers, (widely used for most communication links longer than 200 meters) the confinement relies on establishing a waveguide. Fiber optics is the overlap of applied science and engineering concerned with such optical fibers. Optical fibers are widely used in fiber-optic communication, which permits transmission over longer distances and at higher data rates than other forms of wired and wireless communications. They are also used to form sensors, and in a variety of other applications. The term optical fiber covers a range of different designs including graded-index optical fibers, step-index optical fibers, birefringent polarization-maintaining fibers and more recently photonic crystal fibers, with the design and the wavelength of the light propagating in the fiber dictating whether or not it will be multi-mode optical fiber or single-mode optical fiber. Because of the mechanical properties of the more common glass optical fibers, special methods of splicing fibers and of connecting them to other equipment are needed. Manufacture of optical fibers is based on partially melting a chemically doped preform and pulling the flowing material on a draw tower. Fibers are built into different kinds of cables depending on how they will be used.

Answered at 12:04 PM on August 19, 2007

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What is computer adaptive test?

Asked by Mujji in Computers & Technology at 12:10 PM on August 20, 2007

Mir Quadeer's Answer

computer-adaptive testing (CAT) is a method for administering tests that adapts to the examinee's ability level. For this reason, it has also been called tailored testing.CAT successively selects questions so as to maximize the precision of the exam based on what is known about the examinee from previous questions.[1] From the examinee's perspective, the difficulty of the exam seems to tailor itself to their level of ability. For example, if an examinee performs well on an item of intermediate difficulty, he will then be presented with a more difficult question. Or, if he performed poorly, he would be presented with a simpler question. Compared to static multiple choice tests that nearly everyone has experienced, with a fixed set of items administered to all examinees, computer-adaptive tests require fewer test items to arrive at equally accurate scores.[1] (Of course, there is nothing about the CAT methodology that requires the items to be multiple-choice; but just as most exams are multiple-choice, most CAT exams also use this format.) The basic computer-adaptive testing method is an iterative algorithm with the following steps:[2] The pool of available items is searched for the optimal item, based on the examinee's current ability estimate The chosen item is presented to the examinee, who then answers it correctly or incorrectly The ability estimate is updated, based upon all prior answers Steps 1–3 are repeated until a termination criterion is met

Answered at 12:43 PM on August 20, 2007

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Which is best C, C++ or C#?

Asked by nisha in Computers & Technology at 9:21 AM on August 17, 2007

Mir Quadeer's Answer

c is the best of all

Answered at 10:40 AM on August 17, 2007

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What is A++ in Computers according to you?

Asked by kash in Computers & Technology at 10:25 AM on August 17, 2007

Mir Quadeer's Answer

A++ stands for abstraction plus reference plus synthesis which is used as a name for the minimalistic programming language that is built on ARS. ARS is an abstraction from the Lambda Calculus, taking its three basic operations, and giving them a more general meaning, thus providing a foundation for the three major programming paradigms: functional programming, object-oriented programming and imperative programming. ARS Based Programming is used as a name for programming which consists mainly of applying patterns derived from ARS, to programming in any language.

Answered at 10:39 AM on August 17, 2007

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