PDI Assignment

8/14/2019 PDI Assignment

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PDIASSIGNMENT

Submitted by

MANAV KAUSHAL

ROLL NO:C0123 25

CSE 3rd Semester (Class of 2016)


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Q 1: Difference between Impact and Non-impact printers.An impact printer is a type of printer that operates by striking a metal or plastic head against an ink ribbon. The inkribbon is pressed against the paper, marking the page with the appropriate character, dot, line, or symbol. Commonexamples of impact printers include dot, daisy-wheel printers, and ball printers. Dot matrix printers work by strikinga grid of pins against a ribbon. Different characters are printed by using different pin combinations. Daisy-wheelprinters use a circular wheel with "petals" that each has a different character or symbol on the end. In order to printeach character, the wheel spins to the appropriate petal and a hammer strikes the petal against the ribbon and thepage. Similarly, ball printers use a spherical ball with raised characters on the outside. The ball spins to eachcharacter before printing it on the page. While impact printers still have some uses (such as printing carbon copies),most printers are now non-impact printers. These printers, such as laser and inkjet printers are much quieter thanimpact printers and can print more detailed images

.

Early printers, such as dot matrix and daisywheel printers were called impact printers, since they operated by striking

an ink ribbon against the paper. Most modern printers, including inkjet and laser printers, don't include an ink ribbon

and are considered to be non-impact printers. Non-impact printers are generally much quieter than impact printerssince they don't physically strike the page. For example, inkjet printers spray tiny drops of ink onto the page, while

laser printers use a cylindrical drum that rolls electrically charged ink onto the paper. Both of these methods are

non-impact and provide an efficient printing process that produces little sound. The low impact nature of inkjet and

laser printers also means they are less likely to need maintenance or repairs than earlier impact printers.

Impact Printer Non-impact Printer1. Produces text and images when tiny wire pins

on print head strike the ink ribbon byphysically contacting the paper.

1. Produces text and graphics on paper without

actually striking the paper.

2. Its speed is slower. 2. Its speed is faster.3. Its printing quality is lower. 3. Its printing quality is higher.4. Produce near letter quality (NLQ) print only,which is just suitable for printing mailing labels,envelopes, or invoices.

4. Letter-quality printouts.

5. Reliable, durable (lasting for a long time). 5. Print head is less durable, inclined towards toclogging and damage.

6. Generally noisy because of the strikingactivity.

6. Generally much quieter than impact printersbecause there is no striking mechanism.

7. Ideal for printing multipart forms because theycan easily print through many layers of paper.

7. Cannot print multipart forms.

8. It is less expensive. 8. It is more expensive.9. Dot-matrix printer. 9. Inkjet printer, laser printer and thermal

printer.

Q 2: What is 3D Graphic Accelerator? List and explain common3D techniques.A type of video adapter that contains its own processor to boost performance levels. These processors arespecialized for computing graphical transformations, so they achieve better results than the general-purpose CPU
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used by the computer. In addition, they free up the computer's CPU to execute other commands while the graphicsaccelerator is handling graphics computations.The popularity of graphical applications, and especially multimedia applications, has made graphics accelerators notonly a common enhancement, but a necessity. Most computer manufacturers now bundle a graphics acceleratorwith their mid-range and high-end systems. Aside from the graphics processor used, the other characteristics that differentiate graphics accelerators are:

Memory : Graphics accelerators have their own memory, which is reserved for storing graphicalrepresentations. The amount of memory determines how much resolution and how many colors can bedisplayed. Some accelerators use conventional DRAM, but others use a special type of video RAM (VRAM),which enables both the video circuitry and the processor to simultaneously access the memory.

Bus : Each graphics accelerator is designed for a particular type of video bus. As of 1995, most are designedfor the PCI bus.

Register width: The wider the register, the more data the processor can manipulate with each instruction. 64 -bit accelerators are already becoming common, and we can expect 128-bit accelerators in the nearfuture.

3D techniques :-

1. Live action: - The standard for shooting live-action films in 3D involves using two cameras mounted so thattheir lenses are about as far apart from each other as the average pair of human eyes, recording two separateimages for both the left eye and the right eye. In principle,

two normal 2D cameras could be put side-to-side but this is problematic in many ways. The only real option isto invest in new stereoscopic cameras. Moreover, some cinematographic tricks that are simple with a 2Dcamera become impossible when filming in 3D. This means those otherwise cheap tricks need to be replacedby expensive CGI. Many 3D camera rigs still in use simply pair two cameras side by side, while newer rigs arepaired with a beam splitter or both camera lenses built into one unit. While Digital Cinema cameras are not arequirement for 3D they are the predominant medium for most of what is photographed. Film options includeIMAX 3D and Cine 160.
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2. 2D to 3D conversion: - In the case of 2D CGI animated films that were generated from 3D models, it is possibleto return to the models to generate a 3D version. For all other 2D films, different techniques must beemployed. For 3D formation each original frame and manipulated them to produce left-eye and right-eyeversions. Dozens of films have now been converted from 2D to 3D. There are several approaches used for 2D to3D conversion, most notably depth-based methods. However, conversion to 3D has problems. Information is

Unavailable as 2D doesn't have information for a perspective view. Some TVs have a 3D engine to convert 2Dcontent to 3D. Usually, on high frame rate content (and on some slower processors even normal frame rate)the processor isn't fast enough and lag is possible. This can lead to strange visual effects.

3. Anaglyph: - Anaglyph images were the earliest method of presenting theatrical 3D, and the one mostcommonly associated with stereoscopy by the public at large, mostly because of non-theatrical 3D media suchas comic books and 3D television broadcasts, where polarization is not practical. They were made popularbecause of the ease of their production and exhibition. The first anaglyph movie was invented in 1915by Edwin S Porter. Though the earliest theatrical presentations were done with this system, most 3D moviesfrom the 1950s and 1980s were originally shown polarized. In an anaglyph, the two images

are superimposed in an additive light setting through two filters, one red and one cyan. In a subtractivelight setting, the two images are printed in the same complementary colors on white paper.
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Glasses with colored filters in each eye separate the appropriate images by cancelling the filter color out andrendering the complementary color black. Anaglyph images are much easier to view than either parallelsighting or crossed eye stereograms, although the latter types offer bright and accurate color rendering,particularly in the red component, which is muted, or desaturated with even the best color anaglyphs. Acompensating technique, commonly known as Anachrome, uses a slightly more transparent cyan filter in thepatented glasses associated with the technique. Process reconfigures the typical anaglyph image to haveless parallax. An alternative to the usual red and cyan filter system of anaglyph is Color Code 3-D, a patented

anaglyph system which was invented in order to present an anaglyph image in conjunction with the NTSCtelevision standard, in which the red channel is often compromised. Color Code uses the complementary colorsof yellow and dark blue on-screen, and the colors of the glasses' lenses are amber and dark blue.

4. Polarized 3D system: - A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye, an example of stereoscopy. To presentstereoscopic images and films, two images are projected superimposed onto the same screen or displaythrough different polarizing filters.

The viewer wears low-cost eyeglasses which contain a pair of different polarizing filters. As each filter passesonly that light which is similarly polarized and blocks the light polarized in the opposite direction, each eye seesa different image. This is used to produce a three-dimensional effect by projecting the same scene into botheyes, but depicted from slightly different perspectives. Several people can view the stereoscopic images at thesame time.

5. Interference filter technology:- Dolby 3D uses specific wavelengths of red, green, and blue for the right eye,and different wavelengths of red, green, and blue for the left eye. Eyeglasses which filter out the very specificwavelengths allow the wearer to see a 3D image. This technology eliminates the expensive silver screensrequired for polarized systems such as RealD, which is the most common 3D display system in theatres. It does,however, require much more expensive glasses than the polarized systems. It is also known as spectral combfiltering or wavelength multiplex visualization . The recently introduced Omega 3D /Panavision 3D system alsouses this technology, though with a wider spectrum and more "teeth" to the "comb" (5 for each eye in theOmega/Panavision system). The use of more spectral bands per eye eliminates the need to color process theimage, required by the Dolby system. Evenly dividing the visible spectrum between the eyes gives the viewer amore relaxed "feel" as the light energy and color balance is nearly 50-50. Like the Dolby system, the Omega
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system can be used with white or silver screens. But it can be used with either film or digital projectors, unlikethe Dolby filters that are only used on a digital system with a color correcting processor provided by Dolby. TheOmega/Panavision system also claims that their glasses are cheaper to manufacture than those used byDolby. In June 2012 the Omega 3D /Panavision 3D system was discontinued by DPVO Theatrical, who marketedit on behalf of Panavision, citing "challenging global economic and 3D market conditions. Although DPVOdissolved its business operations; Omega Optical continues promoting and selling 3D systems to non-theatricalmarkets. Omega Opticals 3D system contains projection filters and 3D glasses. In addition to the passive

stereoscopic 3D system, Omega Optical has produced enhanced anaglyph 3D glasses. The Omegas red/cyananaglyph glasses use complex metal oxide thin film coatings and high quality annealed glass optics.

6. Autostereoscopy:- In this method, glasses are not necessary to see the stereoscopic image. Lenticularlens and parallax barrier technologies involve imposing two (or more) images on the same sheet, in narrow,alternating strips, and using a screen that either blocks one of the two images' strips (in the case of parallaxbarriers) or uses equally narrow lenses to bend the strips of image and make it appear to fill the entire image(in the case of lenticular prints). To produce the stereoscopic effect, the person must be positioned so that oneeye sees one of the two images and the other sees the other. Both images are projected onto a high-gain,corrugated screen which reflects light at acute angles. In order to see the stereoscopic image, the viewer mustsit within a very narrow angle that is nearly perpendicular to the screen, limiting the size of the audience.

3D rendering: - 3D Rendering is the process of producing an image based on three-dimensional data stored withina computer. 3D rendering is a creative process that is similar to photography or cinematography, because you arelighting and staging scenes and producing images. Unlike regular photography, however, the scenes beingphotographed are imaginary, and everything appearing in a 3D rendering need to be created (or re-created) in thecomputer before it can be rendered. This is a lot of work, but allows for an almost infinite amount of creativecontrol over what appears in the scene, and how it is depicted. The three-dimensional data that is depicted couldbe a complete scene including geometric models of different three dimensional objects, buildings, landscapes, andanimated characters - artists need to create this scene by Modeling and Animating before the Rendering can bedone. The 3D rendering process depicts this three-dimensional scene as a picture, taken from a specified locationand perspective. The rendering could add the simulation of realistic lighting, shadows, atmosphere, color, texture,and optical effects such as the refraction of light or motion-blur seen on moving objects - or the rendering mightnot be realistic at all, and could be designed to appear as a painting or abstract image.

Q 3: Explain the working of CRT with diagram.
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Stands for "Cathode Ray Tube." CRT is the technology used in traditional computer monitors and televisions. Theimage on a CRT display is created by firing electrons from the back of the tube to phosphors located towards thefront of the display. Once the electrons hit the phosphors, they light up and are projected on the screen. The coloryou see on the screen is produced by a blend of red, blue, and green light, often referred to as RGB.

The beam penetration method for displaying color pictures has been used with random-scan monitors. Two layersof phosphor, usually red and green, are coated on to the inside of the CRT screen, and the displayed color dependson how far the electron beam penetrates into the phosphor layers. Shadow-mask methods are commonly used inraster-scan systems (including color TV) because they produce a much wider range of color than the beampenetration method. A shadow-mask CRT has three phosphor color dots at each pixel position. One phosphor dotemits a red light, another emits a green light, and the third emits a blue light. This type of CRT has three electronguns, one for each color dot, and a shadow- mask grid just behind the phosphor coated screen. Figure belowillustrates the delta-delta shadow-mask method, commonly used in color CRT systems. The three electron beam

are deflected and focused as a group onto the shadow mask, which contains a series of holes aligned with thephosphor-dot patterns. When the three beams pass through a hole in the shadow mask, they activate a dottriangle, which appears as a small color spot the screen the phosphor dots in the triangles are arranged so thateach electron beam can activate only its corresponding color dot when it passes through the shadow mask.
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Q 4: What is multimedia? Explain the various components ofmultimedia.

As the name implies, multimedia is the integration of multiple forms of media. This includes text, graphics, audio,

video, etc. For example, a presentation involving audio and video clips would be considered a "multimedia

presentation." Educational software that involves animations, sound, and text is called "multimedia software." CDsand DVDs are often considered to be "multimedia formats" since they can store a lot of data and most forms of

multimedia require a lot of disk space. Due to the advancements in computer speeds and storage space, multimedia

is commonplace today. Multimedia uses computers to present text, audio, video, animation, interactive features,

and still images in various ways and combinations made possible through the advancement of technology. By

combining media and content, those interested in multimedia can take on and work with a variety of media forms to

get their content across. This is an exciting new field for those interested in computers, technology, and creative

career options. Multimedia can be accessed through computers or electronic devices and integrates the various

forms together. One example of multimedia would be combining a website with video, audio, or text images.

Components of Multimedia:-

TextIt may be an easy content type to forget when considering multimedia systems, but text content is by far the mostcommon media type in computing applications. Most multimedia systems use a combination of text and othermedia to deliver functionality. Text in multimedia systems can express specific information, or it can act asreinforcement for information contained in other media items. This is a common practice in applications withaccessibility requirements. For example, when Web pages include image elements, they can also include a shortamount of text for the user's browser to include as an alternative, in case the digital image item is not available.

ImagesDigital image files appear in many multimedia applications. Digital photographs can display application content orcan alternatively form part of a user interface. Interactive elements, such as buttons, often use custom imagescreated by the designers and developers involved in an application. Digital image files use a variety of formats andfile extensions. Among the most common are JPEGs and PNGs. Both of these often appear on websites, as theformats allow developers to minimize on file size while maximizing on picture quality. Graphic design softwareprograms such as Photoshop and Paint.NET allow developers to create complex visual effects with digital images.

AudioAudio files and streams play a major role in some multimedia systems. Audio files appear as part of applicationcontent and also to aid interaction. When they appear within Web applications and sites, audio files sometimes needto be deployed using plug-in media players. Audio formats include MP3, WMA, Wave, MIDI and RealAudio. Whendevelopers include audio within a website, they will generally use a compressed format to minimize on downloadtimes. Web services can also stream audio, so that users can begin playback before the entire file is downloaded.


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VideoDigital video appears in many multimedia applications, particularly on the Web. As with audio, websites can streamdigital video to increase the speed and availability of playback. Common digital video formats include Flash, MPEG,AVI, WMV and QuickTime. Most digital video requires use of browser plug-ins to play within Web pages, but in manycases the user's browser will already have the required resources installed.

AnimationAnimated components are common within both Web and desktop multimedia applications. Animations can alsoinclude interactive effects, allowing users to engage with the animation action using their mouse and keyboard. Themost common tool for creating animations on the Web is Adobe Flash, which also facilitates desktop applications.Using Flash, developers can author FLV files, exporting them as SWF movies for deployment to users. Flash also usesAction Script code to achieve animated and interactive effects.

Q 5: Explain PCI and ISA bus structure in detail with the help ofdiagrams.

PCI ( Peripheral Component Interconnect )

PCI stands for Peripheral Component Interconnect. The PCI bus can be populated with adapters requiring fast access

to each other and/or system memory and that can be accessed by the processor at speeds approaching that of the

processors full native bus speed. It is very important to note that all read and write transfer over the PCI bus can be

performed as burst transfers. The length of the burst is determined by the bus master. The target is given the start

address and the traction type at the start of the transaction, but is not told the transfer length. As the master

becomes ready to transfer each data item, it informs the target whether or not its the last one. The transaction

completes when the final data item has been transferred.

The host/PCI bridge frequently referred to as the North Bridge; connect the host processor bus to the rootPCI bus.


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The PCI-to-ISA Bridge, frequently referred to as the South Bridge, connects the root PCI bus to the ISA (orEISA) bus. The south Bridge also typically incorporates the Interrupt Controller, IDE Controller, USB host

Controller, and the DMA Controller. The North and South Bridges comprise the chipset.

One or more PCI-to-PCI bridges (not shown) may be embedded on the root PCI bus, or may reside on a PCIadd-in card.

In addition, a chipset may support more than one North Bridge (not shown).

Major PCI Features

Feature Description

Processor Independence Components designed for the PCI bus are PCI-specific, not processor-

specific, thereby isolating device design from processor upgrade

treadmill.

Support for up toapproximately 80 PCI

functions per PCI bus

A typical PCI bus implementation supports approximately tenelectrical loads, and each device presents a load to the bus. Each

device, in turn, may contain up to eight PCI functions.

Support for up to 256

PCI buses

The specification provides support for up to 256 PCI buses.

Low-power

consumption

A major design goal of the PCI specification s the creation of a system

design that draws as little current as possible.

Bursts can be performedon all read and write

transfers

A 32-bit PCI bus supports a 132Mbytes per second peak transfer ratefor both read and write transfers, and a 264Mbytes per second peak

transfer rate for 64-bit PCI transfers. Transfer rates of up to

528Mbytes per second are achievable on a 64 bit, 66MHz PCI bus.

Bus speed Revision 2.0 spec supported PCI bus speeds up to 33MHz. Revision

2.1 add support for 66MHz bus operation.

64-bit bus width Full definition of a 64-bit extension.

Access time As fast as 60ns (at a bus speed of 33MHz when an initiator parked onthe PCI bus is writing to a PCI target).

Concurrent bus

operation

Bridges support full bus concurrency with processor bus, PCI bus (or

buses), and the expansion bus simultaneously in use.

Bus master support Full support of PCI bus masters allows peer-to-peer PCI bus access, as

well as access to main memory and expansion bus device through

PCI-to-PCI and expansion bus bridges. In addition, a PCI master can

access a target that resides on another PCI bus lower in the bus

hierarchy.

Hidden bus arbitration Arbitration for the PCI bus can take place while another bus master is


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performing a transfer on the PCI bus.

Low-pin count Economical use of bus signals allows implementation of a functional

PCI target with 47 pins and an initiator with 49 pins.

Transaction integrity

check

Parity checking on the address, command and data.

Three address spaces Memory, I/O and configuration address space.

Auto-Configuration Full bit-level specification of the configuration registers necessary to

support automatic device detection and configuration.

Software Transparency Software drivers utilize same command set and status definition

when communicating with PCI device or its expansion bus-oriented

cousin.

Add-In Cards The specification includes a definition of PCI connectors and add-in-cards.

Add-In Card Size The specification defines three card sizes; long, short and variable-

height short cards.

ISA (Industry Standard Architecture)

Since about 1984, standard bus for PC I/O functions has been named ISA ( Industry Standard Architecture ). It is stillused in all PCs to maintain backwards compatibility. In that way modern PCs can accept expansion cards of the oldISA type. ISA was an improvement over the original IBM XT bus, which was only 8 bit wide. IBM's trademark is ATbus. Usually, it is just referred to as ISA bus. ISA is 16 bit wide and runs at a maximum of 8 MHz However; it requires2-3 clock ticks to move 16 bits of data. The ISA bus works synchronous with the CPU. If the system bus is faster than10 MHz, many expansion boards become flaky and the ISA clock frequency is reduced to a fraction of the system busclock frequency. The ISA bus has a theoretical transmission capacity of about 8MBps. However, the actual speeddoes not exceed 1-2MBps, and it soon became too slow.

Two faces

The ISA bus has two "faces" in the modern PC:

The internal ISA bus, which is used on the simple ports, like keyboard, diskette drive, serial and parallelports.

As external expansion bus, that can be connected with 16 bit ISA adapters.

ISA slots are today mostly used for the common 16 bit SoundBlaster compatible sound cards.


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Problems

The problem with the ISA bus is twofold:

It is narrow and slow. It has no intelligence.

The ISA bus cannot transfer enough bits at a time. It has a very limited bandwidth. Let us compare the bandwidths ofISA bus and the newer PCI bus:

Bus Transmission time Data volume per transmissionISA 375 ns 16 bitPCI 30 ns 32 bit

Clearly, there is a vast difference between the capacities of the two buses. The ISA bus uses a lot of time for everydata transfer, and it only moves 16 bits in one operation. The other problem with the ISA bus is the lack ofintelligence. This means that the CPU has to control the data transfer across the bus. The CPU cannot start a newassignment, until the transfer is completed. You can observe that, when your PC communicates with the floppydrive, while the rest of the PC is waiting. Quite often the whole PC seems to be sleeping. That is the result of a slowand unintelligent ISA bus.

Problems with IRQs (Interrupt Requests)

The ISA bus can be a tease, when you install new expansion cards (for example a sound card). Many of theseproblems derive from the tuning of IRQ and DMA, which must be done manually on the old ISA bus. Everycomponent occupies a specific IRQ and possibly a DMA channel. That can create conflict with existing components.

The ISA bus is out

As described, the ISA bus is quite outdated and should not be used in modern PCs. There is a good chance, that this"outdated legacy technology" (quoting Intel) will disappear completely. The USB bus is the technology that willreplace it. It has taken many years to get this working and accepted, but it works now. Intel's chip set 810 was thefirst not to include ISA support.

Q 6: An 8 disk pack has 300 tracks per surface. There are 20

sectors per track and 256 bytes per sector. What is the storagecapacity of disk? How many cylinders are their?

Given
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No. Of disks = 8

No. Of tracks per surface = 300

No. Of sectors per track = 20

Bytes per sector = 256

Storage capacity of disk = 8 x 2 x 300 x 20 x 256 = 24576000 bytes or 24567 KB or 24.567 MB

*Note: One disk has two surfaces.

No. Of cylinders = There are 300 tracks therefore 300 cylinders will be there.

Q 7: Write short notes on optical disc and optical mouse.

Optical Disc An optical disc is an electronic data storage medium that can be written to and read using a low-powered laser beam. Originally developed in the late 1960s, the first optical disc, created by James T. Russell, storeddata as micron- wide dots of light and dark. A laser read the dots, and the data was converted to an electrical signal,

and finally to audio or visual output. However, the technology didn't appear in the marketplace until Philips and Sonycame out with the compact disc (CD) in 1982. Since then, there has been a constant succession of optical discformats, first in CD formats, followed by a number of DVD formats. Optical disc offers a number of advantages overmagnetic storage media. An optical disc holds much more data. The greater control and focus possible with laserbeams (in comparison to tiny magnetic heads) means that more data can be written into a smaller space. Storagecapacity increases with each new generation of optical media. Emerging standards, such as Blu-ray, offer up to 27gigabytes (GB) on a single-sided 12-centimeter disc. In comparison, a diskette, for example, can hold1.44 megabytes (MB). Optical discs are inexpensive to manufacture and data stored on them is relatively imperviousto most environmental threats, such as power surges, or magnetic disturbances.
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Optical Mouse An optical mouse is an advanced computer pointing device that uses a light-emitting diode (LED),an optical sensor, and digital signal processing (DSP ) in place of the traditional mouse ball and electromechanicaltransducer. Movement is detected by sensing changes in reflected light, rather than by interpreting the motion of arolling sphere. The optical mouse takes microscopic snapshots of the working surface at a rate of more than 1,000images per second. If mouse moves, the image changes. The tiniest irregularities in the surface can produce imageswell enough for the sensor and DSP to generate usable movement data. The best surfaces reflect but scatter light; anexample is a blank sheet of white drawing paper. Some surfaces do not allow the sensor and DSP to functionproperly because the irregularities are too small to be detected. An example of a poor optical-mousing surface isunfrosted glass. In practice, an optical mouse does not need cleaning, because it has no moving parts. This all-electronic feature also eliminates mechanical fatigue and failure. If the device is used with the proper surface,sensing is more precise than is possible with any pointing device using the old electromechanical design. This is anasset in graphics applications, and it makes computer operation easier in general.

Anatomy of optical mouse
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Q 8: Explain SCSI, EISA bus architecture in detail with the helpof disgram.

Ans:- EISA ( Extended Industry Standard Architecture )

EISA is a superset of the ISA 8 and 16-bit architecture, extending the capabilities of ISA while still maintaining

compatibility with ISA expansion boards.

EISA introduces the following improvements over ISA:

Supports intelligent bus master expansion cards. Improved bus arbitration and transfer rates. Facilitates 8, 16 or 32-bit data transfers by the main CPU, DMA and bus master devices. An efficient synchronous data transfer mechanism, permitting single transfers as well as high-speed burst

transfers. Allows 32-bit memory addressing for the main CPU, Direct Memory Access (DMA) devices and bus master

cards.

Shareable and/or ISA compatible handling of interrupt requests. Automatic steering of data during bus cycles between EISA and ISA masters and slaves. 33MB/second data transfer rate for bus masters and DMA devices. Automatic configuration of the system board and EISA expansion cards.

EISA systems maintain full backward compatibility with the ISA standard. EISA connectors are a superset of the

16-bit connectors on ISA system boards, permitting 8 and 16-bit ISA expansion cards to be installed in EISA slots.While maintaining full compatibility with ISA expansion boards and software, EISA also offers enhancements inperformance and functionality for EISA boards as well as some ISA boards. EISA systems support a 32-bit addressbus. The main CPU, bus master expansion cards and DMA devices may access the entire 4GB memory space. ISAmemory expansion cards can be used without modification to populate the lower sixteen megabytes. EISAmemory expansion cards can add as much memory as needed for the application, up to the theoreticalmaximum of 4GB. The EISA bus uses a synchronous transfer protocol. Bus master cards, DMA and the mainprocessor synchronize their bus cycles to the bus clock. The synchronous transfer protocol also provides thecycle control necessary to execute burst cycles with a transfer rate of up to 33 MB/second. EISA provides anumber of bus cycle types covering a range of transfer speeds for different applications. The standard bus cyclerequires two bus clock cycles, while the main CPU, DMA and bus masters are permitted to generate burst cycles

requiring one clock cycle per transfer.


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EISA feature/Benefit Summary

Feature BenefitBackward compatible with all ISAexpansion boards

Customer base retains value of installed ISA cards.

Board size 63 square inches of board space permitsimplementation of powerful, highly-integratedexpansion cards.

+5V dc at approximately 4.5Aavailable at each expansion slot

Enough power for expansion cards employing a largeamount of highly-integrated logic.

32-bit address and data buses Support for 4GB of memory and 32-bit transfers.Programmable level- or edge-triggered interrupt recognition

Interrupt request lines may be shared by multipledevices.

Enhanced DMA capabilities Both ISA and EISA DMA devices have access to memoryabove 16MB. New bus cycle types and 32-bit data busallow faster transfer speeds (rates of up to 33 MB/sec).

Bus Master Support Support for up to fifteen bus master expansion cards,fast burst bus transfers, automatic data bus steering andcontrol lone translation.

Automatic system configuration Supports automatic configuration of the EISA systemboard and EISA expansion cards each time the system ispowered up. Also provides help to the end user inconfiguring older ISA expansion cards.

SCSI (Small Computer System Interface)

SCSI is a set of standards for physically connecting and transferring data between computers and peripheral devices.

The SCSI standards define commands, protocols and electrical and optical interfaces. SCSI is most commonly used forhard disks and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices. The SCSI standard defines command sets for specific peripheraldevice types; the presence of "unknown" as one of these types means that in theory it can be used as an interface toalmost any device, but the standard is highly pragmatic and addressed toward commercial requirements. SCSI is anintelligent, peripheral, buffered, peer to peer interface. It hides the complexity of physical format. Every deviceattaches to the SCSI bus in a similar manner. Up to 8 or 16 devices can be attached to a single bus. There can be anynumber of hosts and peripheral devices but there should be at least one host. SCSI uses handshake signals betweendevices, SCSI-1, SCSI-2 have the option of parity error checking. Starting with SCSI-U160 (part of SCSI-3) allcommands and data are error checked by a CRC32 checksum. The SCSI protocol defines communication from host tohost, host to a peripheral device, peripheral device to a peripheral device. However most peripheral devices areexclusively SCSI targets; incapable of acting as SCSI initiators unable to initiate SCSI transactions themselves.Therefore peripheral-to-peripheral communications are uncommon, but possible in most SCSI applications.The Symbios Logic 53C810 chip is an example of a PCI host interface that can act as a SCSI target.

SCSI is available in a variety of interfaces. The first, still very common, was parallel SCSI (now also called SPI), whichuses a parallel bus design. As of 2008, SPI is being replaced by Serial Attached SCSI (SAS), which uses a serial design
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but retains other aspects of the technology. Many other interfaces which do not rely on complete SCSI standards stillimplement the SCSI command protocol; others (such as iSCSI) drop physical implementation entirely while retainingthe SCSI architectural model. iSCSI, for example, uses TCP/IP as a transport mechanism. SCSI interfaces have oftenbeen included on computers from various manufacturers for use under Microsoft Windows, Mac OS, Unix,Commodore and Linux operating systems, either implemented on the motherboard or by the means of plug-inadaptors. With the advent of SASand SATA drives, provision for SCSI on motherboards is being discontinued. A fewcompanies still market SCSI interfaces for motherboards supporting PCIe and PCI-X.

Q 9: Explain the difference and working of Isolated I/O andMemory Mapped I/O.

Ans:- Memory-mapped I/O (MMIO) and Port-mapped I/O (PMIO) (which is also called isolated I/O) are twocomplementary methods of performing input/output between the CPU and peripheral in a computer. An alternativeapproach is using dedicated I/O processors commonly known as channels on mainframe computers thatexecute their own instructions. Memory-mapped I/O (not to be confused with memory-mapped file I/O) uses thesame address bus to address both memory and I/O devices the memory and registers of the I/O devices are

mapped to (associate with) address values. So when an address is accessed by the CPU, it may refer to a portion ofphysical RAM, but it can also refer to memory of the I/O device. Thus, the CPU instructions used to access thememory can also be used for accessing devices. Each I/O device monitors the CPU's address bus and responds to anyCPU access of an address assigned to that device, connecting the data bus to the desired device's hardware register. To accommodate the I/O devices, areas of the addresses used by the CPU must be reserved for I/O and must not beavailable for normal physical memory. The reservation might be temporary the Commodore 64 could switchbetween its I/O devices and regular memory or permanent. Port-mapped I/O often uses a special class of CPUinstructions specifically for performing I/O. This is found on Intel microprocessors, with the IN and OUT instructions.These instructions can read and write one to four bytes (outb, outw, outl) to an I/O device. I/O devices have aseparate address space from general memory, either accomplished by an extra "I/O" pin on the CPU's physicalinterface, or an entire bus dedicated to I/O. Because the address space for I/O is isolated from that for mainmemory, this is sometimes referred to as isolated I/O.

Isolated I/O Sr.No. Memory Mapped I/O Isolated I/O uses separate memory space. 01 Memory mapped I/O uses memory from the

main memory.

Limited instructions can be used. Those are

IN, OUT, INS, OUTS.

02 Any instruction which references to

memory can be used.

This does not take memory from main

memory.

03 It takes memory from main memory which

reduces the memory available for

applications.

The addresses for Isolated I/O devices are

called ports.

04 Memory mapped I/O devices are treated as

memory locations on the memory map.

IORC & IOWC signals expands the circuitry. 05 IORC & IOWC signals has no functions in this
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case which reduces the circuitry.A total of 1mb address space is allowed formemory applications.

06 Complete 1mb of memory cannot be usedas they are a part of the memory.

One of the disadvantages is that the datatransfer only occurs between the I/O portand the AL, AX registers.

07 There is data transfer restriction in case ofmemory mapped instructions.

Q 10: What do you mean by Resolution, Dot pitch and refreshrate? Compare the features of CRT and LCD display.

Ans:- Resolution

Refers to the sharpness and clarity of an image. The term is most often used to describe monitors, printers, and bit-mapped graphic images. In the case of dot and laser printers, the resolution indicates the number of dots per inch. For example, a 300-dpi (dots per inch) printer is one that is capable of printing 300 distinct dots in a line 1 inch long.This means it can print 90,000 dots per square inch. For graphics monitors, the screen resolution signifies thenumber of dots (pixels) on the entire screen. For example, a 640-by-480 pixel screen is capable of displaying 640distinct dots on each of 480 lines, or about 300,000 pixels. This translates into different dpi measurementsdepending on the size of the screen. For example, a 15-inch VGAmonitor (640x480) displays about 50 dots per inch.Printers, monitors, scanners, and other I/O devices are often classified as high resolution, medium resolution, or lowresolution . The actual resolution ranges for each of these grades is constantly shifting as the technology improves.Different resolutions are shown below:

Dot Pitch

Dot pitch, or "pixel pitch," is a measurement that defines the sharpness of a monitor's display. It measures thedistance between the dots that display the image on the screen. This distance is very small and is typically measuredin fractions of millimetres. The smaller the dot pitch, the sharper the picture. Dot pitch applies to both CRTmonitorsand flat-screen displays. While some large-screen CRTs have dot-pitches as high as 0.51 mm, most computer displayshave a dot pitch between 0.25 and 0.28 mm. Similarly, most LCDdisplays have a dot pitch between 0.20 and 0.28

mm. Some high-end displays used for scientific or medical imagery have dot pitches as low as 0.15 mm. Thesedisplays usually cost several times as much as consumer displays of the same size. While the terms "dot pitch" and"resolution" are related, they have different meanings. A display's resolution refers to how many pixels can bedisplayed on the screen. For example, a 20" monitor may have a maximum resolution of 1680 x 1050 pixels. When adisplay is set to its native resolution (typically the maximum resolution), it may display exactly one pixel per dot.
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However, if the resolution is reduced, the pixels will be larger than the dots used to display the image on the screen.In this case, each pixel is mapped onto multiple dots.

Refresh Rate

Computer monitors often have a "maximum refresh rate" listed in their technical specifications. This number,

measured in hertz (Hz), determines how many times the screen is redrawn each second. Typical refresh rates

for CRTmonitors include 60, 75, and 85 Hz. Some monitors support refresh rates of over 100 Hz. The higher the

refresh rate, the less image flicker you will notice on the screen. Typically a refresh rate of less than 60 Hz will

produce noticeable flicker, meaning you can tell the screen is being redrawn instead of seeing a constant image. If

the refresh rate is too slow, this flicker can be hard on your eyes and may cause them to tire quickly. As if sitting at a

computer for several hours wasn't hard enough! To avoid flicker, you should set your monitor to use the maximum

refresh rate possible. This setting is found in the Monitors control panel in Windows and the Displays system

preference in Mac OS X. While 60 Hz is considered a good refresh rate, some people will find that 85 Hz issignificantly better. The maximum refresh rate is determined by three factors: 1) The rate your video card supports,

2) the rate your monitor supports, and 3) the resolution your monitor is set at. Lower resolutions (i.e. 800x600)

typically support higher refresh rates than higher resolutions (i.e. 1600x1200). If you have an LCDmonitor, you may

not be able to adjust the refresh rate. This is because most LCD monitors come with a standard refresh rate that is

well above the "flicker" point. LCD monitors produce fewer flickers than CRT monitors because the pixels on an LCD

screen stay lit longer than CRT monitors before they noticeably fade.
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Difference between CRT and LCD

LCD CRT

Size (screen viewable size) Viewable size is reduced by 0.1 Viewable size is reduced by 0.99to 1

Thickness Minimum 1 inch; Pretty slim Bulky due to the heavy back

Weight Lighter Heavier

Image Quality Slightly less sharp images Sharper images

Energy Consumption Consumes less energy Consumes more energy

Refresh Rate Needs refresh rate (72hzminimum)

No refresh rate (fixed at 72hz)

Screen Flatness 100% 90 degree flatness Only Mitsubishi and Sonysaperture grille are 100% flat, restare not

Radiation Small amount of radiation Has a significant amount ofradiation

Glare Less glare More glare

Automatic Readjustment Auto resize button; readjusts thepixels

The Auto-fit does not properlyreadjusts the image

Burn-In Doesnt not face burn -in; butsusceptible to image persistence

Burn-in can occur

Running Temperature Cooler than CRT The back gets warm

Dead / Stuck Pixel Can happen Doesnt happen as images arepainted

Price Expensive compared to CRT Cheaper

Resolution Native resolution works best,other resolutions may lose imagequality

Can be used till max resolutionwithout losing image quality; hasmultiple resolutions

Contrast 15000:1 Ratio changes according to types.Can range from 150:1 to 250:1

Life Span 60,000 hours Approximately 43,800; dependson usage

Colors 32 bit 8-bit max, 16.7 million colors.

Viewing Angle Depends on the technology Wide viewing angle


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Blackness Blackness varies from dark grayto gray

True black

Benefits Panels weigh less than plasma;use less energy; light; thinner;emits less electromagneticradiation; no bleeding or

smearing

Easy to move as cannot be wallmounted; good picture quality;cheaper; wide viewing quality;sharper image quality; multiple

resolutionsLimitations Picture slightly less natural and

"film like" than plasmas; slowerrefresh rate; limited viewingangle; blacks are brighter;susceptible to burn-out andimage persistence; dead or stuckpixels may appear

Heavier, small screens; oldtechnology (obsolete);susceptible to burn-ins

Q 11: Write a Short note on Video Drivers and DLP projectors .A video driver is a piece of software which allows your graphics hardware to communicate with your operatingsystem. Drivers in general allow your computer to utilize parts of it, and without them, the machine would notfunction. This is because usually a graphics device communicates in its own language, which is more sophisticated,and a computer communicates in its own language, which largely deals with general commands. Therefore, a driveris required to translate between the two, and convert general commands into specific commands, and vice versa, sothat each of the devices can understand the instructions and results.

Short for Digital Light Processing , a new technology developed by Texas Instruments used for projecting imagesfrom a monitor onto a large screen for presentations. Prior to the development of DLP, most computer projection

systems were based on LCDtechnology which tends to produce faded and blurry images. DLP uses tiny mirrorshoused on a special kind of microchip called a Digital Micro mirror Device (DMD) . The result is sharp images that canbe clearly seen even in a normally lit room.

Q 12: Explain the concept of multi-monitors. Explain thefeatures of VGA .

Ans:- Multi-monitor , also called multi-display and multi-head, is the use of multiple physical display devices, such

as monitors, televisions, and projectors, in order to increase the area available for computer programs running on a

single computer system. The use of two such displays is called dual display, dual screen or dual monitor. Researchstudies show that, depending on the type of work, multi-head may increase the productivity by up to 40-50%.

Multiple Monitor Support has two components: The hardware component and the software one. The following

paragraphs take a look at these components in detail.
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The Hardware Component

The hardware component in Multiple Monitor configurations refers to the ability of the display card to support more

than one display outputs that can be configured independent of one another. The display card should be able to

support and allow resolutions and color depths for each monitor separately. In addition to being able to use the

display outputs independently, one should also consider the use of display processor (known as Graphics Processing

Units - GPUs) to drive the outputs. The GPUs reside on the display card and the cards can "time-share" the GPUs to

the display outputs or can have dedicated GPUs per display output. For display intensive applications, dedicated

GPUs per display output gives a better performance than the time-shared one. The other factor to consider is the

amount of memory available to each of the GPU. The amount of memory directly affects the display resolution and

color depth. As a side note, a true color (32-bit color) 1024 x 768 display resolution requires 3MB of display memory

per monitor. Most of the new laptops have dual-monitor support built-in. The laptop display forms one monitor and

the additional display output forms the second monitor output that can be connected to the projector.

The Software Components

Once you have the necessary hardware in your machine, its the turn of the software to recognize the hardware's

capabilities and utilize them.

The Operating System

The operating system (like Microsoft Windows) needs to recognize multi-monitor configurations and provide a

vendor-neutral way of accessing the features of such configurations. The applications (such as PowerPoint) use this

vendor-neutral way to provide better features. Microsoft Windows 98, Me, Windows 2000, XP, 2003 all have built-insupport to recognize multi-monitor configurations.

Features of VGA (Video Graphics Array) There are cleared stream to external multimedia devices such as TV sets or DVD players through a dedicated VGA

port. VGA is widely used computer graphics format which provides high definition 1080p output. VGA cable productsare still widely used as not all modern TVs support 1:1 pixel mapping technology presented by HDMI. It providesbrighter and better performance when using VGA technology. VGA cable performance is also better when used withgaming consoles such as Xbox 360 or Sony PS3. There are certain drawbacks of VGA cable technology that with VGAcable, you need to connect external audio cable which is pretty annoying.


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Q 13: Explain the importance of digital recording techniques.Encode the bit stream 01101101 as Non return to zero and asin differential Manchester encoding.

Ans:- In a digital recording system, sound is stored and manipulated as a stream of discrete numbers, each number

representing the air pressure at a particular time. The numbers are generated by a microphone connected to acircuit called an ANALOG TO DIGITAL CONVERTER, or ADC. Each number is called a SAMPLE, and the number ofsamples taken per second is the SAMPLE RATE. Ultimately, the numbers will be converted back into sound by aDIGITAL TO ANALOG CONVERTER or DAC, connected to a loudspeaker.

Digital devices usually require less maintenance than analog equipment. The electrical characteristics of most circuitelements change with time and temperature, and minor changes slowly degrade the performance of analog circuits.Digital components either work or don't, and it is much easier to find a chip that has failed entirely than one that ismerely 10% off spec. Many analog systems are mechanical in nature, and simple wear can soon cause problems.Digital systems have few moving parts, and such parts are usually designed so that a little vibration or speedvariation is not important. For digital cassettes, the read/write head moves as well as the tape in order to maintain ahigh enough speed to keep the bits at a manageable size. For optical disc recording technologies suchas CDs or DVDs, a laser is used to burn microscopic holes into the dye layer of the medium. A weaker laser is used toread these signals. This works because the metallic substrate of the disc is reflective, and the unburned dye prevents

reflection while the holes in the dye permit it, allowing digital data to be represented. In addition, digitally encodedinformation is more durable than analog information, again because circuits are responding only to the presence orabsence of something rather than to the precise characteristics of anything. As you have seen, it is possible to designdigital systems so that they can actually reconstruct missing or incorrect data. You can hear every little imperfectionon an LP, but minor damage is not audible with a CD.

Differential Manchester encoding (also known as CDP; Conditioned Diphase encoding) is a method of encoding datain which data and clock signals are combined to form a single self -synchronizing data stream. It is a differential, usingthe presence or absence of transitions to indicate logical value. A '1' bit is indicated by making the first half of thesignal equal to the last half of the previous bit's signal i.e. no transition at the start of the bit-time. A '0' bit isindicated by making the first half of the signal opposite to the last half of the previous bit's signal i.e. a zero bit is

indicated by a transition at the beginning of the bit-time. In the middle of the bit-time there is always a transition,whether from high to low, or low to high. A reversed scheme is possible, and no advantage is given by using eitherscheme. A related method is Manchester encoding in which the meaningful transitions are the mid-bit ones, andthese encode data by their direction (positive-negative is one value; negative-positive is the other).

Q 14: Explain in detail the significance and working ofkeyboard and status generator.Ans:- The significance of the keyboard is that through it you communicate with the brain of the computer to make itdo your bidding. Without the keyboard you would have no means of communicating with the computer to make it

do what you needed. Two nice features of the keyboard are the number keypad for those that are familiar with 10-key, and the function keys which allow the user to utilize shortcuts.The keyboard is an essential part of the computing system which is lying on the concept of typewriter keyboardhaving arrangement of buttons and keys working as electronic switches and mechanical levers. Consumers of
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electronic devices and systems should know that keyboard is a input device of the computing system. One shouldknow that the keyboard is having characters engraved and printed on these keys as every pressing key typicallyshowing single written symbol. Most of the keys of the keyboard release letters, numbers, and signs. Not only thismany keys are manufactured for showing actions and computer commands in computing industries.

Keyboards use a variety of switch technologies. Capacitive switches are considered to be non-mechanical becausethey do not physically complete a circuit like most other keyboard technologies. Instead, current constantly flowsthrough all parts of the key matrix. Each key is spring-loaded and has a tiny plate attached to the bottom of it. Whenyou press a key, it moves this plate closer to the plate below it. As the two plates move closer together, the amountof current is flowing through the matrix changes. The processor detects the change and interprets it as a key pressfor that location. Capacitive switch keyboards are expensive, but they have a longer life than any other keyboard.Also, they do not have problems with bounce since the two surfaces never come into actual contact.Signal generators, also known variously as function generators, RF and microwave signal generators, pitchgenerators, arbitrary waveform generators, digital pattern generators or frequency generators are electronic devicesthat generate repeating or non-repeating electronic signals (in either the analog or digital domains). They aregenerally used in designing, testing, troubleshooting, and repairing electronic or electro acoustic devices; thoughthey often have artistic uses as well.

There are many different types of signal generators, with different purposes and applications (and at varying levelsof expense); in general, no device is suitable for all possible applications. Traditionally, signal generators have beenembedded hardware units, but since the age of multimedia-PCs, flexible, programmable software tone generatorshave also been available.
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Q 15: Explain the difference between synchronous andasynchronous buses with proper timing diagram.Ans:- Synchronous occurs at regular intervals. The opposite of synchronous is asynchronous. Most communicationbetween computers and devices is asynchronous -- it can occur at any time and at irregular intervals.Communication within a computer, however, is usually synchronous and is governed by the microprocessor clock.Signals along the bus, for example, can occur only at specific points in the clock cycle.

Synchronous Bus Asynchronous BusTransmitter and receivers are synchronized ofclock.

Transmitters and receivers are not synchronizedby clock.

Data bits are transmitted with synchronization ofclock.

Bits of data are transmitted at constant rate.

Character is received at constant Rate. Character may arrive at any rate at receiver.Data transfer takes place in block. Data transfer is character oriented.

Start and stop bit are required to establishcommunication of each character

Start and stop bits are required to establishcommunication of each character.

Used in high-speed transmission. Used in low-speed transmission.

Asynchronous communicationsThis is the method most widely used for PC or simple terminal serial communications.In asynchronous serial communication, the electrical interface is held in the mark position between characters. Thestart of transmission of a character is signaled by a drop in signal level to the space level. At this point, the receiverstarts its clock. After one bit time (the start bit) come 8 bits of true data followed by one or more stop bits at themark level. The receiver tries to sample the signal in the middle of each bit time. The byte will be read correctly if theline is still in the intended state when the last stop bit is read. Thus the transmitter and receiver only have to haveapproximately the same clock rate. A little arithmetic will show that for a 10 bit sequence, the last bit will beinterpreted correctly even if the sender and receiver clocks differ by as much as 5%. Asynchronous is relativelysimple, and therefore inexpensive. However, it has a high overhead, in that each byte carries at least two extra bits:a 25% loss of line bandwidth. A 56kbps line can only carry 5600 bytes/second asynchronously, in ideal conditions.
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Synchronous communicationsIn synchronous communications, data is not sent in individual bytes, but as frames of large data blocks. Frame sizesvary from a few bytes through 1500 bytes for Ethernet or 4096 bytes for most Frame Relay systems. The clock isembedded in the data stream encoding, or provided on separate clock lines such that the sender and receiver arealways in synchronization during a frame transmission. Most modern WAN framing is built on the High-Level DataLink Control (HDLC) frame structure. An HDLC frame has the following general structure:

The flag is asequence01111110 which delimits the start of the frame. A technique known as bit stuffing is used to insert additional zerosinto the data so that a flag sequence never appears anywhere but at the start and end of a frame. These extra bitsare "unstuffed" again by the receiver.The address field is usually one byte, but may be more. It is used to indicate the sender or intended receiver of theframe. It is possible to have multiple stations connected to a single wire, and to design the system so that eachreceiver only "sees" frames with its own address. By this means multiple stations can communicate with each otherusing just one line (for instance on a Local Area Network).

Advantages Disadvantages

FLAG ADDRESS CONTROL DATA PAYLOAD CRC BYTES FLAG


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Asynchronoustransmission

Simple, doesn't requiresynchronization of bothcommunication sides

Cheap, because Asynchronoustransmission require less hardware

Set-up is faster than othertransmissions, so well suited for

applications where messages aregenerated at irregular intervals, forexample data entry from thekeyboard and the speed depends ondifferent applications.

Large relative overhead, ahigh proportion of thetransmitted bits are uniquelyfor control purposes andthus carry no usefulinformation

Synchronoustransmission

Lower overhead and thus, greaterthroughput

Slightly more complex Hardware is more expensive

Q 16: Explain different types of ROM. Draw a diode ROMwhich transfer from 3 bit memory code to access 3 code value.Ans:- Computer memory on which data has been pre-recorded. Once data has been written onto a ROM chip, itcannot be removed and can only be read. Unlike main memory (RAM), ROM retains its contents even when thecomputer is turned off. ROM is referred to as being non-volatile, whereas RAM is volatile. Most personalcomputers contain a small amount of ROM that stores critical programs such as the program that boots thecomputer. In addition, ROMs are used extensively in calculators and peripheral devices such as laser printers, whose fonts are often stored in ROMs.

Types of ROM

Programmable read-only memory (PROM), or one-time programmable ROM (OTP), can be written to orprogrammed via a special device called a PROM programmer . Typically, this device uses high voltages topermanently destroy or create internal links (fuses or anti fuses) within the chip. Consequently, a PROM canonly be programmed once.

Erasable programmable read-only memory (EPROM) can be erased by exposure to strong ultraviolet light(typically for 10 minutes or longer), then rewritten with a process that again needs higher than usual voltageapplied. Repeated exposure to UV light will eventually wear out an EPROM, but the endurance of mostEPROM chips exceeds 1000 cycles of erasing and reprogramming. EPROM chip packages can often beidentified by the prominent quartz "window" which allows UV light to enter. After programming, thewindow is typically covered with a label to prevent accidental erasure. Some EPROM chips are factory-

erased before they are packaged, and include no window; these are effectively PROM. Electrically erasable programmable read-only memory (EEPROM) is based on a similar semiconductor

structure to EPROM, but allows its entire contents (or selected banks ) to be electrically erased, thenrewritten electrically, so that they need not be removed from the computer (or camera, MP3 player, etc.).Writing or flashing an EEPROM is much slower (milliseconds per bit) than reading from a ROM or writing to aRAM (nanoseconds in both cases).

Electrically alterable read-only memory (EAROM) is a type of EEPROM that can be modified one bit at atime. Writing is a very slow process and again needs higher voltage (usually around 12 V) than is used forread access. EAROMs are intended for applications that require infrequent and only partial rewriting.EAROM may be used as non-volatile storage for critical system setup information; in many applications,

EAROM has been supplanted by CMOS RAM supplied by mains power and backed-up with a lithium battery. Flash memory (or simply flash ) is a modern type of EEPROM invented in 1984. Flash memory can be erased

and rewritten faster than ordinary EEPROM, and newer designs feature very high endurance (exceeding1,000,000 cycles). Modern NAND flash makes efficient use of silicon chip area, resulting in individual ICs with
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a capacity as high as 32 GB as of 2007; this feature, along with its endurance and physical durability, hasallowed NAND flash to replace magnetic in some applications (such as USB flash drives) . Flash memory issometimes called flash ROM or flash EEPROM when used as a replacement for older ROM types, but not inapplications that take advantage of its ability to be modified quickly and frequently.

Q 17: Explain IRQ.Ans:- Stands for "Interrupt Request." PCs use interrupt requests to manage various hardware operations. Devicessuch as sound cards, modems, and keyboards can all send interrupt requests to the processor. For example, whenthe modem needs to run a process, it sends an interrupt request to the CPU saying, "Hey, hold up, and let me do mything!" The CPU then interrupts its current job to let the modem run its process. It is important to assign differentIRQ addresses to different hardware devices is because the interrupt request signals run along single IRQ lines to acontroller. This interrupt controller assigns priorities to incoming IRQs and sends them to the CPU. It's kind of liketaking a number at the local deli, except the hardware usually only has to wait a couple of nanoseconds instead oflike twenty minutes). Since the interrupt controller can control only one device per IRQ line, if you assign the sameIRQ address to multiple devices, you are likely to get an IRQ conflict. This can cause a range of errors from notallowing network connections to crashing your computer. So make sure you assign unique IRQs to new hardwareyou install and avoid the frustration and keyboard throwing that conflicts can cause.

Alternatively;

In a computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops arunning program and allows a special program, an interrupt handler, to run instead. Interrupts are used to handlesuch events as data receipt from a modem or network, or a key press or mouse movement. The interrupt requestlevel (IRQL) is the priority of an interrupt request.
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Interrupt lines are often identified by an index with the format of IRQ followed by a number. For example, on theIntel 8259 family of PICs there are eight interrupt inputs commonly referred to as IRQ0 through IRQ7 typically, onsystems using the Intel 8259, 16 IRQs are used. IRQs 0 to 7 are managed by one Intel 8259 PIC, and IRQs 8 to 15 by asecond Intel 8259 PIC. The first PIC, the master, is the only one that directly signals the CPU. The second PIC, theslave, instead signals to the master on its IRQ 2 line, and the master passes the signal on to the CPU. There aretherefore only 15 interrupt request lines available for hardware. On early APIC systems with only 16 IRQs or withonly Intel 8259 interrupt controllers, PCI interrupt lines were routed to the 16 IRQs using a PIR integrated into thesouth-bridge.
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On newer systems using the Intel APIC Architecture, typically there are 24 IRQs available, and the extra 8 IRQs areused to route PCI interrupts, avoiding conflict between dynamically configured PCI interrupts and staticallyconfigured ISA interrupts.

Q 18: What is device driver and explain its role?Ans:- In computing, a device driver is a computer program that operates or controls a particular type of device that isattached to a computer. A driver typically communicates with the device through the computer bus orcommunications subsystem to which the hardware connects. When a calling program invokes a routine in the driver,the driver issues commands to the device. Once the device sends data back to the driver, the driver may invokeroutines in the original calling program. Drivers are hardware-dependent and operating-system- specific. They usuallyprovide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.

A device driver simplifies programming by acting as translatorbetween a hardware device and the applications or operating systems

that use it. Programmers can write the higher-level application code independently of whatever specific hardwarethe end-user is using the role of device drivers is to act as a code through which the device interfaces with theoperating system. It is a program that performs the function of controlling ant device that is attached to thecomputer. They are small files that are required by parts of the computer such as the keyboard, the mouse and thegraphic cards.

Some Windows programs are virtual device drivers . These programs interface with the Windows Virtual MachineManager. There is a virtual device driver for each main hardware device in the system, including the hard disk drivecontroller, keyboard, and serial and parallel ports. They're used to maintain the status of a hardware device that haschangeable settings. Virtual device drivers handle software interrupts from the system rather than hardwareinterrupts.
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