Classes of Computers

8/2/2019 Classes of Computers

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Classes of ComputersAnalog Computer , Digital Computer , Hybrid Computer


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Analog ComputerOperates on continuous physical orelectrical magnitudes, measuring ongoingcontinuous analog quantities such as

voltage, current, temperatures andpressure

e.g. heart monitors and fetal monitors


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Digital Computer

operates on discrete discontinuousnumerical digits using the binarynumbering system

Data are represented by numbers, letter,and symbols


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Hybrid ComputerContains both features of analog computerand digital computer

Used for specific applications

Found in monitoring equipments thatconverts analog signals to digital ones fordata processing.


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Types of ComputersSupercomputers , Mainframes , Microcomputers ,Handheld Computers


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Supercomputers

Specially designed for scientific applicationsrequiring gigantic amount of calculations

World class number cruncher

Designed primarily for analysis of scientific andengineering problems and for tasks requiringmillions or billions of computational operations andcalculations

Found primarily in areas such as defense andweaponry, weather forecasting, and scientificresearch


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Mainframes

Fastest and most expensive type of computer

Large multiuser central computer that meets thecompeting needs - especially large amounts of repetitive calculations of bills, payrolls and the like - of a large organization

Can serve a large number of users at the sametime

Large memory capacity and fast operating andprocessing time, and it can process a large numberof functions (multiprocessing) at one time


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Microcomputers

Also known as Personal Computers or PCs

Used for independent applications as well asserving as a desktop link to the programs of themainframe

Serve as stand-alone workstations and can belinked to a network system to increase theircapabilities

Also available as portable, laptop, notebook,handheld computers


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Handheld Computers

Smaller in size than the standard desktopmicrocomputer

Some claim to have almost the samefunctionality and processing capabilities asthe standard desktop microcomputer

Limited in expansion possibilities, abilityto serve as full participants in officenetwork, and peripherals they cansupport.


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Common HardwarePeripherals

Keyboard , Monitor , Mouse and Trackball , Floppy Disk/Diskettes and CD-ROMs , Touch Pad and Mouse

Button , Light Pen/Touch Screen , Optical Character

Recognition (OCR) , Magnetic-Ink CharacterRecognition (MICR) , Voice Synthesizer , Imaging ,Digital Versatile Disk (DVD) , Printers , Modems


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KeyboardMost common input device

Six (6) section of keys:

1. typewriter keys (QWERTY)

2. function keys (F1-F12)

3. numeric keys (0-9)

4. cursor keys

5. toggle keys (Num Lock, Caps Lock, Scroll Lockand Insert/Typeover

6. special operation keys (Home, Tab, End, Del,Print Screen, etc.)


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Monitor

Similar to a television screen

Allows user to see images, programs,

commands the user sends to thecomputer, and results of the computerswork or the output.


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Mouse and Trackball

Mouse hand-controlled mechanicaldevice that electronically instructs thecursor to move across the video displayscreen or monitorTrackball developed for people whoprefer stationary device; has ball on top,and movement of the cursor is controlledby the fingers rolling the ball in place


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Floppy Disk/Diskettesand CD-ROMs

Both serve as input and output data

Floppy disk flexible Mylar plastic oxide-coated disk thinly covered with magneticspots

CD-ROM can store around 640 MB of data therefore much more useful mediumfor the larger data text, and graphics filesthat many users wish to store and movefrom computer to computer


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Touch Pad and Mouse Button

Touch pad developed by makers of laptop computers for use in place of mouse; flat, rectangular depression on thekeyboard that senses pressure andmovement of the users finger


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Light Pen/Touch Screen

Light pen photosensitive device thatresponds to light images when placedagainst a monitor screen

Touch screen involves the use of aspecial filter on a monitor screen thatallows screen to sense the pressure of the users finger on a particular position of the screen


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Optical Character Recognition

(OCR)Specialized computer input media thatallows data to be read directly from aform of document

OCR devices convert the optical marks,characters, and bar codes into electricalsignals that become computer input

e.g. electronic optical scanning device,wand reader, bar code reader


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Magnetic-Ink CharacterRecognition (MICR)

Characters are made of magnetizedparticles printed on paper

Most common example is the magnetizedcharacters imprinted on checks, whichmost banks use.


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Voice Synthesizer

Allows user to input data into thecomputer by speaking into a connectedmicrophone

Also known as speech synthesizer, itdigitizes the sound for processing by theCPU


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ImagingExamples are computerized axialtomography (CAT Scans) and magneticresonance imaging (MRI)

Several different types of image inputdevices are available that primarilytransform images from various types of graphics into digital form, which the

computer can accept represent on thescreen, and process.


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Digital Versatile Disk (DVD)

Looks and feels like CD-ROM but holdsmuch more information and contains

many more multimedia features


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PrintersConverts information produced by the computer systeminto printed form, rendering data in binary system intoreadable English.

Major types of printed output include (1) printed hard

copy (paper), microfilm (microfiche), photographs, andgraphic copy

Laser printers use fonts or typefaces as their printingelements, making documents look like they weretypeset; also used for printing graphic images andillustrations

Inkjet and bubble-jet printers fire small bursts of inkon the paper

Bubble-jet printers use special heating elements toprepare the ink whereas inkjet printers use piezoelectriccrystals to ionize the ink


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Modems

Communication device used to connect aterminal with a mainframe or anothercomputer

Modem (modulating and demodulating)translates digital data into waves (analog)for transmission over the communicationlines to the computer system and converts

the waves back to their original digitalform for input into the computer

Documents

Classes of Computers