2.1.1 overview of computer system

8/4/2019 2.1.1 Overview of Computer System

http://slidepdf.com/reader/full/211-overview-of-computer-system 1/41

Overview of computersystem

Define computer system



Introduction• Theses devices areexamples ofcomputerhardware. Acomputer systemneeds to have

these hardware tofunction.



Computer System• A computer system is defined ascombination of a components designed toprocess data and store files .

• A computer system consists of four majorhardware components : input devices ,output devices , processor and storagedevices.

• A computer system requires hardware,software and a user to fully function.



Hardware• Computerhardware consistsof :– Input devices– Processor– Output device

– Storage devices



Software• Computer software– System software

• Examples :• BIOS program•

Operating system• Utility programs• Programming languages

– Application software• Examples : word

processing, spreadsheet,databases, accounting,games, internet browserand desktop publishing.



User• Computer userrefers to theperson who uses acomputer for anypurpose such asfor work,

businesses orentertainment.



Peripheral devices



Information ProcessingCycle

•Know the function of the centralprocessing unit (CPU)

•Describe information processing cyclewhich include input, process and output

using block diagram



Introduction• Do you know how a computer works? Weuse the computer in our everyday lives butnot all of us know how this machine

operates.• Human uses the brain to think, makedecisions and process information. Acomputer has a brain too, and the brain ofa computer is the processor or the centralprocessing unit (CPU) that processesinformation.



The Central Processing

Unit• The central processing unit or the CPU isthe brain of the computer.

• All processing activities are done in theCPU. It utilizes the computer memory toexecute instructions from applicationsoftware and accomplish a task.

• For example: editing a letter, drawing apicture and sorting numbers.



Cont… • The processor must be connected to

input devices, output devices and

storage devices to carry out theabove mentioned tasks.



The informationprocessing cycle

• User will put the data to be processed by theprocessor.

• The storage holds databases, files andprograms. The output devices present theprocessed data as a useful information productsfor the user.



Cont…



Input• Input is any data or instructions that weenter into the computer system forprocessing.

• There are some common ways of feedinginput data into the system, which are :– Typing on a keyboard– Pointing with a mouse– typing the hours from the timecards into a

spreadsheet.– scanning the survey cards with a card reader– typing jokes into a word processor



• CPUaccepts instruction from the user andtranslates the instruction into readableinformation (decode)

• Typical input devices:keyboards, mice, flatbed scanners, barcode readers, joysticks, digital datatablets (for graphic drawing), electroniccash registers



Process• For every instruction, the controlunit repeats a set of four basicoperations called the machine cycle:



Cont… – Fetching -the process of obtaining a

program instructions or data item frommemory.

– Decoding-the process of translating aprogram instruction into signals that thecomputer can execute.

– Executing - the process of implementingthe instructions in a program.

– Storing -the process of writing the resultto the storage or memory.



• DATA is converted into INFORMATION



Storage• Storage is a location which data instruction

and information are held for future use.• Every computer uses storage to hold

system software and application software.• A storage medium , also called secondary

storage is the physical material in thecomputer that keeps data, instruction andinformation.

• A storage device is the computer hardware

that records or retrieves items to andfrom storage media.



Cont…



Output• Output is data that has been

processed into a useful form , calledinformation. There are four types ofoutput, which are texts, graphics,audio and video.

• The text consists of characters thatare used to create texts, sentencesand paragraphs.



Cont… • Graphics are digital

representation of non textinformation such asdrawings, charts andphotographs.

• Audio is music, speech orany other sound.

• Video consists of imagesthat provide theappearance of full motion.



• CRT (cathode ray tube) monitors and LCDdisplays

• printers• sound cards/speakers• printers• plotters

• special purpose displays (e.g. the floorindicator in a lift)



• The series of input , process , output ,and storage activities is very often

called the information processingcycle .



1. Form into a group of 4.2. Turn on your computer.3. Surfing the internet and find the images about input,

processor, output and storage.4. Place the images into a table.Example:

1 Input

2 Output3 Processor4 storage

GROUP ACTIVITY

2.1.1 overview of computer system

Documents