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Post on 16-Jan-2017
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Computer is an electronic Machine that can be programmedTo do a wide variety of tasks .Desktop and laptop are example of personal computer ( PCs)
Example of personal computer
Types of Computers i.Mini computer : It is powerful computer that can support many users at a time
ii.Maninframe:It is a large, high-powerComputer that can performBillions of calculations From multiple sources at theSame time.
iii. Super computer:It is a machine that can processBillion of instruction in aSecond and is used to solveExtremely complexCalculations.
Characteristics of computeri. Speed Computer speed is measured In Megahertz(MHz)Or gigahertz(GHz)
ii. Storage :A computer has internalStorage (memory)as well as External . In secondary storage,Large amounts of data & programsCan be stored for future use.
iii. Calculations/operationsA computer can performArithmetical & logicalOperation.
iv. Accuracy :A computer is highly accurate In doing calculations. It givesAn accurate output resultProvided correct input data isFed into in.
v. Reliability :A computer have very low failure vate.vi. Versatility :Various tasks can be Performed on a computer.
vii. Communication : Used to exchange message or data through Computer Network
viii. Diligence :A computer can continuouslyWork for hours withoutMaking any errors.It dose not get tried.
Components of computer Input devices :The input or instructions to the computer is given through input devices such as keyboard, mouse, scanner , etc.
Example:Mouse :It is a device that allows you to point things on the screen of the monitor, click, and open files & folders.
Output devices:Output devices are used to show the result of the operation performed by the computer such as monitor, printer
Monitor :This device operates like a TV set and lets the users see how the computer is responding to their commands
Central Processing Unit : CPU is the most important component of a computer. It is responsible for executing various instructions, performing arithmetic and logic operations and controlling various input/output devices. So CPU is called as brain of the computer.
The first step in this cycle is to fetch instructions from memory.To decode the instructions and organize the decoded information.Involves the execution of instructions.To write-back the results that occurred during execution step.The CPU undergoes a series of four steps, to complete its cycle of operations.
Three major unit of CPUi. Storage or memory unitMemory is the area of a computer where all the data and instructions are stored.
Types of memory
:Primary memory IT IS THE MAIN MEMORY OF THE COMPUTER. IT STORES THE OPERATING SYSTEM PROGRAMS AND DATA CURRENTLY USED BY THE CPU. IT CONSISTS OF RANDOM ACCESS MEMORY ( RAM) & READ ONLY MEMORY (ROM)
RAM : RAM contains storage cells that can be accessed directly for read and Write operations. It is used temporarily store data while the CPU working on it.
There are two types of RAM : dynamic (DRAM) & Static ( SRAM)SRAM retains the data as long as the power is on SRAM is primarily used for small amounts of memory , called registers, in a computers CPU and for fast cache memory.DRAM is smaller in the size than SRAM, but is much slower it also stored data for a very short time .Therefore data stored in DRAM needs to be refreshed periodically even when the power is on. Because of its small size, DRAM is generally used for the main memory of the computer
:ROM ROM is unlike RAM . It dose not lose data when power is switched off. Once data is written on a ROM, we cannot rewrite on it. ROMs are used for storing programs that are essential parts of a computers operations, such as bootstrap program that starts a computer & loads its operating system that addresses external devices in a personal computer.
There are three types of ROMs.PROM- Programmable ROM. The information recorded on this cannot be erased.EPROM-Erasable programmable ROM. The information recorded on EPROM can be erased by exposing it to UV light.EEPROM- Electrically erasable programmable ROM. The information recorded on EEPROM can be erased by using electrical signals.
Secondary memory Secondary memory refers to auxiliary storage devices like the hard disk, floppy disk, CD ROM, DVD, etc. these are called the non volatile memory devices or the permanent storage devices.
Control unit (CU)Control unit manage the operation of the CPUARITHMETIC LOGIC UNITIt perform arithmetic and logical operations
Output IPO Cycle
Applications of computeri. Education institutions Help teachers prepare assignmentsImpart computer aided learning Explore and use online resources Help students make projectsKeep track of grades Make circularsKeep and maintain all accounts
Photo of education institutions
Hospital administrationRecording/maintaining the medical history of the patientsDiagnosis of diseases Monitoring the condition of patients
Banks:Opening new accounts & managing the existing onesMaintaining & updating customer information Tracking & recording transactionsManaging online transactionsStoring information about products and services offered by the bank
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