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Lecturer: Dalia Mirghani

Year : 2014/2015

Computer For Health Sciences

COMP101

Lec.2: Computer HardwareLec.2: Computer Hardware

Foundation year

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• A computer is a machine that takes in data and instructions as (input), works with the data as (processing), gives the processed information back to the user as (output).

• The computer uses a series of 0s and 1s to describe data and to represent information.

What is a computer ?

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Desktop computer System

Parts of the computer

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1) Mainframes:• These are the largest and most powerful of computers. The

biggest of these are sometimes called Supercomputers. • Cost:

Mainframes are also the most expensive machines in terms of both initial cost and maintenance. A mainframe can cost millions.

Mainframe computer

Types of Computer

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2) Network computer• Network computers are also sometimes known as

thin clients or dumb terminals.• Network computers provide remote access to a

mainframe.

• Cost: Network computers are relatively simple devices, hence they are fairly cheap.

Types of Computer

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3) Personal computers• Personal computers or PCs for short are the type of computer

that most users are familiar with. Because they are usually found on users desks, they are also sometimes called desktop computers.

• Cost• The cost of a personal computer is greater than that of a network

computer or PDA but less than that of a laptop and a very small fraction of the price of a mainframe.

Types of Computer

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4) Laptop• Laptops or Notebooks are similar to personal computers

except that they comprise an integrated unit.

• Cost:More expensive than personal computers.

Types of Computer

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5) PDA / Personal Digital Assistant:• The PDA is the smallest of all computers. Their main

task is to maintain a diary and keep contact lists.• Most PDAs are able to connect to a personal computer

so that data can be exchanged.• Cost: • Usually a PDA is less expensive than a personal

computer.

Types of Computer

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• A computer system is made up of :

1.Hardware - The physical components.

2.Software – The programs or lists of instructions.

Computer system

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• A hardware is physical parts of the computer you can actually touch.

• The hardware for a computer system consists of: 1. Input devices.

2. System unit.3. Output devices.4. Secondary storage devices.

Hardware

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• Input devises are hardware components that convert data from an external source into electronic signals understood by the computer.

• Input device types:

Key Board

ScannerMicrophone

Digital Camera

Barcode Reader Mouse

1. Input Devices

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2. System Unit

The system unit

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1. Motherboard:– It contains slots for the processor chip, memory slots, and

slots for adapter cards for video, sound, and connection to peripheral devices.

2. Processor chip (CPU):– The Central Processing Unit (CPU) is the portion of

a computer system that carries out the instructions of a computer programs. It acts as the BRAIN OF COMPUTER.

Main system unit components:

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3. Memory:– Memory is a form of semiconductor storage that resides

insides the computer on a motherboard . It stores operating system commands, programs and data.

Main Memory types:1. ROM (Read Only Memory) is permanent memory that

has been burned on the chip at the factory. 2. RAM ( Random Access Memory) stores data that the

computer needs to use temporarily.

Main system unit components:

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4. Hard drive or Hard disk– The hard drive is the data center of the computer where the

software is installed, and where your documents and other files are stored.

– The hard drive is used to stores data permanently.

5. CD/DVD ROM– Often called CD-ROM or DVD-ROM drive, these let your

computer (read /write ) CDs or DVDs.

Main system unit components:

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6. Power supply– A power supply box convert the power available at the wall

socket to the power necessary to run the computer.

Main system unit components:

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• Devices that allow a computer to give information to the user.

• Output device types:

Printer

Headsets

Data Projector

Speakers

Monitor

3.Output Devices

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• The computer has both primary and secondary storage spaces.

1) Primary storage devices – Memory.

2) Secondary storage devices :

4. Secondary storage devices

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2 )Secondary storage devices as:

CD/DVD

USB

Floppy disk

SD Card

Secondary storage devices

Internal hard drive.External hard drive.

Hard disk

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• The performance of a computer is determined by a number of factors, all of which work together.1. CPU:The model of the CPU and its speed are the first factors that determine computer performance.

Computer Performance

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2. RAM: If a computer does not have sufficient RAM, it has to make use of the hard disk to store intermediate data that it would normally store in RAM, this will slow down the computer.

Computer Performance

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3. Number of applicationsThe more open applications and documents will place a burden on the processing power of the computer. For best performance, only open the applications and documents you need.

Computer Performance

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4. Graphics cards:The graphics card is the unit that converts the signals from the CPU into a form that can be displayed on the monitor.

Computer Performance

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Queries???