Lecturer: Dalia Mirghani Foundation year Lec.2: Computer Hardware Computer For Health Sciences COMP101 Lecturer: Dalia Mirghani Year : 2014/2015

What is a computer ? 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.

Desktop computer System Parts of the computer Desktop computer System

Types of Computer 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 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 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 4) Laptop Cost: Laptops or Notebooks are similar to personal computers except that they comprise an integrated unit. Cost: More expensive than personal computers.

Types of Computer 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.

Computer system A computer system is made up of : 1.Hardware - The physical components. 2.Software – The programs or lists of instructions.

Hardware 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.

1. Input Devices Input device types: Input devises are hardware components that convert data from an external source into electronic signals understood by the computer. Input device types: Microphone Scanner Key Board Digital Camera Barcode Reader Mouse

2. System Unit The system unit

Main system unit components: Motherboard It contains slots for the processor chip, memory slots, and slots for adapter cards for video, sound, and connection to peripheral devices. 1. 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: 2. 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: 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: 6. Power Supply A power supply box convert the power available at the wall socket to the power necessary to run the computer.

3.Output Devices Devices that allow a computer to give information to the user. Output device types: Monitor Printer Data Projector Speakers Headsets

4. Secondary storage devices The computer has both primary and secondary storage spaces. 1) Primary storage devices – Memory. 2) Secondary storage devices :

Secondary storage devices 2) Secondary storage devices as: Internal hard drive. External hard drive. Hard disk USB SD Card Floppy disk CD/DVD

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

Computer Performance 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 3. Number of applications The 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 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.

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