Lecture # 2 Computer Hardware

Computers are all around! Grocery store Schools Libraries Bank Mail Malls We interact with computers everyday! We interact with computers everyday!

A computer is an electronic device, operating under the control of instructions (software) stored in its own memory unit, that can accept data (input), manipulate data (process), and produce information (output) from the processing. Generally, the term is used to describe a collection of devices that function together as a system. Computer System

A computer can convert data into information that is useful to people. A complete computer system includes four distinct parts: Hardware Software Data User A computer is an electronic device used to process data. Computer System

Understanding Computer programmable machine A computer is a programmable machine that receives input, stores and manipulates data/information, and provides output in a useful format.

Hardware All the machinery and equipment in a computer system Software All the instructions that tell the computer how to perform a task Computers consist of hardware and software. If you can touch it, its hardware

Off and On Computers only recognize off and on, like a light switch These switches are represented as binary digits or… bits Instructions and data are composed only of a series of bits

Why Is A Computer So Powerful? The ability to perform the information processing cycle with amazing speed. Reliability (low failure rate). Accuracy. Ability to store huge amounts of data and information. Ability to communicate with other computers

How Does a Computer Know what to do? It must be given a detailed list of instructions, called a compute program, algorithms or software, that tells it exactly what to do. Before processing a specific job, the computer program corresponding to that job must be stored in memory. Once the program is stored in memory the computer can start the operation by executing the program instructions one after the other.

What Are The Primary Components Of A Computer ? Input devices. Central Processing Unit (containing the control unit and the arithmetic/logic unit). Memory. Output devices. Storage devices.

Input Process Output Data Information Storage How a Computer System Works

Function of Computer System Data handling IInput PProcess OOutput SStorage

Off and On Computers only recognize off and on, like a light switch These switches are represented as binary digits or… bits Instructions and data are composed only of a series of bits

A binary digit (bit) is the smallest unit of information that your computer can process. A bit can be either 1 (on) or 0 (off). ASCII is a common coding system used to represent all characters, symbols and numbers in binary form. In ASCII a group of 8 bits is called a byte. HARDWARE: Your Physical Interface

Example: – If you type cool on the keyboard, your keyboard would change it into four bytes as follows: C o o l HARDWARE: Your Physical Interface

Bytes Eight bits form a single byte – is One Byte of Information Byte Values: – = 0 – = 255 As a result, binary numbers almost always written as a full byte ( ).

We count in Base 10 (Decimal) Ran out of symbols (0-9), so increment the digit on the left by one unit.

Computers count in Base 2 (Binary) Counting in Binary is the same, but with only two symbols – On (1) – Off (0)

Converting Binary to Decimal = 172

Converting Binary to Decimal = 81

Converting Binary to Decimal = 23

Size Matters Computer memory and storage capacities are represented by their size (megs, gigs, etc) – 1, 0 = 1 bit – 4 bits = 1 hex character (nibble) – 8 bits = 1 byte – 2^10 = 1,024 bytes or 1 Kilobyte (thousand) – 2^20 = 1,048,576 bytes or 1 Megabyte (million) – 2^30 = 1,073,741,824 or 1 Gigabyte (billion) – 2^40 = 1,099,511,627,776 bytes or 1 Terabyte (trillion)

Generic Input devices Accept data or commands and convert them to electronic form Getting data into the computer –Typing on a keyboard –Pointing with a mouse –Scanning with a wand reader or bar-code reader

Keyboard Data is entered by manually typing certain keys. A keyboard typically has 101 or 105 keys. Most keyboards use the QWERTY layout, named for the first six keys in the top row of letters. Generic Input Devices Rollup Keyboards gaming keyboard

Generic Input Devices MOUSE Is a pointing device which is used to control the movement of a mouse pointer on the screen to make selections from the screen. The bottom of the mouse contains a mechanism that detects movement of the mouse.

Specialized Input Devices