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Essential introduction to computers – Part 1. Outline. Computers and computer literacy What is a computer? The information processing cycle Data versus information Components of a computer Input devices The central processing unit The main memory Output devices
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Outline • Computers and computer literacy • What is a computer? • The information processing cycle • Data versus information • Components of a computer • Input devices • The central processing unit • The main memory • Output devices • Where does the power of a computer come from? • Hardware versus software
Computers and computer literacy • Examples of computers? • Desktop, laptop, palmtop, … • Computer literacy: • Knowledge of the computer components • Knowledge of how a computer works • Knowledge of computer uses
UNIX – Most Popular High End OS Ken invented UNIX in cooperation with Dennis and Dennis invented the C Programming Language Dennis Ritchie Ken Thompson
UNIX – On A PDP-11 In 1971This was Dr. Brown’s First Ever “Personal Computer”.012 MB RAM!
What is a computer? • A computer is a programmable, multiuse machine that: • Accepts input • Processes it • Stores the processing results • Provides output • Communicates with others (For example: Other computers on a network such as the Internet)
The information processing cycle • Basic operations of a computer: • Input • Processing • Output • Secondary storage
Data versus information • Data --> Facts • Information --> Meaning
Components of a computer … • Five major categories of devices • Input devices • System unit -- Processing & memory (CPU & RAM) • Output devices • Storage devices • Communications devices • Note: Input, output, storage, and communications devices are also called peripheral devices
Components of a computer ... • Examples of computer devices: • Input --> Keyboard; Mouse; Scanner • System unit --> CPU; Main Memory • Output --> CRT; Printer; Sound • Secondary storage --> Floppy Disk; Hard Disk; Magnetic Tape; Optical Disc (CD-ROM) • Communications -->Wired; Wireless; Modem
Components of a computer ... – The keyboard • A typical keyboard has: • Standard typewriter keys -- QWERTY • Enter key or Return key • Cursor movement keys • Numeric keys • Function keys -- For frequent tasks • Special-purpose keys -- Backspace, Delete, Insert, Esc, Ctrl, and Alt. • The start key is used for accessing system resources in Windows.
Standard Typewriter Keys Function Keys Numeric Keypad Keys The keyboard ... Special Purpose Keys Cursor Movement Keys
Components of a computer ... – The mouse • The mouse is used with a Graphical User Interface (GUI). • Usage: • Rolled about on a desktop -- Directs a pointer on the screen. • Has a number of buttons (+a wheel). • Can be used to: click on an item or to drag it and drop it. • Types of mice: • Mechanical • Optical • Cordless
Components of a computer ... – The Central Processing Unit CPU carries out instructions retrieved from main memory. C U CPU contains the CU and the ALU ALU Registers
Components of a computer ... – The main memory • Also known as memory, primary storage, internal memory, or Random Access Memory (RAM). • It is the working storage or “working space”. • Holds data, instructions, and intermediate results.
Components of a computer ... – Printers • Impact printers: Dot matrix printers are the most common impact printers. • Non-impact printers: • Ink-jet printers • Laser printers • Measuring the speeds of different printers
Components of a computer ... – Computer screens • Cathode Ray Tube (CRT) screens • Liquid Crystal Display (LCD) screens • The pixel is the smallest unit of any screen image • Measuring the resolutions of different computer screens
Where does the power of a computer come from? • Five factors make a computer powerful in carrying out its basic operations: • Speed • Reliability • Accuracy • Storage capacity • Ability to communicate with other computers
Hardware versus software • Hardware Circuitry and physical components • Software (also programs or computer programs) consist of step-by-step instructions that tell the computer how to perform tasks • Each program is written in a computer programming language • Most computers carry out the instructions of a program in a sequential manner (meaning one instruction after another until the whole program is completed)