Intro to Computers

• Computers are used everywhere including work, school and at home
• Daily activities often depend on computers
• Computers are used for local and global communication
• People use computers to manage schedules, balance checkbooks, pay bills, transfer funds, and buy or sell stocks

Computer definition

• An electronic device operating under the control of instructions is stored in its memory
• An electronic machine accepts data, processes it with calculations, and generates the desired output
• The term "Computer" derives from the Latin word 'Computerae', meaning 'to compute'
• Computers combine hardware and software to convert data into information, but cannot think like humans

Fathers of Computers

• Charles Babbage is named the father of computers
• Alan Turing is known as the father of modern computers

Functioning of a Computer System

• Computers perform four basic functions

Included in these functions are:

• Input: Data or information entered into a computer
• Processing: Actions taken on data to convert it into meaningful information
• Output: Making processed data available to the user
• Storage: storing Data and programs permanently

Computer Terms

Included in these terms are:

• Hardware: Physical elements of a computer system, such as keyboard, scanner, printer, and display screen
• Software: Tells hardware what to do to accomplish tasks, e.g., Word processors, web browsers
• Data: Unprocessed raw facts and figures like numbers, text
• Information: Processed, organized, and structured data presented in a useful context
• Instruction: A command given to a computer in computer language
• Program: A set of instructions given to perform a task

Information processing cycle

• Computers process data (input) into information (output)
• Computers often hold data, information, and instructions in storage for future use
• Instructions provide steps that tell the computer how to perform a particular task
• The series of input, process, output, and storage is referred to as the information processing cycle

Components of a Computer

• The internal design varies across models, but the basic organization remains the same
• Five units, also called "The functional units", correspond to basic operations

Input Unit/Input devices

• This links the external environment to the system
• Data and instructions enter in forms depending on the input device used
• Input devices transform data into binary codes for the computer's primary memory
• Input units accept instructions and data from the outside world
• Input units convert instructions and data into a computer-acceptable format
• Input units supply converted instructions and data to the computer for processing

Output Unit/Output devices

• The output unit supplies computation information and results to the external world and links the computer with the external environment
• Computers work with binary code, so results are produced in binary form
• Output units convert results to a readable human form
• Output units accept results produced, which are not easily understood
• Output units convert coded results into a human-readable form
• Output units supply the converted results to the outside world

Storage Unit/Devices

• This stores data and instructions entered through input units before processing
• Storage keeps results produced after processing before being passed to output units
• The storage unit, or main storage, provides space for data, instructions, intermediate results, and final results
• The specific functions of the storage unit is to store all data to be processed and the processing instruction from input devices
• The storage unit is responsible for storing intermediate and final processing results before they output

Central Processing Unit (CPU)

• Consists of registers, arithmetic and control circuits that interpret and execute instructions.
• The CPU transfers instructions and input data from main memory to registers, and then executes them in the stored sequence
• The CPU transfers output data from registers to main memory when necessary
• Modern CPUs attach to a CPU "socket" on the motherboard and require a heat sink and fan to dissipate heat

CPU subsystems:

• Control unit (CU)
• Arithmetic logic unit (ALU)
• Registers

CPU Clock Speed

• The clock speed of a processor is the number of instructions it can process per second, measured in gigahertz (GHz)
• A CPU with a clock speed of 3.0 GHz can process 3 billion instructions each second

CPU Cores

• Some devices have single-core or multi-core processors
• Multi-core means that the CPU has multiple processors working side by side, which doubles the instructions processed

Arithmetic and Logic Unit (ALU)

• Contains the electronic circuitry that executes arithmetic and logical operations on data
• This performs arithmetic and logical calculations and uses registers to hold data

Control Unit (CU)

• Directs and controls the activities of internal and external devices
• The CU interprets instructions, determines what data is needed, its storage location, and sends control signals to devices

Register

• Special purpose and high-speed temporary memory units
• They store data, instructions, addresses, and intermediate processing results
• The number and size of registers vary by processor

How a Computer Works

• Press the power button to start the computer
• Computer sends signals to the power supply
• The power supply converts alternative current to direct current
• All components receive power, counters ensure no problem, then sends signals to CPU and motherboard
• Processor clears leftover data in memory registers and gives registers a hexadecimal number
• This number is the location of the first instruction and tells the CPU it is ready
• If the computer passes the POST, or power on self test, then the compuer looks at the CMOS (Complementary Metal Oxide Semiconductor) chip
• This chip contains information such as system time, date, and hardware details, as well as loading the device drivers

Advantages of Using Computers

• Multitasking: Computers can perform multiple tasks and calculations quickly
• Speed: Computers can complete tasks in seconds due their incredible processing speed -Data/Storage: Low-cost solution for saving huge data
• Accuracy: Computers perform calculations with accuracy
• Communications: can communicate with other computers wirelessly

Computer Disadvantages

• Unemployment: Automation reduces the need for people
• Time and Energy: Computers can be used without purpose playing games etc
• Data Security: Data can be accessed by unauthorized personnel
• Computer Crimes: Computers can be used for hacking and stealing data.
• Privacy Violation: Personal data can be violated if records are not protected
• Health Risks: Prolonged use can cause injuries or disorders
• Environment: Disposal processes pollute the environment

Networks and Internet

• A network is a collection of computers and devices connected, often wirelessly through communications devices
• The Internet is a worldwide network connecting millions of businesses, governments, educational institutions, and individuals

People use the Internet daily to:

• Communicate
• Access information
• Shop for goods and services
• Bank and invest
• Take classes
• Access entertainment
• Download media
• Share information

Computer Software

• Software/Programs tell computers what tasks to perform and how
• User interface controls how you enter data and instructions, and how information is displayed

Software displays a graphical user interface (GUI), which utilizes

• Text
• Graphics
• Visual images such as icons

Software Categories

• Icons: miniature image that represents an object -System software: Designed to run a computer's hardware and applications functioning as the interface between hardware and user applications
• Application software: Designed for the end-user. Includes database programs, word processors, web browsers etc.
• Installing and running programs: Setting up software to work with computer, printer, and other hardware components.

Categories of Computers

• Computers are divided into categories based on size and computing power

From smallest to Biggest

• Handheld computers
• Personal computers
• Servers
• Mainframe computers
• Supercomputers

Handheld Computer Features

• Small keyboard or touch-sensitive screen, designed to run on batteries, and be used as electronic appointments, address book, calculator, and notepad
• Devices can send/receive e-mail, collect maps, and make voice calls via cellular service

Personal Computers

• Microcomputers designed to meet individual computing needs such as word processing, photo editing, e-mail, and Internet access
• Configurations include desktops, notebooks, tablets, and netbooks

Desktop Computers

• Fit on a desk, run on electrical outlet power, and have a separate keyboard
• Housed in a vertical or horizontal case, and are popular for offices, schools, and homes

Notebook Computer

• Lightweight personal computers incorporate a screen, keyboard, storage, and processing into a single unit
• Can run on electrical outlet or battery, ideal for mobile uses, and more expensive than desktops

Tablet Computers

• Feature a writing or drawing pad, and slate tablet configurations that lack a keyboard and resemble a clipboard

Servers

• Serve Data to computers connected to a network and are technically any device. Devices are offered like Servers of blade and storage to allow store and distribution across a network

Mainframe Computers

• Large and expensive computers capable of simultaneously processing data for many users
• Mainframes are generally deployed to provide storage, processing, and management for large data which starts in hundrends of thousands of dollars and can even exceed a million

Supercomputers

• Fastest computers in the world, which helps to tackle complex tasks that are not practical for other computers
• Supercomputers are used for breaking codes, modeling weather systems, and simulating nuclear explosions

Computer Applications in Society

Present in Fields, Like

• Education
• Banking
• Marketing
• Travel

Business

• Speed, accuracy, reliability, and versatility make it an integral part of all business organizations
• Used for payroll, budgeting, sales analysis, financial forecasting, employee database management, and stock maintenance.

Banking

• Today's banking relies heavily on computers
• Banking operations and records are maintained using computers, and ATMs enable easier customer transactions

Insurance

• Helpful for insurance companies to keep records updated, maintain databases of clients, and show policies

Education

• Provides lots of facility to the education system and known as CBE (Computer Based Education), involving control, delivery and evaluation of learning

Misc facts/Tit-bits

• The first computer architecture was introduced by John Von Neumann in 1948
• EDVAC constructed at the Moore school of Engineering (USA) and was the first electronic computer constructed at the Moore school of Engineering (USA)
• ENIAC was known as the worlds first successful electronic computer
• The microprocessor is the main concept behind fourth generation of computers
• The performance of computers rely on the size of registers, RAM, speed of system clock and the size of cache memory
• Measure the speed of processor in millions of cycles per second or megahertz (MHz)