Introduction to Computers

What is a Computer?

• A computer is a machine that performs tasks or calculations based on a set of instructions, or programs
• Fully electronic computers first appeared in the 1940s as massive machines requiring entire teams to operate
• Today's computers are thousands of times faster and can fit on a desk, lap or even in a pocket
• Computers use hardware and software together
• Hardware is the parts you can see and touch, including the case and everything inside
• The CPU, or microprocessor, is the most important hardware component as it translates instructions and performs calculations
• Monitors, keyboards, mice, and printers are hardware devices
• Input devices like a mouse and keyboard allow computers to process input
• Output devices like monitors and printers allow computers to display output
• Millions of the world's population use computers

Uses of Computers

• Word processing software corrects spelling and grammar
• Copy/paste features and the ability to print multiple copies make word processing efficient
• Word-processed documents are easier to read than handwritten ones and can include images
• The internet is a network of almost every computer in the world
• Computers store a large amount of information
• Email allows near-instant communication with people across the globe
• Chat software and video conferencing tools enable real-time communication
• Digital audio and video composition and editing are made easier by computers
• Special effects in movies are created using computers
• Desktop publishing software enables users to create page layouts for entire books
• Computers help diagnose diseases, find cures, and store patient data in medicine
• Software is used in magnetic resonance imaging and surgery
• Computers perform over a million calculations per second, which allows for complex mathematical tasks
• Banks use computer software for all financial transactions, providing security, speed, and convenience
• Software is used to book travel and hotel reservations online
• Software is embedded in mobile phones
• Software controls flight, targets ballistic missiles, and restricts access to atomic bombs for defense purposes
• E-learning software offers an alternative to traditional books
• Online gambling is now commonplace thanks to computers
• Examinations can be taken and results can be received online
• Businesses, shops, and supermarkets use software for billing, taxes, accounting, and predicting business trends
• Artificial intelligence software is used in stock markets, online trading, and automated factories
• Certificates can be created and modified using software
• ATM software authenticates users and dispenses cash
• Matrimonial websites are used to find partners for marriage

Other Computer Uses

• News can be accessed through numerous websites
• Alumni websites help people reconnect with classmates
• Robots are controlled by software
• Washing machines and microwave ovens are operated by software
• Software can store contact information, generate plans, schedule appointments, and set deadlines
• Greeting cards can be sent and received digitally
• Software is used for making umpiring decisions in sports
• Simulation software can help athletes practice and identify flaws in technique
• Pilots use software to simulate flying
• Supercomputers can analyze and predict weather

Computer Types

• Computers are categorized as analog, digital, and hybrid based on their operational principle

Analog Computers

• Analog computers are nearly extinct
• Analog computers perform several mathematical operations simultaneously
• They use continuous variables and mechanical or electrical energy

Hybrid Computers

• Hybrid computers combine digital and analog technologies
• Digital segments manage process control by converting analog signals to digital ones
• An example of a hybrid computer being a bomb site on a WW2 bomber with series of continuous gears
• Another example is a hospital computer that measures heartbeat
• Hybrid machines are typically used in scientific and industrial applications

Mainframe Computers

• Mainframe computers are used by large organizations for critical applications like bulk data processing and ERP
• Mainframes can host multiple OSs, function as virtual machines, and replace small servers

Microcomputers

• Microcomputers have a microprocessor and CPU
• Microcomputers are smaller than mainframes
• When microcomputers have a keyboard/mouse, they are called personal computers
• Microcomputers contain a monitor, input/output devices, RAM, and a power supply
• Microcomputers are suited for single-user tasks

Types of Personal Computers

• Desktops are for single location use and have affordable spare parts and are popular for daily use in workplaces and households
• Laptops are miniaturized, optimized for mobile use, and run on a single battery or adapter, plus have an integrated keyboard, touchpad, and LCD
• PDAs (Personal Digital Assistants) are handheld computers called palmtops, that incorporate a touch screen and memory cards, Bluetooth, and Wi-Fi
• Minicomputers bridge the gap between mainframes and microcomputers, called mid-range systems or workstations, and were smaller third generation computers in the 1960s
• Supercomputers are effective for calculation-intensive tasks, such as quantum physics, mechanics, weather forecasting and molecular theory, and use parallel processing
• Wearable computers are worn on the body for behavior modeling and health monitoring, are integrated into daily routines, and continuously track human actions

Operating Systems

• An Operating System or OS is software with programs and data that runs computers, managing computer hardware resources, and provides common services to execute programs
• Operating systems need to be self-booting
• An OS has a brand name, and each brand has different versions of OS

Common Brands

• Windows and Mac are common OS brands
• UNIX/Linux, Google Chrome OS, and Novel are also brands
• For Microsoft, DOS came before Windows and was not a Graphical User Interface(GUI) OS

Windows versions

• CE
• 3.x
• 95
• 98
• 98 SE
• ME
• NT
• 2000
• XP
• Vista
• 7

Mac Versions

• Apple DOS 3.1
• Apple System 1-7
• Mac OS 8
• Mac OS 9
• Mac OS 10
• Mac OS X
• Unix/Linux began in 1957 when Bell Labs wanted an operating system for their computer center, which was running various batch jobs
• Bell Labs developed the BESYS operating system

Unix/Linux

• Has many variations that have evolved
• Brands include: BSD, FreeBSD, SCO/Caldera, Red Hat, Solaris, Linux
• Linux was not started until 1991, being the noted UNIX OS

Today's Computers

• Multi-user OS allows multiple users to use the same computer at the same time
• Multiprocessing OS supports more than one computer processor
• Multitasking OS allows multiple software processes to run simultaneously
• Multithreading OS allows different parts of a software program to run concurrently

Basic Components

• Motherboard
• CPU - Central Processing Unit
• RAM - Random Access Memory
• Video Card
• Power Supply
• Hard disk or drive
• Optical Drive

Hardware and Software

• Hardware exists within the tower of a desktop computer
• Hardware consists of the physical components of the computer
• Software refers to the programs and systems that operate within the hardware
• The motherboard is the heart of the computer, being its largest and most vital component which attaches every other component
• Memory, accessory cards, and CPUs attach to the motherboard
• Drives and peripherals use wired connections to communicate

Motherboard

• Varies in speed, features, capacity, and CPU support
• It also differs in size and layout, which is commonly referred to as the form factor
• A CPU, aka Central Processing Unit, is the brain of the computer, connecting to other components to perform all of the "thinking"
• What a CPU actually does is perform mathematical calculations, translated into useful functions through software
• RAM, aka Random Access Memory comes in modules of predefined amounts
• It is found on the motherboard, in one, two, or four slots, storing information temporarily, for short term use
• RAM stores information for files that are currently being used by the CPU
• RAM memory is different from a hard disk which stores information permanently for long term use

Graphics Card

• A Graphics card, aka video card, translates information into text and graphics
• Most motherboards have a slot called the AGP slot, aka Advanced Graphics Port, specifically designed for graphics
• Modern graphics adapters usually incorporate some memory to improve performance
• The power supply supplies power to other computer components, which is why many wires come from it
• The power supply is positioned at the back top corner of the computer case, and has a built-in fan to keep itself, and the computer, cool
• The hard disk is like a filing cabinet, storing the programs and data accessed by the computer when needed
• The computer accesses the hard drive through RAM memory, storing needed information as a temporary workspace
• The originally stored information is undisturbed and left as is until the file is saved
• Storing or saving information will write it to the hard disk, replacing or modifying the old file
• Save data to a new file, or install new software, the information is written to an available, unused portion of the disk

Optical Drive

• Sits at the front of a computer for ease of access
• Uses a laser to read and write information to CDs and DVDs