COMPUTER BASICADVANCING TECHNOLOGY INTRODUCTION TO COMPUTERSA computerA computer is an electronic device or set of devices that work under the control of a stored program accepting data from outside itself and processing it to produce information.Qualities of a computerIt’s automatic – i.e can work with minimum human intervention once supplied with data and instructions.It’s a data processor – processes raw facts and figures to produce information.It’s a storage device – store information for later reference.It’s electrical – requires some form of power to drive it.Advantages of using computersStores large chunks of information in limited space.Speed – performs tasks in very short periods (in comparison to working manually)Efficiency – creates an all around saving on space and time.Consistency – gives the same results given the same data and instructions.Secrecy – information is fairly protected if the computer is well managed.Versatility – can do the same thing over and over again without being worn out.Disadvantages of computersComputers are expensive.Cuts down employment opportunities.Needs expertise, which is expensive to hire and maintain.Loss of information is not well managed.COMPUTER SYSTEMIt’s made up of the following:Hardware Software Orgware/ OperatorComputer hardware consists of all physical components of a computer.Hardware equipments fall under the following categories:Input devicesCentral Processing Unit (CPU)Output devicesPeripheral devices: These are devices for input, storage and output.Input devices: Used for inputting data and instructions.Examples: Keyboard, Mouse, Plotters and Scanners.Output devices: Are used to relay what is internal to a computer to the outside world.Central Processing Unit (CPU)All processing is done in the CPU.The CPU is divided into 3 major parts namely:Control Unit (C.U)-Carries out instructions and tells the rest of the computer what to do.Arithmetic and Logic unit (ALU)-Carries out all arithmetic and logic operations.Main Memory-Holds current data and instructionsThe main memory is divided into four parts.Read Only Memory (ROM) – Contents of ROM are permanent and it holds some system files necessary for the boot process.Random Access Memory (RAM) – This is the computer’s working area and it holds data and instruction that is currently in use.Qualities of RAMVolatile – It loses its contents when power goes off.Expandable – An upgrade can be done to increase a machine’s memory size.N/B The larger the main memory the faster the computer.In computer systems, the main memory is referred to as Primary Storage.Secondary StorageExamples include floppy diskettes, compact disk (CD), zip drives.Storage space in computers is in form of units called Bytes.1000 bytes = Kilo Byte, 1 Million Bytes = Mega Byte, 1 Billion Byte = 1 Giga Byte (GB)KINDS OF COMPUTERSThere are two kinds of computers.Analog computers.They are used to manipulate analog data (continuous and non-countable).Examples of their application is in air traffic control systems.Digital computers.They are widely used in the research, business and education sectors.Types of Digital ComputersThere are four types of computers namely:Super computersMain frame computers.Mini computersMicro computersA Super ComputerThis is a big computer that is extremely powerful. It requires a lot of expertise to operate. It’s extremely expensive to procure and to maintain. A Main frame ComputerThis is a very large and powerful computer. It is a general-purpose computer with a range of input and output devices and in most cases several CPU’s. it is a very expensive computer.A Mini ComputerIt can be described as a scaled down version of the main frame. It also has a range of input and output devices.A Micro ComputerIt is a small, cheap general-purpose computer. They include personal computers (PC’s), laptops/ notebooks.MouseLeft Mouse ButtonThis is used to:Issue commandsMove itemsSelectHigh light (by holding down the left mouse button and dragging)Right Mouse ButtonThis is used to: Retrieve commandsCreate shortcutsKeyboard Parts of the keyboard:Functional Keys – used for shortcuts(F1 – F12) i.e F1 is used to activate help notes in windows or DOS environments.Additional Keys – Print Screen, Scroll lock, Pause, Insert, Home, Page up, Delete, End and Page down.Arrow Keys – Facilitate horizontal and vertical movementThe keyboardTyping keyboard – contains Alphabets, numerals and a number of punctuation marks. Numeric Keypad It is positioned on the extreme right.+ Used for AdditionEnterUsed for Equal sign* Used for Multiplication/Used for Division-Used for SubtractionSpecial KeysCaps Lock – for capital lettersTab key – for indenting a paragraphShift key – shift from upper case characters to lower case and vice versaControl key – ctrlAlternate key – altSpace bar – on pressing it the cursor moves one space to the rightEnter/Return - Moves the cursor down one line and to the left margin. Enter also process commands such as choosing an option in a dialog (message) boxes and submitting a form.Del or Delete - Deletes the character at cursor and/or characters to the right of the cursor and all highlighted (or selected) text.Bksp or Backspace - Deletes the character to the left of cursor and all highlighted text.Tab - Moves the cursor five spaces to the right (number of spaces are usually adjustable). Tab moves to the next field in a form or table (Shift-Tab for previous field).Esc or escape - Cancels a menu or dialog boxArrow keys - Moves the cursor around document without changing textFunction keys or f keys - Access commands by themselves or in combination with the three command keys; CTRL, SHIFT, and ALTBasic Typing RulesPlace one space between each word, after a punctuation mark and at the end of a sentence. Always start a sentence with a capital letter. Use capitals for names, addresses, provinces and countries, places, organizations, businesses, associations, schools, colleges, universities, days of the week, months, holidays, nationalities, ethnic groups and languages.Learning the keyboard is the first step to learning computers. Learning involves practice. It really is as simple as that. There are two kinds of typing.The first is called Touch Typing. The Touch Typist uses the Home Keys (asdf for the left hand and jkl; for the right) and all the fingers on both hands as well as the thumbs for the Space Bar while typing. There are many commercial and public domain programs that are designed to teach this method.The other method is some times called 'Hunt and Peck' or depending on finger strength 'Search and Destroy'. This involves using one or more fingers on one or two hands to type. It is a perfectly acceptable way of using a computer and many people get along fine with this technique.STARTING A COMPUTERTurn the power button on the CPU (Central Processing Unit) then turn on the power button on the VDU (Visual Display Unit).Booting Booting is the process by which the computer loads system files into the main memory.This process also involves carrying out of diagnostic tests.Cold Booting - This is the starting the computer by simply turning off the power button and then turning it on again.Warm Booting - This is the Re-starting of the computer by pressing ctrl + alt & delete keys.PROGRAMS (SOFTWARE)A program is a set of instructions, in a language known to the computer telling the computer what to do. There are basically 3 types of software but we shall only tackle two at this stage:System SoftwareThese are programs concerned with effective performance of the computer hardware. They make it easy for people to handle the computer. There are several types of system software namely:Operating systemsLanguage translatorsUtilities or service programsCommunication softwareOperating System - This is a program that controls and coordinates the computer operation. Some operating systems are machine specific but there are some standard ones. Examples of operating systems are Ms DOS, Windows 95, Windows 98, Windows 2000, Windows XP, Windows 2007, Windows Vista, etc.Application SoftwareThese are programs written to solve specific problems and can be divided into two major groups.User Application ProgramsApplication PackagesUser Application ProgramsThese are custom programs written to meet a user’s specific needs. This may be done by in house programmers or a software house under contract.Application PackagesThese are ready made purchased by user. They cover common business functions and they have many functions in many business application. They include spreadsheets used for preparation of budgets, planning etc. word processors used for preparation of documents, databases used to set up database.FILE EXTENSIONSThey identify the source program of fie. The system adds these extensions automatically once the document has been saved.The file name and the file extension are separated by a dot.They are listed below:DOC – word documentMDB – access databaseXLS – excel spreadsheetPPT – power pointSYS – system filesCOM – command filesWINDOWS(Operating System)Ms Windows is a multitasking operating system.G.U.I – Graphical User Inter-phaseWindows has an outstanding feature called WIMP.W – Windows (working area)I – Icons (graphical representation of items)M – Mouse (input devices)P – Pull down menusFunctions of Operating SystemJob Control – e.g. Loading of programs into the main memory, facilitating continuous processing, passing control from one job to another.Memory managementKeep details of resources use e.g. number of files stored, space occupied and the available free space remaining.Detect and report errors. During operation the OS checks the process of operation and if an error is detected it is reported to operator.Input and output control. The OS control the operation of input and output devices such they can accept input data and instructions as well as output information in an efficient manner.Support multiprogramming. The OS schedules and controls the running of several programs at once.Various parts of the desktopTop right of the corner – short cut bar, used to start up programs without necessarily going to the start button.Icons – these are graphical representations in the computer.Start button – initializes most operations in the computer.Task bar – on it lies the start button, time etc.Wall paper – backgroundDialog BoxesThese are electric forms through which the user inputs data and information for the computer to complete task.Part of the dialog boxTitle bar – contains the titleMenu bar – fie, edit, view, optionSelection tabsToolbar – the pictures in a rowList box – Named, LookingCombo boxText box – plain box containing textPreview window – where the results of a product can be previewed.Command button – find now, stop, new searchOpen button – the white buttonsCheck box (small square)Status bar – gives us a report on a procedure or the i.e. status 48 fields foundClosing buttonCREATING FOLDERSFolders are memory locations set apart for the storage of particular files.Click on startPoint to programsWindows explorerClick oncePoint to file (on the menu bar)Click on it oncePoint to newThen folder and click onceType the name of your folderCreating a sub folderDouble click on the folder in which you want to create sub-folders.Click on the file and point to newType the name of the sub-folderRenaming a folderClick on it once to selectClick on the file (in the menu-bar) then re-name and click.Type the new name.Deleting a folderClick on it onceClick on fileClick on deleteCREATING A FOLDER ON THE DESKTOP