SECTION 1 Components of a Computer System

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1 SECTION 1 Components of a Computer System 1.a. What is hardware? Hardware is the electronic and mechanical equipment that make up the computer. These parts are needed by the computer to communicate with the outside world, pretty much in the way we have our eyes to see, our hands to write, our voice to speak, and so on. The computer consists of components including the input devices, output devices, a system unit, storage devices and communications devices. More on input devices, output devices and storage devices will be covered in another section. The system unit is a case that contains electronic components of the computer that are used to process data. The circuitry of the system unit is usually part of or is connected to a circuit board called the motherboard. Two main components on the motherboard are the processor and memory. The processor is the electronic component that interprets and carries out the basic instructions that operate the computer. Memory consists of electronic components that store instructions waiting to be executed and data needed by those instructions. IT 0417 Notes 5

2 The extra devices outside the computer are called the peripherals. Peripherals include: monitor, keyboard, mouse, printer and speakers. A special kind of peripheral that is not meant to handle communication between a human and a computer is a modem. This is a device which allow communication between two computers through a telephone line. can 1.b. What is software? Software is the set of instructions that tells the computer how to perform a task. The two main types of software are: Operating System program that controls the operations of the computer and its devices. It acts as a mediator between the user and the machine, making sure each understand the other. Examples: Linux UNIX Solaris MS Windows XP Mac OS Application Software a program designed to perform a specific function directly for the user such as word processing, spreadsheets, databases, etc. Word processor one of the more widely used types of application software; allows a user to create and manipulate documents containing mostly text and sometimes graphics. IT 0417 Notes 6

3 Typing a letter Typing a report Spreadsheet application software that allows a user to organize data in rows and columns and to perform calculations on data. Typically a spreadsheet is like a big piece of paper that has been divided into rectangles (called cells) into which we can put data. The spreadsheet stores not only the data values but also the position of the data on the sheet. So, for example, the third cell down in the second column might store '3'; if the third row down is 'March' and the second column is '2 nd ', the single value '3' might mean that there were three bookings on the second of March, or there were three people absent on the second of March. A spreadsheet is designed to store and manipulate data like a database. Spreadsheets can be used to predict future trends by using mathematical formulae in computer models. Spreadsheets can be used to do simulations. If a situation is too dangerous or too expensive to do in real life, a spreadsheet can be used to predict what will happen. For instance, there are not many pilots who would be willing to fly a plane to discover the answer to the question 'If this aircraft is made to corner very tightly, will the wings stay on?', so a spreadsheet is produced instead. All the measurements of the strains and stresses on the wings are added to the spreadsheet, along with details of the mathematical formulae that show how the measurements are all connected. The spreadsheet can then predict whether or not the wings will stay on. This is called a model not a wooden model, but a mathematical model. It doesn't look like a plane, just a lot of numbers, but if you are clever with spreadsheets, it can tell you more about what the plane will do in real life than a wooden model ever could. Data-handling software the major use of computers is not calculations or communications, but storing and handling data. More processor power is used around the world in looking after and manipulating stored data than all the other processing put together. What do we mean by data handling? It is the ability of the computer to store, search and find data. Database Management System program that allows user to create a computerized database; add, search, change, and delete data in the database; sort and retrieve data from the database; and create forms and reports from data in the database. Used to store information about workers in a factory. Store student's details in school Desktop Publishing (DTP) software application software used by professional designers to create sophisticated documents that can contain text, graphics and special layouts. Writing/creating a book Newsletters Bulletins IT 0417 Notes 7

4 CAD/CAM CAD stands for computer-aided design. This is exactly what it says: the computer is used to help people design things. CAM stands for computer-aided manufacture. This helps with the second stage, to help computer-controlled machines to make the product from the design made with CADs. To design circuit boards and other electronic circuits because they tend to be made up of standard parts and the parts are repeated many times, which can be done on the computer by a simple copy and paste operation. After the design is completed, then the design is sent to the CAM to help the machines automatically produce the products. 1.c. What is the difference between hardware and software? A computer system can roughly be divided into 3 parts: Hardware the complex set of wires and electronic equipment that will obey a simple set of commands. Software the commands the computer has to obey. Documents - the electronic equivalent of pieces of paper on which the programs will write. 1.d. The main components of a general-purpose computer Central Processing Unit (CPU) The CPU is the electronic component on a computer's motherboard that interprets and carries out the basic instructions that operate the computer. Main/Internal memory (including ROM and RAM) This is the type of memory that can be read from and written to by the processor and other devices. Programs and data are loaded into RAM from storage devices such as a hard disk and remain in the RAM as long as the computer has continuous power. RAM (Random Access Memory): consists of memory chips that can be read from and written to by the processor and other devices. Most RAM is volatile, which means that it loses its contents when the power is removed from the computer. ROM (Read Only Memory): refers to memory chips storing permanent data and instructions. The data on most ROM chips cannot be modified. ROM is nonvolatile, which means its contents are not lost when power is removed from the computer. Input Devices An input device is any hardware component that allows users to enter data and instructions into a computer. Examples include: keyboard, mouse, touchscreen, etc. (more details in the next section). Output Devices An output device is any type of hardware component that conveys information to one or more people. Examples include: monitor and printer. IT 0417 Notes 8

5 Secondary/Backing storage Storage holds data, instructions, and information for future use. Examples include: floppy disks, CD ROMs, USB thumb drives, etc. (more details in the next section). 1.e. Two main types User Interfaces of Operating Systems Graphical User Interface (GUI) employs the use of Windows, Icons, Menus and Pointers (WIMPs) to make interaction with the user more user friendly. GUIs also typically allow more than one way of doing things so that users can choose the method most convenient for them. Command line interface uses commands that the user must memorize in order to carry out. IT 0417 Notes 9

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