introduction to computer
- 1. Introduction To Computer By Areh Kelvin
- 2. Introduction and Definition of Computer The 20th century saw the birth of one of the most important tools widely in use today called a computer. Today, computers are used for communication, management, research, drawing and design as well as entertainment. This 21st century is being referred to as the digital age A computer is an electronic device that accepts user input (data) and processes it under the influence of a set of instructions referred to as programs to produce the desired output generally referred to as information. • Data are the raw facts may not make much meaning to the user. • Programs are set of instructions that instruct a computer what to do. • Information is result after data has been processed.
- 3. Computer Hardware & Software Computer Hardware These are physical parts such as the system unit and peripheral devices. Peripheral devices connect to the system unit. They include: Input devices. Central processing unit (CPU), Output devices. Storage devices. Computer Software Software - software is the instructions given to the computer that tells it what to do. A computer cannot do anything without instructions. A computer must first read instructions before it can start to work. These instructions are called operating system software. When a computer is turned on, the first thing it does is find and read its system software. This software tells the computer how to work; how to be a computer. Once a computer has done this and is “booted up” or ready to go, it can read other instructions called application software. This type of software tells the computer how to do a specific task with a user, like writing a report, playing a game, or creating a graph.
- 4. Computer Parts There are 4 basic types of computer parts: a) Input devices - parts of the computer that allow information or data to be given to the computer like keyboard or a mouse. b) Storage devices – parts of the computer that hold information. The primary storage device is the computer’s memory called RAM (random access memory). It remembers everything that is read, input, or output. But, because the computer’s memory is on a temporary area—it forgets everything when turned off—it must have another place to store information permanently. This secondary storage device is usually a disk. c) Processing device – part of the computer that processes and controls the flow of information; it actually does the work. The one part of the computer that handles this job is the central processing unit or CPU. d) Output devices - parts of the computer that gives out information generated by the computer, like a monitor, printer or speaker.
- 5. Input – Process - Output
- 6. Basic Concepts – GUI – A Graphical User Interface – which uses visual displays to eliminate the need for typing commands. – Directory tree – a pictorial representation of your disc’s structure. – Boot – to start up the computer and load the DOS. – BIOS – The BASIC Input/Output System. It allows the core of the operating system to communicate with the hardware. – Bit – a binary digit, the smallest unit of information that can be stores either as 1 or 0. – Byte – a grouping of binary digits (0 or 1) which represent information. – CPU – the Central Processing Unit – the main chip that executes all commands. – Disc – a device which you can store programs and data
- 7. Basic Concepts – Cold boot – the process of starting your PC by switching it on. – Warm boot - the process of starting your PC by using the Ctrl+Alt+Del key combination. – File – the name given to an area on disc containing a program or data. – Filename – the name given to a file. It must not exceed 8-characters in length and can have up to 3-characters. – File extension – the optional three-letter suffix following the period in a filename. – Processor – The electronic device which performs calculations. – Prompt – A symbol that appears on a monitor to indicate that DOS is ready to receive input or commands, such as A> or C>. – Peripheral – A device attached to a PC.
- 8. Basic Concepts – Network Interface Card (NIC) - A board that provides network communication capabilities to and from a computer. – Network Operating System (NOS) - Operating system designed to pass information and communicate between more than one computer. Examples include AppleShare, Novell NetWare, and Windows NT Server. – Node - End point of a network connection. Nodes include any device attached to a network such as file servers, printers, or workstations. – Node Devices - Any computer or peripheral that is connected to the network. – Peer-to-Peer Network - A network in which resources and files are shared without a centralized management source. – Physical Topology - The physical layout of the network; how the cables are arranged; and how the computers are connected. – Point-to-Point - A direct link between two objects in a network. – Ports - A connection point for a cable.
- 9. Basic Concepts – Topology - There are two types of topology: physical and logical. The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Logical topology is the method used to pass the information between workstations. Issues involving logical topologies are discussed on the Protocol chapter – Tree Topology - LAN topology similar to linear bus topology, except that tree networks can contain branches with multiple nodes. – WAN (Wide Area Network) - A network connecting computers within very large areas, such as states, countries, and the world. Workstation - A computer connected to a network at which users interact with software stored on the network. – Business Information Systems: Information systems within a business organization that support one of the traditional functions of business such as marketing, finance, or production. Business information systems can be either operations or management information systems. – Control: The systems component that evaluates feedback to determine whether the system is moving toward the achievement of its goal and then makes any necessary adjustments to the input and processing components of the system to ensure that proper output is produced
- 10. Basic Concepts – Operations Support Systems: Include office automation systems, transaction processing systems, and process control systems. – People Resources: IS Specialists and end users. – Process Control Systems: Computer-based systems that control an ongoing physical process such as petrochemical production. – Programs: A set of instructions that cause a computer to perform a particular task. – Procedures: Set of instructions used by people to complete a task. – Strategic Information Systems: Information systems that provide a firm with competitive products and services that give it a strategic advantage over its competitors in the marketplace. – Subsystem: A system that is a component of a larger system – System: A system is a group of interrelated components working together toward a common goal by accepting inputs and producing outputs in an organized transformation process.
- 11. TYPES OF COMPUTERS – Super Computers Unlike mainframes and minicomputers, supercomputers are used for the heavy stuff like weather maps, construction of atom bombs, finding oil, earthquake prediction, and sciences where a lot of calculations must be done. They are also used to help governments eavesdrop on anything passing through telephone, data lines, e-mail, or radio waves; and anything that is written, etc. Historically, a supercomputer is associated with the fastest computer available or the largest in size. Supercomputing means "mass computing at ultra high speed." Though all contemporary personal computers perform in the tens or hundreds of megaflops (millions of calculations per second), they still cannot solve certain problems fast enough.
- 12. TYPES OF COMPUTERS – Laptops/notebooks A laptop computer or simply laptop (also notebook computer, notebook and notepad) is a small mobile computer, typically weighing 1.4 to 5.4 kg, although older laptops may weigh more. Laptops usually run on a single main battery or from an external AC/DC adapter that charges the battery while also supplying power to the computer itself even in the event of a power failure. – Mainframe Computer Mainframes are computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, ERP, and financial transaction processing. The term probably originated from the early mainframes, as they were housed in enormous, room-sized metal boxes or frames.
- 13. TYPES OF COMPUTERS – Minicomputers Introduced in the early 1960s and announced a new era in computing. They are relatively low cost and small. Historically, a mini is associated with de-centralized computing. Meaning most computing takes (physically) place on the mini itself – Microcomputers A microcomputer is a computer with a microprocessor as its central processing unit. Another general characteristic of these computers is that they occupy physically small amounts of space when compared to mainframe and minicomputers. Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers Monitors, keyboards and other devices for input and output may be integrated or separate.
- 14. Computers and their Functions Computer - An electronic device that receives data and computes high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes and presents information. A computer has four functions: THE INFORMATION PROCESSING CYCLE Accepts data Input Process data Processing Produces data Output Stores result Storage
- 15. DOS & Windows Comparison of DOS and Windows DOS WINDOWS Command line interface GUI Terminate and stay resident (TSR) memory – one at a time The memory is dynamic – can load many programs at the same time Does not allow multi-tasking – run only one program job at a time Allows multi-tasking – run many programs/jobs simultaneously Filename is limited to only 8.3 characters characters Filename has upto 128 characters - 128.3, 4 characters No spaces in filename Allows spaces in filename
- 16. System Software System software does fundamental tasks such as computer boot up and system control. System software are further classified into: 1. Operating system : An operating system is a program that manages the computer hardware resources and controls the execution of application programs. Examples are: Microsoft Windows 98/2000/Me/2003/Vista UNIX Linux MacOS 2. Utility software : Utility software also called service programs are special programs used to enhance perform both at system and user levels. System level utilities optimizes system performance while application level utilities help in smooth running of application programs. Examples are Norton utility McAfee suites
- 17. System Software 3. Network Software Networking software enables computers and other peripheral devices connected on a network to communicate and share resources. Examples are: 1. Novell Netware 2. UNIX 3. Windows NT based operating systems 4. Firmware Firmware, also referred to as stored logic is an integration of both hardware and software on a single silicon chip. These are mostly packaged as ROM chips.
- 18. Application of Computer, Advantages and Disadvantages Computers have become important tools in our day-to-day’s operations. Some of the areas computers are used are in: Engineering In engineering computers are used for designing using computer aided design (CAD) software. Modelling and testing processes etc. In Biosystems engineering, computers are being used for biometric analysis, genetic engineering and cloning etc. Space exploration would hardly be impossible without the assistance of computers. Manufacturing Computers have made industrial processes more efficient through optimization scheduling, process control, and using robots to perform automated manufacturing process control which are otherwise dangerous to human beings.
- 19. Application of Computer – Communication : The integration of computers and communication technologies is what is being referred to as ICT. This merger has resulted to more efficient communication using computers and other handheld devices such as mobile phones used to facilitate sending and receiving of messages over the internet. Computers also control many telecommunications equipment. – Education and research : Computers are used in educational institution as teaching aid, online teaching especially in open and distance learning and to enhance management. Internet contains a lot of information for researchers, scholars and teachers/lecturers.
- 20. Advantages and disadvantages of computer – Advantages of computers 1. Large storage of data in small amount of space. 2. Quick and accurate calculations than humans. 3. Continuously work with repetitive work( contusive environment). 4. Simulation of dangerous situations. ₋ Disadvantages 1. Expensive to introduce. 2. Health hazards. 3. Downtime-. 4. Redundancy in the work place. 5. It can lead to misuse of information.