Lec1 Basic Concepts.pdf

ICT 141 COMPUTING SKILLS FUNDAMENTALS I FACULTY OF SCIENCE Lecture 1: Basic Concepts of IT Computing Skills Fundamentals 1 Learning Objectives In this lecture you will learn: Definition of a Computer B...

ICT 141 COMPUTING SKILLS FUNDAMENTALS I FACULTY OF SCIENCE Lecture 1: Basic Concepts of IT Computing Skills Fundamentals 1 Learning Objectives In this lecture you will learn: Definition of a Computer Basic Functions of a Computer How different Components of a Computer Work together to achieve a particular task Storage and Peripheral Devices Different Types Of Computers Servers Computing Skills Fundamentals 2 What is a Computer? Computer: A machine that accepts input data and instructions, and processes/manipulates the data to produce useful results/Output. Computer Receives Data from user User Processes the Data Sends back results Computing Skills Fundamentals 3 What is a Computer cont..? It consists of Hardware and Software: – Hardware: The physical/or tangible part of a computer – Software: Computer programs that run on Computer Hardware; Both System and Application Software Computing Skills Fundamentals 4 Benefits of a Computer Computers are very fast. Modern computers, even those commonly sold in retail stores, can perform millions of operations in a second. Computers are very accurate. When a computer is programmed correctly and when its input is without error, the accuracy of the output, as made possible by the capabilities of the processor, is virtually guaranteed. Computers have very large storage capacities. They can store huge amounts of data in very small physical spaces. The also enable very fast and convenient access to stored data. Computers perform large numbers of tasks without getting tired. Computer programs written to predict weather patterns could run for days or longer. If this was done manually by humans, they could get tired, allowing mistakes to creep in, leading to erroneous results. Computing Skills Fundamentals 5 Uses of Computers in everyday life Education: The Promise of More Interactive & Individualized Learning – Online Learning, or distance learning, is becoming common. Tutoring, simulation, and avatars are also aspects of IT in education: Health: High-Tech for Wellness – Telemedicine: Medical care via telecommunications lets doctors treat patients from far away. – Health websites provide medical information. Government & Electronic Democracy: – help governments to improve services, including police services – Online voting is becoming common. – Information is easier to disseminate. Computing Skills Fundamentals 6 Uses of Computers in everyday life cont.. Jobs & Careers – People now use computers to post résumés and find jobs. – IT is used in starting new business ventures. – Basic computer skills are needed for most jobs: Your Personal Life – “Digital is embedded into the fiber of every aspect of our culture and our personal lives”– public safety and security; in the home; entertainment; finance; communications; traveling; shopping; medical care; and so on. Computing Skills Fundamentals 7 Basic functions of a computer The basic operations of a computer: All computers use 4 basic operations + communications: – Input: What goes into the computer system – Processing: The manipulation a computer does to transform data into information – Storage: Primary storage, or memory, is temporary storage for data waiting to be processed Secondary storage is permanent storage: media such as hard disk, DVDs, and CDs – Output: What comes out—the results of processing, such as on the screen, printouts, sound – Communications: Sending and receiving data Computing Skills Fundamentals 8  9 Computing Skills Fundamentals Computer Devices Different devices are required to perform the 4 basic functions: – Input is received through input devices such as mouse, keyboard, touch screen, etc. – Processing on the data received is carried out by the CPU and working memory, which is within the system Unit – After data processing output devices are used to display the results, example Monitor, Printer – This output can then be stored for later use on storage devices such as hard disk, magnetic tape, memory stick etc. NB: Some devices can be used for several purposes; e.g. a printer, scanner and photocopier can be combined as one physical device. Computing Skills Fundamentals 10  Output hardware – Video – Sound cards – Speakers – Monitor – Printer Communications hardware – Modem Computing Skills Fundamentals 11 Basic PC System Computing Skills Fundamentals 12 More on Basic Functions of a Computer The parts mentioned work together to perform four basic functions of a computer: – Input – Processing – Output – Storage Computing Skills Fundamentals 13 Central Processing Unit Central Processing Unit(CPU) – basic instructions that operate the computer are carried out here; responsible for managing everything the computer does – It consists of :  Arithmetic and Logic Unit- This is where calculations are done i.e. it executes all arithmetic and logical operations  Control Unit- Carries out the instructions stored in the CPU. The order in which instructions are carried out is controlled here. Coordination of all hardware operations  Main (working) Memory- works with the CPU closely to hold data and instructions for processing Computing Skills Fundamentals 14 Processing Central Processing Unit CPU Arithmetic/L Control Unit ogic Unit Output Input Memory Secondary Storage Computing Skills Fundamentals 15 Main Memory/Primary Memory There are two types: Read Only Memory (ROM) – Holds data that can be stored and used but cannot be modified – Typically contains manufacturer’s instructions – Non volatile Random Access Memory (RAM) – Temporarily stores/holds data that the CPU is currently processing (Analogy - Workbench) – Volatile Computing Skills Fundamentals 16 Secondary Memory/Mass Storage Permanent storage, stores day as long as you want Stores data that the computer is NOT currently Processing (Analogy – Cabinet) Persistent memory that keeps data even when power is switched off Secondary -backing storage, mass storage Relatively low speed Relatively cheaper than main memory Computing Skills Fundamentals 17 Secondary Storage Devices Examples of Storage Devices: – Magnetic Tape –Common for Backup storage – Hard Disk – CD/DVD R – Flash Drive Computing Skills Fundamentals 18 Exercise: Storage Primary vs Secondary Storage In which Categories does each of these two devices belong? Computing Skills Fundamentals 19 Exercise: Peripheral Devices External devices connected to the computer(System Unit) to provide input and output. Can you think of any? Computing Skills Fundamentals 20 Peripheral Devices Input Devices Output Devices keyboard monitor mouse projector digital pen printer joystick speakers keyboard scanner Both Input/Output microphone external hard drives digital camcorders touch screen Computing Skills Fundamentals 21 Types of Computers Today there are many types of computers, very difficult to keep track of how many are out there, but these can be categorized and be classified under few categories: The classification is generally according to: – Their Speed – Processing Capabilities – Price – Size Computing Skills Fundamentals 22 All Computers, Great & Small: The Categories of Machines Computers come in different sizes; they also function as clients and/or servers. There are five basic computer sizes. 1. Supercomputers 2. Mainframes 3. Workstations 4. Microcomputers/Personal Computers 5. Microcontrollers Computing Skills Fundamentals 23 Types of Computers cont.. Examples Minicomputers Supercomputer Mainframe Computing Skills Fundamentals 24 1. Supercomputers Supercomputers are used in very special situations. Priced from $1 million to over $350 million. High-capacity machines with thousands of processors that can perform more than several quadrillion calculations per second. Faster and largest computer available. Used for government census, weather forecasting, designing aircraft, scientific projects, etc. The Titan (U.S.A.) computer is currently the largest supercomputer. Computing Skills Fundamentals 25 2. Mainframes Mainframe computers are used in many large businesses. – Capable of supporting hundreds of users simultaneously – Mainly used by large organizations for critical applications such as registration, records, reports – Priced from $5,000 to $5 million – Process billions of instructions per second – Size is dependent on the use – Used by banks, airlines, insurance companies, colleges, and the like for millions of transactions Computing Skills Fundamentals 26 3. Workstations Workstations are used for graphics, special effects, and certain professional applications. A special computer designed for technical or scientific and professional applications – Expensive, powerful personal computers – Used for scientific, mathematical, engineering, computer- aided design (CAD), computer-aided manufacturing (CAM) applications – Used for designing cars, drugs, movie special effects – Are usually connected to a network Note that a workstation can also refer to a computer connected to a server Computing Skills Fundamentals 27 4. Microcomputers/Personal Computers Microcomputers are used by individuals as well as businesses, and they can be connected to networks of larger computers. There are many types of microcomputers. – Personal computers that cost $500 to over $5,000 – Used either stand-alone or in a network – Types include: desktop, tower, notebooks (laptops), netbooks, tablets, mobile devices, personal digital assistants (PDAs), and e-readers Computing Skills Fundamentals 28 Types of Microcomputers (1) Desktop and tower PCs Tower PC Desktop PC Notebooks & netbooks Tablets Computing Skills Fundamentals 29 Types of Microcomputers (2) Mobile devices & PDAs E-readers Also called embedded computers, microcontrollers are tiny, specialized microprocessors inside appliances and automobiles. – They are in microwaves, programmable ovens, blood- pressure monitors, air bag sensors, vibration sensors, MP3 players, digital cameras, keyboards, car systems, etc. Computing Skills Fundamentals 30 Servers The word server describes the way a computer—whether mainframe, workstation, or PC—is used. A server, or network server , is a central computer that holds collections of data (databases) and programs for connecting or supplying services to PCs, workstations, and other devices, which are called clients. These clients are linked by a wired or wireless network. The entire network is called a client-server network. Purpose: Hold data and programs for clients to access and to supply services for clients. Computing Skills Fundamentals 31 Computing Skills Fundamentals 32