Ms. Minerva A. Lagarde

Transcription

1 Ms. Minerva A. Lagarde

2 Introduction Objectives At the end of this module, you should be able to: 1. explain how a computer works; 2. state the functions of each basic hardware component of a computer system; and 3. classify computers.

3 Computers - electronic device that accepts data, stores and processes the data, and generates information as output. Data input Computer (stores and processes data) output Info Fig 1.1 A Computer

4 Calculator vs. Computer Calculator is controlled through direct human intervention. example: 9+3=12 Computer processes the data and does the calculations automatically without human intervention by following a set of instructions (program).

5 Computers - Machines that process data under the control of a program. Data Program input Computer output Program Info Fig 1.2 A computer processes information under the control of a program

6 Computer System - Hardware Component - Software Component

7 Main memory Input Device Central Processing Unit (CPU) Output Device Secondary memory Fig 1.3 Basic computer components

8 Input and Output Devices Allow us to communicate with the computer. Examples: Input devices keyboard and mouse Output devices display screen (monitor)

9 Central Processing Unit (CPU) does data processing. 2 Parts: Control Unit (CU) takes care of the fetching and decoding process Arithmetic/Logic Unit (ALU) performs the arithmetic and logical operations using some electronic circuitry. Q: What specific component of the computer does the arithmetic computations? A: The arithmetic/logic unit (ALU)

10 Main memory and Secondary memory Consider the following example: (9-2)*(3+1)=28 bits (binary digits 0 and 1) and bytes 8 bits = 1 byte 1 kilobyte = 1024 bytes (2 10 ) 1 megabyte = 1024 kilobytes 1 gigabyte = 1024 megabytes

11 Computer Memory consists of main memory and secondary memory. Main memory vs. secondary memory technology used.

12 Memory Type Technology Limitations, Advantages and Disadvantages Main Memory Uses electric current Very expensive Fast access Volatile Secondary Memory Uses magnetic material Relatively cheap Slow access Non-volatile Q: Why do computers need to use both types of memories (main and secondary)? A: It uses main memory to be able to process data at high speeds (remember how the memory is used as temporary storage?), and it uses secondary memory to preserve data.

13 Two classes : Applications software and systems software Applications software programs used by people to solve their individual needs Examples: word processors ( to compose documents) and spreadsheet programs ( to perform calculations on numbers places in a table). Systems software programs that control the operations of the computer hardware.

14 Microcomputers small desktop systems made popular by IBM in the early 80s. Minicomputers - are more powerful than microcomputers ; intended to support several users who are concurrently doing different tasks. Example: Sun SPARCstation, DEC Alpha and the SGI Indigo.

15 Mainframes - large systems that can process huge amounts of data at a very high rate. Minicomputers vs. Mainframes Main difference is their input/output capacity and applications for which it is used. Minicomputer 2-5 GB of disk space; normally used for interactive applications Mainframes might have 100 GB of disk space; used for large transaction processing such as banking applications which involve huge databases.

16 Supercomputers - the fastest computers and achieve processing speeds more than 10 times that of the minicomputers. Used in highly specialized applications such as weather forecasting and space exploration. Q: Differentiate between microcomputers and minicomputers A: Microcomputers are less powerful than minicomputers. They are designed for individual use, while minicomputers are designed to handle several users at a time.

17 Name of Computer Year Constructed Features Mark 1 ENIAC (Electronic Numerical Integrator And Computer) 1944, at Harvard University 1946, at University of Pennsylvania First electromechanical computer Used electromechanical switching devices First fully electronic digital computer Used vacuum tubes Worked about 1,000 times as fast as Mark 1 Performed approximately 5,000 Arithmetic operations per Second

18 Name of Computer Year Features EDVAC (Electronic Discrete Variable Automatic Computer) UNIVAC I (UNIVersal Automatic Computer) 1949 First computer with program stored in its memory Used vacuum tubes 1951 First computer to be mass-produced and commercially available Used vacuum tubes Q: What distinguishes the first-generation, second-generation and third-generation computers from one another? A: The technology used. First-generation computers use vacuum tubes, second-generation computers use transistors, and third-generation computers use integrated circuits.

19 A computer is a machine that accepts data, processes the data by following a set of instructions (program), and outputs results. A computer system consists of the hardware part and the software part. The hardware refers to the physical component, while the software refers to the programs that the computer execute.

20 The basic hardware components of a computer are the input and output devices, the central processing unit, the main memory, and the secondary memory. The computer software are classified into applications software and systems software. Computers are categorized into four classes, namely, microcomputers, minicomputers, mainframes and supercomputers

21 What are the four (4) classifications of computers (4points)? What are five basic hardware components (5 points)? What distinguishes the first-generation, second generation, and third-generation computers from each other (3 points)?