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Computer and IT

Computer and IT. Ms. L.L. Cheuk Mr. Albert Hong. Mode of Assessment. The assessment will consist of two written papers and an individual coursework assignment. The allocation of marks and the duration are as follows: Paper 1 (core module) 60% 2 hours Paper 2 (elective module) 20% 1 hour

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Computer and IT

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  1. Computer and IT Ms. L.L. Cheuk Mr. Albert Hong

  2. Mode of Assessment • The assessment will consist of two written papers and an individual coursework assignment. The allocation of marks and the duration are as follows: • Paper 1 (core module) 60% 2 hours • Paper 2 (elective module) 20% 1 hour • Paper 3 (coursework) 20%

  3. Candidates are required to choose one of the following elective modules: • Algorithm and Programming • Organisation of Computer • Data Communications and Networking • Multimedia Production and Web Authoring

  4. Paper 1 • Paper 1 consists of two sections, A and B. • Section A will consist of multiple-choice questions, all of which are to be attempted. • Section B will consist of 5 questions, all of which are to be attempted. Both sections will cover the syllabus in the core module.

  5. Paper 2 • Paper 2 consists of 4 questions, all of which are to be attempted. • All questions will cover the syllabus in the elective modules that candidates choose.

  6. Paper 3 • Paper 3 is an individual coursework assignment. Candidates are required to choose an assignment from a list issued by the Hong Kong Examinations and Assessment Authority during the year before the examination according to their chosen elective module. • They are required to produce a report which will demonstrate their ability to analyse a problem and so identify requirements, and to make appropriate use of knowledge in the elective module in providing solutions which they will design, implement, test and evaluate. • The assignments will be assessed continuously and marked internally by school teachers, and the assessment will be moderated by the chief

  7. Material to be covered in S4 • Computer and Information Technology (Volume 1) • Section 1

  8. Material to be covered in S4 • Computer and Information Technology (Volume 2) • Section 3 • Section 4 • Section 5

  9. Section 1 • What is IT? • Application of IT • Data and Information • Application software • Effective Presentation

  10. Section 3 • Internet technology • Internet activities • Web Authoring

  11. Section 4 • Problem solving procedures • Programming Languages • Programming concepts

  12. Section 5 • Legal and ethical issues • Social impact • Impact of upcoming technologies • Computer and Internet Securities

  13. Section 1 Information processing and presenation

  14. Information Technology • The technology used to create, store, exchange, and use information • Mainly computer technology • Also, communication, audio, video, etc.

  15. Why computer? • Speed • Reliability • Accuracy • Storage capacity • Communication ability

  16. Application of IT • Clothing • Eating and food • Housing • Transportation • Finance and commerce • Communications • Education

  17. Application of IT • Science • Health and Medicine • Law enforcement • Government • Robotics

  18. Chapter 2 Data and Information

  19. Data • Raw data • Example – 19740729 • Meaningless if not organised or being understood

  20. Information • Processed data • Organised, meaningful and useful • Used in decision making

  21. Data & Information Data current time, Time that school startswhen you wake up processing Information How much time you have to get ready for school

  22. Data representation in computer • A computer is a binary machine • A computer can only understand 0 and 1 • Data are stored in computer in term of binary digit (bit)

  23. Number system • A number system consists of a set of digits • The number of digits in the set is known as the base of the system • Example –the base of the binary system is the base of the decimal system is

  24. Place value • In 1974(10) • 4 represent 4 x 100 • 7 represent 7 x 101 • 9 represent 9 x 102 • 1 represent 1 x 103

  25. Exercise • In 1974(8) • 4 represent • 7 represent • 9 represent • 1 represent • The decimal value of 1974(8)

  26. Conversion • From decimal to binary • Repeated division

  27. Conversion between binary, octal and Hexadecimal • Each octal digit corresponds to __ binary digits • Each hexadecimal digit corresponds to __ binary digits

  28. Bits and Bytes • In computer, basic unit of storage is byte • One byte = 8 bits

  29. ASCII • American standard code for information interchange • Each ASCII code = an 8-bit binary code • Used to store letter, digit, symbol and control character in computer

  30. Chinese characters • 8 bits can represent 28 different codes • There are more than 10,000 Chinese character • Two bytes are used to represent codes

  31. Database Approach Database file file file record record record field field character character character

  32. Key field • Key field or primary key • Used to identify the records in a table • Must have a unique key value

  33. Data collection • Direct input • Manual input

  34. Source of errors • Data source errors • Transcription errors • Transposition errors

  35. 3.2 Data verification • Checking the accuracy of data that has been copied from one medium to another • Done at data preparation or data input stage • Methods of verification • Even if the data have been entered accurately (verified), the data may still be invalid because the source documents contain errors

  36. 3.3 Data validation • Checking of data before they are processed • Ensure data are valid and acceptable for processing

  37. Validation • Presence check – to make sure that data are present • Range check – To make sure that the data lie within a certain range. Also called reasonableness check • Data type check

  38. Validation • Consistency check – checking of data by comparing them with previous data • Control total – also called batch total. Calculated to ensure no data are missing. • Hash total – similar to control total, but the total calculated has no meaning

  39. Validation • Check digit – extra digit appended to a code consisting of a series of numbers or characters • Calculated from the series of numbers • Used to validate HKID card no., bar codes, bank account no.

  40. Modulo 11 check • Divide the code by 11 and use the remainder as the check digit • Does not pick up transposition errorsboth 526328 and 536228 are correct code

  41. Weighted modulo 11 check • Overcome weakness in modulo 11 check • Each digit in the code is multiplied by a weight before the calculation of reminder

  42. Processing data • Searching • Linear search • Binary search • Index search • Sorting • Bubble sort • Merging

  43. Processing information • Reorganization – output the information in other format for use in other situation • Conversion – produce new information • Example – Final exam mark = 0.7 x exam mark + 0.3 x homework mark

  44. Communication and Transmission • Communication • Transmission • Compression • Parity check

  45. Mode of processing • Batch processing • Real-time processing

  46. Chapter 4 Effective Presentation

  47. Multimedia Elements • Text • Sound • Graphics • Animations • Videos

  48. Planning for presentation • Time constraints • Tools • Compatibility • Activities?

  49. Selecting appropriate information • Topic • Contents

  50. Organizing information • Refining – logical sequence, sections • Interactivity

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