Exam Notes

STEM Education National Schools of Excellence

  • Teachers’ Resource Book for Grades 11 & 12.
  • Focuses on Science, Technology, Engineering, and Mathematics.

Overview of the STEM Curriculum

  • Introduced in Schools of Excellence in 2021.
  • Technology is a core domain.
  • Aims to provide advanced knowledge in Computer Science for Grade 11 students.
  • Ultima Thulë Ltd developed the curriculum.

Table of Contents Highlights

  • Module 1: Binary Computing
    • Introduction to Binary System
    • Data Representation (Numbers, Characters, Images, Sounds)
  • Module 2: Fundamentals of Database Systems (DBMS)
    • Database Concepts and Architecture
    • Database Models
  • Module 3: Building a Relational Database with MS Access
    • Databases, Tables, and Fields
    • Design View, Field Properties, and Relationships
    • Queries, Forms, and Macros

Binary Computing (Module 1)

  • Focus is on understanding how computers read code using the binary system.
  • Binary digits (0s and 1s) help the computer read written code.

History of Binary Numbers

  • Appeared in multiple cultures before the 16th century.
  • Egypt: Horus-Eye Fraction uses binary fractions to measure grains and liquids.
  • China: Ching contains a binary notation representing quaternary divination.
  • India: Pingala developed a binary system for prosody using short and long syllables.
  • Leibniz: Studied the Ching and developed the binary system used in modern computers.

Boolean Logic

  • George Boole introduced Boolean algebra in 1854.
  • Values are TRUE and FALSE, denoted as 1 and 0.
  • Main logical operations: Conjunction (AND), Disjunction (OR), Negation (NOT).

Z1 Computer

  • The first freely programmable computer used Boolean Logic and Binary Floating Point Numbers.
  • Designed by Konrad Zuse from 1936 to 1938.

Terms and Definitions

  • Computer: An electronic device storing and processing data in binary form.
  • Binary: A numeric system using two digits - 0 and 1.
  • Bit: A single binary digit (0 or 1).

Binary Information

  • Data is stored in computers as Binary Information.
  • The computer’s memory is composed of tiny storage locations known as Bits.
  • 1 Byte = 8 Bits.

Bits as Switches

  • Computers recognize 0s and 1s as tiny switches (ON or OFF).
  • Transistors act as tiny binary switches controlling electricity flow.

Decimal Number System

  • Employs 10 as its base (0, 1, 2, 3, 4, 5, 6, 7, 8, 9).

Binary Number System

  • Employs 2 as its base (0 and 1).
  • Uses 2n2^n to represent different values, where n is the number of bits.

Conversion Examples

  • Example: What are 111121111_2 in Decimal?
  • The "1" on the left is in the "2×2×2" position, so that means 1×2×2×2(=8)1 × 2 × 2 × 2 (= 8)
  • The next "1" is in the "2×2" position, so that means 1×2×2(=4)1 × 2 × 2 (= 4)
  • The next "1" is in the "2" position, so that means 1×2(=2)1 × 2 (= 2)
  • The last "1" is in the ones position, so that means 1
  • Answer: 1111 = 8 + 4 + 2 + 1 = 15 in Decimal

Data Representation

  • Computers store various data types in binary form.
  • Numbers are represented by 0s and 1s.
  • Characters are first converted to numeric codes, then stored as binary.
  • Common coding scheme: ASCII (American Standard Code for Information Interchange).
    • Contains a set of 128 numeric codes of 7 bits.

Topic 3: Data Representation as Binary - Images

  • Pixel: Basic unit of a digital image.
  • Bitmap Images: Images made of up individual pixels
  • Each pixel's color is represented as a binary number.
    • 1 bit - 2 colors
    • 2 bits - 4 colors
    • 3 bits - 8 colors
    • and so on
  • Digital images are made up of pixels, and each pixel in an image is made up of binary numbers.

Topic 4: Data Representation as Binary - Sounds

  • Sound is vibrations that travel though a medium.
  • Sound waves have volume (amplitude) and pitch (frequency).
  • The samples can then be converted to binary. They will be recorded to the nearest whole number
  • The frequency at which samples are taken is called the sample rate, and is measured in Hertz (Hz)
    Most CD-quality audio is sampled at 44 100 or 48 000 KHz.
  • When we start recording process you lose some of the sound quality during conversion of analogue signal to a digital (binary) format.
    • If you want to increase the quality of the recorded audio, you need to increase the sample rate.

Module 2: Fundamentals of Database Systems

  • Database system is an important course to learn in Software Development because it provides a systematic method of creating, updating, storing, and retrieving information in a database.
  • Aim of this module is to have students develop skills and knowledge in collecting data, storing them in a database and managing it using different database models

Topic 1: Database Concepts and Architecture

  • Learning about databases and how to manage it can provide you with hands-one learning experience that can develop basic and advanced programming skills.
  • What is Data: Data can be anything; any information or fact
  • Types of Database Architecture
    • 1-tier or Single tier Architecture
    • 2-tier or Two tier Architecture
    • 3-tier or Three tier Architecture
    • N-tier Architecture

Topic 2: Database Models

  • Types of Conceptual Data Models:
    • Entity-Relationship Model
    • Object-oriented Model
  • Types of Logical Data Models:
    • Relational Model
    • Hierarchical Model