Introduction to Computer Science and Information Systems

Posted on Nov 5, 2024 in Computers

1. Introduction to Information Systems (SI)

1.1 Introduction

Life in society requires processing and transmitting information. Methods have evolved from smoke signals and telegraphs to modern computers.

Informatics Definition: The science of automatic information processing.

The evolution and development of informatics has been spectacular!

1.2 SI: Software and Hardware

Computer Definition: A machine composed of electrical elements (hardware) with high calculation capacity and speed.

Software is needed for computers to work.

  • Operating System: Free or Proprietary
  • Applications:
    • Freeware
    • Shareware
    • Proprietary

What defines an application?

  1. Type of license
  2. Development language (Visual Basic, Java, etc.)
  3. Platforms (OS compatibility)
  4. Requirements
    • Hardware: Graphics card
    • Software: JVM, Framework 2.0
  5. Versions
  6. Standards

Firmware: A block of program instructions for specific purposes, stored in ROM, controlling the electronic circuitry of a device.

Examples: Applications managing electrical components in mobile phones, PCs, game consoles, and DTT receivers.

1.4 Hardware Components

  1. CPU (Central Processing Unit)
    • UAL (Arithmetic Logic Unit)
    • Control Unit
  2. RAM (Random Access Memory)
  3. Drivers
  4. I/O Unit
  5. Buses
  6. Peripheral Units

1.4.1 Processor Components

A) Control Unit: The brain. Retrieves, interprets, processes information, and sends commands to other components.

B) UAL (Arithmetic Logic Unit): Performs arithmetic operations (addition, subtraction, multiplication, division, involution, modulus) and Boolean logic (greater than, less than, greater than or equal to, not greater than, AND, OR).

4.2 Memory: Functions, Types, and Characteristics

Memory stores programs and data.

Types of Memory

a) External Storage: Larger capacity, slower than internal memory, non-volatile (e.g., hard drives, floppy disks, DAT, pen drives, web storage).

b) Internal Memory:

  • RAM (Random Access Memory)
  • ROM (Read-Only Memory)

RAM

(Refer to Figure 1.5, page 14)

Memory is composed of bi-stable electronic elements, each storing one bit (1 or 0). 8 bits form 1 byte. Data needs refreshing.

Types of RAM (Page 14)

  1. DRAM (Dynamic RAM)
  2. SRAM (Static RAM): Faster, more expensive than DRAM, used in cache.
  3. SDRAM (Synchronous Dynamic RAM)
  4. DDR RAM (Double Data Rate SDRAM): Accesses data twice per clock cycle.

ROM

ROM (Read-Only Memory) contains programs to start the computer (BIOS).

Initially stored in PROM, now in EPROM. Saved in CMOS memory. CMOS has a battery and a clear button. BIOS settings can be accessed at boot (Del, F2, etc.).

Other types: VRAM (video memory), CDRAM (cache memory).

(Study Figure 17, page 17)

EMS

32-bit system, 32-bit processor.

64-bit system, AMD Athlon 64-bit processor.

4.4 Peripherals

Peripherals are hardware devices that allow interaction with the PC (mouse, keyboard, monitor), data storage/reading, printing, scanning, and transmitting/receiving data (modem, router, VOIP).

Classified as input, mixed (input/output), and output devices.

Connected through ports (parallel, serial, PS/2, USB, HDMI, Firewire).

OS recognizes peripherals via Plug & Play. Device drivers are usually required.

5. Software Components

5.1 Data Types

Data: Abstract representation of information (e.g., name, average rating, photo, song, video).

Data Classification

  • Input (from mouse, keyboard)
  • Output (monitor, printer)
  • Intermediate (swap file, print queue)

Classification by Change

  • Fixed (constant, e.g., VAT, exchange rate)
  • Variable (continuously changing, e.g., cursor position, free memory)

Classification by Usage

  • Numerical (0-9)
  • Alphabetical (A-Z, a-z)
  • Alphanumeric (0-9, A-Z, a-z, special characters)
  • Others: Date/Time, Logical (Yes/No)