Computer Fundamentals and Types

Computer Definition

• A programmable electronic device that processes data and produces output based on a set of instructions called a program.
• Types of computers include analog, digital, and hybrid.

Digital Computer Types

• Embedded computers: small, specialized computers built into larger devices.
• Mobile devices: portable computers with cellular connectivity.
• Personal computers: general-purpose computers for individual use.
• Midrange servers: powerful computers designed for multi-user use.
• Mainframe computers: large, powerful systems capable of handling massive amounts of data.
• Supercomputers: the most powerful computers designed for complex calculations and simulations.

Hardware

• The physical components of a computer.
• Central Processing Unit (CPU): Performs arithmetic and logical operations, controls data movement, and executes instructions.
  • ALU: Arithmetic Logic Unit, handles math and logic operations.
  • Control Unit: Coordinates data flow and instruction execution.
  • Registers: High-speed storage units for temporary data.
• Memory: Stores data and instructions.
  • Primary Memory: Directly accessible by the CPU, including:
    • RAM: Random Access Memory, volatile memory used for active data.
    • ROM: Read-Only Memory, non-volatile memory holding permanent instructions.
  • Secondary Memory: External storage not directly accessible to the CPU, providing permanent long-term storage, such as hard disks, DVDs, USB drives, etc.
• Input devices: Allow users to provide data to the computer, such as keyboards, mice, webcams, barcode scanners, microphones, touch screens.
• Output devices: Display processed information from the computer, such as monitors, printers, speakers, projectors, plotters.

Software

• Programs and instructions that tell the computer hardware what to do.
• Computer programming: The process of creating sequences of instructions for computers.
• Types of software:
  • System software: Programs designed to manage and control hardware and run application programs.
  • Application software: Programs designed for end users to perform specific tasks.
  • Operating Systems: System software that manages and controls computer hardware, runs other programs, and interacts with the user. Examples: DOS, Windows, Unix, Linux, Mac OSX.

Programming Languages

• Similar to human languages, using a specific syntax and reserved keywords.
• Can be classified as:
  • High-level Languages: Portable and use more human-readable instructions (ex: Cobol, Basic, C, C++, C#, Java).
  • Assembly Language: Uses mnemonics (English-like terms) to create instructions for specific machines.
  • Machine Languages: Uses binary code (1s and 0s) to create instructions directly understood by the computer.

Program Development Life Cycle (PDLC)

• Steps involved in developing a program:
  • Problem definition: Clearly define the problem to be solved.
  • Problem analysis: Understanding the requirements of the problem.
  • Algorithm development: Creating a step-by-step solution (sequence of operations) for the problem.
  • Coding: Writing the program code.
  • Testing and debugging: Identifying and fixing errors in the code to ensure desired output.
  • Maintenance: Using the program and addressing any issues or enhancements requested by users.

Algorithm Development Methods

• Pseudocode: Using natural language to outline the steps of an algorithm (e.g., using English).
• Flowchart: Using a diagram to visually represent the flow of a program and its steps.

Program Code Convertors

• Assembler: Translates assembly language code into machine code.
• Interpreter: Translates high-level language code into machine code line by line.
• Compiler: Translates high-level language code into machine code (executable file).

Structured Programming

• Also known as modular programming.
• Focuses on logical structure rather than data organization.
• Uses a top-down approach to divide programs into smaller, logical blocks of code called functions.
• Each function performs a specific task, making programs easier to understand and modify.