Unit II: Number System, OS, and Programming Tools

Course: Fundamentals of Information Technology
Code: CAIDC101

Table of Contents

Number System and Codes

Number systems are used to represent numbers and characters in a computer-readable format.

Binary: Base-2 system using only 0 and 1.
Octal: Base-8 system using digits 0 to 7.
Hexadecimal: Base-16 system using digits 0-9 and letters A-F.
Conversion of Bases: The process of changing a number from one base (e.g., Decimal) to another (e.g., Binary).

BCD (Binary Coded Decimal): Represents each decimal digit by a 4-bit binary code.
ASCII: Standard 7-bit or 8-bit code for representing characters.
EBCDIC: 8-bit character encoding used primarily on IBM mainframes.
Gray Codes: A binary system where two successive values differ in only one bit position.

Operating System: A system software that manages computer hardware, software resources, and provides common services for computer programs.

Memory Management: Allocating and de-allocating memory space.
Processor Management: Deciding which process gets the processor when and for how much time.
Device Management: Managing device communication via their respective drivers.
File Management: Keeping track of information, location, uses, and status of files.

Operating systems are categorized based on their processing capabilities.

Windows: A proprietary graphical operating system developed by Microsoft.
Linux: An open-source operating system known for its security and CLI (Command Line Interface).
Differences: Windows is typically user-friendly for beginners (GUI focus), while Linux is highly customizable and preferred for servers.

These tools are essential for translating human-readable code into machine language.

Tool	Description
Assembler	Translates assembly language programs into machine code.
Compiler	Translates the entire high-level source code into machine code at once.
Interpreter	Translates high-level source code into machine code line by line.
Linker	Combines multiple object files generated by the compiler into a single executable file.
Loader	Loads the executable program into the main memory for execution.

Algorithm: A step-by-step logical procedure to solve a specific problem.
Pseudo-code: An informal, high-level description of an algorithm using plain English mixed with programming logic.
Flowchart: A graphical representation of the sequence of operations in an information system or program.
Computer Programs: The final implementation of algorithms in a specific programming language.

Exam Tip: Be prepared to differentiate between Compilers and Interpreters; this is a frequent question.
Common Mistake: Confusing Binary (Base 2) with BCD. Remember BCD specifically maps decimal digits.
Mnemonic: "ACL" for translation tools - Assembler, Compiler, Linker.

Q: What is a Gray code used for?
A: It is often used in digital communications and error correction because only one bit changes at a time.

Q: What is the main role of a Linker?
A: To link object modules together to form a complete executable program.