Unit II: Number Systems, OS, and Programming Tools

Course: Fundamentals of Information Technology
Code: CADSC101

Table of Contents

Number Systems & Character Representation
Binary Codes (BCD, ASCII, EBCDIC, Gray)
Operating System Basics & Functions
Types of OS and Windows vs Linux
Programming Language Tools (Compiler, Interpreter)
Algorithms, Pseudo-code, and Flowcharts
Exam Focus: Tips & FAQs

Number Systems

Number systems are the mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner.

Common Bases

Binary (Base 2): Uses 0 and 1.
Octal (Base 8): Uses digits 0 to 7.
Decimal (Base 10): Uses digits 0 to 9.
Hexadecimal (Base 16): Uses digits 0-9 and letters A-F.

Conversion of Bases

Computers convert all human-readable data into binary for processing. Conversion involves dividing (from decimal) or multiplying (to decimal) by the target base.

[Image of Number system conversion chart]

Character Representation and Codes

Specific coding schemes are used to represent characters and numbers in a format the computer can understand.

BCD (Binary Coded Decimal): Each decimal digit is represented by a fixed number of binary bits.
ASCII (American Standard Code for Information Interchange): A standard code for representing text in computers.
EBCDIC: An 8-bit character encoding used mainly on IBM mainframe.
Gray Code: A binary numeral system where two successive values differ in only one bit.

Operating System (OS)

Definition: An Operating System is a system software that acts as an interface between the user and the computer hardware.

Functions of an Operating System

Process Management: Managing execution of multiple programs.
Memory Management: Allocating and de-allocating memory space.
File Management: Keeping track of files stored on storage devices.
Device Management: Controlling input and output devices through drivers.

[Image of Operating System functions diagram]

Types of Operating Systems

OS can be categorized based on how they process tasks.

Batch OS: Jobs are collected in batches and processed together.
Multi-programming OS: Multiple programs run on a single processor simultaneously.
Time-sharing OS: Allows multiple users to use the computer at the same time.
Real-time OS: Used where time constraints are very strict (e.g., missiles, medical).

Windows vs. Linux

Feature	Windows	Linux
Kernel Type	Hybrid	Monolithic
User Interface	Primarily GUI	GUI and powerful CLI
Open Source	No (Proprietary)	Yes (Free/Open)

Programming Language Tools

These tools translate high-level code into machine language.

Assembler: Translates Assembly language to Machine code.
Compiler: Translates the whole program at once.
Interpreter: Translates the program line by line.
Linker: Links various object files to create an executable.
Loader: Loads the executable into memory for execution.

Algorithms and Flowcharts

Before writing a computer program, a logical plan is created.

Algorithm: A step-by-step procedure to solve a problem.
Pseudo-code: Informal description of an algorithm using plain English.
Flowchart: Graphical representation of an algorithm using symbols.

Exam Focus & Tips

Exam Tip: Practice Binary to Hexadecimal conversions; they are guaranteed marks.
Common Mistake: Thinking an Interpreter and Compiler are the same. Remember: Compiler = Whole; Interpreter = Line-by-line.
Mnemonics: B-O-D-H for Number Systems (Binary, Octal, Decimal, Hex).

Frequently Asked Questions

Q: What is the base of Hexadecimal?
A: 16 (Digits 0-9 and A-F).

Q: Define a Linker.
A: It is a tool that combines multiple object files into a single executable file.