Introduction to Computer Systems

Computer Basics

• A computer is an electronic device that takes input, processes it, and produces output.

Fixed vs Programmable Computers

• Fixed computers are designed to perform a specific task and cannot be programmed.
• Programmable computers can be programmed to perform different tasks.

Calculators vs Computers

• Calculators are designed to perform mathematical calculations only.
• Computers can perform a wide range of tasks beyond calculations.

Input and Output

• Input devices: keyboard, mouse, scanner, etc.
• Output devices: monitor, printer, speaker, etc.

RAM vs ROM

• RAM (Random Access Memory): temporary storage for data and programs, volatile (loses data when power off).
• ROM (Read-Only Memory): permanent storage for data and programs, non-volatile (retains data when power off).

Secondary Storage

• Necessary to store large amounts of data when the computer is turned off.
• Types of secondary storage: Hard Disk Drive (HDD), Solid-State Drive (SSD), Flash Drive, CD-ROM, DVD-ROM, etc.
• Technologies used: magnetic, optical, solid-state.

CPU (Central Processing Unit)

• ALU (Arithmetic Logic Unit): performs mathematical and logical operations.
• Busses: pathways for data transfer between components.
• Clock: regulates the pace of operations.
• Registers: small amount of on-chip memory for temporary storage.
• Control Unit: retrieves and executes instructions.

Operating System

• Manages memory allocation and deallocation.
• Executes programs and manages program execution.
• Manages input and output operations.
• Manages user interface (GUI) and communication between devices.

Binary System

• Binary is a number system with base 2, using only 0 and 1.
• Denary (decimal) to binary conversion: replace each digit with its binary equivalent.
• Binary to denary conversion: replace each binary digit with its decimal equivalent.

Binary Maths

• Add three binary numbers together by performing bitwise operations.

Data Sizes

• Bit: smallest unit of data, represents a single binary digit (0 or 1).
• Nibble: 4-bit unit of data.
• Byte: 8-bit unit of data.
• Kilobyte (KB): 1024 bytes.
• Megabyte (MB): 1024 kilobytes.
• Gigabyte (GB): 1024 megabytes.
• Terabyte (TB): 1024 gigabytes.