Computer Systems Fundamentals

Computer Systems

• A computer is an electronic device that can perform calculations, process information, and store data.

Fixed vs Programmable Computers

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

Calculators vs Computers

• Calculators are designed to perform mathematical calculations only.
• Computers are designed to perform a wide range of tasks, including calculations, processing information, and storing data.

Input and Output

• Input devices: devices that provide data or instructions to the computer, such as keyboards, mice, and scanners.
• Output devices: devices that display or produce the results of the computer's processing, such as monitors, printers, and speakers.

Memory

RAM vs ROM

• RAM (Random Access Memory): volatile memory that stores data temporarily while the computer is running.
• ROM (Read-Only Memory): non-volatile memory that stores data permanently and cannot be changed.

Secondary Storage

• Necessary because RAM is volatile and limited in capacity.
• Types of secondary storage: Hard Disk Drives (HDD), Solid-State Drives (SSD), Flash Drives, CDs, DVDs, Blu-ray Discs.
• Technologies used: magnetic, optical, solid-state.

CPU

• Components of a CPU:
  • ALU (Arithmetic Logic Unit): performs mathematical calculations and logical operations.
  • Busses: connections between components that allow data to be transferred.
  • Clock: regulates the timing of the CPU's operations.
  • Registers: small amount of memory built into the CPU.
  • Control Unit: manages the flow of data and instructions.

Operating System

• Role of the operating system:
  • Managing Memory: allocating and deallocating memory for programs.
  • Program execution: running and managing programs.
  • Managing Input and Output: controlling input/output devices.
  • Managing User Interface (GUI): providing a visual interface for users.
  • Managing Communication: managing communication between devices and programs.

Binary

• Binary is a number system that uses only two digits: 0 and 1.
• Binary can be converted to and from denary (decimal) numbers.

Binary Conversion

• Convert denary to binary: using place values (2^0, 2^1, 2^2, ...) to convert decimal numbers to binary.
• Convert binary to denary: using place values to convert binary numbers to decimal.

Binary Maths

• Binary addition: adding two or more binary numbers together.

Data Sizes

• Units of measurement for data:
  • Bit: a single binary digit.
  • Nibble: 4 bits.
  • Byte: 8 bits.
  • Kilobyte (KB): 1024 bytes.
  • Megabyte (MB): 1024 kilobytes.
  • Gigabyte (GB): 1024 megabytes.
  • Terabyte (TB): 1024 gigabytes.