Computer Organization and CPU Basics

Basic Concepts

• Computer organization examines the physical components and their interactions within a computer system.
• Computer architecture focuses on the functional operation of the computer system.
• Crucial components include the CPU, memory (RAM, ROM), input/output devices, and buses.
• Understanding computer organization aids in comprehending software-hardware interaction.
• It provides a fundamental understanding of computer operation.

The Central Processing Unit (CPU)

• The CPU acts as the computer's "brain."
• It performs arithmetic and logical operations, fetches instructions, and executes them.
• A CPU comprises an Arithmetic Logic Unit (ALU), a Control Unit, and registers.
• The ALU executes calculations.
• The Control Unit manages data and instruction flow within the CPU.
• Registers are fast, small memory locations for temporary data storage.

Memory

• Memory stores data and instructions needed by the CPU.
• Two primary types are RAM (Random Access Memory) and ROM (Read-Only Memory).
• RAM is volatile, losing data when power is off.
• ROM is non-volatile, retaining data without power.
• RAM stores currently active programs and data.
• ROM typically stores permanent instructions, like boot-up code.
• Cache memory is a speedy, small memory for faster access to frequently used data.

Input/Output (I/O)

• Input devices allow data entry (e.g., keyboard, mouse, microphone).
• Output devices display or transmit data (e.g., monitor, printer, speakers).
• Specialized controllers facilitate CPU communication with I/O devices.
• Modern systems often include peripherals like scanners, cameras, and network interfaces.

Buses

• Buses are electrical pathways connecting computer components.
• They transmit data, addresses, and control signals between components.
• Types include the data bus, address bus, and control bus.
• The data bus carries data.
• The address bus specifies memory locations.
• The control bus transmits control signals (e.g., read/write).
• Bus width determines the amount of data transferred simultaneously.

Instruction Cycle

• The CPU executes instructions in a continuous cycle; fetch, decode, execute, and store.
• This cycle continuously operates while the computer is on.
• Instructions are usually machine code, binary instructions for the CPU.

Number Systems

• Computers primarily use the binary (base-2) number system for data.
• Binary representation is crucial in computer systems.
• Decimal (base-10), hexadecimal (base-16), and other systems are used for a more compact or human-readable representation.

Basic Computer Organization Models

• Models describe how components connect.
• The von Neumann architecture is a core model.
• Data and instructions share the same memory space.
• Modern computers evolve based on similar principles using the von Neumann model.
• Other models exist like Harvard architecture, that separates instruction and data memory physically.
• Understanding these models provides an overview of the structure of computers.

Computer Performance

• Computer performance evaluates various factors such as CPU clock speed (GHz), memory access time, I/O speeds, and the number of CPU cores.
• Bus architecture efficiency also impacts performance.