In-depth Notes on Computer Organisation
Overview of Key Topics in IB Computer Science
System Design: Architecture planning of software and systems.
Computer Organisation: Parts of the computer and interactions.
Networks: Communication and resource sharing among computers.
Computational Thinking: Problem-solving with algorithms.
Abstract Data Structures: Data organization for efficiency.
Resource Management: Allocation of computing resources.
Control D: OOP (Object-Oriented Programming): OOP principles in HL and SL.
Computer Architecture
CPU Architecture
Central Processing Unit (CPU):
ALU: Arithmetic and bitwise operations.
CU: Directs processor operations.
Registers: Temporary data storage.
Primary Memory
RAM: Volatile memory for data and instructions.
ROM: Non-volatile memory for firmware.
Cache Memory: Fast memory for frequently accessed data.
Machine Instruction Cycle
Essential operation of CPUs: Fetch-Execute Cycle from boot to shutdown.
Stages of the Fetch-Execute Cycle
Fetching: Retrieves instructions from RAM to Registers.
Decoding: Interprets instructions for actions.
Executing: Performs actions based on decoded instruction (e.g., calculates area).
Storing Results: Saves executed instruction results in memory/registers.
Simplified Model of Machine Instruction Cycle
Components:
Program Counter (PC): Next instruction to be fetched.
Memory Address Register (MAR): Holds fetched instruction address.
Memory Data Register (MDR): Stores retrieved instruction.
Current Instruction Register (CIR): Current instruction being processed.
Accumulator: Immediate results storage.
Data Pathway: PC ➔ MAR ➔ MDR ➔ CIR ➔ CU ➔ ALU for execution.
Additional Notes
Data and Address Buses:
Data bus carries actual data.
Address bus carries data location. Understanding these is key for exams.
Tips for Exam Preparation
Review CPU component roles and types of memory (RAM, ROM, Cache).
Familiarize with programming code and machine operations.
Explain detailed fetch-execute cycle significance.