Computer Architecture Essentials and Cheat Sheet

Certainly! Here is a cheat sheet for computer architecture:

1. Central Processing Unit (CPU)

• The "brain" of the computer that executes instructions.
• Consists of the Control Unit (CU) and the Arithmetic Logic Unit (ALU).
• Fetches instructions from memory, decodes them, and executes them.

2. Memory Hierarchy

• Registers: Fastest and smallest storage units located within the CPU.
• Cache: High-speed memory that stores frequently accessed data.
• Main Memory (RAM): Larger storage used to hold data and instructions.
• Secondary Storage: Non-volatile storage devices like hard drives and SSDs.

3. Instruction Cycle

• Fetch: The CPU fetches the next instruction from memory.
• Decode: The instruction is decoded to determine the operation.
• Execute: The instruction is executed by the ALU.
• Store: The result is stored in memory or a register.

4. Instruction Set Architecture (ISA)

• The interface between hardware and software.
• Defines the instructions a CPU can execute and their format.
• Examples: x86, ARM, and MIPS.

5. Pipelining

• A technique to increase instruction throughput.
• Breaks instruction execution into stages to allow parallelism.
• Stages: Fetch, Decode, Execute, Memory, and Writeback.

6. Caches

• Level 1 (L1) Cache: Small and fast cache directly connected to the CPU.
• Level 2 (L2) Cache: Larger cache that sits between the L1 cache and main memory.
• Level 3 (L3) Cache: Optional cache, usually shared among multiple cores.

7. Virtual Memory

• A technique to use disk storage as an extension of RAM.
• Allows running more programs than can fit in physical memory.
• Involves swapping data between RAM and disk.

8. Parallel Processing

• Multiple processors or cores working together to execute tasks.
• Increases performance and enables concurrent execution.
• Types: SIMD (Single Instruction, Multiple Data) and MIMD (Multiple Instruction, Multiple Data).

9. Instruction-Level Parallelism (ILP)

• Exploiting instruction-level parallelism to enhance performance.
• Techniques: Superscalar (multiple instruction issue) and out-of-order execution.

10. Input/Output (I/O)

• Communication between the computer and external devices.
• Devices: Keyboard, mouse, display, storage, network interfaces, etc.
• I/O devices use interfaces like USB, HDMI, SATA, and Ethernet.

Remember, this cheat sheet provides a high-level overview of computer architecture concepts. For a more comprehensive understanding, consider referring to textbooks or online resources specific to the architecture you are studying.