**Computer Architecture Classification:**

1. Classification Based on Instruction and Data Stream (IS, SIMD, MISD, MIMD)

• SISD (Single Instruction Stream, Single Data Stream):

  • Description: The simplest form of computer architecture where a single instruction is executed on a single data stream at a time.
  • Example: Traditional uniprocessor systems like early computers.

• SIMD (Single Instruction Stream, Multiple Data Streams):

  • Description: A single instruction is executed on multiple data elements simultaneously. This is typically used in vector processors and applications like graphics processing.
  • Example: Modern processors with vector capabilities, used in tasks like image and signal processing.

• MISD (Multiple Instruction Streams, Single Data Stream):

  • Description: Multiple instructions are applied to the same data stream. This type of architecture is rarely used in practice.
  • Example: Some specialized applications in fault-tolerant computing or parallel processing.

• MIMD (Multiple Instruction Streams, Multiple Data Streams):

  • Description: Multiple instructions are executed simultaneously on different data streams. This is common in modern multi-core processors.
  • Example: Multicore processors, supercomputers, and cloud computing systems.

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2. Classification Based on Memory and Control Unit Design (Von Neumann vs. Non-Von Neumann)

• Von Neumann Architecture (Princeton Architecture):

  • Description: In this classic architecture, both program instructions and data share the same memory and data bus. It is the most common architecture used in general-purpose computers.
  • Key Components:
  • Registers: Store data temporarily for quick access.
  • Arithmetic & Logic Unit (ALU): Performs calculations and logical operations.
  • Control Unit: Directs the flow of data between memory and CPU.
  • System Bus: Transfers data between the CPU and memory.
  • Main Memory: Stores both instructions and data.
  • Example: Most general-purpose computers.

• Non-Von Neumann Architecture:

  • Description: This architecture can have separate memory systems for data and instructions, allowing for parallel processing.
  • Subcategories:
  • Harvard Architecture: Utilizes separate memory for program instructions and data, improving speed by allowing simultaneous access to both.
  • Modified Harvard Architecture: Combines aspects of Von Neumann and Harvard architectures to balance flexibility and performance.