Von Neumann Vs Harvard Architecture | Parameters of Von Neumann | Parameters of Harvard Architecture

Summary

This educational video script delves into the fundamental differences between Von Neumann and Harvard architectures in computing. It explains how each architecture accesses memory for data and code, with Von Neumann using a common memory and Harvard having separate memories. The script highlights the implications on memory types, buses, program execution, control signals, space requirements, and costs, ultimately showing that Harvard, while more expensive, offers superior performance due to its parallel data and code access.

Takeaways

• 🧠 The main topic is the comparison between Von Neumann architecture and Harvard architecture in terms of how they access memory with the CPU.
• 📚 In Von Neumann architecture, there is a common memory for both data and code, whereas in Harvard architecture, data and code have separate memories.
• 🔍 CPU access to data and code is bidirectional in Von Neumann architecture, allowing both reading and writing, but in Harvard, code is read-only from ROM, and data is handled bidirectionally in RAM.
• 🚀 Harvard architecture allows for parallel execution of code and data due to separate memory and addressing, while Von Neumann architecture executes code serially.
• 🛣️ Von Neumann uses common buses for address and data for both code and data access, while Harvard has separate buses for data address and code address.
• 🔄 Program execution in Von Neumann architecture is serial, which may require more machine cycles compared to the parallel access in Harvard architecture.
• 📈 Harvard architecture requires more control signals due to the separate memory spaces for data and code, increasing system complexity.
• 💰 The cost of implementing Harvard architecture is higher than Von Neumann due to the need for separate memory spaces and addressing mechanisms.
• 📏 Von Neumann architecture requires less space on the board because it uses a single memory for both data and code, making it more compact.
• ⏱️ Harvard architecture offers better performance with parallel access to data and code, but at the cost of increased complexity and cost.
• 🔧 Initially, microcontrollers and microprocessors used Von Neumann architecture, but they have shifted towards Harvard for improved performance.

Q & A

What is the main difference between von Neumann architecture and Harvard architecture?

The main difference is that in von Neumann architecture, there is a common memory for both data and code, while in Harvard architecture, there are separate memories for data and code.

How does the CPU access data and code in von Neumann architecture?

In von Neumann architecture, the CPU accesses data and code through a common memory, using a single address for both, which allows for bidirectional data flow (reading and writing).

What type of memory is used for data and code in Harvard architecture?

In Harvard architecture, RAM (Random Access Memory) is used for data memory to allow bidirectional access, and ROM (Read-Only Memory) is used for code memory, which is read-only.

What is the advantage of separate memory for data and code in Harvard architecture?

The advantage is that it allows for parallel execution of code and data access, as separate addresses are available for code and data, leading to more efficient processing.

How does the use of separate buses in Harvard architecture affect memory access?

The use of separate buses for data and code in Harvard architecture allows for separate addressing, which enables simultaneous read and write operations for data and code, improving memory access efficiency.

What is the difference in program execution between von Neumann and Harvard architectures?

In von Neumann architecture, program execution is serial, as the same memory is used for both code and data. In contrast, Harvard architecture allows for parallel execution due to separate memories for data and code.

How does the number of control signals differ between the two architectures?

Von Neumann architecture requires fewer control signals due to its common memory, typically just memory read and write signals. Harvard architecture, with separate memories, requires more control signals for data memory read/write and code memory read.

What is the impact of memory type on the cost and space requirements of the architecture?

Von Neumann architecture, with a single memory for data and code, requires less space and is less costly. Harvard architecture, with separate data and code memories, requires more space and is more costly due to the need for additional addressing and bus interfaces.

Why did microcontrollers and microprocessors initially use von Neumann architecture and later shift to Harvard architecture?

The initial use of von Neumann architecture was due to its lower cost and simplicity. The shift to Harvard architecture was to achieve better performance through parallel data and code access.

What does the term 'machine cycle' refer to in the context of program execution?

A machine cycle refers to the sequence of operations performed by the CPU, such as reading data, writing data, or fetching the opcode of a program, which are necessary for the execution of a program.

How does the script suggest enhancing the understanding of the two architectures?

The script suggests comparing different parameters such as memory access, memory type, buses, program execution, control signals, space requirement, and cost to enhance the understanding of von Neumann and Harvard architectures.