Memory System Architecture

In this section, we’re going to learn about what I believe is the most important part of the computer’s architecture: the memory system. Moving data from point A to point B is one of the main bottlenecks in all of today’s systems. Shown above is a picture of HBM (high-bandwidth memory) which is a relatively new memory technology primarily used in GPUs and other accelerators to try to overcome this memory bottleneck.

Memory intro and Technology

In this section, we’ll be talking about how memory works and memory technology. We’ll find that while there are many different memory technologies, none are “best”.

• Turing Lecture
• Computing technology past to present
• Moore’s Law and Dennard scaling
• Energy and Power of CMOS Devices
• QUIZ CMOS Energy, Power, and Moore’s Law

• Reading for this section
• Introduction: Why does memory architecture matter?
• Memory technology
• Moving data around

Caches and the Memory Hierarchy

Since no one technology is the best, we want to create a memory hierarchy with caches. We will discuss the underlying principles that make caches efficient, and how hardware caches are designed.

• Memory hierarchy introduction
• Basic caching
  • Combining memory technologies into a single system
  • Locality and caching
  • Cache performance
• Memory hierarchy
• Cache design
  • Direct-mapped caches
  • Set-associative caches
• Replacement policies
• Write-back policies
• Summary of caches

Virtual memory

Finally, we’ll step up a level and look at how operating systems allow multiple programs to share a single memory through virtualization.

• Virtualization
• Virtual memory
  • Page-based virtual memory
  • Multi-level page tables
• Performance and virtual memory
• Virtual virtual memory

154B Assignment 4 DUE 3/1

201A Assignment 4 DUE 3/1

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