ALU Design using multiplier

Memory Design

Memory Hierarchy

• A hierarchical organization of memory systems to optimize performance and capacity
• Levels of memory:
  1. Registers: Small, fast, on-chip memory built into the CPU
  2. Cache: Small, fast, on-chip memory that stores frequently accessed data
  3. Main Memory: Larger, slower, off-chip memory that stores program data
  4. Secondary Storage: Slow, high-capacity storage devices (e.g., hard drives)

Cache Memory

• Cache Hit: When the CPU finds the required data in the cache
• Cache Miss: When the CPU does not find the required data in the cache
• Cache Replacement Policies: Strategies to replace cache lines when the cache is full
  • LRU (Least Recently Used): Replace the least recently used cache line
  • FIFO (First-In-First-Out): Replace the oldest cache line

Main Memory

• Memory Organization: The way memory is divided into blocks, pages, and frames
  • Blocks: Fixed-size chunks of memory
  • Pages: Fixed-size chunks of memory, divided into blocks
  • Frames: Fixed-size chunks of physical memory
• Memory Protection: Mechanisms to prevent unauthorized access to memory
  • Base and Limit Registers: Define the boundaries of a program's memory space
  • Segmentation: Divide memory into logical segments or regions

Virtual Memory

• Virtual Address Space: The address space used by a program
• Physical Address Space: The actual memory addresses used by the computer
• Memory Mapping: The process of translating virtual addresses to physical addresses
• Page Fault: When the CPU encounters a page not in physical memory
  • Page Replacement: The process of replacing a page in physical memory with a new one

Memory Interleaving

• Memory Interleaving: A technique to improve memory access performance
• Bank Interleaving: Divide memory into multiple banks, each accessed independently
• Channel Interleaving: Divide memory into multiple channels, each accessed independently

Memory Design

Memory Hierarchy

• Memory systems are organized in a hierarchical manner to optimize performance and capacity
• The hierarchy consists of registers, cache, main memory, and secondary storage
• Registers are small, fast, on-chip memory built into the CPU
• Cache is small, fast, on-chip memory that stores frequently accessed data
• Main memory is larger, slower, off-chip memory that stores program data
• Secondary storage is slow, high-capacity storage devices (e.g., hard drives)

Cache Memory

• A cache hit occurs when the CPU finds the required data in the cache
• A cache miss occurs when the CPU does not find the required data in the cache
• Cache replacement policies are strategies to replace cache lines when the cache is full
• LRU (Least Recently Used) policy replaces the least recently used cache line
• FIFO (First-In First Out) policy replaces the oldest cache line

Main Memory

• Memory organization involves dividing memory into blocks, pages, and frames
• Blocks are fixed-size chunks of memory
• Pages are fixed-size chunks of memory, divided into blocks
• Frames are fixed-size chunks of physical memory
• Memory protection mechanisms prevent unauthorized access to memory
• Base and limit registers define the boundaries of a program's memory space
• Segmentation divides memory into logical segments or regions

Virtual Memory

• A virtual address space is the address space used by a program
• A physical address space is the actual memory addresses used by the computer
• Memory mapping translates virtual addresses to physical addresses
• A page fault occurs when the CPU encounters a page not in physical memory
• Page replacement replaces a page in physical memory with a new one

Memory Interleaving

• Memory interleaving is a technique to improve memory access performance
• Bank interleaving divides memory into multiple banks, each accessed independently
• Channel interleaving divides memory into multiple channels, each accessed independently

Memory Design

Memory Hierarchy

• A hierarchical structure of memory systems balances performance, capacity, and cost.
• Four levels of memory:
• Registers: small, fast, and expensive, built into the CPU.
• Cache: small, fast, and expensive, located on or near the CPU.
• Main Memory: larger, slower, and less expensive, located on the motherboard.
• Secondary Storage: largest, slowest, and least expensive, located on disk or SSD.

Memory Types

• Volatile Memory: loses data when power is turned off.
  • Examples include RAM and Cache.
• Non-Volatile Memory: retains data when power is turned off.
  • Examples include ROM, Flash Memory, and Hard Disk.

Memory Organization

• A Word is a unit of memory accessed as a single entity.
• A Byte is a group of 8 bits, also accessed as a single entity.
• An Address is a unique identifier for a memory location.
• The Address Bus carries address signals from the CPU to memory.

Memory Access

• Sequential Access: memory is accessed in a sequential manner (e.g., magnetic tapes).
• Random Access: memory can be accessed directly and randomly (e.g., RAM).
• Memory Interleaving: a technique to improve memory access by dividing memory into multiple modules.

Cache Memory

• A Cache Hit occurs when the CPU finds required data in the cache.
• A Cache Miss occurs when the CPU does not find required data in the cache.
• Cache Replacement Policies decide which cache line to replace when the cache is full.
  • Examples include FIFO, LRU, and Optimal.

Virtual Memory

• A Virtual Address is an address used by the CPU to access memory.
• A Physical Address corresponds to a physical location in memory.
• The Page Table maps Virtual Addresses to Physical Addresses.
• A Page Fault occurs when the CPU tries to access a page not in physical memory.