1. CS 140 Lecture Notes: Virtual Memory
Load-Time Relocation ∞
Operating System
Process 3
Process 6
Process 1
CS 140 Lecture Notes: Virtual Memory

2. CS 140 Lecture Notes: Virtual Memory
Base & Bounds Example
Virtual Address Space
2000
1420 SP
RETURN
140
... 66
... 62
CALL 140
CS 140 Lecture Notes: Virtual Memory

3. x86-64 Address Translation
64-bit Virtual Address 16 9 9 9 9 12
not used
Page Table
Page Directory (PML2)
Page Directory Pointer Table (PML3) 40 12
PML4 Table
Page Frame
Offset
52-bit Physical Address
PML4 Base
CS 140 Lecture Notes: Virtual Memory

4. Accessing User Memory write(fd, buffer, length) Pages
User Address Space (Virtual)
OS Address Space (Physical)
CS 140 Lecture Notes: Virtual Memory

5. OS and User in Same Address Space∞
Operating System
Stack
Data
Code
CS 140 Lecture Notes: Virtual Memory