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
2000
1420 SP
Process
Virtual
Address
Space
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
PML1 (Page Table)
PML2 (Page Directory)
PML3 (Page Directory Pointer Table)
PML4 40 12
Page Frame
Offset
PML4 Base
52-bit Physical Address
CS 140 Lecture Notes: Virtual Memory

4. User Address Space (Virtual) OS Address Space (Physical)
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