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

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

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

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
Code
Data
Stack
Operating System ∞
CS 140 Lecture Notes: Virtual Memory

6. CS 140 Lecture Notes: Virtual Memory