Memory Models

Question 1

What is protected mode as it relates to memory?

Answer 1

In protected mode, the CPU processor can access:
– Up to 4GB memory
– memory protection / privilege level / multi‐tasking
– Supports Virtual-­‐8086 mode
*Used by most modern OS

Question 2

What is a flat memory model?

Answer 2

Model where the address is linear across an address space enabling access to address space directly.

Question 3

What is the virtual memory model?

Answer 3

The virtual memory model consist of 4GB on a 32bit Linux system with 1GB going to the kernel and 3GB for the user space.

Question 4

How can you view a process in memory?

Answer 4

A user could use:
“pmap [PID#] -d”
“cat /proc/[PID]/maps”
(gdb) “info proc mappings”