Operating Systems 2017F Lecture 11

Video

Video from the lecture given on October 12, 2017 is now available. (I thought there was a recording fail during the lecture but seems that it worked fine. If there are any glitches let me know!)

Notes

In-Class

Virtual memory
--------------

every process has a virtual address mapping
kernel maintains mapping of virtual->physical memory
  - these are page tables

accessing page tables in main memory on every memory access
  - crazy slow

cache of virtual->physical memory mappings

on every memory access
 - check the cache for the mapping, use if there (fast)
 - if not, check the page table (slow)

TLB is the cache of virtual->physical memory mappings
 "translation lookaside buffer"

Table:
  virt prefix -> phys prefix (top 20 bits on 32-bit architectures)
  - "every" entry is checked in parallel on each access

Code

Files from the lecture are available.