![suomeksi](http://www.cs.Helsinki.FI/gif/f-fi.gif)
Operating Systems II, Spring 2005, HW 3
This will be covered in practise session during the week 15 (12-14.4.2005)
- Replacement algorithm
- Problem 8.5 from text book [Stal05, s. 384] (Probl. 8.3 [Stal01])
- What is special with this situation? What can you deduce from it?
- VSWS
- Problem 8.16 from text book [Stal05] (Probl. 8.13 [Stal01])
- What if Q was global, but dynamic. Give a similar mechanism for this
case. Compare it to the mechanism given in (a). When would it be better?
When worse?
- Clock-algorithm
- Which page would be replaced in situation in Fig. 8.16 (b) [Stal05] (Fig. 8.16 [Stal01])?
- When exactly is use-bit set and reset? (Fig 8.16)
- If modified bit is also use, when is that exactly set and reset?
(Fig 8.18 [Stal05] tai kuva 8.18 [Stal01]) - How much variance is there in the gap between the hands in Fig.
8.23 [Stal05] ( kuva 8.23 [Stal01])?
Who varies it and how much? What does the gap value mean? - How is the moving hand speed varied in Fig 8.23
or is it a constant?
What does moving hand speed mean?
- Cleaning policy
- What does Cleaning Policy really mean?
- Why is it not integrated with Replacement Policy? Advantages? Problems?
- Give an example on a situation where replacement is needed, but cleaning is not.
- What happens, if a reference occurs to a page while it is been cleaned?
- What happens, if a reference occurs to a page right after it has been cleaned?
- Linux. Linux memory management maps a conquous virtual memory area into
a contiquous block of physical frames.
- What is the gain with this approach?
- What problems does it cause?
- What are the biggest differences in
- W2K
- Linux
Fetch policy? Placement policy? Replacement policy? Cleaning policy? Load control? Resident set?
(If you were not at the lecture, check (e.g.) Ch. 10.4 and 11.5 [Tane01] for a little bit more thorough W2K and Linux VM presentation than that given in Ch 8 [Stal05])
Teemu Kerola 30.03.2005 13:49