os08-final - Operating System Final Exam. for 2008 Fall...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Operating System Final Exam. for 2008 Fall Semester Date: 01-14-2009, Time: 09:10 a.m.- 10:40 a.m. Name: Student ID: Dept: There are 9 problems in this examination with the indicated points of each (sub)problem. The total points fo this exam. is 110. Please do all of them. 1. [Basic Concepts](30%) These are 10(a-j) true or false problems. If your answer is false please give the true statement with respect to the original false one. (a) (3%) [Dynamic Loading vs. Dynamic Linking] With dynamic loading, a routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. With dynamic linking, a stub is included in the image for each library-routine reference. Dy- namic loading requires special support from the operating system but dynamic linking generally does not require help from the operating system. (b) (3%) [Memory Fragmentation] Contiguous memory allocation scheme suffers from internal fragmentation as address spaces allocated contigu- ously and holes develop as old processes dies and new processes are ini- tiated. But pure segmentation suffers from external fragmentation as a segment of a process is laid out contiguously in physical memory and fragmentation would occur as segments of dead processes are replaced by segments of new processes. 2 (c) (3%) [Belady’s Anomaly] The Belady’s anomaly cannot be shown in the stack page-replacement algorithms. Like optimal page replacement, LRU page replacement done not suffer from Belady’s anomaly because they all belong to a class of stack page-replacement algorithms. (d) (3%) [Working-Set Model] The working-set model is based on the assumption of locality. The most important property of the working set is its size. If we compute the working-set size, WSS i , for each process in the system, we can then consider D = ∑ WSS i , where D is the total demand for frames. Thus process i needs WSS i frames. If the total demand D is less than the total number of available frames m , e.g. ( D < m ), thrashing will occur, because some processes will not have enough frames....
View Full Document

This note was uploaded on 12/29/2009 for the course INFO ENGI 9801 taught by Professor Wu during the Spring '09 term at 東京国際大学.

Page1 / 9

os08-final - Operating System Final Exam. for 2008 Fall...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online