CS 377 Homework 5

Due date: Tuesday, April 29th, 23:30

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Everyone must hand in their own work. Place in your Hand-In directory
(~/cs377/hw5/) an ASCII file (i.e., raw text) called "hw3.txt" or a
postscript file called "hw3.ps" that contains your name, user id, and
answers to the questions listed below. If you use a non-ASCII editor
(e.g., MSword), please make sure that you save your final file in
ASCII or postscript format (we will not be able to grade your
assignment if it is not one of these formats). In MSword, there is a
'save text' option in the save dialog box. You can check the ascii
format on the linux side by using the shell commands 'cat', 'more', or
'less'. Answers need not be more than a few sentences (please keep you
answers to the point).

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File System Implementation
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1.
What are the three components which comprise disk latency?

2.
a) Why is changing file size hard in contiguous allocation?  
b) Is this easy or difficult in case of a linked list based 
   technique?

3.

a) Bit vector based free space management is inefficient unless the
   entire vector is kept in memory. How much memory would you need 
   for a 20 GB disk assuming 512 byte blocks?  Report your answer in KB.

b) What does this tell you about using a bit vector based technique
   for large disks?


Paging and Memory Management
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4.
Explain the difference between internal and external fragmentation.


5. 
Describe the following allocation algorithms:
a) First fit
b) Best fit
c) Worst fit

6.
Why are page sizes always powers of two?

7.
How much time did you spend on this assignment?