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<H2>CSE 120 -- Homework #4</H2><FONT color=blue size=+1><B>Out:
11/26</B></FONT><BR><FONT color=red size=+1><B>Due: 12/3</B></FONT>
<OL>
<LI>Chapter 11: 11.5, 11.9, 11.12
<P>11.5 What are the advantages and disadvantages of recording the name
of the program that creates a file with the file's attributes (as is done in
the Macintosh operating system)?
<P>11.9 Give an example of an application in which data in a file should
be accessed in the following order:
<P> a. Sequentially<BR> b. Randomly<BR>
<P>11.12 Consider a system that supports 5000 users. Suppose that you
want to allow 4990 of these users to be able to access one file.
<P> a. How would you specify this protection scheme in
Unix?<BR> b. Could you suggest another protection scheme that can
be used more effectively for this purpose than the scheme provided by
Unix?<BR>
<P></P>
<LI>Chapter 12: 12.9, 12.10
<P>12.9 How do caches help improve performance? Why do systems not use
more or larger caches if they are so useful?
<P>12.10 In what situations would using memory as a RAM disk be more
useful than using it as a disk cache?
<P></P>
<LI>[Crowley] A file system is the data structure that holds files and
directories.
<UL>
<LI>Is it possible to have two file systems on a single physical disk drive?
Why or why not?
<LI>Is it possible to have a file system that spans two physical disk
drives? Why or why not?
<LI>Is it possible to have a file that is not in a file system? Why or why
not?
<LI>The mount operation allows you to graft the directory tree from one file
system onto the directory tree of another file system. Does this mean that a
file can span both file systems? Why or why not? </LI></UL>
<P></P>
<LI>On a Unix file system, how many disk read operations are required to read
the first block of the file "/home/solaris/ieng9/cs120f/file"? Assume that the
master block is in memory, but nothing else. Also assume that all directories
are one block in size. </LI></OL><PRE>
</PRE>
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<ADDRESS><A href="mailto:voelker@cs.ucsd.edu">voelker@cs.ucsd.edu</A>
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