Assignment 9: Chapter 9 and 10
This assignment is to be completed individually, not as a group.
Please make sure that you're using the same edition of the book.
There is no guarantee that older editions use the same numbering for
problems. Please submit a single tar file.
Note that problems may intentionally differ slightly from the ones
shown in the book.
- 9.1: Give an example that illustrates the problem with restarting
the block move instruction (MVC) on the IBM 360/370 when the source and
destination regions are overlapping. (There can be multiple concurrent
- 9.4: A certain computer provides its users with a virtual-memory
space of 230 bytes. The computer has 220 bytes of
physical memory. The virtual memory is implemented by paging, and the
page size is 4096 bytes. A user process generates the virtual address
11123456. Explain how the system establishes the corresponding physical
location. Distinguish between software and hardware operations.
- 9.5: Assume we have a demand-paged memory. The page table is held
in registers. It takes 6 milliseconds to service a page fault if an
empty page is available or the replaced page is not modified, and 30
milliseconds if the replaced page is modified. Memory access time is 80
nanoseconds. Assume that the page to be replaced is modified 60 percent
of the time. What is the maximum acceptable page-fault rate for an
effective access time of no more than 200 nanoseconds?
- 9.8: Discuss situations under which the most frequently used
page-replacement algorithm generates fewer page faults than the least
recently used page-replacement algorithm. Also discuss under what
circumstance the opposite holds.
- Using the Love book and other sources, summarize the virtual memory
mechanisms used in Linux 2.6. In particular, how are pages replaced? Is
there a distinction between 'clean' and 'dirty' pages? Can parts of the
kernel be swapped out?
- 9.16: Is it possible for a process to have two working sets, one
representing data and another representing code? Explain why this would
or would not be helpful.
- How do you construct links in Linux (or Solaris)? For each method,
- Can you create a cycle of links? (Attempt and show what happens when
you try to access the file)
- Can the link refer to a directory?
- What happens when the file pointed is removed?
- Can the link span file systems?
You should demonstrate the behavior in each case by showing a test case
and the resulting error message or output.
- As mentioned in class, Unix supports files with 'holes'. Write a
test program that illustrates this behavior, using
- Implement advisory file locking between two processes, using
flock(). You should also investigate what happens after a
process exits. What happens when a second process request a lock? Your
test program should allow the user to configure the lock option
(LOCK_SH, LOCK_EX, ...).
- Write a test program that investigates what happens when a file is
deleted while it is open. In other words, a program opens the file,
deletes it via
unlink(), writes additional data to the file
and then closes the file. When does the file disappear, if ever? What
stat() show after each step?
- Compare the performance of
fread() when reading a large file (100 MB or so). You
should measure the performance, i.e., the time to read the file from
beginning to end, for read blocks of 100, 200, 512, and 1024 bytes.
- Investigate when NFS "stale file handles" occur, even though NFS is
by Henning Schulzrinne