CS 170, Fall 1999
ANNOUNCEMENTS
The most recent announcements are listed first.
Students should
check this page regularly.
- Dec 20: Final grades have been computed. The sorted grades are:
A+, A+, A+, A+, A+, A+, A, A, A, A, A, A, A, A, A, A-, A-, A-, A-, B+,
B+, B+, B+, B+, B+, B+, B+, B, B, B, B, B, B, B, B, B, B, B, B-, B-, C+,
C, F.
- Dec 19: Project 4 has been graded, and grades have been mailed
- Dec 8: There will be no demos for project 4.
There isn't enough time left.
Project 4 will be graded solely on correctness.
- Dec 7: All the projects & quizzes will
count towards the grade.
- Dec 7: Quiz 2 has been graded.
The sorted scores (out of 25) are: 24, 22, 22, 22, 22, 22, 21, 21, 21,
20, 20, 20,
19, 19, 18, 18, 18, 18, 17, 17, 17, 17, 16, 15, 15, 14, 14, 14, 14, 14
13, 13, 13, 12, 11, 10, 10, 8, 6, 6, 5, 5, 4. The exam papers for
Ventura-based students have been sent to the Ventura center.
-
Common problems:
- Only one person got problem 5 right. The key idea is that
you need some way for the operating system to get control
when a page is referenced for the first time. The only ways an OS
gets control are system-calls and faults/interrupts. System-calls
not possible in this case. That leaves faults. The fault-based
way to simulate the
used bit would be to use the valid bit: set the valid bit to
zero when loaded into TLB. When the page is referenced, this will
cause a fault. The fault handler checks the pagetable -- sees that
the page is actually valid, sets the used bit in the pagetable
and sets the valid bit in the TLB entry (so that you don't get
a fault on every single reference to the page). Partial
credit if you mentioned
an alternative technique to keep track of the recency info but
did not describe when/how this technique would be invoked.
- Many of you mistook the dirty bit for copy-on-write. I am
surprised since copy-on-write was a part of project 3.
- Dec 3: sign-up sheet for project 3 is outside Eng I, 2121. Remember,
it is your responsibility to schedule a demo.
- Dec 3: Grades for project 2 have been mailed. If you didn't receive them,
send mail to david@cs.ucsb.edu
- Dec 1: Project 4 is available here.
It is due on Dec 14. For questions regarding this project,
send mail to zoran@cs.ucsb.edu
- Nov 18: sign-up sheet for project 2 demos is outside my office
(Engineering I, 2121).
- Nov 17: the due date for Project 3 has been moved to
Dec 2.
- Nov 17: Discussions for next week (11/24 and 11/26) are cancelled, due
to the holiday weekend.
Office hours are also being moved (for next week
only):
- David: Monday(11/22) 8-9:30, Tuesday(11/23) 8-9:30
- Zoran: Tuesday(11/23) 7-8, Wednesday(11/24) 8-9
- Nov 17: Project 3 is available here.
It is due Nov 30 1999. For questions regarding this project,
send mail to david@cs.ucsb.edu.
- Nov 16: Quiz 1 has been graded. Grading policy:
- Problem 1: (15 points)
- -5 points if concurrent operations on different buckets
are not allowed (usually because global locks/semaphores
were used)
- -5 points if there is a race condition of some sort. Or if
there is a deadlock.
Common case: readers and writers do not share a synchronization
variable (and can proceed independently).
- -5 points if writer priority is not implemented (or not
implemented correctly). Two or three
people got this right.
- Problem 2: (15 points)
- +5 points if you suggest per item locks
- +5 points if you suggest the previous item needs to be locked
- +5 points if you suggest per bucket locks are needed to
protect the head of the bucket list.
- And if you give me working code, five additional points
The sorted scores are: 25, 20, 18, 15, 13, 13, 13, 13, 12, 11,
11, 10, 10, 8, 8, 8, 8, 8, 8, 8, 8, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0
- Oct 30: Project 2 is available here.
It is due Nov 14 1999. For questions regarding this project,
send mail to david@cs.ucsb.edu.
- Oct 29: sign-up sheet for project 1 demos is outside my office
(Engineering I, 2121).
- Oct 29: For students taking this class in Ventura, the quiz on Nov 2
will be proctored at the Ventura center. This will be at the same time
as the class. That is, at 9:30am.
- Oct 27: Project 1, problem 6: By "print the state of the stack", we
mean print all the elements in the stack in the stack order.
- Oct 25: Instead of having a single midterm, we will be having
two quizzes. The first quiz will be on Nov 2
and will contain synchronization problems. The midterm
problems from Spring 99 are available here. Solutions for these problems
can be found here and here.The
second quiz will be on Dec 2.
Each quiz will be worth 10% of the grade.
- Oct 22: Problem 4 of project 1 has been updated. Update is marked
like this.
- Oct 19: Project 1 is available here.
It is due midnight at the end of Oct 29th. Questions to Zoran
(zoran@cs.ucsb.edu).
- Oct 17: Three person project groups are not possible.
We expect project groups to have two persons. If you so desire,
you can go it alone. But no three person groups.
- Oct 15: A tutorial and information on CVS is available here.
- Oct 7: Project 0 is available here.
- Sep 30: you will need to form two-person groups for this class. Send me
mail with names and email addresses for your group. If you are unable
to find a partner, send me mail.
- Sep 30: discussion sections begin next week. There is no discussion
section tomorrow.
CS 170 home
page for Fall 1999