- This is a 24h take-home exam.
- The exam runs from 12:00 (noon) on Fri, 7 Nov 2008 to
12:00 (noon) on Sat, 8 Nov 2008
- The basic exam question is available now, but the papers you
are asked to analyse will be made available only at 12:00 (noon) on Fri, 7 Nov 2008.
- The papers will be available electronically via this WWW page.
Email Gernot if you need hardcopies so we can try to
- The total exam is worth 35 marks.
- You will lose 3.5 marks for each hour, or part thereof, your
submission is late.
- You are not to get any help from anyone on the exam. You should
not talk to anyone else about the exam from the time you receive
the full details until you submit your solution.
- You have the choice of three different ways to submit your
- Submit a hardcopy by the deadline (12:00 (noon) on Sat, 8 Nov 2008). It must be accompanied by the signed
certification of sole
authorship. It must be submitted to Gernot Heiser,
Kevin Elphinstone, Rafal Kolanski, Dhammika Elkaduwe or
Nicholas FitzRoy-Dale in person. In
addition, you must submit an electronic version (PDF) within three
days of the end of the exam.
- Submit an electronic copy (PDF), via the give system, by the
deadline, and submit a hardcopy, including the signed certification of sole authorship,
within three days of the end of the exam.
- Submit, via the give system, by the deadline, a digitally
signed electronic copy (PDF). This must contain your full name,
student number, date, and the following declaration:
I hereby declare that this submission is my own work, and I have
not received any help whatsoever.
The file must be signed with PGP/GPG, be ASCII-armoured, and have an
extension .pdf.asc. This is
achieved (when using PGP 6.0 or later) with the command:
pgp -sa <file>
or, using GPG, with the command
gpg -sa <file>
See the GPG Example for how to use
GPG for signing and check that you've got it right.
Notes on electronic submissions
- In the cases where a paper submission is also required (cases 1 and
2 above), the electronic submission, when printed on a CSE printer, must
appear exactly as the submitted hardcopy.
- The submission must be in PDF format (and use the extension
- The submission must be made via the give system, mark
- If using give, check you can submit your exam (or any
exam report) well before the deadline. We will have little sympathy for
submission issues if you raise them five minutes before the deadline.
- Make sure that you only use Type-1 fonts, as others are
unprintable on some printers. LaTeX users can ensure the use of Type-1
fonts by producing a PostScript file with the command
dvips -Pwww -o file.ps file
and then converting this to PDF.
Notes on digitally signed submissions
Digitally signing your submission only makes sense if we can verify your
signature. I therefore require you to have your signature signed by
Gernot or Kevin beforehand, or within three days of the end of the
exam. Therefore, if you want to use the digital signature option, do the
- Familiarise yourself with PGP (or GPG). We will not
provide tutorials on this, it's up to you. Get yourself a public key
if you don't have one. Follow the recommended safeguards to keep
it secure. It will be like your normal signature!
- See Gernot or Kevin with your key and proof of identity. He
will then sign your key.
- This signed key can then be used to sign your exam. (Feel
free to get others to sign your key as well.) If you get your key
signed after the exam, make sure that it is the same key as used for
signing the exam.
- Make sure that PGP or GPG is installed on the system you are
going to use to write your exam, and that you can use it reliably. If
you stuff up, it's your own problem.
You are given two research papers (the links will be active from
12:00 (noon) on Fri, 7 Nov 2008):
- Paper 1: Weinhold and Härtig:
“VPFS: Building a virtual private file system with a small trusted
computing base”, 3rd EuroSys, Glasgow, April 2008
- Paper 2: Padioleau, Lawall, Hansen
and Muller: “Documenting and Automating Collateral Evolutions
in Linux Device Drivers”, 3rd EuroSys, Glasgow, April 2008
Here is an actual solution
from a student taking the exam (2400 words and 1550 words for papers 1
and 2, respectively). Others found further issues with paper 1:
- the evaluation doesn't provide much insight in where the costs
are, not even whether they are inherent in the approach or
- not supporting directory reads is much more limiting than the
- the flat directory structure is likely to produce scalability
problems that aren't addressed
- loss of some meta-data (tree roots) is fatal and hard to prevent
You are to read, understand, and critically assess the papers. Questions
you may want to ask yourself for each of the papers:
These are only hints, I am not asking you to explicitly answer all these
for each paper. However, you may find those questions helpful in
critically analysing the papers. Imagine you are a reviewer for a
conference to which the papers have been submitted, and you are to judge
their contribution to the field.
- What problem is it trying to address?
- How well does it address the issue?
- How well do they motivate the value of solving the problem. Is
the problem a real problem? Is the problem/work significant?
- How does it relate to other work? Does
it reference relevant other work (as far as you can tell), does it
do the other work justice? Has it all been done before?
- How technically sound is it? Does their argumentation, the
presented data convince you? Should they have been looking at other
- How good are the results?
- How good/deep is their analysis?
- How easy would it be to reproduce their results?
- How general are their results? Can they be applied to other
systems? Did we learn some general truth?
Note that all papers are in fact published (and therefore cannot be
all that bad :-). In order to get an idea of what program committees at
top systems conferences are looking for, have a look at this classic!
What to submit
You are to submit a report which summarises for each paper the basic
ideas behind their work. You are to give a critique of the technical
merits, achievements and shortcomings (if any). The papers are not
directly related, so you don't have to compare them.
I am intentionally not specifying a length limit. However, I
strongly encourage you to be concise. Lengthy submissions will almost
certainly be unfocussed and waffly. I cannot imagine a decent job in
excess of 3000 words, and would imagine that a very good submission
would stay well below 2000 words total. If your report gets longer than
this you should step back and try to focus.
Note: In order to help us to perform an unbiased assessment of
your report, we would appreciate if you do not put your name on
the report itself, only your student ID. Of course, your name
must appear on the certificate that is attached to the report. However,
as long as this certificate is on a separate page, we can assess the
reports without looking at names.
What I will be looking for
You will be marked on the level of understanding and critical analysis
portrayed in you submission. All relative to what can be reasonably
expected from you (I know that none of you have a PhD in OS yet :-)
You may find it useful to look at the 1999,
2000, 2002, 2003, 2004, 2005,
and 2007 exams,
and the sample reports provided there.
16 Nov 2008.