CS239 Final Exam
Available: 3:00 p.m. December 17,1998 via the course web page
Due date: 3:00 p.m. December 18, 1998 at 3564 Boelter Hall

The questions below are based on a paper that appeared in the SOSP97 conference
entitled  "Disco: Running Commodity Operating Systems on Scalable Multiprocessors."
It can be found online at
http://fmg-www.cs.ucla.edu/classes/239_2.fall98/papers/SOSP97/disco.ps

As with the midterm exam, you are free to use course notes, textbook, and other
static materials.  Discussions with others is prohibited.

Each answer should probably be about 300-500 words.

The Disco paper describes a virtual machine monitor mechanism to enable
"commodity operating systems" to run on a "scalable multiprocessor" system.

Question One:
To what extent does the scalability of the underlying hardware environment
extend upwards, through Disco to operating system instances, and then on to the
application level?  For example, is Disco truly scalable?  How does an OS
benefit/suffer from scaling below it?  Can a process family, single process,
and/or thread benefit from the scalability at the lowest level?

Question Two:
Compare and contrast the value and services of the Disco environment, with a
loosely equivalent environment composed of an identical number of
single-processor conventional hosts.  Assuming that the hardware costs ($$) are
identical, in what circumstances would the Disco multiprocessor system be
preferred?  And in what cases would a collection of uniprocessors be better?

Question Three:
Discuss the security and reliability implications of Disco, compared with
conventional uniprocessor and/or multiprocessor operating systems.