CS439: Principles of Computer Systems
(Source: Alison Norman.)
Due: 11:59 PM Monday, April 29, 2013 Homeworks
will be submitted electronically. Please refer to
the homework turnin instructions.
(UPDATE 4/29/13, 9:22 PM: ignore this question; it's a repeat. Apologies.)
In class, we covered the idea of remote procedure calls. We discussed
difficulties encountered when one attempts to implement a remote
procedure call. Name four of the difficulties. There are
additional complications when the procedure executes a system
call. What are the complications and how might you fix them?
Adapted from Tanenbaum page 607.
The network file system (NFS) protocol provides reliability via
which of the following?
a) at-most-once semantics
b) at-least-once semantics
c) two-phase commit
In two-phase commit, suppose the coordinator fails after writing
"COMMIT" to disk and sending "COMMIT" to all
participating nodes but before any of the nodes receive this
message. Suppose that the "COMMIT" message reaches i of
the n participants and that the participants implement a protocol
in which they communicate with one another when they suspect that the
coordinator has failed. What is the minimum number of participants that
must receive the "COMMIT" message to allow the
participants to complete the transaction without waiting for the
coordinator to recover?
Considering all the pieces of the operating system we have discussed,
describe the steps the OS takes when performing a context switch.
Assume that processes are waiting in the ready queue.