Comp111 - Operating Systems
Quiz 2 - Nov 27, 2012 - closed book
Please fill in the blanks. Each blank is worth 5 points.
Blanks with the same number have the same answer.
- The word ____page____ has several incompatible meanings
in Operating Systems.
In one sense, it refers to how ____virtual/process____ memory is
managed. In another sense, it refers to how disk files
- A processing unit is in balance if its input rate equals its
____output rate____. In this case,
____Little's____ Law says that L = λW, where L is
the ____jobs in system____, λ is the
____arrival rate______, and W is the ____waiting time/time in system____.
- A scheduler is fair if every process in the run queue
receives the same ____amount of time____. "Completely fair
scheduling" tries to insure this by storing the run queue as a red-black
tree of processes whose search key is the ____time____
for which the process has executed so far. At each scheduling step,
the process with the ____least/leftmost____ key is executed, and
then moved to where it then belongs in the tree.
- Inside an operating system, most structures are
____arrays____. Dense ones are sometimes ____cached____, while
sparse ones are sometimes ____hashed____.
- A page of memory in a process maps to a ____frame____ of
memory in the operating system.
- The function
malloc allocates one
____page/frame____ of memory at a time from the operating
system, and then packages it for your use. On average, a call to
malloc returns ____more____ memory than you
requested. The justification for this apparent waste is
that as a result,
free can run in
- A disk file is identified via a(n)
____inode____ that describes access
privileges and where its contents are, but does not contain its
____name____, which is instead
contained in the directory in which the file resides.
- (Extra credit) A translation lookaside buffer looks superficially
like a hash table, but actually functions as a
____cache____ of recently looked-up addresses.