Comp111 - Operating Systems
Quiz 2 - Dec 3, 2014 - closed book
Closed book and notes. No electronic devices allowed. Please fill
in the blanks. Each blank is worth 5 points. Blanks with the same
number have the same answer.
Little's laws are based upon the assumption that the system is in
________1________ so that the ________2________
and output of the system occur at the same
________3________ rate. If λ is an arrival rate,
then ________4________ represents the corresponding time
between arrivals. M/M/1 queues assume in addition that arrivals and
processing have ________5________ statistical
The ________6________ scheduler for linux minimizes
computation at the expense of non-optimal
________7________. The main feature of this scheduler is
that every process in the run queue gets a constant amount of runtime
In an operating system, ________9________ fragmentation
refers to unused space in the memory space of the requesting process,
while ________10________ fragmentation refers to unused
space outside the requesting process in the operating system.
In a file system, a(n) ________11________ documents the
location of a file, while a(n) ________12________ documents
its name. In order to create a file one must initialize these and
also mark the disk space required as ________13________.
This is typically done through the use of
The buddy system guarantees that if one frees and then reallocates the
same amount of storage, one will always get the
________15________ memory back when asking again. This is
because the freed block is linked at the ________16________
of the appropriate free list.
The fact that multiple processes share the same kernel descriptor for
the same file means that output from the processes is appended to the
file in ________17________. If multiple processes write to
independent kernel descriptors, then the content of the file is
determined by the ________18________ process to close it.
The I/O subsystem is a concatenation of multiple producer-consumer
systems. For example. in writing to the raw disk, the producer is
________19________, while the consumer is the
(Extra credit) The Ext2 filesystem and its derivatives only
function properly because of the ________21_________
subsystem for the raw disk device.