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Test 1
Operating Systems and Networking
CS330
Fall 2007
Time: 1 hour and 45 minutes
Answer any five from the following
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What is the difference between a multiprogramming and a time-sharing system? In what
significant ways does the issue of security tend to plague such systems? Could this be reduced or
avoided in a dedicated machine?
In the class, we did explore the peer-to-peer systems vis-à-vis the client-server systems. Explain
the way they do differ from each other. Briefly evaluate each system from (a) performance, and,
(b) the security points of view.
Give examples of I/O bound and CPU bound applications. If one wants to optimize system
performance which type of applications should preferably be chosen to execute first before the
others – CPU bound, or I/O bound applications? State your reasons. Will this choice be predicated
by the mix ratio of CPU bound to I/O bound jobs? Explain your answer.
Direct memory access is used for high-speed I/O devices to reduce CPU’s execution load.
a. How does the CPU coordinate its activity with the device to execute a DMA session
efficiently?
b. Given that a DMA session is in progress, how does a CPU takes over the control of the
memory bus?
What is the purpose of a system call? How do the system calls relate to the underlying operating
system and to the concept of dual-mode (kernel-mode and user-mode) operations?
What are the two modes of Inter-process communication (IPC)? What are the strengths and
weaknesses of these approaches?
The following image shows a Petri-net design of two processes engaged in communication.
Explain how they are communicating. We ignore the necessity of sending any acknowledgement
from the receiver to the sender.
One of the cited appeals of a microkernel based operating systems is flexibility. Explain how
architectural ‘flexibility’ does allow one to implement a more adaptive platform for user
applications.
Describe the differences among the short-term, medium term and long-term scheduling.