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<H2>CSE 120 (Fall 2002) -- Homework #1</H2><FONT color=blue size=+1><B>Out:
10/1</B></FONT><BR><FONT color=red size=+1><B>In: 10/8</B></FONT>
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<P>
<LI>Chapter 1: 11
<P>1.11 Consider the various definitions of operating system. Consider
whether the operating sytem should include applications such as web browsers
and mail programs. Argue both pro and con positions, and support your
answers.
<P></P>
<LI>Chapter 2: 3, 5, 6, 8
<P>2.3 What are the differences between a trap and an interrupt? What
is the use of each function?
<P>
<P>2.5 Which of the following instructions should be priviledged?
<BR>a. Set value of timer<BR>b. Read the Clock<BR>c. Clear Memory<BR>d. Turn
off interrupts<BR>e. Switch from user to monitor mode<BR>
<P>
<P>2.6 Some computer systems do not provide a privileged mode of
operationin hardware. Is it possible to construct a secure operating system
for these comptuers? Give arguments both that it is and that it is not
possible.
<P>
<P>2.8 Protecting the operating system is crucial to ensureing that
the computer system opeartes correctly. Provision of this protection is the
reason for dual mode opeartion, memory protection, and the timer. To allow
maximum flexibility, however, you should also place minimla constraints on
the use.<BR>The following is a list of instructions that are normally
protected. What is the minimal set of instructions that must be protected?
<BR>a. Change to user mode <BR>b. Change to monitor mode <BR>c. Read from
monitor memory <BR>d. Write into monitor memory <BR>e. Fetch an instruction
from monitor memory <BR>f. Turn on timer interrupt <BR>g. Turn off timer
interrupt
<P></P>
<LI>Chapter 3: 9
<P>3.9 Why does Java provide the ability to call from a Java program
native methods that are written in, say, C or C++? Provide an example where
a native method is useful.
<P></P>
<LI>[Crowley] Suppose the hardware interval timer only counts down to zero
before signalling an interupt. How could an OS use the interval timer to
keep track of the time of day?
<P></P>
<LI>[Tanenbaum] One reason GUIs were initially slow to be adopted was the
cost of the hardware needed to support them. How much video RAM, in bytes,
is needed to support a 25 line X 80 row character monochrome text screen?
How much for a 1024 X 768 24-bit color bitmap? What was the cost of this RAM
at 1980 prices ($5/KB)? How much is it now (say, $0.5/MB)? </LI></OL><PRE></PRE>
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<ADDRESS><A href="mailto:voelker@cs.ucsd.edu">voelker@cs.ucsd.edu</A>
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