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hw1.html
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>LBSC 690: Information Technology | Assignment #1</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link rel="stylesheet" href="style.css" type="text/css" />
</head>
<body>
<table width="100%"><tr><td align="right"><img alt="University of Maryland, College of Information Studies" src="images/logo.jpg"/></td></tr></table>
<hr/>
<h2>LBSC 690: Assignment #1 (Fall 2008)</h2>
<p>This assignment is due before class on 9/17. To turn in your
assignment, send me an email with the subject "LBSC 690 assignment
#1". In the message body, either type your answers to attach a
document that contains the answer. Show your work, as it will provide
an opportunity to receive partial credit.</p>
<p>Consider the specifications of a computer system that you might
consider buying:</p>
<blockquote>
Processor type: Intel Core 2 Duo<br/>
Processor speed: 2.5 GHz<br/>
Hard drive: 200 GB, 10 ms access time<br/>
RAM: 2 GB, 50 ns access time<br/>
Peripherals: DVD-RW<br/>
</blockquote>
<p>Although we talked about modern processors having multiple "cores",
for this assignment assume that all operations are performed by a
single core. To simplify calculations, you can assume that 1 megabyte
is 1,000,000 (one million) bytes, 1 gigabyte is 1,000,000,000 (one
billion) bytes, etc.</p>
<p>Answer the following questions:</p>
<ol>
<li><p>If you buy some 4.7 GB DVDs, how many would you need to back up
a full hard drive to DVDs (assuming no compression)? At 30 cents per
DVD, how much would a full backup cost? At 10 minutes per DVD, how
long would a full backup take?</p></li>
<li><p>Now let's see how much stuff that hard drive can hold. Assume
you have access to the following information for all 300 million
people in the United States:</p>
<blockquote>
Name: 40 characters<br/>
Phone Number: 10 characters<br/>
SSN: 9 characters<br/>
taxes owed: one four-byte number<br/>
</blockquote>
<p>Assume that each character is stored in one byte.</p>
<p>Would all of these data fit on the hard drive of the computer
described above? If not, how big a hard drive would you need? If so,
what fraction of the disk would this fill?</p>
</li>
<li><p>Now let's see how long it would take to read that much data off the
disk. Assume you have a hard drive large enough to store all the
data.</p>
<p>Suppose you wanted to add up the taxes owed by all 300 million
people. Assume that you access the data in a random order, and that
you start a new disk access for each person (in the specifications
above I have provided the latency of disk access). How long would it
take to access all the data? Could this be done in a second? In a
minute? In an hour? In a day? In a month? In a year?</p>
</li>
<li><p>Assume for the sake of comparison that all of this data could fit
in RAM.</p>
<p>How long would it take to access all the data from RAM? In the
specifications above I have provided the latency of RAM access. Could
this be done in a second? In a minute? In an hour? In a day? In a
month? In a year?</p>
</li>
<li><p>Which is faster, RAM or the hard disk?</p></li>
<li><p>Now let's see how long it would take to move the bits around.</p>
<p>How long would it take to move the contents of your entire hard
drive to your friend's computer in California over a modem? Over DSL?
Over a dedicated T1 line? Overnight mail?</p>
</li>
</ol>
<p style="padding-top: 25px"><a href="index.html">Back to main page</a></p>
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<small>This page, first created: 7 Sep 2008; last updated:
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