Download WEB RESEARCH PROJECTS TECHNOLOGY IN FOCUS: UNDER

WEB RESEARCH PROJECTS
TECHNOLOGY IN FOCUS:
UNDER THE HOOD
Discussion Questions
1. Define and discuss the purpose of cache memory. Discuss the difference between Level
1, Level 2, and Level 3 cache.
Answers will vary.
Cache memory is small blocks of temporary storage designed to hold only the most
recent or frequently accessed instructions for the CPU. Because cache memory is
located closer to the CPU, it can be accessed more quickly than RAM. This makes it
possible for the CPU to do its work faster by reducing the time it takes to retrieve and
store these instructions.
When the CPU needs to fetch an instruction from memory, it will search Level 1 cache,
then Level 2, then Level 3 (if it exists.) If it doesn’t find what it’s looking for in cache
memory, it will make the longer journey to RAM for the instruction.
Level 1 cache is built directly onto the CPU chip and stores commands most recently
used. Level 2 cache can either be located on the CPU chip, but farther away from the
CPU, or on a separate chip on the motherboard near the CPU. Level 2 cache generally
has a larger capacity than Level 1 cache, but it takes somewhat longer to access it.
Level 3 cache is a newer addition to storage technology. It can have a relatively large
storage capacity, giving it the capability of storing entire programs.
2. List and discuss the function of the four steps in the cycle of the CPU.
The four steps are fetch, decode, execute, and store.
In the fetch stage, when a program begins to run, the 1s and 0s that make up the
program’s binary code must be “fetched” from their temporary storage location in
RAM and moved to the CPU before they can be executed.
The chief goal of the decode stage is for the CPU’s control unit to decode the
program’s instructions into commands the CPU can understand. The CPU knows and
recognizes only patterns of 0s and 1s—it cannot understand assembly language
directly—and human-readable instructions are translated into long strings of binary
code, known as machine language.
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall
In the execute stage, the ALU receives data from the CPU’s registers to perform
mathematical operations such as addition, subtraction, multiplication, and division. It
tests the comparison of values such as greater than, less than, or equal to 1. The ALU
also performs logical OR, AND, and NOT operations. The ALU is specially designed
to execute such calculations flawlessly with incredible speed.
The last stage is store. The result produced by the ALU is stored back in the registers.
The instruction itself will explain which register should be used to store the answer.
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall
TECHNOLOGY IN FOCUS 4: UNDER THE HOOD
Web Project 1: It’s All About Speed: DNA Computing
You read in this Technology in Focus how Moore’s Law, predicting the growth in the
number of transistors on a processor, came about. The world is in need of information, and
fast. How fast can computers go? This book references how DNA computers use chemical
reactions to perform calculations. Using the following Web sites and any other research you
might find, write a short paper describing the advances of DNA computing and where it
stands today in terms of useful applications. Also list some of the advantages and
disadvantages to DNA computing.
Suggested Web Sites
http://computer.howstuffworks.com/dna-computer.htm
http://www.cs.virginia.edu/~robins/Computing_with_DNA.pdf
http://www.casi.net/D.BioInformatics1/D.Fall2000ClassPage/DC1/dc.htm
http://www.peterindia.net/DNAComputing.html
Suggested Keywords
DNA computing, biotechnology, computer processors
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall
TECHNOLOGY IN FOCUS 4: UNDER THE HOOD
Web Project 2: Supercomputers: The Most Powerful Computers in the World
Supercomputers are needed to process the most complex computing tasks. Write a short report detailing
three things that supercomputers are often used for. Why are they necessary for these tasks? In addition,
use the top500 site (see the link below) to answers to these questions:
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How many countries have at least one supercomputer?
What country has the most supercomputers?
Which country has the fastest supercomputer?
What is the most common application for supercomputer processing?
What company makes the majority of the CPUs used by supercomputers?
Suggested Web Sites
http://en.wikipedia.org/wiki/Supercomputer
http://computer.howstuffworks.com/mdgrape-3.htm
http://www.thocp.net/hardware/supercomputers.htm
http://top500.org/lists/2009/11
Suggested Keywords
supercomputers, what are supercomputers used for, applications for supercomputers
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall