OPS235 Lab 5 - Fedora17

OPS235 Lab 5 - Loopback Filesystems, Archives, Compiling from Source

Caution!
This lab is under construction.

Objectives

1. To create and use loopback filesystems in read-write mode
2. To create and use archive files (tar and tar.gz)
3. Compiling software from source code
4. Customizing system startup

References

• man pages for mount, fstab, tar, gzip, make, chkconfig, dd, service
• Resources on the web:
  • Services in Fedora 12
  • How to use the dd command

Required Material

• SATA Hard Disk with Fedora 12 (the same one used for Lab 3 and 4)
• Lab log book

Prerequisites

• Completion of Labs 1-4

Introduction

There are two techniques used to place multiple files within one file: the first is to create a filesystem within a file, and the second is to use an archive program to create an archive file. Archive files are often used to contain source code for software; in this lab you will also be compiling software from a source code archive. Finally, you will modify your system startup to eliminate unnecessary services and configure your system to automatically mount a partition.

Investigation 1: How do you create and use a filesystem in a regular file?

Use fedora3
Perform these steps in the fedora3 virtual machine.

1. Login using your Learn ID
2. Create an empty file that is exactly 3 MB in size:
   • dd if=/dev/zero of=/tmp/fstest bs=1k count=3072
3. How does this command ensure that the file is 3 MB in size? What is in the file at first?
4. Create an ext3 filesystem within the newly-created file /tmp/fstest. Note the warning message/question that appears
5. Mount the filesystem (remember to use the loopback option; refer to Lab 1 if required). Use a mountpoint of your choosing.
6. Copy the files /etc/services and /etc/protocols to the filesystem mounted in the previous step
7. Unmount the filesystem
8. Test your filesystem to be sure that the files /etc/services and /etc/protocols were in fact copied into the filesystem within the file named /tmp/fstest.
9. How much space is left in that filesystem? (Hint: df -h).

Make sure that your lab notes answer the Investigation 1 question.

Investigation 2: How do you create an archive file?

Use fedora3
Perform these steps in the fedora3 virtual machine.

Warning!
Don't miss the . at the end of the tar commands below! It specifies what should go into the archive: the contents of the current directory.

1. Change your working directory to /usr/share/doc/sudo*
2. Use the tar (tape archiver) command to create an archive file named /tmp/archive1.tar
   • tar cvf /tmp/archive1.tar .
3. What do the options c, v, and f mean?
4. Record the archive file size.
5. Compress the file using gzip:
   • gzip /tmp/archive1.tar
6. Record the archive file size after compression.
7. Make sure you're still in /usr/share/doc/sudo* and then create a compressed archive:
   • tar cvzf /tmp/archive2.tgz .
8. What does the z option do?
9. Compare the sizes of /tmp/archive1.tar.gz and /tmp/archive2.tgz. Why are they so close in size?

Answer the Investigation 2 question.

Investigation 3: How do you restore files from an archive?

Use fedora3
Perform these steps in the fedora3 virtual machine.

1. Create the directory /tmp/extract1 and make it your current working directory (change into that directory).
2. Unzip the first archive you created:
   • gunzip /tmp/archive1.tar.gz
3. Extract the files from the first archive:
   • tar xvf /tmp/archive1.tar
4. Are all the files there?
5. Compare /tmp/extract1/README and /usr/share/doc/sudo*/README. Are they exactly the same? Why?
6. Create the directory /tmp/extract2 and make it your current working directory.
7. Extract the files from the second archive:
   • tar xvzf /tmp/archive2.tgz
8. Note that this time a separate gunzip command was not needed. Why?
9. Compare the README file in this directory with the original file. Are they exactly the same?

Answer the Investigation 3 question.

Investigation 4: How do you build software from source code?

Compiling requires the correct tools to be installed.
In order to build software from source code, you must have the appropriate software development tools (such as make and gcc) and libraries (such as GTK) installed. The required tools will vary depending on the computer languages used in the software being built.

1. Go to the directory /tmp
2. Use the wget command to download the "tar ball" that contains the source code for the NLED text editor.
   • wget http://cdot.senecac.on.ca/software/nled/nled_2_52_src.tgz
3. Extract the files. Change to the newly-extracted directory (/tmp/nled-2.52)
4. Check to see if there is a file named configure. If so, run it; if not, skip this step. (Most but not all source code archives contain this file)
5. Check to see if there is a file named Makefile or makefile. If so, type the command:
   • make

You may need to install gcc (GNU C Compiler) and ncurses-devel (Development Library) in order to complete this step successfully. Use yum to install these packages if you get an error message saying the cc command was not found or the ncurses library is not found.
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