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?

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.