ITS 2330 - Linux III

Chapter 4: Managing the File System

Objectives:

This lesson takes place in week 5 Objectives important to this lesson:

  1. Creating a filesystem
  2. Maintaining a filesystem
  3. Configuring a filesystem
Concepts:

Chapter four begins with an observation that you need a filesystem to provide the illusion that the data you store is arranged in some kind of order. This is not always so, but a filesystem makes it look like the data in your files is organized and that they are separate from one another. It's an illusion, but it is a comforting and useful one.

Page 142 provides a list of five filesystems that you could encounter on a Linux machine. Pages 143 and 144 offer four more. For any of these choices, it is necessary to partition a drive, part of a drive, or several drives that will hold one filesystem. The text discusses using the mkfs command to apply a filesystem to a new volume. In the example on page 145:

sudo mkfs.ext4 /dev/sdb1

the word sudo is used to apply superuser rights for the process, the subobject .ext4 is stated to specify the kind of filesystem to use, and a path is provided to specify where to do the formatting.

As we discussed earlier, the new filesystem must be added to the general virtual filesystem of the virtual directory. This is not automatic. The attachment is called mounting. Attaching the new filesystem can be done temporarily or persistently. You start by picking a point in the virtual directory where the new system will mount. This needs to be an empty folder, so it is best if you create one for this purpose. This folder will be called the mount point.

  • temporary attachment: use the mount command to mount the filesystem, and the umount command to un-mount it
  • persistent attachment: place an entry for the filesystem in the /etc/fstab file (the Filesystem Table); the entry needs six fields as discussed on pages 154 and 155

The text does not discuss a lot things about the virtual directory that just feel wrong to the average Windows user. To address that, I am giving you access to this short lecture on Linux files that may fill in a gap or two.


The assignments for this week do not seem to address the material in this chapter, so I am going to add another topic that should be more useful to you.

In our discussions last weekend, Matt Hansel and I determined that you probably have not had any formal exposure to Wireshark, the standard network packet sniffing tool, in your curriculum. That will be remedied now. In the video below, the presenter talks you through downloading and installing Wireshark.


In the video below, the presenter runs talks about using Wireshark to watch what is happening on his PC. He also give us simple way to gather a series of packets for analysis using his browser.