Red Hat Linux Fedora For Dummies [Electronic resources] نسخه متنی

Introducing the Linux File System Tree

Linux sees all its parts, except its network, as files. Linux accesses files, directories, and devices as file addresses. Linux refers to drives and drive partitions by using a system of letters and numbers; for example, /dev/hda may be the name of the first IDE hard drive, and /dev/sdb may be the name of the second SCSI hard drive.

You can compare the Linux file system to a tree, as shown in Figure 4-1, which shows three subdirectories of root (more than a dozen subdirectories are in the root directory); a subdirectory is a directory within a directory. The top of the upside-down tree, represented by a / (slash), is the root directory. A series of limbs, branches, and leaves extends below the root: Limbs are mount points, the branches that extend from the limbs are directories, and the leaves on those branches are your files.

Figure 4-1: The Linux file system resembles an upside down tree.

TipEach mount point is a drive partition or remote file system (such as your DVD or CD-ROM drive) that is mounted, or made visible to, a directory of the limb above it. Whenever a disk partition or remote file system is mounted on the directory branch, it turns that branch into another limb, allowing even more branches to be positioned and attached below the mount point.

Red Hat Linux needs at least a root partition in your directory structure and a swap space partition. The root partition is used to store all your personal and system files and directories; Linux uses swap space, the Hamburger Helper of the computer world, to extend your memory beyond the limit of your random access memory (RAM). If you have 512MB of RAM and 512MB of swap space, for example, you can run programs that use 1GB of memory.

This configuration isn’t much different from the Windows and MS-DOS file systems. Windows uses the concept of a hierarchical directory tree. However, the syntax is somewhat different. The top-level directory in Red Hat Linux, root, is designated with a forward slash (/). Every subsequent subdirectory name follows that initial slash. For example, the home directory is a subdirectory of root and is shown as /home. In the Windows world, the root directory is designated with an initial backslash (\). The famous C: is synonymous with C:\. The theme for both operating systems is carried forward when dividing subdirectories: Linux uses forward slashes, and Windows uses backslashes. Your home directory is then shown as /home/me in Linux and as \user directories\me in Windows.

Technical StuffAnother primary difference between Linux and Windows file systems is that Linux requires you to explicitly mount file systems. Windows does so automatically. Explicitly mounting the file system isn’t as onerous as it sounds. Red Hat Linux installs utilities that automatically sense and mount file systems when necessary. For example, the default Red Hat Linux configuration mounts a DVD or CD-ROM automatically whenever you insert it in the drive.

The Workstation installation type we describe in Chapter 3 automatically sets up your root and swap partitions in addition to an additional boot partition used for storing the Red Hat Linux kernel and other files used for booting your computer. (The Personal Desktop installation type uses the same partitioning scheme as the Workstation installation type.)

The next section describes how to start and stop Linux.

Introducing the Linux File System Tree

Linux sees all its parts, except its network, as files. Linux accesses files, directories, and devices as file addresses. Linux refers to drives and drive partitions by using a system of letters and numbers; for example, /dev/hda may be the name of the first IDE hard drive, and /dev/sdb may be the name of the second SCSI hard drive.

You can compare the Linux file system to a tree, as shown in Figure 4-1, which shows three subdirectories of root (more than a dozen subdirectories are in the root directory); a subdirectory is a directory within a directory. The top of the upside-down tree, represented by a / (slash), is the root directory. A series of limbs, branches, and leaves extends below the root: Limbs are mount points, the branches that extend from the limbs are directories, and the leaves on those branches are your files.

Figure 4-1: The Linux file system resembles an upside down tree.

TipEach mount point is a drive partition or remote file system (such as your DVD or CD-ROM drive) that is mounted, or made visible to, a directory of the limb above it. Whenever a disk partition or remote file system is mounted on the directory branch, it turns that branch into another limb, allowing even more branches to be positioned and attached below the mount point.

Red Hat Linux needs at least a root partition in your directory structure and a swap space partition. The root partition is used to store all your personal and system files and directories; Linux uses swap space, the Hamburger Helper of the computer world, to extend your memory beyond the limit of your random access memory (RAM). If you have 512MB of RAM and 512MB of swap space, for example, you can run programs that use 1GB of memory.

This configuration isn’t much different from the Windows and MS-DOS file systems. Windows uses the concept of a hierarchical directory tree. However, the syntax is somewhat different. The top-level directory in Red Hat Linux, root, is designated with a forward slash (/). Every subsequent subdirectory name follows that initial slash. For example, the home directory is a subdirectory of root and is shown as /home. In the Windows world, the root directory is designated with an initial backslash (\). The famous C: is synonymous with C:\. The theme for both operating systems is carried forward when dividing subdirectories: Linux uses forward slashes, and Windows uses backslashes. Your home directory is then shown as /home/me in Linux and as \user directories\me in Windows.

Technical StuffAnother primary difference between Linux and Windows file systems is that Linux requires you to explicitly mount file systems. Windows does so automatically. Explicitly mounting the file system isn’t as onerous as it sounds. Red Hat Linux installs utilities that automatically sense and mount file systems when necessary. For example, the default Red Hat Linux configuration mounts a DVD or CD-ROM automatically whenever you insert it in the drive.

The Workstation installation type we describe in Chapter 3 automatically sets up your root and swap partitions in addition to an additional boot partition used for storing the Red Hat Linux kernel and other files used for booting your computer. (The Personal Desktop installation type uses the same partitioning scheme as the Workstation installation type.)

The next section describes how to start and stop Linux.