File systems are a crucial component of any operating system. They provide a method for storing and organizing computer files and the data they contain to make it easy to find and access them. This section will cover the basic concepts of file systems, their structures, and how they manage data on storage devices.

A file system is a way of organizing and storing files on a storage device, such as a hard drive, SSD, or USB drive. It defines how data is stored, accessed, and managed.

• Storage Management: Allocates space for files and directories.
• File Naming: Provides a way to name and organize files.
• File Access: Manages how files are read, written, and executed.
• File Protection: Ensures that files are protected from unauthorized access.
• File Integrity: Maintains the integrity of files and ensures data is not corrupted.

• Hierarchical File Systems: Organize files into a tree structure with directories and subdirectories.
• Flat File Systems: Store all files in a single directory without any hierarchy.
• Network File Systems: Allow files to be accessed over a network.
• Distributed File Systems: Spread files across multiple servers or locations.

The boot block contains the necessary code to start the operating system. It is usually located at the beginning of the storage device.

The superblock contains metadata about the file system, such as its size, the number of files it can hold, and pointers to other important structures.

An inode (index node) is a data structure that stores information about a file, such as its size, permissions, and pointers to the data blocks where the file's content is stored.

Data blocks are the actual storage locations where the file's data is stored. Each file is divided into one or more data blocks.

Directories are special files that contain a list of filenames and their corresponding inodes. They provide a way to organize files into a hierarchical structure.

The file system keeps track of free space on the storage device to know where new files can be stored. This can be managed using free lists or bitmaps.

Let's look at a simple example of how a file system might be structured on a Unix-like operating system.

1. mkdir example_dir: Creates a new directory named example_dir.
2. cd example_dir: Changes the current directory to example_dir.
3. touch example_file.txt: Creates a new empty file named example_file.txt.
4. ls -l: Lists the contents of the current directory in long format, showing details like file permissions, number of links, owner, group, size, and modification time.

1. Create a directory named test_dir.
2. Inside test_dir, create a subdirectory named sub_dir.
3. Inside sub_dir, create a file named test_file.txt.
4. Navigate back to the parent directory (test_dir).

Solution

1. Use the ls -i command to list the inode numbers of files in the current directory.
2. Create a hard link to test_file.txt named test_file_link.txt.
3. Verify that both files have the same inode number.

Solution

In this section, we covered the basics of file systems, including their definition, functions, and types. We also explored the key structures within a file system, such as the boot block, superblock, inodes, data blocks, directory structure, and free space management. Practical examples and exercises were provided to reinforce the concepts learned.

In the next section, we will delve into directory structures, exploring how files and directories are organized within a file system.