File System Design and Implementation

File System Design and Implementation

A file system is a method used by operating systems to store, retrieve, and organize files on a storage device such as a hard drive or SSD.

Designing and implementing a file system involves several key components:

1. Storage Management: Allocating and managing disk space efficiently, including techniques such as block allocation and free space management.
2. File Structure: Defining the structure of files and directories, including metadata such as file names, permissions, and timestamps.
3. File Access: Providing mechanisms for applications to read from and write to files, including file I/O operations and file locking.
4. Error Handling: Implementing robust error handling and recovery mechanisms to ensure data integrity in the event of system failures or disk errors.

Lab Activity: Simple File System Implementation

Below is a simple implementation of a file system in Python:

        class File:
            def __init__(self, name):
                self.name = name
                self.contents = ""

            def write(self, data):
                self.contents += data

            def read(self):
                return self.contents

        class Directory:
            def __init__(self, name):
                self.name = name
                self.children = {}

            def add_child(self, child):
                self.children[child.name] = child

        class FileSystem:
            def __init__(self):
                self.root = Directory("/")

            def create_file(self, path):
                components = path.split("/")
                current_dir = self.root
                for component in components[:-1]:
                    if component not in current_dir.children:
                        current_dir.add_child(Directory(component))
                    current_dir = current_dir.children[component]
                current_dir.add_child(File(components[-1]))

            def write_to_file(self, path, data):
                components = path.split("/")
                current_dir = self.root
                for component in components[:-1]:
                    if component not in current_dir.children:
                        return "File not found"
                    current_dir = current_dir.children[component]
                if components[-1] not in current_dir.children:
                    return "File not found"
                current_dir.children[components[-1]].write(data)
                return "Write successful"

            def read_from_file(self, path):
                components = path.split("/")
                current_dir = self.root
                for component in components[:-1]:
                    if component not in current_dir.children:
                        return "File not found"
                    current_dir = current_dir.children[component]
                if components[-1] not in current_dir.children:
                    return "File not found"
                return current_dir.children[components[-1]].read()

        # Example usage
        fs = FileSystem()
        fs.create_file("/documents")
        fs.write_to_file("/documents/note.txt", "This is a test note.")
        print(fs.read_from_file("/documents/note.txt"))
    

This code demonstrates a basic implementation of a file system with support for creating directories, creating files, writing data to files, and reading data from files.