A Linux-inspired Virtual File System written in C that simulates inode-based file management similar to Unix file systems.

📂 Custom Virtual File System (CVFS)

A Custom Virtual File System (CVFS) implemented in C Programming that simulates the internal working of a Linux file system.
This project demonstrates how operating systems manage files using inodes, file descriptors, and memory management.

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📌 Project Overview

The CVFS project is a command-line based system programming project that replicates file system behavior such as:

• File Creation
• File Opening
• File Reading
• File Writing
• File Deletion
• File Information Display
• Command Manual System

The entire system runs in RAM using dynamic memory allocation.

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🎯 Objectives

• Understand Linux File System Architecture
• Implement inode-based file management
• Simulate file operations
• Learn System Programming Concepts
• Strengthen Data Structures knowledge

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⚙️ Technology Used

Technology	Purpose
C Programming	Core implementation
Data Structures	Inode and file management
Dynamic Memory Allocation	File storage
GCC Compiler	Compilation
CLI (Command Line Interface)	User interaction

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🖥️ User Interface

The system uses Command Line Interface (CLI).

Example commands:

create file1 3
open file1 3
write file1
read file1 10
ls
unlink file1

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🧱 System Architecture

The CVFS system is composed of the following components:

User Commands
      |
      v
+-------------------+
|   Command Parser  |
+-------------------+
          |
          v
+-------------------+
|       UFDT        |
| (File Descriptor) |
+-------------------+
          |
          v
+-------------------+
|     File Table    |
+-------------------+
          |
          v
+-------------------+
|       Inode       |
+-------------------+
          |
          v
+-------------------+
|    Data Blocks    |
+-------------------+

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🗂 Data Structures Used

Superblock

Tracks total and free inodes.

struct SUPERBLOCK
{
    int TotalInodes;
    int FreeInodes;
};

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Inode

Represents file metadata.

struct inode
{
    char FileName[50];
    int InodeNumber;
    int FileSize;
    int FileActualSize;
    int FileType;
    char *Buffer;
    int LinkCount;
    int ReferenceCount;
    int Permission;
    struct inode *next;
};

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File Table

Stores information of opened files.

struct filetable
{
    int ReadOffset;
    int WriteOffset;
    int Count;
    int Mode;
    struct inode *ptrinode;
};

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UFDT (User File Descriptor Table)

Maps file descriptors to file tables.

struct ufdt
{
    struct filetable *ptrfiletable;
};

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📜 Supported Commands

Command	Description
create <name> <permission>	Create new file
open <name> <mode>	Open file
read <name> <size>	Read file
write <name>	Write into file
close <name>	Close file
ls	List all files
unlink <name>	Delete file
man <command>	Display command manual
help	Display all commands
exit	Exit CVFS

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🔄 Project Flow

Start Program
      |
Initialize Superblock
      |
Create Inode Linked List
      |
Accept User Command
      |
Parse Command
      |
Execute Function
      |
Display Output
      |
Repeat Until Exit

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▶️ How to Run the Project

Step 1: Compile

gcc cvfs.c -o cvfs

Step 2: Run

./cvfs

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💻 Example Output

CVFS : > create file1 3
File created successfully with file descriptor : 0

CVFS : > write file1
Enter data : Hello World

CVFS : > read file1 11
Hello World

CVFS : > ls
file1

CVFS : > unlink file1
File deleted successfully

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📸 Output Screenshots

File Creation

CVFS > create file1 3
File created successfully

File Reading

CVFS > read file1 11
Hello World

Listing Files

CVFS > ls
file1

File Deletion

CVFS > unlink file1
File deleted successfully

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⚠️ Limitations

• Data stored only in RAM
• No directory structure
• Limited inode count
• No multi-user support

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🚀 Future Enhancements

• Persistent storage
• Directory support
• Multi-user system
• File encryption
• GUI interface

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📚 Learning Outcomes

This project helps understand:

• File System Architecture
• Inode-based File Management
• File Descriptors
• Memory Management
• System Programming

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👨‍💻 Author

Sahil Rajaram Thorat

• 📍 Pune, Maharashtra
• 💻 C / C++ / Java Developer
• 🔗 GitHub: https://github.com/SahilThorat11

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