The Customised Virtual File System (CVFS) is a C++-based, in-memory file system emulator that replicates core UNIX-like file system behaviors. It is designed for educational and research purposes, providing a hands-on understanding of file system internals such as inode management, file operations, and user-space interaction.
- In-Memory File System: All operations are performed in RAM, with no disk I/O.
- UNIX-like Commands: Supports commands such as
creat,open,read,write,ls,stat,fstat,truncate,rm,lseek,close, andcloseall. - Custom Shell Interface: Interactive CLI for file system operations.
- File Metadata Management: Implements superblock, inode table, file table, and UFDT (User File Descriptor Table).
- Permission Handling: Supports read, write, and read-write permissions.
- Resource Management: Handles file descriptors, reference counts, and memory allocation.
- Superblock: Tracks total and free inodes.
- Inode Table: Stores metadata for each file (name, size, type, permissions, etc.).
- File Table: Maintains open file state (offsets, mode, reference count).
- UFDT: Maps file descriptors to file table entries.
- Buffer: Each file has a dedicated buffer for its contents.
For detailed diagrams and flowcharts, see docs/CustomisedVirtualFileSystem_Project_Documation.pdf.
- GCC/g++ compiler (Linux/Windows)
- Command-line terminal
git clone https://github.com/yourusername/CustomisedVirtualFileSystem.git cd CustomisedVirtualFileSystem/src g++ Source_Code.cpp -o CVFS./CVFSOnce started, the shell accepts the following commands:
| Command | Description | Example Usage |
|---|---|---|
creat <name> <perm> | Create a new file with permissions | creat myfile 3 |
open <name> <mode> | Open an existing file | open myfile 1 |
read <name> <bytes> | Read bytes from a file | read myfile 100 |
write <name> | Write data to a file (prompts for input) | write myfile |
ls | List all files | ls |
stat <name> | Show file metadata by name | stat myfile |
fstat <fd> | Show file metadata by descriptor | fstat 0 |
truncate <name> | Remove all data from a file | truncate myfile |
rm <name> | Delete a file | rm myfile |
lseek <name> <off> <whence> | Change file offset | lseek myfile 10 0 |
close <name> | Close a file | close myfile |
closeall | Close all open files | closeall |
help | Display help information | help |
exit | Exit the shell | exit |
Permissions:
1= Read2= Write3= Read & Write
Abhishek Atole CVFS :> creat test 3 File is successfully created with file descriptor : 0 Abhishek Atole CVFS :> write test Enter the data to write file : Hello, CVFS! 13 bytes gets written successfully in the file Abhishek Atole CVFS :> read test 13 Hello, CVFS! Abhishek Atole CVFS :> ls File Name Inode number File iSize Link iCount test 1 13 1 Abhishek Atole CVFS :> exit Thank-you for using My Virtual File System-
Final Run Executable Screenshot:
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Hard Disk Info Diagram:
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Inode Information Diagram:
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RAM Processing Diagram:
Contributions, issues, and feature requests are welcome!
Please open an issue or submit a pull request.
This project is licensed under the MIT License.
Abhishek Atole
LinkedIn • GitHub