mkfs.hefs is a command-line utility used to format a block device or disk image with the High-throughput Extended File System (OpenHeFS) used by NeKernel. This tool initializes a OpenHeFS volume by writing a boot node and configuring directory and inode index regions, block ranges, and volume metadata.

🛠 Features

Writes a valid BootNode to the specified output device or file.
Sets disk size, sector size, and volume label.
Supports user-defined ranges for:
- Index Node Directory (IND)
- Inodes (IN)
- Data blocks
UTF-8 encoded volume label support.
Fully compatible with NeKernel's VFS subsystem.

🧪 Usage

mkfs.hefs -L <label> -s <sector_size> \
          -b <ind_start> -e <ind_end> \
          -bs <block_start> -be <block_end> \
          -is <in_start> -ie <in_end> \
          -S <disk_size> -o <output_device>

🧾 Arguments

Option	Description
-L	Volume label (UTF-8, internally stored as UTF-16)
-s	Sector size (e.g., 512)
-b -e	Start and end addresses for the Index Node Directory (IND) region
-bs -be	Start and end addresses for the Block data region
-is -ie	Start and end addresses for the Inode region
-S	Disk size in gigabytes
-o	Path to the output device or image file

All address-based inputs (-b, -e, etc.) must be specified in hexadecimal format.

🧷 Notes

Default sector size is 512 bytes.
Default volume name is "HeFS_VOLUME", defined as kOpenHeFSDefaultVolumeName.
The tool writes a BootNode at the beginning of the index node range.
A CRC-safe magic signature is embedded for boot and integrity validation.
After writing the metadata, the tool flushes and closes the file stream.

💻 Example

mkfs.hefs -L "MyHeFS" -s 512 \
          -b 0x1000 -e 0x8000 \
          -bs 0x8000 -be 0x800000 \
          -is 0x800000 -ie 0xA00000 \
          -S 128 -o hefs.img

This will create a 128 GiB formatted OpenHeFS image named hefs.img with specified region boundaries.

📁 BootNode Structure

The BootNode stores key filesystem metadata:

struct BootNode {
  char     magic[8];
  char16_t volumeName[64];
  uint16_t version;
  uint16_t diskKind;
  uint16_t encoding;
  uint64_t diskSize;
  uint32_t sectorSize;
  uint64_t startIND, endIND;
  uint64_t startIN, endIN;
  uint64_t startBlock, endBlock;
  uint64_t indCount;
  uint16_t diskStatus;
};

⚠️ Error Handling

Prints usage and exits on invalid/missing arguments.
Exits with error if the output device cannot be opened or written to.
Checks for zero sector size or disk size to prevent invalid formatting.

📚 Source Location

Part of the OpenHeFS Tooling module and used during system setup or disk preparation for NeKernel.

© License

Copyright (C) 2025,
Amlal El Mahrouss – Licensed under the Apache 2.0 license.