echfs

The echfs filesystem is a 64-bit FAT-like filesystem which aims to support most UNIX and POSIX-style features while being extremely simple to implement. Ideal for hobbyist OS developers who want a simple filesystem and don't want to deal with old crufty FAT (which isn't UNIX/POSIX compliant either), or complex filesystems such as ext2/3/4.

Keep in mind that this is still a work in progress, and the specification might change. I'll try to keep everything backwards compatible (in a clean way) when I add new features or make modifications to the filesystem.

In this repo you can find the full specification in the spec.txt file, and a utility to manipulate the filesystem (echfs-utils). You can compile and install the echfs-utils program using make the usual way.

A FUSE implementation of a filesystem driver named echfs-fuse is also provided (thanks to Geertiebear).

Build dependencies

echfs-fuse depends on libuuid, libfuse, and pkg-config. (On Debian/Ubuntu based distros, the packages are called uuid-dev, libfuse-dev, and pkg-config, respectively).

On systems where FUSE is not available, it is possible to compile echfs-utils exclusively by running make utils instead of make and make install-utils instead of make install.

Building

make
sudo make install

Usage

echfs-utils

echfs-utils is used as echfs-utils <flags> <image> <command> <command args...>, where a command can be any of the following:

• import, which copies to the image with args <source> <destination>
• export, which copies from the image with args <source> <destination>
• ls, with arg <path> (can be left empty), it lists the files in the path or root if the path is not specified
• mkdir, with arg <path>, makes a directory with the specified path.
• format, with arg <block size> formats the image
• quick-format with arg <block size> formats the image

There are also several flags you can specify

• -f ignore existing file errors on import
• -m specify that the image is MBR formatted
• -g specify that the image is GPT formatted
• -p <part> specify which partition the echfs image is in
• -v be verbose

echfs-fuse

echfs-fuse is used as echfs-fuse <flags> <image> <mountpoint>, with the following flags:

• -m specify that the image is MBR formatted
• -g specify that the image is GPT formatted
• -p <part> specify which partition the echfs image is in
• -d run in debug mode (don't detach)

Creating a filesystem

A filesystem can be created with the following commands

dd if=/dev/zero of=image.hdd bs=4M count=128
parted -s image.hdd mklabel msdos
parted -s image.hdd mkpart primary 2048s 100%
echfs-utils -m -p0 image.hdd quick-format 512