This code was branched from Adam Cozzette's work which was written in C. I wanted to add object hierarchy and other OOP methods. So I've taken the code and rewritten many of the pieces to allow for a C++ compilation.
The section below is Adam's description of BUSE which is still fitting:
This piece of software was inspired by FUSE, which allows the development of Linux file systems that run in userspace. The goal of BUSE is to allow virtual block devices to run in userspace as well. Currently BUSE is experimental and should not be used for production code.
Implementing a block device with BUSE is fairly straightforward. Simply fill
struct buse_operations (declared in buse.h) with function pointers that
define the behavior of the block device, and set the size field to be the
desired size of the device in bytes. Then call buse_main and pass it a
pointer to this struct. busexmp.c is a simple example example that shows how
this is done.
The implementation of BUSE itself relies on NBD, the Linux network block device, which allows a remote machine to serve requests for reads and writes to a virtual block device on the local machine. BUSE sets up an NBD server and client on the same machine, with the server executing the code defined by the BUSE user.
BUSE comes with an example driver in buseRAMDevice.c that implements a 128 MB
memory disk. To try out the example code, run make and then execute the
following as root:
modprobe nbd
./bin/buseMainTest RAM /dev/nbd0
You should then have an in-memory disk running, represented by the device file
/dev/nbd0. You can create a file system on the virtual disk, mount it, and
start reading and writing files on it:
mkfs.ext4 /dev/nbd0
mount /dev/nbd0 /mnt
The other example driver is 'buseLODevice.c' which creates a loopback interface. You can use it with: ./bin/buseMainTest LO /dev/sda1 /dev/nbd1
You can also chain the two programs together by replacing '/dev/sda1' with '/dev/nbd0'.