a driver and a loader to mount disks as read only device.
This software is a driver and a loader to mount USB flash memory, USB HDD and FireWire HDD as read only device.
When a device is mounted by this driver, MacOS X recognizes it as read-only.
In other words, this software works as if a write-protect switch of a device.
And the driver does not care the format of device, so it works for not only HFS but also FAT.