The Minix FileSystem was the file system used by Minix, and was described in "Operating Systems: Their design and implementation" by AndrewTannenbaum.
The Minix file system had a number of limitations:
The Minix File system was used a lot on floppies where it's overhead was low. It's design also leant itself to being a file within the FileSystem of the host OperatingSystem when Minix was run as a process within another OperatingSystem.