MINIX file system

The Minix file system is the default file system used when installing Minix.

Design and implementation

A Minix file system has six components:

• The Boot Block which is always stored in the first block. It contains the boot loader that loads and runs an operating system at system startup.
• The second block is the Superblock which stores data about the file system, that allows the operating system to locate and understand other file system structures. For example, the number of inodes and zones, the size of the two bitmaps and the starting block of the data area.
• The inode bitmap is a simple map of the inodes that tracks which ones are in use and which ones are free by representing them as either a one (in use) or a zero (free).
• The zone bitmap works in the same way as the inode bitmap, except it tracks the zones
• The inodes area. Each file or directory is represented as an inode, which records metadata including type (file, directory, block, char pipe), ids for user & group, three timestamps that record the data & time of last access, last modification and last status change. An inode also contains a list of addresses that point to the zones in the data area where the file or directory data is actually stored.
• The data area is the largest component of the file system, using the majority of the space. It is where the actual file and directory data are stored.

History

When Linux was first released in October 1991, the Minix file system was the only one available. This changed with the introduction of the Extended file system in April 1992, however it is still used by some Linux distributions as the format for bootable disks or other situations where a low-overhead file system is needed.