Advanced Operating Systems

1
Advanced Operating Systems

• The Minix File System

2
Minix design

• Minix was developed by Andrew Tanenbaum at the
  Free University in Amsterdam
• Is a message passing kernel
• File System is an independent process

3
Layout of the Minix file system
4
Minix file system

• Uses zone to handle large disc drives
• a zone can equal a multiple of a block
• On a floppy a zone a block
• Uses bit maps for fast lookup and allocation of
  inodes and zones
• 2 versions
• V1 64mb file limit, smaller inode
• V2 the same as standard UNIX fs

5
Minix Super Block
6
Minix super block

• The super block has lots of space, can contain
  information that could be worked out
• Disc and incore versions
• Holds pointers incore to free inode and zone bit
  maps

7
Assignment

• Need to understand inode and data block
  assignment processes alloc_inode
• Understand how file deletion works the role of
  unlink, and free_inode
• Change super block structures and management
• Need new bit maps
• Change pointers to free inode and zone blocks
• Understand how free_bit and alloc_bit work