Week 8

VL 15

File Systems (cont.)

• inodes (cont.)
• MBR (booting)
• FATx - MS-DOS
• UNIX-V7
• structure of a hard disk
  • shortest seek time first (sstf)

RAID Systems

• RAID 0
• RAID 1
  • mirroring
  • duplexing
• RAID 2 - bit-level striping, too complicated due to the need to synchronize hard disks
• RAID 3 - XOR (reconstructing ), implementation is also very complex
• RAID 4
• RAID 5
• RAID 6 - like RAID 5 but wwith reed-solomon codes instead of XOR.

VL 16 - 04.06.25

• structure of file systems, block, blockgroups
• linux file systems: ext2, ext3, ext4, zfs.

Deadlocks

• deadlocks, deadlock example (p. 16)
• how to prevent deadlock: first we define a system model
• conditions for a resource deadlock
  • mutual exclusion: …
  • hold and wait: …
  • no preemption: …
  • circular wait: …
• this conditions must occur simultaneously for a deadlock to take place.
• resourcen-belegungs-graph (RB Graph)
  • multiple instances of a resource
• cycle detecting algorithms
  • recource vectors and resources rest vector
  • current allocation matrix
  • request matrix
• how to resolve deadlocks: