Operating Systems 1

Tutorial 9

1. UNIX has a daemon process which periodically writes dirty blocks from the block cache to disk. Why?
2. What is the advantage of a journalled file system (or database)? Disadvantages?
3. Distinguish between a full backup and an incremental backup.
4. In UNIX, what are two differences between 'character devices' and 'block devices'?
5. Why is device independence an important goal for operating systems?
6. What's an advantage of a UNIX-style unified namespace for files and devices, over the MS-DOS approach of separate namespaces for each device?
7. Describe the tradeoff in UNIX-style file protection bits, versus a full-blown protection matrix.
8. What is an access control list?