Lecture 15 home work

In preparation for the lecture about file system, read the V6 code carefully. You should have a good idea of the big picture. Answer these questions:

Suppose a program creates a file "foo", writes 1 byte (containing "a") to it, calls close, and the power fails right after the call to closef() on line 5854 completes. What are the possible states that the disk is in? More specifically:

• Is there an inode for "foo" stored on the disk? If so, what is its contents?
• Is there a data block for "foo" stored on the disk? If so, what is its contents?
• Is there a directory entry for "foo"? Why? Why not?