Discussion questions: file systems
Please work out these problems before your next discussion section. The
GSIs and IAs will go over these problems during the discussion section.
Use the fs_inode and fs_direntry data structures from Project 4 (from
Note: Blocks are 512 bytes, and inodes are block-sized.
What is the minimum and maximum number of disk blocks
that must be brought into memory in order to read the first
block of the file /etc/passwd?
A big file /bigfile that is 4 blocks in size is stored in the file system.
a. Draw out how /bigfile is laid out on disk. Include all inodes
and data blocks required to store the file. Assume there are no other files.
b. A user program makes a read request from offset 1 from /bigfile.
How many disk accesses are required to process the request?
c. i) How many disk accesses are required to process a read request on
offset 2 of /bigfile?
ii) How many accesses would it be if we had cached the blocks from part b?
d. If we wanted to add a new directory, /foo, how many new disk
blocks do we need to allocate? Update your diagram from part a with the new disk
e. A request for a new file, /foo/bar, has been made. How many new
disk blocks do we need to allocate? Update your diagram from part a with the new