FILE SYSTEMS

Q13) (File Systems) One way to use contiguous allocation of the disk and not suffer from holes is to compact (defragment) the disk every time a file is removed. Since all files are contiguous, copying a file requires a seek and rotational delay to read the file, followed by the transfer at fullspeed. Writing the file back requires the same work. Assuming:

• a seek time of 5 msec,
• a rotational delay of 5 msec,
• a transfer rate of 100 MB/sec,
• and an average file size of 8KB,

a) (10 pts) How long does it take to read a file into main memory and then write it back to the disk at a new location?

b) (15 pts)Using these numbers, how long would it take to compact the half of a 16-GB disk assuming that the disk is completely full and half of the data needs to be moved during compaction?