Question

contiguous allocation of the disk

OS

One way to use contiguous allocation of the disk and not suffer from holes is to compact the disk every time a file is removed. Since all files are contiguous, copying a file requires a seek and a rotational delay to read the file , followed by the transfer at full speed. Writing the file back requires the same work. Assuming a seek time of 5 msec , a rotational delay of 4 msec , a transfer rate of 8MB/sec and an average file size of 8KB, how long does it take to read a file into main memory then write it back to the disk at a new location? Using these numbers , how long would it take to compact a 8GB disk? Would that be a good idea?

It is not recommended to compact the disk every time you remove a file, as a small number of holes does not matter much in read/write operation, it is only recommended on a periodic basis depending on how frequently you remove file from your disk. All speeds being taken into consideration, it is worth doing the operation as if you compare the overall time taken to defrag/compact your disk viz a viz the speed enhancement you get in return for your next cycle of operations is still worth.