On a traditional hard drive with spinning magnetic platters, the time it takes t
ID: 3571424 • Letter: O
Question
On a traditional hard drive with spinning magnetic platters, the time it takes to execute a read is the sum of the seek time and the block read time. The seek time is the amount of time it takes the hard drive to physically locate the requested data, and the block read time is the amount of time it takes the data to be read off the disk. If a file is split across multiple blocks, then the drive must seek to each individual block and read it.
One study found that the average file size on a Linux system is 2475 bytes long. How long does it take to read the average file on a system with 1024-byte (1KB) block sizes? What about 2048 bytes (2KB) and 4096 bytes (4KB)? Suppose a seek time of 10 microseconds and a block read time of 3 microseconds.
Explanation / Answer
For 1024 block size: File has to be splitted across min 3 blocks. So seekTime + 3*(blockTime) = 19 microseconds.
For 2048 block size: File to splitted in 2 blocks. So 2*(blockTime) + seekTime = 16 microseconds
For 4096 block size. 1 block will suffice. So time taken = 13 microseconds.