Question

Operating system try to ensure that consecutive blocks of a file are stored on consecutive disk blocks. Why is doing so very important with magnetic disks? If SSDs were used instead, is doing so still important, or is it irrelevant? Explain why?

Answer 1

Thanks for the question.

Here are the answer !

Why is doing so very important with magnetic disks?

Using hard disks or magnetic disks, the OS tries to ensure that when a file is stored it should be stored in the consecutive blocks of the disk in consecutive disk blocks. This is important as the magnetic disk moves with the intention to access the disk. If the magnetic disk moves a lot, then it takes much more time to access the information. The contiguous allocation on consecutive disk blocks makes sure that the blocks of the file are kept contiguously. Thus performance is fast in this scenario where reading the consecutive disk blocks require no major movement of the disk head.

If SSDs were used instead, is doing so still important, or is it irrelevant? Explain why?

But for SSDs, it is a different case. As the SSDs have no moving parts and they use flash memory to store the data and provide with improves performance, read/write speed and reliability thus the consecutive disk allocation does not make any difference in case of an SSD.