Given a UNIX file system with 1024-byte blocks, how many disk accesses are needed to access bytes 2500-2503 of a file (assume the file control block is already in memory, but no data blocks are cached): (A) 1; (B) 2; (C) 3; (D); 4.

(A) 1

Explanation:

In UNIX the file system the file system is a central part of the operating system. The file system is for storage and retrieval of information. Programs that form the UNIX system also stores information in files.

UNIX file systems supports three files namely: ordinary file, directory files, device files or special files.

If we need to access bytes 2500-2503 it means the bytes are within the third block. So we will need only one access.

Note this is because the file control block (inside) is within the memory. If file control block was not in the memory we would have needed more disk accessses.