GATE 2026 OS PYQs | File System and IO Scheduling

Consider a hard disk with a rotational speed of 15000 rpm. The time to move the read/write head from a track to its adjacent track is 1 millisecond. Initially, the head is on track 0. The number of sectors per track is 400, and the sector size is 1024 bytes. It is necessary to transfer data from 10 randomly located sectors in each of the following tracks in the order: 5, 12, and 7. The total time for the data transfer (in milliseconds) from the hard disk is ______. (rounded off to one decimal place) [GATE 2026 || SET-1 NAT || 2-mark]

To keep track of free blocks in a file system, one of the two approaches is generally used — using bitmaps (bit vectors) or using linked lists. Consider that the linked list approach is used to keep track of free blocks in a file system.

Assume that:

• Disk size = 16 GB
• Block size = 2 KB
• Block numbers used are 32-bit long
• A single pointer of size 4 bytes is used in each block of the list to point to the next block of the list

The number of blocks required to hold the free disk block numbers is ________. [GATE 2026 || SET-2 NAT || 2-mark]