GATE CS 2018 Q53 — I/O Scheduling

Consider a $512$ GB hard disk with $32$ storage surfaces. There are $4096$ sectors per track and each sector holds $1024$ bytes of data. The number of cylinders in the hard disk is _________.

Consider a disk with the following specifications: rotation speed of $6000$ RPM, average seek time of $5$ milliseconds, $500$ sectors/track, $512$-byte sectors. A file has content stored in $3000$ sectors located randomly on the disk. Assuming average rotational latency, the total time (in seconds, rounded off to $2$ decimal places) to read the …

Consider the following five disk access requests of the form (request id, cylinder number) that are present in the disk scheduler queue at a given time. $(P, 155), (Q,85), (R,110),(S, 30), (T,115)$ Assume the head is positioned at cylinder $100$. The scheduler follows Shortest Seek Time First scheduling to service the requests. Which one of the following …

Cylinder a disk queue with requests for $I/O$ to blocks on cylinders $47, 38, 121, 191, 87, 11, 92, 10.$ The C-LOOK scheduling algorithm is used. The head is initially at cylinder number $63$, moving towards larger cylinder numbers on its servicing pass. The cylinders are numbered from $0$ to $199$. The total head movement (in number of cylinders) …

Consider a disk pack with a seek time of $4$ milliseconds and rotational speed of $10000$ rotations per minute (RPM). It has $600$ sectors per track and each sector can store $512$ bytes of data. Consider a file stored in the disk. The file contains $2000$ sectors. Assume that every sector access necessitates a seek, and the average rotational …

Suppose the following disk request sequence (track numbers) for a disk with $100$ tracks is given: $45, 20, 90, 10, 50, 60, 80, 25, 70.$ Assume that the initial position of the R/W head is on track $50$. The additional distance that will be traversed by the R/W head when the Shortest Seek Time First (SSTF) algorithm is used compared to the SCAN …