OPERATING SYSTEM

The time to move the disk arm to the desired cylinder in hard disk is known as
(i) rotational latency
(ii) seek time
(iii) positional time
(iv) disk time

An I/O port typically consists of four registers-status, control, ______ and ______ registers.
(i) system in, system out
(ii) flow in, flow out
(iii) data in, data out
(iv) input, output

Consider a disk queue with requests for I/O to blocks on cylinders. 98 183 37 122 14 124 65 67. Considering FCFS (first cum first served) scheduling, the total number of head movements is, if the disk head is initially at 53 is?
(i) 600
(ii) 630
(iii) 620
(iv) 640

An I/O port typically consists of four registers-status, control, ______ and ______ registers.
(i) system in, system out
(ii) data in, data out
(iii) flow in, flow out
(iv) input, output

Consider a disk queue with requests for I/O to blocks on cylinders: 98, 183, 37, 122, 14, 124, 65, 67. Considering SSTF (shortest seek time first) scheduling, the total number of head movements is, if the disk head is initially at 53 is?

Suppose a disk drive has cylinders, numbered 0 to 299. The current head position of the disk is at 90. The queue of pending requests, in FIFO order is 36, 79, 15, 120, 199, 270, 89, 170. Calculate the average cylinder movements for Shortest-Seek Time First (SSTF) algorithm. Mention the disadvantages of SSTF.

Compare and contrast between linked and indexed disk allocation strategies.

Explain shortest-seek-time-first (SSTF) disk scheduling. Why SSTF scheduling tends to favour middle cylinders over the innermost and outer-most cylinders?

Write short note on: I-node

The open-file table is used to maintain information about files that are currently open. Should the operating system maintain a separate table for each user or just maintain one table that contains references to files that are currently being accessed by all users? If the same file is being accessed by two different programs or users, should there be separate entries in the open-file table?