GATE 2022 Rapid Revision Quiz 10

Which of the following is/are tautology?

To avoid deadlock in TCP ____ is used.

Consider following 2 queries with relation schema :

Student (ID., name, DEPT)

Courses (CID.ID, Grade, DEPT)

Q1: Select *

      From Student S

      Where not exists (select *

                                 from Course C

                                 Where C.ID = S.ID and C.Id> 4.0)

Q2:(_ID (Student) – π_ID(σ_{Grade> 4.0} (Course))) ⋈Student.

Which of the following query results “all students who never got a grade above 4.0” ?

Disk request come into disk driver for cylinders 10, 22, 20, 2, 6, 40 and 31 in that order. The disk head is currently positioned over 30 and seek takes 3 msec per cylinder moved. The total seek time using SCAN algorithm is ________ (in msec). [Assume 1st read/write head moving towards increasing (highest number) direction].

[Note : There are 61 cylinder numbered from 0-60.]

Consider the following statement regarding a system having m resources of a particular type and n processes using those resources:

1) The maximum need of each process is between 1 and m resources.

2) The sum of all maximum needs is less than m + n.

For the given system to be deadlock free, choose the correct statement?

Consider the following languages :
L₁ : {< M, q > | M is a Turing Machine that visits state q on some input within 15 steps}.
L₂ : {< M > | M is a Turing Machine, |M| < 200 where |M|is number of states in machine}.
Which of the following is correct ?