Q1.Consider the following two phase locking protocol. Suppose a transaction T accesses (for
read or write operations), a certain set of objects {O1, . . . , OK}. This is done in the following
manner:
Step 1. T acquires exclusive locks to O1, . . . , Ok in increasing order of their addresses.
Step 2. The required operations are performed.
Step 3. All locks are released.
This protocol will
Answer : Option AExplaination / Solution:
2PL ensures serializability and here as we are following linear order in acquiring the locks
there will not be any deadlock.
Q2.Consider a carry look ahead adder for adding two n-bit integers, built using gates of fan-in at
most two. The time to perform addition using this adder is
Answer : Option BExplaination / Solution: No Explaination.
Q3.Consider that B wants to send a message m that is digitally signed to A. Let the pair of private
and public keys for A and B be denoted by for x = A, B, respectively. Let Kx(m)
represent the operation of encrypting m with a key Kx and H (m) represent the message
digest. Which one of the following indicates the CORRECT way of sending the message m
along with the digital signature to A?
Q4.Consider an arbitrary set of CPU-bound processes with unequal CPU burst lengths
submitted at the same time to a computer system. Which one of the following process
scheduling algorithms would minimize the average waiting time in the ready queue?
Answer : Option AExplaination / Solution:
SRTF is pre emptive SJF which produces less average waiting time.
Which is the weakest normal form that the new database satisfies, but the old one does not?
Answer : Option AExplaination / Solution:
candidate key is (volume, number, start page, end page)
(Volume number) → year is a partial dependency. So original table is in 1NF but not in 2NF
Q9. Which of the following decision problems are undecidable?
I. Given NFAs N1 and N2, is L(N1) ∩ L(N2) = Φ?
II. Given a CFG G = (N, Σ, P, S) and a string x ∈ Σ∗, does x ∈ L(G)?
III. Given CFGs G1 and G2, is L(G1) = L(G2)?
IV. Given a TM M, is L(M) = Φ?
Answer : Option CExplaination / Solution:
There is no known algorithm to check whether the language accepted by TM is empty.
Similarly there is no algorithm to check whether language CFG’s are equivalent.