GATE CSE 2017 SET-2
Q51.
Two transactions T_1 \; and \; T_2 are given as: T_{1}:r_{1} (X)w_{1}(X)r_{1}(Y)w_{1}(Y) T_{2}:r_{2}(Y)w_{2}(Y)r_{2}(Z)w_{2}(Z) where r_{i}(V) denotes a read operation by transaction T_{i} on a variable V and w_{i}(V) denotes a write operations by transaction T_{i} on a variable V. The total number of conflict serializable schedules that can be formed by T_1 \; and \; T_2 is _____________.Q52.
Let L(R) be the language represented by regular expression R. Let L(G) be the language generated by a context free grammar G. Let L (M) be the language accepted by a Turning machine M. Which of the following decision problems are undecidable ? I. Given a regular expression R and a string w, is w\in L(R)? II. Given a context-free grammar G, L(G)=\phi? III. Given a context-free grammar G, is L(G)=\Sigma* for some alphabet \Sigma? IV. Given a Turning machine M and a string w, is w\inL(M)?Q53.
The next state table of a 2-bit saturating up-counter is given below. \begin{matrix} Q_{1} & Q_{0} & Q_{1}^{+} &Q_{0}^{+} \\ 0 & 0 & 0 & 1 \\ 0 & 1 & 1 & 0\\ 1 & 0 & 1 & 1\\ 1 & 1 & 1 & 1 \end{matrix} The counter is built as a synchronous sequential circuit using T flip-flops. The expression for T_1 \; and \; T_0 areQ54.
Consider socket API on a Linux machine that supports connected UDP sockets. A connected UDP socket is a UDP socket on which connect function has already been called. Which of the following statements is/are CORRECT ? I. A connected UDP socket can be used to communicate with multiple peers simultaneously. II. A process can successfully call connect function again for an already connected UDP socket.