1
GATE CSE 2015 Set 2
MCQ (Single Correct Answer)
+2
-0.6
Consider a simple checkpointing protocol and the following set of operations in the log.

(start, $$T4$$); (write, $$T4, y, 2, 3$$); (start, $$T1$$); (commit, $$T4$$); (write, $$T1, z, 5, 7$$);
(checkpoint);
(start, $$T2$$); (write, $$T2, x, 1, 9$$); (commit, $$T2$$); (start, $$T3$$), (write, $$T3, z, 7, 2$$);

If a crash happens now and the system tries to recovver using both undo and redo operations, what are the contents of the undo list and the redo list?

A
Undo: $$T3,T1;$$ Redo: $$T2$$
B
Undo: $$T3,T1;\,{\mathop{\rm Re}\nolimits} do:T2,T4$$
C
Undo: none; Redo: $$T2,T4,T3,T1$$
D
Undo: $$T3,T1,T4;\,\,$$ Redo : $$T2$$
2
GATE CSE 2015 Set 2
MCQ (Single Correct Answer)
+2
-0.6
Consider two relations $${R_1}\left( {A,B} \right)$$ with the tuples $$(1,5), (3,7)$$ and $${R_2}\left( {A,C} \right) = \left( {1,7} \right),\left( {4,9} \right).$$
Assume that $$R(A,B,C)$$ is the full natural outer join of $${R_1}$$ and $${R_2}$$. Consider the following tuples of the form $$(A,B,C): a = (1,5,null),$$ $$b = (1,null,7),$$ $$c = (3, null, 9),$$ $$d = (4,7,null),$$ $$e = (1,5,7),$$ $$f = (3,7,null),$$ $$g = (4,null,9).$$ Which one of the following statements is correct?
A
$$R$$ contains $$a, b, e, f, g$$ but not $$c, d.$$
B
$$R$$ contains all of $$a, b, c, d, e, f, g.$$
C
$$R$$ contains $$e, f, g$$ but not $$a, b.$$
D
$$R$$ contains $$e$$ but not $$f, g.$$
3
GATE CSE 2015 Set 2
Numerical
+1
-0
The minimum number of $$JK$$ flip-flops required to construct a synchronous counter with the count sequence $$\left( {0,0,1,1,2,2,3,3,0,0,...} \right)$$ is ____________.
Your input ____
4
GATE CSE 2015 Set 2
Numerical
+2
-0
The number of min-terms after minimizing the following Boolean expression is _______________ . $$$\left[ {D' + AB' + A'C + AC'D + A'C'D} \right]'$$$
Your input ____
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