Technical and aptitude

hi Friends …..
There were two sections in the DRDO paper(CS)

Technical and aptitude

1.APTITUDE:-
There were 50 questions in this section,questions were from simple reasoning.or I can say that reasoning was very easy,there were verbal and non-verbal type questions.
but there were also questions from English and G.K.
Although it was not mention in prospect that English and G.K questions will come,
Some G.K.questions were easy like–Tank Developed by DRDO(Arjun).
PRITHVI is what kind of missile(surface to surface).
mahatma Gandhi during breaking ognsalt rule move up to(Dandi)…etc..

2.Technical

Questions of this section were average,not easy not tough.
questions were as I remember Mostly from Automata so prepare well Automata.
String generating ques. were there.

(A)The class of context-free language is not closed under
1.Concatenation
2.Union
3.Intersection(ans)
4.None

(b)Which of the following sentence is generated by the production Grammer.
s->aSbA
A->dccA
1.abbbd
2.aabccd(ans)
3.aabd
4.ababcd

(C) Hard disk has a rotation speed of 7200RPM. then the latency time is
a) .4
b) .6
c) .7
d) .9

some questions were from C output they were easy.

2 questions were related to Time-Complexity.

study from following books.

Computer Organization—William Stallings,Morris Mano

Theory of Computation—Aho and Ullman

Compiler Design—–Ullman

Operating systems—-Galvin

computer Networks—-William Stallings