Information Technology

Information Technology

Information Technology
| Computer Networks | | Databases | | Operating System | | Compiler Design | | Theory of Computation | | Algorithms | | Programming and Data Structures | | Computer Organization and Architecture | | Digital Logic |
Q.1
Given the following state table of an FSM with two states A and B, one input and one output: 

If the initial state is A = 0, B = 0, what is the minimum length of an input string which will take the machine to the state A = 0, B = 1 with Output = 1?
A. 3
B. 4
C. 5
D. 6
Answer : Option A
Explaination / Solution:
No Explaination.


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Q.2
The transport layer protocols used for real time multimedia, file transfer, DNS and email, respectively are
A. TCP, UDP, UDP and TCP
B. UDP, TCP, TCP and UDP
C. UDP, TCP, UDP and TCP
D. TCP, UDP, TCP and UDP
Answer : Option C
Explaination / Solution:

Real time multimedia needs connectionless service, so under lying transport layer protocol used is UDP File transfer rums over TCP protocol with port no-21 DNS runs over UDP protocol within port no-53 Email needs SMTP protocol which runs over TCP protocol within port no – 25

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Q.3
Which one of the following hash functions on integers will distribute keys most uniformly over 10 buckets numbered 0 to 9 for i ranging from 0 to 2020?
A. h(i) = i2 mod 10
B. h(i) = i3 mod 10
C. h(i) = (11*i2) mod 10
D. h(i) = (12*i) mod 10
Answer : Option B
Explaination / Solution:

If we take first 10 elements, number of collisions taken by the hash function given by option (B) is less when compared to others.

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Q.4
Which one of the following is not a client server application?
A. Internet chat
B. Web browsing
C. E-mail
D. Ping
Answer : Option A
Explaination / Solution:
No Explaination.


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Topic: Databases Tag: CS GATE 2009
Q.5
Consider the following relational schema: Suppliers (sid:integer, sname: string, city:string, street: string) Parts (pid:integer, pname: string, color:string) Catalog (sid:integer, pid:integer, cost: real)
Consider the following relational query on the above database:
SELECT S.sname
FROM Suppliers S
WHERE S.sid NOT IN (SELECT C. sid
FROM Catalog C
WHERE C.pid NOT IN (SELECT P.pid
FROM Parts P
WHERE P.color<> ‘blue’)) 
Assume that relations corresponding to the above schema are not empty. Which one of the following is the correct interpretation of the above query?
A. Find the names of all suppliers who have supplied a non-blue part
B. Find the names of all suppliers who have not supplied a non-blue part
C. Find the names of all suppliers who have supplied only blue parts
D. Find the names of all suppliers who have not supplied only blue part
Answer : Option A
Explaination / Solution:
No Explaination.


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Topic: Databases Tag: CS GATE 2012
Q.6
Suppose R1  are two relation schemas. Let r1 and r2 be the corresponding relation instances. B is a foreign key that refers to C in R2. If data in r1 and r2 satisfy referential integrity constrains, which of the following is ALWAYS TRUE?
A. ΠB(r1) − ΠC (r2) =∅
B. ΠC (r2 ) − ΠB (r1) =∅
C. ΠB (r1) = ΠC (r2)
D. ΠB (r1) − ΠC (r2) ≠∅
Answer : Option A
Explaination / Solution:
No Explaination.


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Q.7
What is the optimized version of the relation algebra expression  where A1, A2 are sets of attributes in with A⊂ Aand F1, F2 are Boolean expressions based on
A.
B.
C.
D.
Answer : Option A
Explaination / Solution:
No Explaination.


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Q.8
 A database of research articles in a journal uses the following schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, YEAR, PRICE) 
The primary key is (VOLUME, NUMBER, STARTPAGE, ENDPAGE) and the following functional dependencies exist in the schema.
(VOLUME, NUMBER, STARTPAGE, ENDPAGE)  → TITLE 
(VOLUME, NUMBER                                              → YEAR 
(VOLUME, NUMBER, STARTPAGE, ENDPAGE)  → PRICE
The database is redesigned to use the following schemas. 
(VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, PRICE) (VOLUME, NUMBER, YEAR) 
Which is the weakest normal form that the new database satisfies, but the old one does not?
A. 1NF
B. 2NF
C. 3NF
D. BCNF
Answer : Option A
Explaination / 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

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Q.9
Which one of the following is TRUE for any simple connected undirected graph with more than 2 vertices?
A. No two vertices have the same degree
B. At least two vertices have the same degree
C. At least three vertices have the same degree
D. All vertices have the same degree
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.10
 Let the page fault service time be 10ms in a computer with average memory access time being 20ns. If one page fault is generated for every 106 memory accesses, what is the effective access time for the memory?
A. 21ns
B. 30ns
C. 23ns
D. 35ns
Answer : Option B
Explaination / Solution:

 P = page fault rate 
EA = p × page fault service time 
+(1 - p) × Memory access time


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