GATE CS 2011

Question 11

A computer handles several interrupt sources of which the following are relevant for this question.

. Interrupt from CPU temperature sensor (raises interrupt if 
  CPU temperature is too high)
. Interrupt from Mouse(raises interrupt if the mouse is moved 
  or a button is pressed)
. Interrupt from Keyboard(raises interrupt when a key is 
  pressed or released)
. Interrupt from Hard Disk(raises interrupt when a disk 
  read is completed)

Which one of these will be handled at the HIGHEST priority?

• Interrupt from Hard Disk
• Interrupt from Mouse
• Interrupt from Keyboard
• Interrupt from CPU temperature sensor

Question 12

Consider a relational table with a single record for each registered student with the following attributes.

1. Registration_Num: Unique registration number
   of each registered student
2. UID: Unique identity number, unique at the 
   national level for each citizen
3. BankAccount_Num: Unique account number at
   the bank. A student can have multiple accounts
   or join accounts. This attribute stores the 
   primary account number.
4. Name: Name of the student
5. Hostel_Room: Room number of the hostel 

Which one of the following option is INCORRECT?

• BankAccount_Num is candidate key
• Registration_Num can be a primary key
• UID is candidate key if all students are from the same country
• If S is a superkey such that S∩UID is NULL then S∪UID is also a superkey

Question 13

Which one of the following circuits is NOT equivalent to a 2-input XNOR (exclusive NOR) gate?

• A
• B
• C
• D

Question 14

The simplified SOP (Sum Of Product) form of the boolean expression (P + Q\' + R\') . (P + Q\' + R) . (P + Q + R\') is

• (P\'.Q + R\')
• (P + Q\'.R\')
• (P\'.Q + R)
• (P.Q + R)

Question 15

The minimum number of D flip-flops needed to design a mod-258 counter is.

• 9
• 8
• 512
• 258

Question 16

A thread is usually defined as a "light weight process" because an operating system (OS) maintains smaller data structures for a thread than for a process. In relation to this, which of the following is TRUE?

• On per-thread basis, the OS maintains only CPU register state
• The OS does not maintain a separate stack for each thread
• On per-thread basis, the OS does not maintain virtual memory state
• On per-thread basis, the OS maintains only scheduling and accounting information

Question 17

• Q3 is planar while K4 is not
  

• Neither K4 nor Q3 are planar
  

• Both K4 and Q3 are planar
  

• K4 is planar while Q3 is not
  

Question 18

The lexical analysis for a modern computer language such as Java needs the power of which one of the following machine models in a necessary and sufficient sense?

• Finite state automata

• Deterministic pushdown automata

• Non-Deterministic pushdown automata

• Turing Machine

Question 19

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 10^6 memory accesses, what is the effective access time for the memory?

• 21ns
• 30ns
• 23ns
• 35ns

Question 20

Consider a hypothetical processor with an instruction of type LW R1, 20(R2), which during execution reads a 32-bit word from memory and stores it in a 32-bit register R1. The effective address of the memory location is obtained by the addition of a constant 20 and the contents of register R2. Which of the following best reflects the addressing mode implemented by this instruction for operand in memory?

• Immediate Addressing

• Register Addressing

• Register Indirect Scaled Addressing

• Base Indexed Addressing