CS and IT Gate 2017 Set-2 Questions with Answer

Given:
32-bit IEEE-754 representation: 00111110011011010000000000000000
To find:
The closest decimal value of the given floating-point number.
Solution:
First, let me split the 32 bits into the sign, exponent, and mantissa fields according to the IEEE-754 single-precision format:
Sign bit, s = 0 (1 bit)
Exponent, E = 01111100 (8 bits)
Mantissa, M = 11011010000000000000000 (23 bits)
Since the sign bit is 0, the number is positive.
Now, converting the exponent field from binary to decimal:
E = (01111100)₂ = 64 + 32 + 16 + 8 + 4 = 124
The bias for single-precision IEEE-754 is 127, so subtracting the bias gives:
Actual exponent, e = E - 127 = 124 - 127 = -3
Next, let me find the normalized significand (1.M):
Significand = 1 + (1 × 2^-1) + (1 × 2^-2) + (0 × 2^-3) + (1 × 2^-4) + (1 × 2^-5) + (0 × 2^-6) + (1 × 2^-7)
Significand = 1 + 0.5 + 0.25 + 0.0625 + 0.03125 + 0.0078125 = 1.8515625
Now, calculating the value of the floating-point number:
Value = (-1)^s × (Significand) × 2^e
Value = 1.8515625 × 2^-3 = (1.8515625) / 8
Value = 0.2314453125 ≈ 2.31 × 10^-1
Comparing with the given choices, the value closest to this is 2.27 × 10^-1.
Answer:
C) 2.27 X 10^-1

Given:
Total number of tape drives = 9
Processes: P1, P2, P3
Allocation: P1 = 3, P2 = 1, P3 = 3
Max Requirement: P1 = 7, P2 = 6, P3 = 5
To find:
Whether the current state of the system is Safe/Not Safe and Deadlocked/Not Deadlocked.
Solution:
First, let me calculate the total allocated tape drives.
Total allocated = 3 + 1 + 3 = 7
Now let me find the currently available tape drives.
Available = Total - Total allocated = 9 - 7 = 2
Next, I need to calculate the remaining Need for each process using Need = Max - Allocation.
For P1: Need = 7 - 3 = 4
For P2: Need = 6 - 1 = 5
For P3: Need = 5 - 3 = 2
Now let me check which process can be satisfied with Available = 2.
Checking P1: Need(P1) = 4 > Available (2), so P1 cannot execute right now.
Checking P2: Need(P2) = 5 > Available (2), so P2 cannot execute right now.
Checking P3: Need(P3) = 2 ≤ Available (2), so P3 can execute and complete.
Once P3 finishes, it releases its allocated tape drives.
New Available = 2 + Allocation of P3 = 2 + 3 = 5
Now check the remaining processes with Available = 5.
Checking P1: Need(P1) = 4 ≤ Available (5), so P1 can run and complete.
Once P1 finishes, it releases its allocated drives.
New Available = 5 + Allocation of P1 = 5 + 3 = 8
Finally, check P2.
Need(P2) = 5 ≤ Available (8), so P2 can also finish.
A safe sequence exists: <P3, P1, P2>.
Since a safe sequence exists, the system is in a Safe state.
By definition, if a system is in a safe state, it is definitely Not Deadlocked.
Answer:
(B) Safe, Not Deadlocked

Given:
Items related to threads in a process:
I. Program Counter
II. Stack
III. Address space
IV. Registers
To find:
Which of these is/are shared by all the threads in a process.
Solution:
Let me recall what is unique to a thread and what is shared among threads of the same process.
A thread is a basic unit of CPU utilization, and each thread must have its own execution context.
So each thread needs its own Program Counter to keep track of which instruction to execute next.
Each thread also needs its own set of CPU registers to hold temporary values.
And each thread needs its own private Stack for local variables and function call management.
So, items I (Program Counter), II (Stack), and IV (Registers) are private to each individual thread.
Now looking at what they share: threads within the same process share the code section, data section, open files, heap, and the entire address space.
Therefore, only the address space (III) is shared by all threads in the process.
Looking at the options, this corresponds to III only.
Answer:
(A) III only