Engineering Questions with Answers - Multiple Choice Questions

MCQs on Protection

1 - Question

The mechanism to provide protection, that is accomplished with the help of read/write privileges is
a) restricted use of segments
b) restricted accesses to segments
c) privileged instructions
d) privileged operations

View Answer

Answer: a
Explanation: The restricted use of segments is accomplished with the help of read/write privileges.




2 - Question

The Local descriptor table (LDT) and Global descriptor table (GDT) are present in
a) privileged instruction check
b) operation reference check
c) segment load check
d) none of the mentioned

View Answer

Answer: c
Explanation: In restricted use of segments i.e. segment load check, the segment usages are restricted by classifying the corresponding descriptors, under LDT and GDT.




3 - Question

The mechanism that is accomplished using descriptor usages limitations and rules of privilege check is
a) privileged instruction check
b) operation reference check
c) segment load check
d) none of the mentioned

View Answer

Answer: b
Explanation: Restricted accesses to segment, also called, operation reference check, is accomplished using descriptor usages limitations, and rules of privilege check.




4 - Question

The mechanism that is executed at certain privilege levels, determined by CPL (Current Privilege Level) and I/O privilege level (IOPL) is
a) restricted use of segments
b) restricted accesses to segments
c) privileged instructions or operations
d) none of the mentioned

View Answer

Answer: c
Explanation: The privileged instructions or operations, also called, privileged instruction check, is executed at certain privilege levels, determined by CPL and I/O privilege level(IOPL), as defined by the flag register.




5 - Question

If CPL is not of the required privilege level, then the instructions that get affected is
a) IRET
b) POPF
c) IRET and POPF
d) None of the mentioned

View Answer

Answer: c
Explanation: The IRET and POPF instructions do not perform any of their functions, if CPL is not of the required privilege level.




6 - Question

If CPL is greater than zero, then the instruction that remains unaffected is
a) IRET
b) POPF
c) IF
d) IRET and POPF

View Answer

Answer: c
Explanation: IF remains unaffected if CPL is greater than zero. No exception is generated for this condition.




7 - Question

The condition, “CPL not equals to zero” satisfies when executing the instruction
a) LIDT
b) LGDT
c) LTR
d) All of the mentioned

View Answer

Answer: d
Explanation: The condition, “CPL not equals to zero” satisfies, when executing the instructions, LIDT, LGDT, LTR, LMSW, CTS and HLT.




8 - Question

While executing the instruction IN/OUT, the condition of CPL is
a) CPL = 0
b) CPL < IOPL
c) CPL > IOPL
d) All of the mentioned

View Answer

Answer: c
Explanation: The condition CPL>IOPL exists, when executing the instructions, INs, IN, OUTS, OUT, STI, CLI and LOCK.




9 - Question

The instruction at which the exception is generated, but the processor extension registers contain the address of failing instruction is
a) LTR
b) INS
c) CTS
d) ESC

View Answer

Answer: d
Explanation: At the ESC instruction, the exception is generated, but the processor extension registers contain the address of failing instruction.




10 - Question

The exception that has no error code on a stack is
a) double exception detected
b) processor extension segment overrun
c) invalid task state segment
d) stack segment overrun

View Answer

Answer: b
Explanation: The processor extension segment overrun has no error code on the stack.




11 - Question

Which of the following is protected mode exception?
a) double exception detected
b) invalid task state segment
c) stack segment overrun
d) all of the mentioned

View Answer

Answer: d
Explanation: Double exception detected, invalid task state segment, stack segment overrun, processor extension segment overrun, are the protected mode exceptions.

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