Access Rights Revocation - Operating System Questions & Answers

1.

Why is it difficult to revoke capabilities ?

   A.) They are too many
   B.) They are not defined precicely
   C.) They are distributed throughout the system
   D.) None of the mentioned

Answer: Option 'C'

​They are distributed throughout the system

2.

What is incorrect methods of revocation of access rights ?

   A.) Immediate/Delayed
   B.) Selective/General
   C.) Partial/total
   D.) Crucial

Answer: Option 'D'

Crucial

3.

What is the reacquisition scheme to revoke capability ?

   A.) When a process capability is revoked then it won’t be able to reacquire it
   B.) Pointers are maintained for each object which can be used to revoke
   C.) Indirect pointing is done to revoke object’s capabilities
   D.) Master key can be used compare and revoke.

Answer: Option 'A'

When a process capability is revoked then it won’t be able to reacquire it

4.

What is false regarding Back-Pointers scheme to revoke capability ?

   A.) List of pointers is maintained with each object
   B.) When revocation is required these pointers are followed
   C.) This scheme is not adopted in MULTICS system
   D.) These point to all capabilities associated with that object

Answer: Option 'C'

This scheme is not adopted in MULTICS system

5.

What is true about Indirection to revoke capability ?

   A.) Capabilities point indirectly to the objects
   B.) Each capability will not have a unique entry in global
   C.) Table entries cannot be reused for other capabilities
   D.) This system was adopted in MULTICS system

Answer: Option 'A'

​Capabilities point indirectly to the objects

6.

What are two capabilities defined in CAP system ?

   A.) data & software capability
   B.) address & data capability
   C.) hardware & software capability
   D.) software capability

Answer: Option 'A'

​data & software capability

7.

What are characteristics of Cambridge CAP system as compared to Hydra system ?

   A.) It is simpler and less powerful than hydra system
   B.) It is more powerful than hydra system
   C.) It is powerful than hydra system
   D.) It is not as secure as Hydra system

Answer: Option 'A'

​It is simpler and less powerful than hydra system

8.

How can Keys be defined or replaced ?

   A.) create [keyname] [bits].
   B.) set-key
   C.) Key
   D.) MAKE [Key Name].

Answer: Option 'B'

​set-key

9.

What are characteristics of Hydra system ?

   A.) It consist of known access rights and interpreted by the system
   B.) A user can of protection system can declare other rights
   C.) Hydra system is not flexible
   D.) Hydra doesn’t provide rights amplification

Answer: Option 'A'

It consist of known access rights and interpreted by the system

10.

What are characteristics of rights amplification in Hydra ?

   A.) This scheme allows a procedure to be certified as trustworthy
   B.) Amplification of rights cannot be stated explicitly in declaration
   C.) It includes kernel rights such as read
   D.) All of the mentioned

Answer: Option 'A'

​This scheme allows a procedure to be certified as trustworthy

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