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Assignment 6 CPSC3125 Operating System Spring, 2016 Coverage:-(Answered)


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only need answers? for 1,5-8. thank you.? Question are located in the attachment below.

Assignment 6


CPSC3125 Operating System Spring, 2016


Coverage: Chapter 9 Security; Chapter 10: Unix and Linux


(10 Points for each question)


Chapter 9: Security


1. Confidentiality, integrity, and availability are three components of security.


Describe an application that integrity and availability but not confidentiality, an


application that requires confidentiality and integrity but not (high) availability, and


an application that requires confidentiality, integrity, and availability.





2. One of the techniques to build a secure operating system is to minimize the size of


TCB. Which of the following functions needs to be implemented inside the TCB and


which can be implemented outside TCB? (a) Process context switch; (b) Read a file


from disk; (c) Add more swapping space; (d) Listen to music; (e) Get the GPS


coordinates of a smartphone.




3. What is a covert channel? What is the basic requirement for a covert channel to






4. Explain which implementation of the protection matrix is more suitable for the


following operations:


(a) Granting read access to a file for all users.


(b) Revoking write access to a file from all users.


(c) Granting write access to a file to John, Lisa, Christie, and Jeff.


(d) Revoking execute access to a file from Jana, Mike, Molly, and Shane





5. Two different protection mechanisms that we have discussed are capabilities and


access- control lists. For each of the following protection problems, tell which of


these mechanisms can be used.


(a) Ken wants his files readable by everyone except his office mate.


(b) Mitch and Steve want to share some secret files.


(c) Linda wants some of her files to be public.




Chapter 10: Unix and Linux


6. Explain how writing UNIX in C made it easier to port it to new machines.





7. The POSIX interface defines a set of library procedures. Explain why POSIX


standardizes library procedures instead of the system-call interface.




8. What does the following Linux shell pipeline do?


grep nd xyz | wc ?l





9. Write a Linux pipeline that prints the eighth line of file z on



standard output.







When the Linux shell starts up a process, it puts copies of


its environment variables, such as HOME, on the process? stack, so


the process can find out what its home directory is. If this process


should later fork, will the child automatically get these variables,








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