Operating Systems Assignment 3: Buffering, Least Privilege Principle, Disk Scheduling Algorithms, and DMA

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College of Computing and Informatics
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Operating Systems
IT-241

Pg. 1 Question FourQuestion Four
Question One
1. What are the three reasons that buffering is performed?
The three purpose of buffering are:
 Synchronization of the speed between different devices: The difference of the
two devices may vary. In case of slow device, the processing of the data may
be slow (Silberschatz, Gagne and Galvin 2018). In case , when the buffer is
full, all the contents are transferred to the fast buffer. In this way two buffers
alternate for the transfer of the data. This is known as double buffering.
 Difference in the data transfer size: The size of data to be transferred may be
different. In this case the use of buffer in done in a networking system for the
breaking of the messages into smaller packets (Silberschatz, Gagne and Galvin
2018). After the receiving of the data, the fragmented messages are
reassembled.
 Supporting for copying semantics: In case, if the non blocking interface
executes the return instructions, the content of the buffer is needed to be copied
to another location, so that the content of the application can be modified after
the execution of return function.
Learning
Outcome(s):
Describe the OS
mechanism for
process
management,
timing, memory,
I/O, file and
concurrency
management.
1.5Mark

Pg. 2 Question FourQuestion Four
Question Two
What is the least privilege principle? Why such a principle aid in the creation of
protection systems?
Least privilege layer is defined as the creation of the abstract layer in a
computing environment. In this situation a user or a process can only access the
information which are necessary and have legitimate purposes for the access. This
provides the concept of user account (Dautenhahn et al. 2015). The access through the
user account will control the access on the content of the system by the users.
The least privilege principal provides the advantage controlling the access and
abstraction of data. This helps to protect sensitive information and data from the users.
In this case, the user can access the necessary part for the uses through user account.
On the other hand, admin can control the whole system through the admin access.
This protects information inform of access control.
Learning
Outcome(s):
Describe the OS
mechanism for
process
management,
timing, memory,
I/O, file and
concurrency
management.
1.5 Mark