OPERATING SYSTEMS FINAL EXAM
QUESTIONS WITH DETAILED VERIFIED
ANSWERS / ALREADY GRADED A / 2025
The Dining Philosopher's Problem is a standard test case for evaluating approaches to implementing: -
ANS-Synchronization
The type of memory that allows for very effective
multiprogramming and relieves the user of
memory size constraints is referred to as: - ANS-Virtual memory
______, which is transparent to
the programmer, eliminates external
fragmentation, provides efficient use of
main memory, and has pieces of fixed,
equal size. - ANS-Paging
______________, which is visible to the
programmer, has the ability to handle
growing data structures, modularity, and
support for sharing and protection. - ANS-Segmentation
Each entry in a _______________
contains control bits and the
corresponding frame number if the page is
resident in memory. - ANS-Page Table
In a segmentation system, each entry in a
______________ contains control bits and
the starting address and the length of the
segment. - ANS-segment table
The aim of processor scheduling is ..... - ANS-to assign processes to be executed by the processor over
time
, T / F - A file is a collection of fields, which is in turn a collection of related records. - ANS-False, opposite
records/fields
T / F - At the lowest level of the file system architecture, device drivers communicate directly with
peripheral devices or their controllers or channels. - ANS-True
The level of the file system architecture that provides a standard interface between applications and the
file systems and devices is often termed the _____________________. - ANS-Access Method
Record access in a pile file can be conducted by: - ANS-A. Exhaustive search
Sequential files are optimal in scenarios involving: - ANS-B. Applications that require the processing of all
records in the file
Indexed sequential files similar to sequential files, but contain two added features: - ANS-C. File index
and overflow file
Why use a multiprocessor? - ANS-To support multiprogramming. Large numbers of independent
processes. To support parallel programming
Job consists of multiple threads and/or processes. Cooperating/communicating threads/processes. Not
independent!
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - Same challenges as
uniprocessor scheduling: - ANS-Fairness, efficiency, throughput, response time...
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - But also new challenges: -
ANS-Ready queue implementation
Load balancing
Processor affinity
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - Disadvantages of Master/
Salve - ANS-Failure of master brings down whole system. Master can become a performance bottleneck.
The scheduling function should perform what five tasks: - ANS-1. Share time fairly among processes
2. Prevent starvation of a process
3. Use the processor efficiently
4. Have low overhead
5. Prioritise processes when necessary (e.g. real
time deadlines)
Long-term scheduling is performed when a new process is created. - ANS-• This is a decision whether to
add a new process to the set of processes that are currently active. (its stages include New & Exit)
Medium-term scheduling is a part of the swapping function. - ANS-• This is a decision whether to add a
process to those that are at least partially in main memory and therefore available for execution. (its
stages include Blocked Suspend & Ready Suspend)
QUESTIONS WITH DETAILED VERIFIED
ANSWERS / ALREADY GRADED A / 2025
The Dining Philosopher's Problem is a standard test case for evaluating approaches to implementing: -
ANS-Synchronization
The type of memory that allows for very effective
multiprogramming and relieves the user of
memory size constraints is referred to as: - ANS-Virtual memory
______, which is transparent to
the programmer, eliminates external
fragmentation, provides efficient use of
main memory, and has pieces of fixed,
equal size. - ANS-Paging
______________, which is visible to the
programmer, has the ability to handle
growing data structures, modularity, and
support for sharing and protection. - ANS-Segmentation
Each entry in a _______________
contains control bits and the
corresponding frame number if the page is
resident in memory. - ANS-Page Table
In a segmentation system, each entry in a
______________ contains control bits and
the starting address and the length of the
segment. - ANS-segment table
The aim of processor scheduling is ..... - ANS-to assign processes to be executed by the processor over
time
, T / F - A file is a collection of fields, which is in turn a collection of related records. - ANS-False, opposite
records/fields
T / F - At the lowest level of the file system architecture, device drivers communicate directly with
peripheral devices or their controllers or channels. - ANS-True
The level of the file system architecture that provides a standard interface between applications and the
file systems and devices is often termed the _____________________. - ANS-Access Method
Record access in a pile file can be conducted by: - ANS-A. Exhaustive search
Sequential files are optimal in scenarios involving: - ANS-B. Applications that require the processing of all
records in the file
Indexed sequential files similar to sequential files, but contain two added features: - ANS-C. File index
and overflow file
Why use a multiprocessor? - ANS-To support multiprogramming. Large numbers of independent
processes. To support parallel programming
Job consists of multiple threads and/or processes. Cooperating/communicating threads/processes. Not
independent!
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - Same challenges as
uniprocessor scheduling: - ANS-Fairness, efficiency, throughput, response time...
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - But also new challenges: -
ANS-Ready queue implementation
Load balancing
Processor affinity
Given a set of runnable threads, and a set of CPUs, assign threads to CPUs - Disadvantages of Master/
Salve - ANS-Failure of master brings down whole system. Master can become a performance bottleneck.
The scheduling function should perform what five tasks: - ANS-1. Share time fairly among processes
2. Prevent starvation of a process
3. Use the processor efficiently
4. Have low overhead
5. Prioritise processes when necessary (e.g. real
time deadlines)
Long-term scheduling is performed when a new process is created. - ANS-• This is a decision whether to
add a new process to the set of processes that are currently active. (its stages include New & Exit)
Medium-term scheduling is a part of the swapping function. - ANS-• This is a decision whether to add a
process to those that are at least partially in main memory and therefore available for execution. (its
stages include Blocked Suspend & Ready Suspend)
