CSE 330 PRACTICE EXAM QUESTIONS WITH
ANSWERS AND EXPLANATIONS
1. During a realistic systems workload, a completed child still has an exit status that its parent
has not
collected. How is that child commonly described?
A. An orphan that is still running
B. A zombie process
C. A ready thread
D. A daemonized kernel task
Correct Answer: B. A zombie process
Explanation: A zombie has finished execution but retains minimal process-table information until
the parent reaps it.
2. A timed practice-exam scenario reports that an HDD head starts at cylinder 60; pending
requests are
[118, 155, 150, 175]. If SSTF always chooses the nearest remaining request, what total head
movement
results?
A. 125 cylinders
B. 140 cylinders
C. 115 cylinders
D. 105 cylinders
Correct Answer: C. 115 cylinders
Explanation: Selecting the nearest request at each step produces a total of 115 cylinders of head
movement.
3. During a realistic systems workload, two pathnames in the same file system refer to the same
inode-like file object. Which feature is this?
A. Hard linking
B. Copy-on-write paging
C. A symbolic link that necessarily stores the target path
D. Memory ballooning
Correct Answer: A. Hard linking
Explanation: Hard links are multiple directory entries for the same underlying file object and
data.
4. During a realistic systems workload, a concurrent stack operation appears to take effect
instantaneously at one point between invocation and response. Which correctness criterion is
being
described?
A. Sequential disk allocation
B. Page coloring
C. Linearizability
D. Earliest-deadline scheduling
Correct Answer: C. Linearizability
Explanation: Linearizability requires concurrent operations to appear as if they occurred
atomically in an order consistent
with real time.
,5. A kernel trace shows that two related processes need a low-overhead communication channel
on the
same host and can coordinate explicit synchronization. Which mechanism is typically fastest for
bulk
data after setup?
A. Repeated signals carrying whole buffers
B. Shared memory
C. A reboot-time configuration file
D. A timer interrupt per byte
Correct Answer: B. Shared memory
Explanation: Shared memory avoids repeated kernel copying for each message, though the
processes must synchronize
access.
6. A kernel trace shows that a short job arrives while a long job is running, and the policy can
immediately preempt the long job when the new job has the least remaining work. Which policy
is this?
A. Nonpreemptive FCFS
B. Static Round Robin with no priorities
C. C-SCAN disk scheduling
D. Shortest Remaining Time First
Correct Answer: D. Shortest Remaining Time First
Explanation: SRTF is the preemptive counterpart of shortest-job-first and always favors the least
remaining CPU time.
7. A timed practice-exam scenario reports that a database service needs to request a privileged
kernel
service without being allowed to execute arbitrary kernel instructions. Which mechanism
provides the
intended controlled entry path?
A. A normal function call that stays entirely in user mode
B. A cache-line fill
C. A bootloader handoff
D. A system call
Correct Answer: D. A system call
Explanation: System calls define controlled transitions from user mode into kernel services with
argument validation and
privilege checks.
8. During a realistic systems workload, a guest driver allocates pages so the hypervisor can
reclaim the
host frames backing them. What memory-management technique is this?
A. Journaling
B. TLB shootdown
C. Ballooning
D. Write-through caching
Correct Answer: C. Ballooning
Explanation: Balloon drivers help the hypervisor reclaim memory cooperatively from a guest.
, 9. A production-style incident reveals that three ready processes arrive together for FCFS
scheduling
with CPU bursts [3, 9, 2]. What is their average waiting time?
A. 4.67 time units
B. 5.00 time units
C. 9.00 time units
D. 7.00 time units
Correct Answer: B. 5.00 time units
Explanation: Under FCFS the waits are [0, 3, 12]; their average is 5.00.
10. During a realistic systems workload, FIFO page replacement has 3 frames and sees reference
string
[1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5]. Starting empty, how many page faults result?
A. 9 page faults
B. 8 page faults
C. 11 page faults
D. 3 page faults
Correct Answer: A. 9 page faults
Explanation: A FIFO simulation replaces the oldest loaded page on each miss after the frames fill,
producing 9 faults.
11. During an operating-system simulation, a kernel keeps drivers, file-system code, networking,
and
scheduling in one privileged address space. Which architectural description is most accurate?
A. A pure microkernel with all services outside the kernel
B. A monolithic-kernel organization
C. A user-level threading library
D. A type-1 hypervisor with no host kernel
Correct Answer: B. A monolithic-kernel organization
Explanation: Monolithic kernels place many core services in the shared privileged kernel address
space.
12. A kernel trace shows that a low-priority thread holds a mutex needed by a high-priority
thread, while
medium-priority threads keep preempting the holder. What scheduling pathology is this?
A. Starvation caused by FIFO queues only
B. Priority inversion
C. A page fault storm
D. A journal replay
Correct Answer: B. Priority inversion
Explanation: Priority inversion occurs when a high-priority task waits indirectly behind
lower-priority work because of lock
ownership.
13. During an operating-system simulation, an HDD head begins at cylinder 89 and FCFS serves
requests [159, 58, 129, 167] in that order. Ignoring rotational latency, what total head movement
occurs?
A. 280 cylinders
B. 140 cylinders
C. 300 cylinders
D. 265 cylinders
Correct Answer: A. 280 cylinders
Explanation: Adding the absolute movement between each successive FCFS position gives 280
cylinders.
ANSWERS AND EXPLANATIONS
1. During a realistic systems workload, a completed child still has an exit status that its parent
has not
collected. How is that child commonly described?
A. An orphan that is still running
B. A zombie process
C. A ready thread
D. A daemonized kernel task
Correct Answer: B. A zombie process
Explanation: A zombie has finished execution but retains minimal process-table information until
the parent reaps it.
2. A timed practice-exam scenario reports that an HDD head starts at cylinder 60; pending
requests are
[118, 155, 150, 175]. If SSTF always chooses the nearest remaining request, what total head
movement
results?
A. 125 cylinders
B. 140 cylinders
C. 115 cylinders
D. 105 cylinders
Correct Answer: C. 115 cylinders
Explanation: Selecting the nearest request at each step produces a total of 115 cylinders of head
movement.
3. During a realistic systems workload, two pathnames in the same file system refer to the same
inode-like file object. Which feature is this?
A. Hard linking
B. Copy-on-write paging
C. A symbolic link that necessarily stores the target path
D. Memory ballooning
Correct Answer: A. Hard linking
Explanation: Hard links are multiple directory entries for the same underlying file object and
data.
4. During a realistic systems workload, a concurrent stack operation appears to take effect
instantaneously at one point between invocation and response. Which correctness criterion is
being
described?
A. Sequential disk allocation
B. Page coloring
C. Linearizability
D. Earliest-deadline scheduling
Correct Answer: C. Linearizability
Explanation: Linearizability requires concurrent operations to appear as if they occurred
atomically in an order consistent
with real time.
,5. A kernel trace shows that two related processes need a low-overhead communication channel
on the
same host and can coordinate explicit synchronization. Which mechanism is typically fastest for
bulk
data after setup?
A. Repeated signals carrying whole buffers
B. Shared memory
C. A reboot-time configuration file
D. A timer interrupt per byte
Correct Answer: B. Shared memory
Explanation: Shared memory avoids repeated kernel copying for each message, though the
processes must synchronize
access.
6. A kernel trace shows that a short job arrives while a long job is running, and the policy can
immediately preempt the long job when the new job has the least remaining work. Which policy
is this?
A. Nonpreemptive FCFS
B. Static Round Robin with no priorities
C. C-SCAN disk scheduling
D. Shortest Remaining Time First
Correct Answer: D. Shortest Remaining Time First
Explanation: SRTF is the preemptive counterpart of shortest-job-first and always favors the least
remaining CPU time.
7. A timed practice-exam scenario reports that a database service needs to request a privileged
kernel
service without being allowed to execute arbitrary kernel instructions. Which mechanism
provides the
intended controlled entry path?
A. A normal function call that stays entirely in user mode
B. A cache-line fill
C. A bootloader handoff
D. A system call
Correct Answer: D. A system call
Explanation: System calls define controlled transitions from user mode into kernel services with
argument validation and
privilege checks.
8. During a realistic systems workload, a guest driver allocates pages so the hypervisor can
reclaim the
host frames backing them. What memory-management technique is this?
A. Journaling
B. TLB shootdown
C. Ballooning
D. Write-through caching
Correct Answer: C. Ballooning
Explanation: Balloon drivers help the hypervisor reclaim memory cooperatively from a guest.
, 9. A production-style incident reveals that three ready processes arrive together for FCFS
scheduling
with CPU bursts [3, 9, 2]. What is their average waiting time?
A. 4.67 time units
B. 5.00 time units
C. 9.00 time units
D. 7.00 time units
Correct Answer: B. 5.00 time units
Explanation: Under FCFS the waits are [0, 3, 12]; their average is 5.00.
10. During a realistic systems workload, FIFO page replacement has 3 frames and sees reference
string
[1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5]. Starting empty, how many page faults result?
A. 9 page faults
B. 8 page faults
C. 11 page faults
D. 3 page faults
Correct Answer: A. 9 page faults
Explanation: A FIFO simulation replaces the oldest loaded page on each miss after the frames fill,
producing 9 faults.
11. During an operating-system simulation, a kernel keeps drivers, file-system code, networking,
and
scheduling in one privileged address space. Which architectural description is most accurate?
A. A pure microkernel with all services outside the kernel
B. A monolithic-kernel organization
C. A user-level threading library
D. A type-1 hypervisor with no host kernel
Correct Answer: B. A monolithic-kernel organization
Explanation: Monolithic kernels place many core services in the shared privileged kernel address
space.
12. A kernel trace shows that a low-priority thread holds a mutex needed by a high-priority
thread, while
medium-priority threads keep preempting the holder. What scheduling pathology is this?
A. Starvation caused by FIFO queues only
B. Priority inversion
C. A page fault storm
D. A journal replay
Correct Answer: B. Priority inversion
Explanation: Priority inversion occurs when a high-priority task waits indirectly behind
lower-priority work because of lock
ownership.
13. During an operating-system simulation, an HDD head begins at cylinder 89 and FCFS serves
requests [159, 58, 129, 167] in that order. Ignoring rotational latency, what total head movement
occurs?
A. 280 cylinders
B. 140 cylinders
C. 300 cylinders
D. 265 cylinders
Correct Answer: A. 280 cylinders
Explanation: Adding the absolute movement between each successive FCFS position gives 280
cylinders.
