CSE 330 STUDY GUIDE QUESTIONS WITH
ANSWERS AND EXPLANATIONS
1. Which explanation best fits this study case: an OS designer moves file-system and driver
services
into protected user processes while leaving only essential IPC, scheduling, and low-level
mechanisms
privileged. What design goal is being pursued?
A. A larger monolithic kernel
B. A microkernel-style reduction of privileged code
C. Elimination of interprocess communication
D. A single-address-space application model
Correct Answer: B. A microkernel-style reduction of privileged code
Explanation: Microkernels reduce trusted kernel code and use IPC to communicate with
user-space services.
2. Consider the following conceptual trace: the OS swaps out an anonymous memory page.
Where is its
data typically preserved for later fault-in?
A. Only in the CPU registers
B. Inside the TLB
C. Backing storage such as swap space
D. In the bootloader
Correct Answer: C. Backing storage such as swap space
Explanation: Anonymous pages have no file source, so modified contents need backing storage
such as swap if evicted.
3. To distinguish two operating-system mechanisms, suppose a process's parent exits first, but
the
child keeps running. What is the child commonly called?
A. A zombie process
B. An orphan process
C. A deadlocked thread
D. A page-table walker
Correct Answer: B. An orphan process
Explanation: An orphan is still alive after its original parent terminates and is typically
reparented by the system.
4. For a study-guide comparison, a process submits a large device transfer and the CPU should
not
copy every byte itself. Which hardware-assisted mechanism best fits?
A. Busy waiting on every byte
B. Direct Memory Access (DMA)
C. A symbolic link
D. A context-free grammar
Correct Answer: B. Direct Memory Access (DMA)
Explanation: DMA lets a device/controller transfer data between device and memory with limited
CPU intervention, usually
interrupting on completion.
,5. Consider the following conceptual trace: three processes arrive together with bursts [6, 9, 4]
and
Round Robin uses quantum 4. What is the average waiting time?
A. 6.33 time units
B. 10.00 time units
C. 8.67 time units
D. 12.67 time units
Correct Answer: C. 8.67 time units
Explanation: Simulating Round Robin gives waiting times [8, 10, 8], so the average is 8.67.
6. A concept-check scenario states that a completed child still has an exit status that its parent
has not
collected. How is that child commonly described?
A. A zombie process
B. An orphan that is still running
C. A ready thread
D. A daemonized kernel task
Correct Answer: A. A zombie process
Explanation: A zombie has finished execution but retains minimal process-table information until
the parent reaps it.
7. Consider the following conceptual trace: the OS designer separates the rule for choosing
which
process should run from the low-level code that performs a context switch. What classic design
principle is illustrated?
A. Copy-on-write
B. Demand paging
C. Separation of policy from mechanism
D. Capability revocation
Correct Answer: C. Separation of policy from mechanism
Explanation: Policy decides what choice to make, while mechanism supplies the machinery for
enforcing that choice.
8. Consider the following conceptual trace: a kernel keeps drivers, file-system code, networking,
and
scheduling in one privileged address space. Which architectural description is most accurate?
A. A monolithic-kernel organization
B. A pure microkernel with all services outside the kernel
C. A user-level threading library
D. A type-1 hypervisor with no host kernel
Correct Answer: A. A monolithic-kernel organization
Explanation: Monolithic kernels place many core services in the shared privileged kernel address
space.
, 9. To distinguish two operating-system mechanisms, suppose 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. Shared memory
B. Repeated signals carrying whole buffers
C. A reboot-time configuration file
D. A timer interrupt per byte
Correct Answer: A. Shared memory
Explanation: Shared memory avoids repeated kernel copying for each message, though the
processes must synchronize
access.
10. To distinguish two operating-system mechanisms, suppose 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.
11. Consider the following conceptual trace: several containers share one host kernel but have
isolated
process, mount, and network views. What distinguishes this from full hardware virtualization?
A. Each container requires its own guest kernel and emulated hardware
B. Containers cannot limit CPU or memory
C. Containers bypass the kernel entirely
D. Containers isolate namespaces/resources while sharing the host kernel
Correct Answer: D. Containers isolate namespaces/resources while sharing the host kernel
Explanation: OS-level containers virtualize user-space environments using namespaces/cgroups
rather than running
separate guest kernels.
12. Consider the following conceptual trace: a device driver repeatedly reads a status register
until a
device becomes ready. What I/O technique is being used?
A. Interrupt-driven I/O
B. Memory ballooning
C. Polling/busy waiting
D. Journaling
Correct Answer: C. Polling/busy waiting
Explanation: Polling repeatedly checks device status and can waste CPU cycles when waits are
long.
ANSWERS AND EXPLANATIONS
1. Which explanation best fits this study case: an OS designer moves file-system and driver
services
into protected user processes while leaving only essential IPC, scheduling, and low-level
mechanisms
privileged. What design goal is being pursued?
A. A larger monolithic kernel
B. A microkernel-style reduction of privileged code
C. Elimination of interprocess communication
D. A single-address-space application model
Correct Answer: B. A microkernel-style reduction of privileged code
Explanation: Microkernels reduce trusted kernel code and use IPC to communicate with
user-space services.
2. Consider the following conceptual trace: the OS swaps out an anonymous memory page.
Where is its
data typically preserved for later fault-in?
A. Only in the CPU registers
B. Inside the TLB
C. Backing storage such as swap space
D. In the bootloader
Correct Answer: C. Backing storage such as swap space
Explanation: Anonymous pages have no file source, so modified contents need backing storage
such as swap if evicted.
3. To distinguish two operating-system mechanisms, suppose a process's parent exits first, but
the
child keeps running. What is the child commonly called?
A. A zombie process
B. An orphan process
C. A deadlocked thread
D. A page-table walker
Correct Answer: B. An orphan process
Explanation: An orphan is still alive after its original parent terminates and is typically
reparented by the system.
4. For a study-guide comparison, a process submits a large device transfer and the CPU should
not
copy every byte itself. Which hardware-assisted mechanism best fits?
A. Busy waiting on every byte
B. Direct Memory Access (DMA)
C. A symbolic link
D. A context-free grammar
Correct Answer: B. Direct Memory Access (DMA)
Explanation: DMA lets a device/controller transfer data between device and memory with limited
CPU intervention, usually
interrupting on completion.
,5. Consider the following conceptual trace: three processes arrive together with bursts [6, 9, 4]
and
Round Robin uses quantum 4. What is the average waiting time?
A. 6.33 time units
B. 10.00 time units
C. 8.67 time units
D. 12.67 time units
Correct Answer: C. 8.67 time units
Explanation: Simulating Round Robin gives waiting times [8, 10, 8], so the average is 8.67.
6. A concept-check scenario states that a completed child still has an exit status that its parent
has not
collected. How is that child commonly described?
A. A zombie process
B. An orphan that is still running
C. A ready thread
D. A daemonized kernel task
Correct Answer: A. A zombie process
Explanation: A zombie has finished execution but retains minimal process-table information until
the parent reaps it.
7. Consider the following conceptual trace: the OS designer separates the rule for choosing
which
process should run from the low-level code that performs a context switch. What classic design
principle is illustrated?
A. Copy-on-write
B. Demand paging
C. Separation of policy from mechanism
D. Capability revocation
Correct Answer: C. Separation of policy from mechanism
Explanation: Policy decides what choice to make, while mechanism supplies the machinery for
enforcing that choice.
8. Consider the following conceptual trace: a kernel keeps drivers, file-system code, networking,
and
scheduling in one privileged address space. Which architectural description is most accurate?
A. A monolithic-kernel organization
B. A pure microkernel with all services outside the kernel
C. A user-level threading library
D. A type-1 hypervisor with no host kernel
Correct Answer: A. A monolithic-kernel organization
Explanation: Monolithic kernels place many core services in the shared privileged kernel address
space.
, 9. To distinguish two operating-system mechanisms, suppose 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. Shared memory
B. Repeated signals carrying whole buffers
C. A reboot-time configuration file
D. A timer interrupt per byte
Correct Answer: A. Shared memory
Explanation: Shared memory avoids repeated kernel copying for each message, though the
processes must synchronize
access.
10. To distinguish two operating-system mechanisms, suppose 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.
11. Consider the following conceptual trace: several containers share one host kernel but have
isolated
process, mount, and network views. What distinguishes this from full hardware virtualization?
A. Each container requires its own guest kernel and emulated hardware
B. Containers cannot limit CPU or memory
C. Containers bypass the kernel entirely
D. Containers isolate namespaces/resources while sharing the host kernel
Correct Answer: D. Containers isolate namespaces/resources while sharing the host kernel
Explanation: OS-level containers virtualize user-space environments using namespaces/cgroups
rather than running
separate guest kernels.
12. Consider the following conceptual trace: a device driver repeatedly reads a status register
until a
device becomes ready. What I/O technique is being used?
A. Interrupt-driven I/O
B. Memory ballooning
C. Polling/busy waiting
D. Journaling
Correct Answer: C. Polling/busy waiting
Explanation: Polling repeatedly checks device status and can waste CPU cycles when waits are
long.
