WGU D686 OBJECTIVE ASSESSMENT 2 NEWEST 2026
ACTUAL EXAM| D686 OPERATING SYSTEMS FOR
COMPUTER SCIENTISTS OA FINAL EXAM WITH 300
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED A+ (MOST RECENT!!)
1. What are the four main goals of an operating system?
A) Speed, graphics, security, cost
B) Execute user programs, convenience, efficiency,
security/stability
C) Multitasking, memory protection, user interface, file naming
D) Interrupt handling, caching, spooling, virtualization
Answer: B
Rationale: The OS acts as a resource allocator and control
program. Its goals are to execute user programs, make the system
convenient, use hardware efficiently, and ensure stability/security .
2. A process is currently being executed by the CPU. Which
state is it in?
A) New
B) Ready
C) Running
D) Waiting
1
,Answer: C
Rationale: The "Running" state means the process instructions are
currently being processed by the CPU core .
3. A process is waiting for an I/O operation (e.g., a disk read)
to complete. Which state does it enter?
A) Running
B) Ready
C) Terminated
D) Waiting
Answer: D
Rationale: While waiting for a resource like I/O or a lock, the
process is moved to the "Waiting" (or Blocked) state and removed
from the CPU.
4. In a von Neumann architecture, what happens during the
instruction-execution cycle?
A) The CPU only writes data to memory
B) The CPU fetches an instruction from memory and stores it in the
instruction register
C) The OS schedules the next process
D) The MMU translates the address
Answer: B
2
,Rationale: The cycle consists of fetching an instruction from memory
(using the Program Counter) and storing it in the Instruction
Register for decoding/execution .
5. Which component is NOT part of a process's execution state
(context)?
A) Program Counter
B) Stack
C) Hard Disk Drive location
D) Register contents
Answer: C
Rationale: The execution state includes CPU registers, program
counter, stack, and heap. Storage location on HDD is part of the
process image on disk, not the active CPU context .
6. The Program Counter (PC) specifically holds:
A) The value of the current calculation
B) The address of the next instruction to be executed
C) The total number of processes
D) The result of the last comparison
Answer: B
Rationale: The PC is a CPU register that always points to the
memory address of the next instruction to be fetched .
3
, 7. Which scheduling algorithm suffers from the "convoy
effect," where short processes get stuck behind a long one?
A) Round-Robin
B) Shortest Job First (SJF)
C) First-Come, First-Served (FCFS)
D) Multilevel Queue
Answer: C
Rationale: FCFS is non-preemptive. If a long CPU-bound process
starts first, all shorter I/O-bound processes must wait, leading to
low device utilization.
8. In Round-Robin scheduling, how is the ready queue
treated?
A) As a stack (LIFO)
B) As a circular queue
C) As a priority heap
D) As a binary tree
Answer: B
Rationale: Round-Robin uses a time quantum. The ready queue is a
circular FIFO queue; each process gets the CPU for one quantum,
then moves to the back .
4
ACTUAL EXAM| D686 OPERATING SYSTEMS FOR
COMPUTER SCIENTISTS OA FINAL EXAM WITH 300
REAL EXAM QUESTIONS AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED A+ (MOST RECENT!!)
1. What are the four main goals of an operating system?
A) Speed, graphics, security, cost
B) Execute user programs, convenience, efficiency,
security/stability
C) Multitasking, memory protection, user interface, file naming
D) Interrupt handling, caching, spooling, virtualization
Answer: B
Rationale: The OS acts as a resource allocator and control
program. Its goals are to execute user programs, make the system
convenient, use hardware efficiently, and ensure stability/security .
2. A process is currently being executed by the CPU. Which
state is it in?
A) New
B) Ready
C) Running
D) Waiting
1
,Answer: C
Rationale: The "Running" state means the process instructions are
currently being processed by the CPU core .
3. A process is waiting for an I/O operation (e.g., a disk read)
to complete. Which state does it enter?
A) Running
B) Ready
C) Terminated
D) Waiting
Answer: D
Rationale: While waiting for a resource like I/O or a lock, the
process is moved to the "Waiting" (or Blocked) state and removed
from the CPU.
4. In a von Neumann architecture, what happens during the
instruction-execution cycle?
A) The CPU only writes data to memory
B) The CPU fetches an instruction from memory and stores it in the
instruction register
C) The OS schedules the next process
D) The MMU translates the address
Answer: B
2
,Rationale: The cycle consists of fetching an instruction from memory
(using the Program Counter) and storing it in the Instruction
Register for decoding/execution .
5. Which component is NOT part of a process's execution state
(context)?
A) Program Counter
B) Stack
C) Hard Disk Drive location
D) Register contents
Answer: C
Rationale: The execution state includes CPU registers, program
counter, stack, and heap. Storage location on HDD is part of the
process image on disk, not the active CPU context .
6. The Program Counter (PC) specifically holds:
A) The value of the current calculation
B) The address of the next instruction to be executed
C) The total number of processes
D) The result of the last comparison
Answer: B
Rationale: The PC is a CPU register that always points to the
memory address of the next instruction to be fetched .
3
, 7. Which scheduling algorithm suffers from the "convoy
effect," where short processes get stuck behind a long one?
A) Round-Robin
B) Shortest Job First (SJF)
C) First-Come, First-Served (FCFS)
D) Multilevel Queue
Answer: C
Rationale: FCFS is non-preemptive. If a long CPU-bound process
starts first, all shorter I/O-bound processes must wait, leading to
low device utilization.
8. In Round-Robin scheduling, how is the ready queue
treated?
A) As a stack (LIFO)
B) As a circular queue
C) As a priority heap
D) As a binary tree
Answer: B
Rationale: Round-Robin uses a time quantum. The ready queue is a
circular FIFO queue; each process gets the CPU for one quantum,
then moves to the back .
4
