Download Windows on ARM (WoA) Developer Practice Exam Questions and more Exams Technology in PDF only on Docsity!
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Question 1. Which component primarily provides the power‑efficiency advantage of Windows on ARM devices? A) High‑performance GPU B) Qualcomm Snapdragon SoC C) Large SSD cache D) Dual‑core x86 processor Answer: B Explanation: Snapdragon SoCs integrate CPU, GPU, and modem on a low‑power ARM architecture, delivering superior energy efficiency for Windows on ARM. Question 2. What is the main architectural difference between ARMv7 and ARMv8‑A that impacts Windows development? A) Introduction of 32‑bit registers only B. Removal of NEON SIMD support C. Addition of AArch64 (64‑bit) execution state D. Support for x86 instruction set natively Answer: C Explanation: ARMv8‑A adds the AArch64 state, enabling 64‑bit addressing and registers, which Windows on ARM uses for native ARM64 binaries. Question 3. In the Windows on ARM stack, which subsystem is commonly referred to as “Prism”?
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A) Windows Subsystem for Linux B) WoA emulation layer handling x86/x64 translation C) DirectX graphics driver D) Power management service Answer: B Explanation: Prism is the internal name for the WoA emulation subsystem that translates x86 and x64 instructions to ARM64 at runtime. Question 4. Which of the following instruction sets is NOT fully supported by the WoA emulation layer for x86 applications? A) SSE B) AVX C) MMX D) NEON Answer: B Explanation: AVX instructions are not fully emulated on WoA; attempts to execute them typically result in illegal‑instruction faults or performance penalties. Question 5. What does DBT stand for in the context of Windows on ARM? A) Direct Binary Transfer B) Dynamic Binary Translation
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Answer: C Explanation: NEON is the Advanced SIMD extension built into ARM64 CPUs and is the recommended way to write vectorized code for Windows on ARM. Question 8. When mixing native ARM64 code with an x86 DLL in the same process, what is a primary risk? A. Increased SSD wear B. Stack overflow due to larger address space C. Incompatible calling conventions across the emulation boundary D. Loss of network connectivity Answer: C Explanation: Native ARM64 code and emulated x86 DLLs use different calling conventions; bridging them can cause crashes or data corruption. Question 9. Which tool provides remote debugging capabilities for a WoA device from Visual Studio? A) Windows Device Portal B) WinDbg Preview with remote target C) PowerShell Remoting D) Device Manager Answer: B
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Explanation: WinDbg Preview can attach to a remote ARM64 device, allowing developers to debug native and emulated code from Visual Studio. Question 10. Which Windows Performance Toolkit component is used to analyze power consumption on WoA devices? A) Windows Performance Recorder (WPR) B) Windows Update Manager C) Disk Cleanup D) Resource Monitor Answer: A Explanation: WPR can capture power and thermal events, which can later be examined in the Windows Performance Analyzer. Question 11. Which driver framework is recommended for writing user‑mode drivers on ARM64? A) WDM (Windows Driver Model) only B) UMDF (User‑Mode Driver Framework) C) Linux Kernel Modules D) DirectX Driver Interface Answer: B Explanation: UMDF is fully supported on ARM64 and simplifies driver development by running in user mode.
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Question 14. Which Windows API is guaranteed to be available for native ARM64 UWP applications? A) Direct3D 12 B) Win32 GDI C) WinRT CoreWindow D) MFC Answer: C Explanation: WinRT CoreWindow is part of the universal API set and is fully supported on ARM64 UWP apps. Question 15. Which of the following is NOT a valid reason to prefer native ARM64 over emulated x86 on WoA? A) Lower CPU usage B) Better battery life C) Access to ARM‑specific NEON intrinsics D) Ability to run 32‑bit Windows services unchanged Answer: D Explanation: Running unchanged 32‑bit Windows services requires emulation; native ARM64 cannot directly execute x86 services. Question 16. What does the “Connected Standby” feature rely on in WoA devices?
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A) Continuous high‑performance CPU cores B) Low‑power ARM cores that stay active while the device appears off C) Dedicated GPU standby mode D) Ethernet wake‑on‑LAN only Answer: B Explanation: Connected Standby uses a low‑power ARM core to keep network and background tasks alive while the main cores are powered down. Question 17. Which compiler flag enables aggressive inlining for ARM64 builds in Visual Studio? A) /O B) /Ob C) /GL D) /arch:AVX Answer: B Explanation: /Ob2 tells the compiler to aggressively inline functions, which can improve performance on ARM64 when used judiciously. Question 18. When profiling an emulated x86 application on WoA, which metric most directly reflects translation overhead? A) GPU utilization percentage B) Number of page faults
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Answer: B Explanation: InkCanvas is a WinRT control that processes stylus and touch input and works natively on ARM64 devices. Question 21. Which of the following best describes the role of the NTOSKRNL.EXE file on WoA? A) It contains only the user‑mode GUI subsystem B) It is the ARM64‑native Windows kernel handling low‑level OS services C) It is a compatibility shim for x86 applications only D) It is a BIOS firmware image Answer: B Explanation: NTOSKRNL.EXE is the core kernel binary compiled for ARM64 on WoA, providing scheduling, memory management, and driver support. Question 22. Which instruction set extension is used by ARM64 to accelerate cryptographic operations on WoA? A) AES‑NI (Intel) B) SHA‑2 extensions (ARMv8 Crypto) C) MMX D) Altivec Answer: B
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Explanation: ARMv8 includes Crypto extensions (AES, SHA‑1/2) that accelerate cryptographic workloads on Windows on ARM. Question 23. In the context of WoA, what does “hot code identification” refer to? A) Detecting code that causes the device to overheat B) Recognizing frequently executed blocks for caching in the DBT engine C) Marking code that requires a license check D) Identifying code that uses GPU shaders Answer: B Explanation: The DBT engine monitors execution frequency and caches “hot” translation blocks to improve emulation performance. Question 24. Which of the following is a recommended practice to reduce power consumption in a background WoA service? A) Busy‑wait on a spinlock for long periods B) Use ThreadPoolTimer with appropriate intervals C) Continuously poll hardware sensors at 1 kHz D) Disable all power‑saving policies in the manifest Answer: B Explanation: Using ThreadPoolTimer allows the service to sleep between executions, conserving CPU cycles and battery life.
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Question 27. Which Windows API call can be used to detect whether the current process is running under WoA emulation? A) IsWow64Process B) GetSystemMetrics(SM_TABLETPC) C) GetCurrentProcessorNumberEx D) GetDevicePowerState Answer: A Explanation: IsWow64Process2 returns information about the process architecture, indicating if it’s an x86/x64 process emulated on ARM64. Question 28. What is the primary purpose of the “/ALIGN” linker option when building ARM64 binaries for WoA? A) To enforce 64‑byte function alignment for better branch prediction B) To align the binary size to a multiple of 1 GB C) To set the memory page size to 4 KB D) To enable automatic GPU offload Answer: A Explanation: /ALIGN controls function and data alignment; on ARM64, aligning to cache‑line boundaries (e.g., 64 bytes) can improve instruction fetch efficiency. Question 29. Which of the following is a limitation when using DirectX 11 on Windows on ARM?
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A) No support for hardware‑accelerated rasterization B) Only software rasterizer (WARP) is available on many ARM devices C) Full support for all DX11 feature levels D) DirectX 11 cannot be used at all on ARM Answer: B Explanation: Many ARM‑based WoA devices lack a full‑featured GPU driver for DX11, falling back to the WARP software rasterizer. Question 30. Which Windows subsystem is responsible for translating Win API calls to WinRT on WoA? A) Win32 on ARM64 thunk layer B) POSIX subsystem C) Hyper‑V virtualization layer D) Windows Subsystem for Linux Answer: A Explanation: The Win32 on ARM64 thunk layer maps traditional Win32 calls to their WinRT equivalents, enabling legacy apps to run. Question 31. Which of the following is the correct way to declare a 128‑bit NEON vector in C++ for ARM64? A) __m128i v; B) float32x4_t v;
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Answer: A Explanation: The SupportedDeviceFamilies element lists families like “Windows.Desktop” and “Windows.ConnectedStandby” that the app targets. Question 34. Which tool can be used to capture a trace of Prism translation activity on a WoA device? A) xperf with the “Prism” provider enabled B) Process Explorer C) Disk Defragmenter D) Regedit Answer: A Explanation: xperf (part of the Windows Performance Toolkit) can enable the Prism ETW provider to record translation events. Question 35. Which of the following best describes “code density” in the context of ARM64 DBT? A) The number of lines of source code per binary megabyte B) The ratio of translated ARM64 instructions to original x86 instructions C) The amount of GPU shader code in a process D) The frequency of cache line fills Answer: B
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Explanation: Code density refers to how many ARM64 instructions are generated to represent a given block of x86 code; higher density can reduce translation overhead. Question 36. To improve the performance of a compute‑intensive loop on WoA, which compiler flag should be used in addition to /O2? A) /fp:fast B) /GL (Whole Program Optimization) C) /arch:ARM D) /favor:INTEL Answer: B Explanation: /GL enables whole‑program optimization, allowing the compiler to better inline and vectorize loops for ARM64. Question 37. Which of the following is a recommended way to detect whether a device is running in “Instant‑On” mode? A) Query the Power Framework (PoFx) for the ACPI _S0 state B) Call GetSystemPowerStatus and check the BatteryFlag C) Check the registry key HKLM\System\CurrentControlSet\Control\Power\InstantOn D) Use the SystemInformation.PowerStatus class in .NET Answer: A
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Question 40. Which of the following is a valid reason to use a “Hybrid” application architecture on WoA? A) To avoid any emulation overhead completely B) To reuse existing legacy x86 libraries while adding new ARM64 modules C) To guarantee that the app will run on all Windows desktops without changes D) To enable direct GPU access without drivers Answer: B Explanation: Hybrid apps combine native ARM64 code with existing x86 libraries, allowing developers to leverage legacy components while still benefiting from native performance where possible. Question 41. Which ETW provider GUID is associated with Prism translation events? A) {9e814aad-9d7c-4c3d-9f3b-4c4c2c5bb0c9} B) {e0c9e9c5-3d5e-4e6a-8b41-8b2c5c1e1e33} C) {4c7bba31-0e7b-4e13-9c8d-5c0c4b6c5c5c} D) {a0e5e5a0-2c5c-4a5e-9f5c-1c2c3d4e5f6a} Answer: B Explanation: The Prism ETW provider uses the GUID {e0c9e9c5-3d5e-4e6a-8b41- 8b2c5c1e1e33} for logging translation start/stop events.
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Question 42. Which Windows runtime component is essential for implementing background tasks that continue during Connected Standby? A) BackgroundTaskBuilder with AllowedExecutionTime set to “Always” B) ThreadPool::CreateThread C) Win32 Service Control Manager D) Task Scheduler “Run whether user is logged on or not” Answer: A Explanation: BackgroundTaskBuilder can request the “Always” execution time attribute, allowing the task to run while the device is in Connected Standby. Question 43. Which of the following best describes the role of “Spinlocks” on ARM64 in WoA? A) They are replaced by futexes for better power efficiency B) They must include a memory barrier (DMB) to ensure correct ordering C) They are not supported on ARM64 kernels D) They automatically yield the processor after one iteration Answer: B Explanation: ARM’s weak memory model requires explicit barriers (e.g., DMB) when implementing spinlocks to guarantee visibility of lock state changes. Question 44. Which of the following is a hardware feature of Snapdragon processors that benefits WoA’s “always‑on” capability?
