omg um0-401 practice test

OMG Certified Real-time and Embedded Specialistâ„¢

Last exam update: Nov 18 ,2025
Page 1 out of 12. Viewing questions 1-15 out of 180

Question 1

An example of a module exhibiting temporal cohesion is a combination of-------

  • A. the control and management of two onboard hardware clocks
  • B. a 40 millisecond periodic navigation function and a 40 millisecond periodic display update function
  • C. several mathematical functions such as the sine, cosine, and arctangent functions
  • D. the vehicle speed and acceleration management functions
Mark Question:
Answer:

B

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Question 2

What two actions must occur in systems that use overlaying with a disk drive backing store? (Choose
two.)

  • A. Only data is stored on the disk and code is stored in RAM.
  • B. A task executing in RAM can also execute code that is stored on the disk.
  • C. The operating system must prevent each task in RAM from accessing RAM outside the area reserved for it.
  • D. The code for the currently executing tasks is stored in RAM and that for the currently inactive tasks is stored on the disk, as managed by the operating system.
Mark Question:
Answer:

C,D

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Question 3

Which two statements about static memory allocation are true? (Choose two.)

  • A. Garbage collection is not required.
  • B. Memory fragmentation does not occur.
  • C. Memory allocation units are always the same fixed size.
  • D. Tasks must inform the run-time (e.g., operating system) the total amount of memory they will need before they begin requesting memory.
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Answer:

A,B

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Question 4

POSIX ----------------------

  • A. is the same as UNIX
  • B. is not designed for real-time systems
  • C. does not support asynchronous I/O
  • D. is an operating system interface standard
Mark Question:
Answer:

D

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Question 5

A scheduler runs tasks to completion instead of pre-empting tasks by time slicing or according to
priority. What two actions will occur? (Choose two.)

  • A. Maximize the number of completed tasks per unit of time
  • B. Minimize the task scheduling and context switching overheads
  • C. Honor the commitment made to complete the task once it has begun executing
  • D. Share the processor time fairly among ready tasks
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Answer:

B,C

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Question 6

Which two statements are true of a monitor for synchronization? (Choose two.)

  • A. No concurrent access by tasks is allowed to any resource(s) within a monitor.
  • B. One monitor may encapsulate any number of resources and their synchronization functions.
  • C. If a requesting task enters a monitor but finds the resource isn'tavailable, the task exits the monitor and is placed at the end of the monitor's external queue.
  • D. If two tasks are waiting in a monitor's queues for separate resources, when the task that has been accessing a resource finishes doing so, all the queues with waiting tasks are served round-robin.
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Answer:

A,B

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Question 7

Which two are POSIX real-time extensions? (Choose two.)

  • A. suspend / resume API's
  • B. direct cyclic executive support
  • C. task synchronization
  • D. priority-based preemptive task scheduling
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Answer:

C,D

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Question 8

Which two of these techniques would successfully avoid mutual exclusion deadlocks? (Choose two.)

  • A. Set up a circular dependency of tasks and resources
  • B. Allow a task's use of a resource to be pre-empted
  • C. Require tasks to acquire and use only one resource at a time
  • D. Require tasks to acquire resources in order of the tasks' priorities
Mark Question:
Answer:

B,C

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Question 9

The priority of a runnable task blocked on a resource request is temporarily changed to be the same
as the priority of another task. Which two phrases could describe the new priority? (Choose two.)

  • A. The priority of the highest priority task
  • B. The priority of the lowest priority task which uses the resource
  • C. The priority of the higher priority task being blocked by the lower priority one
  • D. The ceiling priority of the resource on which the lower priority task is blocked
Mark Question:
Answer:

C,D

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Question 10

What two results occur by changing priorities dynamically? (Choose two.)

  • A. Reduces overhead
  • B. Increases overhead
  • C. May starve lower priority tasks
  • D. Avoids the need for priority queues
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Answer:

B,C

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Question 11

A representative benchmark differs from a synthetic benchmark in that a-------------

  • A. representative benchmark models a representative ideal application
  • B. synthetic benchmark precisely predicts specific application performance
  • C. representative benchmark models a real application's execution characteristics
  • D. synthetic benchmark must be developed by the same team that will build the application
Mark Question:
Answer:

C

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Question 12

Network protocol models are described as layers that--------------

  • A. permit separation of concerns of lower layers (e.g., hardware) from higher layers (e.g., application)
  • B. add increasing efficiency to higher layers (e.g., application) than lower layers (e.g., hardware)
  • C. are highly consistent in number and function among different protocols
  • D. provide efficient application access to network hardware addresses
Mark Question:
Answer:

A

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Question 13

The primary requirement for an RTOS is to--------------

  • A. maximize application speed and minimize memory utilization
  • B. enable fast control and data transfer to critical system devices
  • C. enable the application to meet both its functional and temporal requrements
  • D. permit the application to efficiently access all resources (e.g., I/O and memory)
Mark Question:
Answer:

C

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Question 14

A strictly conforming POSIX application----------

  • A. uses all POSIX functions and standard options
  • B. uses only IEEE tested conforming operating systems
  • C. uses only POSIX required API's for its OS functionality
  • D. runs on all operating systems whose vendors claim POSIX conformance
Mark Question:
Answer:

C

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Question 15

Which statement accurately describes where a "mark" exists in the MDA model hierarchy?

  • A. as part of the PSM
  • B. as part of the PIM
  • C. as part of a transparent layer placed over a PIM
  • D. as part of a transparent layer placed over a PSM
Mark Question:
Answer:

C

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