20 Embedded Linux Interview Questions and Answers

Embedded Linux is a type of Linux operating system that is designed for use in embedded devices and systems. This operating system is lightweight and has a small footprint, making it ideal for devices with limited resources. If you are interviewing for a position that involves embedded Linux, you can expect to be asked questions about your experience and knowledge of the operating system. In this article, we review some of the most common embedded Linux questions and how you should answer them.

Embedded Linux Interview Questions and Answers

Here are 20 commonly asked Embedded Linux interview questions and answers to prepare you for your interview:

1. What is embedded Linux?

Embedded Linux is a version of the Linux operating system that is designed to be used on devices with limited resources, such as embedded systems. Embedded Linux is often used on devices such as routers, TVs, and industrial control systems.

2. Can you explain what a boot loader is in the context of embedded Linux?

A boot loader is a program that is responsible for loading and starting the operating system on a computer or embedded system. In the context of embedded Linux, the boot loader is typically stored in non-volatile memory such as flash memory, and is responsible for loading the Linux kernel and initial RAM disk into memory and starting the kernel.

3. How do you install an operating system on your device?

The first thing you need to do is create a bootable image of the operating system. This can be done using a tool like dd. Once you have the bootable image, you need to write it to a storage device like a USB drive or SD card. Finally, you need to boot your device from the storage device.

4. Is it possible to run more than one application at once on embedded Linux? If yes, then how?

Yes, it is possible to run more than one application at once on embedded Linux. This is done by using a process called “multitasking.” Multitasking allows the operating system to switch between different applications quickly, giving the illusion that all of the applications are running at the same time.

5. What are some common methods used for debugging applications running on embedded Linux devices?

Some common methods used for debugging applications running on embedded Linux devices include using a debugger like gdb, using printk statements, and using a logic analyzer.

6. What’s the difference between a real time OS and general purpose OS like Windows or Linux?

Real time operating systems are designed to respond to events within a set timeframe, while general purpose operating systems are not. This means that real time operating systems are often used in applications where timing is critical, such as in industrial control or robotics.

7. Why is it important to have access to the source code when using embedded Linux?

There are a few reasons why it is important to have access to the source code when using embedded Linux. First, if you encounter any bugs or issues, you will be able to fix them yourself. Second, you will be able to customize the operating system to better suit your needs. And finally, you will be able to stay up-to-date with the latest security patches and updates.

8. What is cross compilation? What problems does it help solve?

Cross compilation is the process of compiling code for one platform on a different platform. This can be useful when you want to compile code for a platform that you don’t have access to, or when you want to compile code for a platform that is different from the one you are working on. Cross compilation can help solve problems by allowing you to compile code for a platform that you wouldn’t be able to otherwise.

9. What happens if there’s not enough memory available for all the processes currently being executed?

If there’s not enough memory available for all the processes currently being executed, then the system will start to swap out processes to disk in order to free up memory. This can lead to decreased performance as processes are moved back and forth between memory and disk.

10. What is the main advantage of using embedded Linux over other RTOSs?

One of the main advantages of using embedded Linux is that it is a very versatile operating system that can be used in a wide variety of devices and applications. It is also relatively easy to work with and has a large community of developers who can contribute to its development.

11. What are the challenges of developing software for embedded systems?

One challenge of developing software for embedded systems is that these systems often have very limited resources in terms of memory and processing power. This can make it difficult to develop complex applications for these systems. Additionally, embedded systems often have specific hardware requirements that can make it difficult to port software from one system to another.

12. Can you explain how the different parts of an embedded Linux system work together?

The different parts of an embedded Linux system work together in order to provide a complete operating system for devices. The kernel is the core of the system and provides the basic functionality for the device. The userland consists of the applications and tools that run on top of the kernel and provide the user interface and other functionality. The bootloader is responsible for loading the kernel and userland on the device.

13. What are some examples of open-source embedded Linux distributions?

Some popular examples of open-source embedded Linux distributions include Buildroot, Yocto Project, and OpenWrt.

14. When can you use virtualization instead of emulation to test your embedded Linux application?

You can use virtualization when you need to test your application on a different hardware platform or when you need to test your application in a different environment. For example, if you need to test your application on a different processor, you can use virtualization to create a virtual machine with the desired processor.

15. In what cases would you choose Android over Embedded Linux as your platform?

Android is generally chosen as a platform for devices that will be used for consumer purposes, such as smartphones and tablets. Embedded Linux is more often used for industrial or commercial applications where a custom operating system is needed.

16. How much memory is consumed by the kernel during normal operation?

The kernel will consume a minimum of around 2 MB of RAM during normal operation. However, the amount of RAM that the kernel will actually consume will depend on a number of factors, such as the number of devices that are connected to the system and the number of processes that are running.

17. What is real-time performance?

Real-time performance is the ability of a system to respond to an event within a specific time frame. This time frame is typically very short, on the order of milliseconds. For systems that require real-time performance, any delays in response can have serious consequences.

18. What are interrupt handlers?

Interrupt handlers are functions that are executed when an interrupt is fired. In embedded systems, interrupts are often used to handle events such as button presses or sensor readings. When an interrupt is fired, the interrupt handler is responsible for reading the data from the event and taking the appropriate action.

19. What sort of technical expertise is required to develop software that runs on top of embedded Linux?

In order to develop software that runs on top of embedded Linux, you will need to have a strong understanding of the Linux operating system. You should also be familiar with the various tools and programming languages that are commonly used to develop software for embedded systems.

20. What is a single board computer?

A single board computer is a computer that is built on a single circuit board. This type of computer is typically used for applications that do not require a lot of computing power, such as embedded systems.