28 Linux Device Driver Interview Questions (With Tips)
By Indeed Editorial Team
Published 25 September 2022
The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.
Device drivers comprise a type of software that allows for the interaction of hardware devices with an operating system. A Linux device driver developer develops, ports, customises, validates and debugs device drivers on Linux. If you want to pursue your career as a Linux device driver engineer or developer, reviewing some interview questions and preparing answers can help you gain confidence and perform better in the interview.
In this article, we list 28 Linux device driver interview questions, provide some sample answers and share some tips to help you better prepare for the interview.
8 Linux Device Driver Interview Questions With Sample Answers
Here are eight Linux device driver interview questions with sample answers you can use as a guide when preparing for your interview:
1. Define Linux device drivers.
This is a basic question that interviewers may ask. They may start the interview with this question. You can briefly define the Linux device driver, including its key characteristic and functions.
Example: 'The Linux kernel device drivers are primarily a common library of privileged, low-level hardware handling routines that are memory-resident. Device drivers for Linux handle the unique qualities of the hardware they are controlling. The fact that it abstracts device handling is one of its fundamental characteristics.'
2. Explain procfs and sysfs.
With this question, the hiring manager may want to determine if you are familiar with different types of file systems. While answering, consider defining proc and sys file systems in simple and precise words.
Example: 'Proc file system, or procfs, is a temporary virtual file system that forms when the system boots and gets destroyed during the system shutdown. It serves as the kernel's command and information hub and contains useful data about the currently active processes. A ram-based filesystem called a sys file system, or sysfs, gives userspace a way to export kernel data structures, their attributes and the connections between them.'
3. What is the fault handling process in Linux?
The hiring manager may ask this question to test your technical knowledge and understanding. Your response to this question may allow the interviewer to determine your practical experience and attention to detail. While responding, define the process in simple terms.
Example: 'After the identification of the virtual address that caused the page fault, the system verifies that the address is valid and that there is no protection access issue. If the virtual address is valid, the system examines the availability of page frames. If there are no available frames, the page replacement algorithm execution occurs to delete a page.'
4. What is the difference between memory-based io and port-based io?
The hiring manager often asks this question to test your general understanding of the input-output process. In response to this question, you can briefly and concisely emphasise the key difference between the two.
Example: 'Mapping of memory-based input-output is into the same address space as program memory and user memory and is accessible in the same manner. Port-based input-output utilises a distinct, dedicated address space and is accessible using dedicated microprocessor instructions.'
5. Explain caching in Linux.
This is a basic question and the interviewer may ask this to test your soft skills, including communication and attention to detail. In your answer, briefly explain caching in Linux.
Example: 'Page cache is the term for the cache in Linux. This is the amount of system memory the kernel reserves for caching file system disc accesses. The purpose of page cache is to improve overall performance. During read system calls in Linux, the kernel verifies the cache contains the requested data blocks.'
6. Define sockets in Linux.
With this question, the hiring manager may want to test whether you are familiar with the basic technical terms in the field. When interviewers ask to define or explain any term, consider describing the term briefly in simple and precise words.
Example: 'Sockets are a method for enabling inter-process communication between programs running on the same server or different servers. Network sockets employ the internet protocol to encapsulate and manage the sending and receiving of data between servers.'
7. Is it necessary to update the driver?
The hiring manager may ask this question to test whether you have a practical understanding of device drivers and their uses. In response to this question, you can elaborate on why it is important to keep device drivers updated.
Example: 'It is important to ensure that the device drivers are up to date. This keeps the computer in good working condition and also prevents potential major damage. Ignoring device driver updates often causes computer issues that might be unrepairable or may cost very high to repair.'
8. What is the difference between user space and kernel space in the context of device drivers?
The hiring manager may ask this question to test your knowledge about user and kernel space. While answering the question, mention the key differences between them. Your answer can also demonstrate your practical understanding of device drivers.
Example: 'In user space, drivers do not have permission to access hardware devices directly. To request access to devices, they require using a system call interface. Whereas within kernel space, drivers have immediate access to hardware devices. This means they can directly access devices without using the system call interface. This can result in more efficient code.'
20 Additional Interview Questions
Linux device driver interview questions aim to assess your personality, previous work experience and knowledge and skills related to Linux device drivers. Here are some additional interview questions you can consider preparing:
Why do you want to pursue your career in Linux device driver development?
Explain the device driver and why it is important.
How do you list all loaded modules in Linux?
What is the difference between insmod and modprobe?
How can you assign parameters to a module?
What is the use of IOCTL in Linux?
How can you find device drivers in Linux?
Describe the zombie process in your own words.
Tell me some ways to allocate the device number.
Discuss the drawbacks of dynamic device number assignment.
Explain the function of the Dev_t type.
How to implement busy looping in Linux?
What is the relation between MMAP and malloc?
Tell me the file from which kernel execution begins.
Name some device drivers used by the Linux system.
Differentiate between interrupt-based I/O and polling-based I/O.
What happens when a packet arrives from the network in Linux?
Explain rowlock and spinlock and their use.
What is the difference between dynamic and static linking in Linux?
Name the best interprocess communication mechanism in Linux.
Tips To Prepare For The Interview
Having some preparation prior to the interview may give you some confidence and help you present yourself better in the interview. Here are some tips to help you better prepare for your Linux device driver interview:
Research the company. Check the company's website, social media, press releases and reviews before the interview to understand its work culture, product and services, goals and mission. This information may assist you in answering questions and demonstrate to the hiring manager you took the time to conduct research.
Read the job description. Consider reading the job description before the interview and finding the preferred skills and keywords mentioned in the description. Try to include all the relevant skills and keywords on your resume to increase your chances of getting the job.
Wear appropriate interview attire. It is important to wear appropriate and clean interview attire as it creates your first impression on the interviewer. You may research suitable interview attire to learn more about the available options.
Practice sample interview questions. Practice your answers to some questions for the Linux device driver interview. You can consider asking your friends or a family member to conduct a mock interview to help you better prepare for the real interview setting.
Understand the STAR method. STAR is an acronym for situation, task, action and result. Learning the STAR method can help you answer more effectively in the interview.
Prepare questions to ask your interviewer. The hiring manager might ask you if you have any questions about the role, business or hiring procedure at the end of the interview. Consider preparing these questions in advance to help ensure you ask appropriate and thoughtful questions during your interview.
Follow up further to the interview. You may email the hiring manager, thanking them for their time and expressing your interest in the position. If they do not respond within a week, consider sending another email to enquire about the status of your application.
Please note that none of the companies, institutions or organisations mentioned in this article is associated with Indeed.
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