Product Perfect

Elixir Nerves is a programming language specifically designed for developing and deploying software on embedded systems. It was developed by the Elixir community, leveraging the power of Elixir and Erlang languages to provide high-level abstractions for low-level hardware communication. The language allows developers to write highly concurrent, fault-tolerant applications with minimal footprint, ideal for IoT devices. Since its inception in 2015, it has gained popularity due to its efficiency and reliability in managing network connections and interfacing with hardware peripherals. References include official documentation from the Nerves Project website (nerves-project.org) as well as various developer forums discussing its use cases.

Ask the right questions secure the right Elixir Nerves talent among an increasingly shrinking pool of talent.

First 20 minutes

General Elixir Nerves app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Elixir Nerves application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

What are the main components of the Nerves framework?

The main components of the Nerves framework are the Nerves bootstrap, Nerves system, Nerves toolchain, and Nerves firmware.

How would you create a new Nerves project?

You can create a new Nerves project by using the mix nerves.new command followed by the name of your project.

What is the role of the Nerves toolchain?

The Nerves toolchain is responsible for cross-compiling the Erlang VM and other C and C++ dependencies for the target hardware.

Describe the difference between Nerves and other Elixir frameworks.

Nerves is specifically designed for developing and deploying firmware for embedded systems, while other Elixir frameworks are typically used for web development or general-purpose programming.

What are the benefits of using Nerves for embedded systems development?

Nerves provides a number of benefits for embedded systems development, including efficient memory usage, fast boot times, and the ability to produce minimal, single-purpose firmware images.

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What you’re looking for early on

Has the candidate displayed a deep understanding of the Elixir language?

Can they explain the Nerves framework and its use cases?

What kind of experience does the candidate have with embedded systems?

Is the candidate comfortable with functional programming concepts?

Next 20 minutes

Specific Elixir Nerves development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

How would you update the firmware of a Nerves device over the network?

You can update the firmware of a Nerves device over the network using the Nerves.Firmware.HTTP or Nerves.Firmware.SSH libraries.

What is the purpose of the Nerves system?

The Nerves system provides the base operating system and platform-specific tools and libraries for the target hardware.

How would you handle hardware-specific code in a Nerves project?

You can handle hardware-specific code in a Nerves project by creating separate modules or functions for each hardware platform and using conditional compilation or runtime checks to determine which code to execute.

What are the steps to deploy a Nerves firmware image to a device?

To deploy a Nerves firmware image to a device, you first need to build the firmware with mix firmware, then you can burn it to an SD card or other storage medium with mix firmware.burn, and finally insert the storage medium into the device and reboot it.

Describe the difference between Nerves and traditional embedded systems development.

Nerves provides a higher-level, more abstracted approach to embedded systems development compared to traditional methods. It allows developers to use Elixir and the Erlang VM, and provides tools for managing dependencies, building firmware, and deploying updates.

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At this point, a skilled Elixir Nerves engineer should demonstrate strong problem-solving abilities, proficiency in Elixir Nerves programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Elixir Nerves.

What does this simple Elixir code do?
IO.puts "Hello, World!"
This code prints the string 'Hello, World!' to the console.
What does this Elixir code do?
defmodule Greeting do
  def hello(name) do
    IO.puts "Hello, #{name}!"
  end
end
This code defines a module named 'Greeting' with a function 'hello' that takes a parameter 'name'. The function prints a personalized greeting to the console.
What will be the output of this Elixir code?
list = [1, 2, 3, 4, 5]
Enum.map(list, fn x -> x * x end)
This code will output a new list where each element is the square of the corresponding element in the original list. The output will be [1, 4, 9, 16, 25].
What does this Elixir code do?
spawn(fn -> 1 + 2 end)
This code creates a new process in Elixir. The new process will execute the function, which adds 1 and 2 together, but the result is not captured or used.

Wrap-up questions

Final candidate for Elixir Nerves Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Elixir Nerves application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you debug a Nerves application?

You can debug a Nerves application using the same tools and techniques as any other Elixir application, such as the IEx.pry function, Logger module, and :debugger module. However, you may also need to use hardware-specific debugging tools depending on the nature of the problem.

What are the challenges of using Nerves for embedded systems development?

Some of the challenges of using Nerves for embedded systems development include dealing with hardware-specific issues, managing cross-compilation of dependencies, and handling network connectivity and firmware updates in a reliable and secure manner.

How would you handle persistent storage in a Nerves application?

You can handle persistent storage in a Nerves application by using the Nerves.Runtime.KV library, which provides a key-value store that is persisted across reboots. You can also use the file system or external storage devices, depending on the requirements of your application.

Elixir Nerves application related

Product Perfect's Elixir Nerves development capabilities

Beyond hiring for your Elixir Nerves engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Elixir Nerves projects, and can engage in multiple capacities.

Elixir Nerves Consultive assessments

Elixir Nerves Application Conversion Assessment Elixir Nerves Application Integration Assessment Elixir Nerves Data & Database Integration Assessment

Custom Elixir Nerves development projects

Custom Elixir Nerves App Conversion Elixir Nerves Custom App Development Process App UI Design for Elixir Nerves Facelifts

Hiring guide for Elixir Nerves Engineers

Elixir Nerves Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the Elixir Nerves engineer at this point.

Elixir Nerves Consultive assessments

Custom Elixir Nerves development projects