Software Development – Richard Callaby

A Continuation of my Review of the book Systems Programming in Linux

Alright, so I am continuing to review this book, which by the way I find to be excellent so far, and with that in mind I am giving summaries of what you can find in each chapter. Of course, I am not one to give away the contents of a book as I believe everyone should really read it themselves to get the full benefit. With that in mind, you will find a link to a discount on this book at the end of this review if you’re so inclined.

Chapter 6: Overview of Filesystems and Files

So, I believe, chapter 6 is basically the ground floor of understanding Linux. It’s all about files—which, let’s be real, is everything in Linux.

We chat about how Linux treats almost everything as a file: regular files, directories, even hardware devices. The core idea is the file descriptor, which is just a small, non-negative integer the kernel gives you when you open a file (like $0$, $1$, and $2$ for standard input, output, and error, respectively). We cover the classic functions:

open() and close(): Pretty obvious, opening and closing the file.
read() and write(): How you actually move data in and out.
lseek(): This is the cool one! It lets you jump to a specific spot in a file to read or write, making it a random access file instead of just a sequential one.

It also introduces the concept of file metadata—stuff like who owns the file, its size, when it was last modified, and its permissions (read, write, execute). The stat family of functions is what you use to grab all that juicy info.

Chapter 7: The Directory Hierarchy

Building on Chapter 6, Chapter 7 zooms out from a single file to the big picture: how all those files are organized.

This is where we talk about the directory hierarchy—that inverted tree structure starting at the root, /. The chapter walks you through the essential directories (like /bin, /etc, /home, /dev, etc.) and what lives inside them.

The key functions here are about navigating and manipulating this structure:

chdir(): Changes the current working directory.
getcwd(): Gets the name of the current working directory.
mkdir() and rmdir(): Making and deleting directories.
link() and symlink(): The difference between hard links and symbolic (soft) links. A hard link is like an alias that points to the data itself, while a symbolic link is just a file containing the path to another file.

Chapter 8: Introduction to Signals

Alright, Chapter 8 is where things get a little more…interesting and asynchronous. Signals are a form of inter-process communication (IPC), but they are very lightweight and often used to notify a process of an event.

Think of a signal like a tap on the shoulder for a running process. For example:

SIGINT (Interrupt Signal): What happens when you press Ctrl+C—it tells the foreground process to stop.
SIGKILL (Kill Signal): A non-catchable, non-ignorable signal that forces a process to terminate immediately. The brute-force method!
SIGCHLD (Child Signal): A parent process gets this when one of its child processes dies or stops.

The chapter explains how a process can deal with a signal:

Ignore it (most signals, not SIGKILL/SIGSTOP).
Catch it, meaning you define a special function (a signal handler) to run when the signal arrives.
Do the default action (usually terminate, dump core, or stop).

Chapter 9: Timers and Sleep Functions

Chapter 9 is all about controlling the flow of time (well, the program’s perception of it, anyway). If you need a program to wait, do something later, or measure performance, this is your go-to chapter.

We talk about different ways to pause or schedule activity:

sleep() and usleep() (or nanosleep()): The simple way to pause your process for a set amount of seconds or microseconds. Great for basic delays.
Interval Timers (setitimer): These are cooler. They let you schedule an action (like sending a signal, often SIGALRM) to happen repeatedly or after a specific delay. This is how you build something that needs to fire an event every, say, 5 seconds.

It also covers functions for getting the current time and performing basic time arithmetic, which is crucial for things like logging and benchmarking.

Chapter 10: Process Fundamentals

This chapter is the heart of Linux multi-tasking! It dives deep into what a process is and how they relate to each other.

Every running program is a process, and they are defined by their unique Process ID (PID). The chapter introduces the most important function in process creation: fork().

fork(): This function creates a nearly identical copy of the calling process (the parent), which becomes the child. They are initially identical, except for their PIDs and the return value of fork().
exec family of functions: This is how the child process stops being an identical copy and becomes a new program. The exec functions load a new executable file into the current process’s memory space, effectively replacing the old program with the new one.
wait()/waitpid(): A parent process uses these to pause and wait for a child process to terminate, collecting the child’s exit status. This is vital to prevent zombie processes (processes that are dead but still take up a slot in the process table because the parent hasn’t acknowledged their death).

Okay, so with that in mind, this book is fantastic. It has really helped me gain a deeper understanding of how Linux works. Of course, there are other additional books you will need to read and review in order to gain a much deeper and broader understanding but this one should definitely be on your bookshelf.

I can safely recommend that you go out and get this book. With the advent of artificial intelligence it is very necessary to obtain curated knowledge from known subject matter experts. The author of this book is definitely a subject matter expert and I am sad to learn he may have retired.

However, with that in mind, I would recommend you pick up this book if this is something you may need to learn about in the near future.

You can find a discount to this book here from nostarch.com.

Trying to adapt the new normal of Artificial Intelligence creeping into the software development field.

There are some pretty rapid developments in the field of software development with the advent of artificial intelligence. Adapting to these changes means you will have to try and change rapidly.

Below I have written a brief article on how you could adapt to these changes. Now, obviously, I am going through this as well so over time I may update this list on this website as I discover ways that others can adapt to this new reality.

Adapting to the adoption of artificial intelligence (AI) in fields like software development and information security requires a combination of upskilling, mindset shifts, and proactive engagement with emerging technologies. Here are some strategies for professionals in the technology field to adapt effectively:

Continuous Learning and Skill Development: Stay updated with the latest advancements in AI technologies and their applications in your field. This may involve enrolling in relevant courses, attending workshops, participating in online forums, or pursuing certifications in AI and machine learning.
Embrace Automation and Augmentation: Understand that AI is not here to replace human workers entirely but rather to augment their capabilities. Embrace automation tools and AI-powered platforms that can streamline repetitive tasks, freeing up time for more creative and strategic endeavors.
Collaborate with AI Systems: Instead of viewing AI as a threat, collaborate with AI systems to enhance productivity and efficiency. Learn how to leverage AI algorithms and tools to optimize software development processes, improve code quality, or strengthen cybersecurity measures.
Adopt AI-Driven Development Practices: Explore AI-driven development practices such as AI-assisted coding, which can help software developers write better code faster. Similarly, in information security, utilize AI-powered threat detection and response systems to bolster cybersecurity defenses.
Enhance Data Literacy: AI heavily relies on data, so improving your data literacy skills is essential. Understand how to collect, clean, analyze, and interpret data effectively to derive meaningful insights and make informed decisions.
Focus on Creativity and Problem-Solving: While AI can handle routine tasks, human creativity and problem-solving skills remain invaluable. Cultivate these skills to tackle complex challenges, innovate new solutions, and add unique value to your projects.
Ethical Considerations: As AI becomes more pervasive, it’s crucial to consider the ethical implications of its use. Stay informed about ethical guidelines and best practices for AI development and deployment, and advocate for responsible AI adoption within your organization.
Stay Agile and Adaptive: The technology landscape is constantly evolving, so cultivate an agile mindset and be prepared to adapt to new developments and trends in AI and related fields.
Networking and Collaboration: Engage with peers, industry experts, and AI enthusiasts through networking events, conferences, and online communities. Collaborate on AI projects, share knowledge, and learn from others’ experiences to accelerate your AI learning journey.
Stay Curious and Open-Minded: Approach AI adoption with curiosity and an open mind. Be willing to experiment with new technologies, learn from failures, and adapt your strategies based on feedback and evolving best practices.

By adopting these strategies, professionals in the technology field can effectively adapt to the increasing adoption of AI and position themselves for success in a rapidly evolving digital landscape.

Now, these are just some of the ideas that came to mind. They may seem obvious to many but implementing them in practice takes a lot of work. Hopefully, since you know these changes are coming you can start to develop a backup plan or other means of making a living. Remember, your job shouldn’t define who you are but rather what you can contribute to this world.

As a software developer you can solve problems and think rationally and logically, that means you should be valuable as an employee regardless of what happens. Eventually, software developers may become even more valuable than they are now as software development becomes highly specialized.

A brief tutorial on how to use SSH

Secure Shell (SSH) is a protocol that provides secure access to remote computers over an unsecured network. It provides a secure channel for communication between two untrusted hosts over an insecure network. SSH is widely used for remote administration of servers and other systems.

SSH works by encrypting all data that is transmitted between the two hosts. This includes the login credentials, commands, and any data transmitted between the two hosts. The encryption ensures that the data is protected from eavesdropping, interception, and tampering.

SSH can be used for a variety of tasks such as:

Logging into a remote server to perform administrative tasks
Copying files between two computers using scp (secure copy)
Running a command on a remote server using ssh

Using SSH to Connect to a Remote Server:

The first step in using SSH is to connect to a remote server. To do this, you’ll need to know the IP address or domain name of the server, as well as your username and password. Once you have this information, you can open a terminal on your local machine and use the following command:

ssh username@server_ip_address

This command will initiate an SSH connection to the remote server with the specified username. You will be prompted to enter the password for the specified user account. Once you’ve entered the correct password, you will be logged in to the remote server.

If you’re connecting to the server for the first time, you may see a message similar to the following:

The authenticity of host 'server_ip_address (server_ip_address)' can't be established.
RSA key fingerprint is SHA256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.
Are you sure you want to continue connecting (yes/no)?

This message is asking you to verify that you trust the remote server. The RSA key fingerprint is a unique identifier that is used to verify the identity of the remote server. If you trust the remote server, you can type “yes” to continue connecting. If you do not trust the remote server, you should type “no” and investigate the issue further.

Copying Files with SCP:

SSH also provides a secure way to copy files between two computers using the scp (secure copy) command. The syntax for scp is similar to that of the cp (copy) command:

scp source_file username@server_ip_address:/destination/path/

This command will copy the source_file to the specified destination path on the remote server. You will be prompted to enter the password for the specified user account.

Running a Command on a Remote Server:

SSH can also be used to run a command on a remote server. This is useful for performing tasks that require administrative privileges or that are easier to perform on the remote server. To run a command on a remote server, use the following command:

ssh username@server_ip_address 'command'

Replace “command” with the command you want to run on the remote server. The output of the command will be displayed in your local terminal.

Conclusion:

SSH is an essential tool for remote system administration and secure file transfer. It provides a secure channel for communication between two untrusted hosts over an insecure network. With SSH, you can connect to a remote server, copy files between two computers, and run commands on a remote server securely

Object Tracking: What you should consider before adding this project type to your portfolio

Object tracking is a popular application of computer vision, which is the ability of machines to interpret and understand visual data from the world around them. In this article, I will walk you through the steps of creating an object-tracking project that you can add to your portfolio for future employers to view. Additionally, I will highlight some key items that you can include in your project to make it stand out.

Step 1: Select a Framework or Library

The first step in creating an object-tracking project is to select a framework or library that you will use. There are several options available, such as OpenCV, TensorFlow, and PyTorch. OpenCV is a popular choice for computer vision tasks due to its ease of use and wide range of functionalities. TensorFlow and PyTorch are deep learning frameworks that provide a lot of flexibility for creating custom object-tracking models.

Step 2: Choose the Object to Track

The second step is to choose the object that you want to track. This can be anything from a person to a vehicle or even a moving ball. You will need to provide sample images or videos that include the object to your code.

Step 3: Collect and Label Data

The next step is to collect and label data. This means gathering a large set of images or videos that include the object you want to track, and labeling each frame with the location of the object. You can use tools like LabelImg or RectLabel to annotate images and generate bounding boxes around the object.

Step 4: Train Your Model

Once you have labeled data, you can train your model. Depending on the framework or library you chose, you can use different techniques to train your model. For example, you can use pre-trained models, fine-tune them on your labeled data, or create your own custom model from scratch.

Step 5: Test Your Model

After training your model, it’s time to test it. You can test your model on new images or videos that include the object you want to track. Make sure to check the accuracy of your model and tweak the parameters if needed.

Step 6: Integrate Object Tracking in Your Project

Once you have a working model, it’s time to integrate object tracking into your project. You can use a combination of techniques such as background subtraction, optical flow, and feature extraction to track the object in real time. Make sure to optimize your code for performance, as object tracking can be computationally intensive.

Items to Include in Your Object Tracking Project

Clear and concise project description – Write a detailed description of your project that explains the problem you are trying to solve, the approach you used, and the results you achieved.
Code samples – Include code samples that demonstrate your knowledge of the framework or library you used. Make sure your code is well-organized and easy to read.
Visualization – Include visualizations that show the object tracking in action. This can be in the form of a video or a set of images with bounding boxes around the tracked object.
Performance metrics – Include performance metrics such as accuracy, precision, and recall to demonstrate the effectiveness of your model.
Optimization techniques – If you implemented any optimization techniques, such as multi-threading or hardware acceleration, make sure to highlight them in your project.
Interactive demo – If possible, create an interactive demo that allows users to upload their own images or videos and see the object tracking in action.

In summary, creating an object-tracking project is a great way to showcase your skills in computer vision and machine learning. By following the steps outlined above and including the key items in your project, you can make it stand out and impress potential employers.

Git Merge Conflicts – What to do when you encounter this issue.

Git is a widely used version control system that allows developers to work on a project collaboratively, making it an essential tool for software development teams. However, when multiple developers are working on the same codebase, it’s not uncommon for conflicts to arise during a Git merge operation. In this article, we’ll explore how to handle Git merge conflicts and some tips to make the process more efficient.

What is Git merge conflicts?

A Git merge conflict occurs when two or more developers modify the same line of code or file, causing a conflict when Git attempts to merge the changes. These conflicts occur when Git can’t automatically reconcile the differences between the different versions of the code, so it’s up to the developer to resolve the conflict.

How to handle Git merge conflicts?

Identify the conflict: The first step in handling a Git merge conflict is to identify the conflict. You can do this by running the “git status” command, which will show you the files with conflicts.
Open the conflicting file: Once you’ve identified the file with a conflict, open it in a code editor. You’ll see the conflicting sections highlighted with “<<<<<<<“, “=======”, and “>>>>>>>”. The “<<<<<<<” and “=======” markers represent the changes made by the two different branches, and the “>>>>>>>” marker represents the end of the conflict.
Resolve the conflict: To resolve the conflict, you need to decide which version of the code to keep and delete the conflicting code. You can also merge the changes manually by editing the code. Once you’ve resolved the conflict, save the file.
Add the changes: After resolving the conflict, you need to add the changes to the index using the “git add” command.
Commit the changes: Finally, commit the changes to the Git repository using the “git commit” command.

Ways to make Git merge conflicts more efficient

Keep commits small: The larger the commits, the more likely you are to encounter merge conflicts. Keeping your commits small and focused will make it easier to identify and resolve conflicts.
Update your local repository regularly: To avoid conflicts, it’s a good practice to update your local repository regularly. This ensures that you’re working on the most up-to-date version of the code.
Use Git rebase: Git rebase is an alternative to Git merge that can help avoid conflicts. Instead of merging changes, Git rebase applies changes from one branch to another, making it easier to keep a clean and linear commit history.
Use a Git GUI tool: Git GUI tools can make resolving conflicts more efficient by providing a visual interface for identifying and resolving conflicts. Some popular Git GUI tools include Sourcetree and GitKraken.
Communicate with your team: Effective communication with your team can help avoid conflicts. If you know that you’ll be working on the same code as another team member, it’s a good practice to communicate and coordinate your changes.

Git merge conflicts are an inevitable part of collaborative software development. While they can be frustrating, understanding how to handle them and following best practices can make the process more efficient. By keeping your commits small, updating your local repository regularly, using Git rebase, using a Git GUI tool, and communicating with your team, you can minimize the likelihood of conflicts and resolve them quickly when they do occur.

How to handle responsive web design and multiple screen sizes.

With today’s technology accessing the World Wide Web has become commonplace. You can access the Web on virtually any device these days. As such, you should design your website or app based on that fact.

There are several modern ways to handle multiple screen sizes using CSS:

CSS Media Queries: Media Queries are the most widely used method for responsive web design. They allow you to apply different styles to different screen sizes using conditions based on screen size, device orientation, and other features.
Flexbox Layout: Flexbox is a layout module in CSS that makes it easier to create flexible and responsive designs. With Flexbox, you can define the layout of your page using flexible containers and flexible items, which adjust to different screen sizes.
Grid Layout: Grid Layout is another layout module in CSS that provides a powerful way to create grid-based layouts. It allows you to define rows and columns and place elements within them, making it easier to create flexible and responsive designs.
Viewport Units: Viewport units are a set of units in CSS that are based on the size of the viewport. They can be used to set the size of elements relative to the viewport, allowing you to create responsive designs that adapt to different screen sizes.
CSS Frameworks: There are many CSS frameworks available that provide pre-written CSS and JavaScript for responsive web design. Some popular CSS frameworks include Bootstrap, Foundation, and Materialize.

Ultimately, the best way to handle multiple screen sizes will depend on your specific needs and the design of your website. It is common to use a combination of these techniques to achieve the desired result.

Node.js vs Angular vs Vue – Three frameworks compared

Node.js, Angular, and Vue.js are three of the most popular JavaScript frameworks used for web development. Each of these frameworks has its own strengths, weaknesses, and unique features, making it important to choose the right one for a particular project. In this article, we will compare Node.js, Angular, and Vue.js to help you decide which one to choose for your next web development project.

Node.js is a server-side JavaScript framework that is built on the Chrome V8 JavaScript engine. It is an open-source, cross-platform runtime environment that can be used to build scalable network applications. Node.js is particularly useful for real-time applications, such as chat applications and online games, as it allows developers to handle multiple connections simultaneously and efficiently. Additionally, Node.js is easy to learn and has a vast library of modules and packages that can be easily integrated into any project.

Angular, on the other hand, is a front-end framework for building dynamic web applications. It is a complete solution for building web applications, from the back end to the front end. Angular is known for its two-way data binding, which makes it easier to keep the model and view in sync. Additionally, Angular is highly modular, which makes it easy to reuse components and maintain large applications. Angular also has a large community of developers and a comprehensive set of tools and resources available.

Vue.js is another popular front-end framework for building user interfaces. It is known for its simplicity and ease of use, making it a popular choice for developers who are new to front-end development. Vue.js also has a small footprint and is highly performant, making it ideal for building fast and responsive web applications. Additionally, Vue.js has a flexible and modular architecture, which makes it easy to integrate with other libraries and tools.

When deciding between Node.js, Angular, and Vue.js, it is important to consider the type of project you are working on. If you are building a server-side application, Node.js is a great choice. If you are building a complex, dynamic web application with a lot of user interaction, Angular is the way to go. If you are building a simple, fast, and responsive web application, Vue.js is the best choice.

In terms of performance, Node.js is known for its fast and efficient runtime environment. Angular is also highly performant, especially when it comes to two-way data binding and dynamic updates to the user interface. Vue.js is also fast and lightweight, making it ideal for building fast and responsive web applications.

When it comes to learning, Node.js and Vue.js are relatively easy to learn compared to Angular. Angular is a more complex framework, with a lot of features and functionality to master. However, Angular also has a large community of developers and a comprehensive set of tools and resources available, making it easier to find help and resources when needed.

Node.js, Angular, and Vue.js are all great frameworks for web development, each with its own strengths, weaknesses, and unique features. The choice between these frameworks will ultimately depend on the type of project you are working on and your specific needs and requirements. If you are building a server-side application, Node.js is a great choice. If you are building a complex, dynamic web application with a lot of user interaction, Angular is the way to go. If you are building a simple, fast, and responsive web application, Vue.js is the best choice.