This post covers some of the major features of OCaml while solving Problem 1 from Project Euler. If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. Let’s get started on this problem by looking at the math facilities provided by OCaml. Start a new interactive session using utop. ...

opam — the OCaml Package Manager — is the tool for installing OCaml and any OCaml tools and libraries. This blog post shows us how to set-up opam to install the OCaml compiler and development tools to support your workflow. Working with Windows The OCaml tools are typically well supported on Linux, with macOS ports available of most binaries. If you are on a Windows, the best supported environment is the Windows Subsystem for Linux. ...

I was first introduced to ML through the Coursera Programming Languages course. After the initial learning curve, I was impressed by the power of the type system and the flexibility of pattern matching. I’ve been wanting to resume my education in functional programming, and am picking up OCaml for a personal project I’m working on. Diving into the OCaml ecoystem, I was drawn to Reason, a new syntax for OCaml, and BuckleScript a compiler that integrates OCaml with the JavaScript ecosystem. The relationship between Reason, BuckleScript, and OCaml can difficult to understand, leading to this blog post about the OCaml compiler pipeline that highlights the intersection between OCaml and BuckleScript. ...

Engineering, for much of the twentieth century, was mainly about artifacts and inventions. Now, it’s increasingly about complex systems. As the airplane taxis to the gate, you access the Internet and check email with your PDA, linking the communication and transportation systems. At home, you recharge your plug-in hybrid vehicle, linking transportation to the electricity grid. At work, you develop code, commit it to a repository, run test cases, deploy to production, and monitor the result. Today’s large-scale, highly complex systems converge, interact, and depend on each other in ways engineers of old could barely have imagined. As scale, scope, and complexity increase, engineers consider technical and social issues together in a highly integrated way as they design flexible, adaptable, robust systems that can be easily modified and reconfigured to satisfy changing requirements and new technological opportunities. ...

Before the Internet became a global network connecting millions of devices, it was a simple research experiment connecting a handful of institutions. In the beginning, the number of unique internet addresses could be measured in the tens. As the network expanded that number quickly grew into the hundreds and thousands and it became difficult to remember and type in IP addresses for each of these hosts. To manage the growing number of network hosts, a simple text file, called HOSTS.txt recorded each host and their IP address. To add your name to the hosts file, you needed to send an e-mail describing the changes you wanted to apply. The authority for the HOSTS.txt file would apply these changes once or twice a week and anyone who wanted to grab the updated list would periodically FTP to the canonical source, grab the latest file, and update their own list of hosts. Naturally, as this small network expanded into, and was eventually replaced by, the Internet, this solution became untenable – there were just too many hosts to keep track of, keep consistent, and to serve from a single canonical file using FTP and manual updates. HOSTS.txt did not scale. ...

Leading software companies have discovered that developing capable technology is not enough to guarantee long-term success. To stay relevant, software leaders need to develop and support the repeatable systems necessary to develop and sustain knowledge and expertise. Many organizations have taken inspiration from Spotify’s culture and adopted the concept of a guild or community of practice to connect engineers throughout the organization and steer them towards common goals. As organizations adopt this model, what is often missing is a clear understanding of the purpose of communities of practice and a repeatable process for developing the communities to their fullest potential. This post provides some guidance based on our experience developing a community of practice at Workiva, it also includes some best practices from the book Cultivating Communities of Practice. ...

Complex processes may require collaboration and coordination of many components. We can model such processes using a Design Structure Matrix to represent information flow among the components, and then optimize the process to avoid rework and downtime. As a simplified example, consider a project with only two tasks: “A” and “B”, and a directed graph representing this system where a vertex represents a task and an edge represents the flow of information between tasks. Depending on the process being modeled, these two vertices can be arranged in one of three different configurations. ...

After graduating from university my (future) wife and I travelled and worked in Kenya as part of the Commonwealth of Learning — an intergovernmental agency dedicated to open learning and distance education. As fortune would have it, my brother had an internship in the neighbouring country of Tanzania during the same time period, and we were able to meet for a few days to enjoy the East African coast in the city of Mombasa. ...

To meet the challenges of scaling systems in size, scope, and complexity, it is useful to look at new approaches and theories to analyze, design, deploy, and manage these systems. A Design Structure Matrix (DSM) is an approach that supports the management of complexity by focusing attention on the elements of complex systems and how they relate to each other. DSM‐based techniques have proven to be very valuable in understanding, designing, and optimizing product, organization, and process architectures. This article explores in more depth how we can use the techniques developed by the design structure matrix community to improve software architecture. ...

A queueing system can be described as the flow of items through a queue. In a queueing system, items arrive at some rate to the system and join one or more queues inside the system. These items receive some kind of service, and when the work is done, they depart the system. A simple queueing system Little’s Law is a pretty simple model of queueing systems. $$ L=\lambda W $$ Little’s Law says that the average number of items in a queueing system, denoted \(L\), equals the average arrival rate of items in the system, \(\lambda\), multiplied by the average waiting time of an item in the system, \(W\). ...