In this week's episode, the season 1 finale, Ron speaks with Jeanne, Matt, and Grace, three former tech interns at Jane Street who have returned as full-timers. They talk about the experience of being an intern at Jane Street, the types of projects that interns work on, and how they've found the transition to full-time work.

Despite a steady stream of newcomers, email still reigns supreme as the chief communication mechanism for the Information Age. At Jane Street, it’s just as critical as anywhere, but there’s one difference: the system at the heart of our email infrastructure is homegrown. This week, Ron talks to Dominick LoBraico, an engineer working on Jane Street’s technology infrastructure, about how and why we built Mailcore, an email server written and configured in OCaml. They delve into questions around how best to represent the configuration of a complex system, when you should build your own and when you shouldn’t, and the benefits of bringing a code-focused approach to solving systems problems.

Equal parts science and art, programming language design is very much an unsolved problem. This week, Ron speaks with Leo White, from Jane Street's Tools & Compilers team, about cutting-edge language features, future work happening on OCaml, and Jane Street's relationship with the broader open-source community. The conversation covers everything from the paradox of language popularity, to advanced type system features like modular implicits and dependent types. Listen in, no programming languages PhD required!

Clock synchronization, keeping all of the clocks on your network set to the “correct” time, sounds straightforward: our smartphones sure don’t seem to have trouble with it. Next, keep them all accurate to within 100 microseconds, and prove that you did -- now things start to get tricky. In this episode, Ron talks with Chris Perl, a systems engineer at Jane Street about the fundamental difficulty of solving this problem at scale and how we solved it.

A conversation with Laurent Mazare about how your choice of programming language interacts with the kind of work you do, and in particular about the tradeoffs between Python and OCaml when doing machine learning and data analysis. Ron and Laurent discuss the tradeoffs between working in a text editor and a Jupyter Notebook, the importance of visualization and interactivity, how tools and practices vary between language ecosystems, and how language features like borrow-checking in Rust and ref-counting in Swift and Python can make machine learning easier.

It’s a software engineer’s dream: A compiler that can take idiomatic high-level code and output maximally efficient instructions. Ron’s guest this week is Greta Yorsh, who has worked on just that problem in a career spanning both industry and academia. Ron and Greta talk about some of the tricks that compilers use to make our software faster, ranging from feedback-directed optimization and super-optimization to formal analysis.

Electronic exchanges like Nasdaq need to handle a staggering number of transactions every second. To keep up, they rely on two deceptively simple-sounding concepts: single-threaded programs and multicast networking. In this episode, Ron speaks with Brian Nigito, a 20-year industry veteran who helped build some of the earliest electronic exchanges, about the tradeoffs that led to the architecture we have today, and how modern exchanges use these straightforward building blocks to achieve blindingly fast performance at scale.

Most software engineers only think about their build system when it breaks; and yet, this often unloved piece of software forms the backbone of every serious project. This week, Ron has a conversation with Andrey Mokhov about build systems, from the venerable Make to Bazel and beyond. Andrey has a lot of experience in this field, including significant contributions to the replacement for the Glasgow Haskell Compiler’s Make-based system and Build Systems à la carte, a paper that untangles the complex ecosystem of existing build systems. Ron and Andrey muse on questions like why every language community seems to have its own purpose-built system and, closer to home, where Andrey and the rest of the build systems team at Jane Street are focusing their efforts.

The ever-widening availability of FPGAs has opened the door to solving a broad set of performance-critical problems in hardware. In this episode, Ron speaks with Andy Ray, who leads Jane Street’s hardware design team. Andy has a long career prior to Jane Street shipping hardware designs for things like modems and video codecs. That work led him to create Hardcaml, a domain-specific language for expressing hardware designs. Ron and Andy talk about the current state-of-the-art in hardware tooling, the economics of FPGAs, and how the process of designing hardware can be improved by applying lessons from software engineering.

Hardcaml itself is open-source software available on Github, along with a collection of associated libraries and tools. Andy has also given a talk on Hardcaml called OCaml All The Way Down, and has a post on Jane Street's blog about some of the testing techniques used with Hardcaml.