JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

AI tools will make it easier to generate low-level code, improving autocomplete capabilities and potentially producing high-quality code.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

As AI tools handle more low-level programming tasks, the role of software designers will increasingly focus on higher-level design, making software design more important than ever.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

It's concerning that universities do not teach software design, especially as it becomes a larger part of developers' responsibilities due to advancements in AI.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Software design is fundamentally about decomposing complex systems into smaller, manageable units that can be implemented independently.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

The two main approaches to software design are top-down and bottom-up, each with its own advantages and pitfalls, and effective design often involves a combination of both.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Good software design helps manage complexity by either eliminating it or using modular design to hide it, allowing users to interact with simpler interfaces.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Designing things twice can lead to better outcomes, as the first idea is often not the best; forcing oneself to think of alternatives can yield superior solutions.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Deep modules, which have simple interfaces but complex functionality, are crucial for managing complexity in software design.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Effective error handling is essential in software design, and reducing the number of exceptions can significantly decrease system complexity.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Design reviews, where multiple minds discuss and critique plans, can lead to better design outcomes and should be encouraged in both academic and industry settings. I believe design permeates the entire development process. You should always do at least a little bit of design upfront, even if it's not a waterfall method.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

If you don't do any design upfront, you're wasting your time on code that is unlikely to be useful.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Software development is like navigating an unknown terrain; sometimes you encounter unexpected obstacles that require you to adapt your approach.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I think design is one of the most amazing creative forms in human history, and I often reflect on what constitutes good design.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

No one teaches software design as a primary element in courses, which has been a concern for me for over a decade.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I believe design can be taught, even to students who have just learned to code.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

The key to learning design is getting feedback and iterating on your work, similar to how writing classes operate.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I think the most important elements of design are pushing towards general-purpose solutions to avoid unnecessary specialization.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I advocate for writing tests when fixing bugs, as it helps ensure that the bug is properly addressed.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

Comments should provide information that isn't obvious from the code, especially for interfaces and member variables.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

AI tools can help compensate for the lack of comments in code, but they shouldn't replace the need for good documentation.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I'm currently working on upstreaming a new transport protocol called Homa into the Linux kernel.

JO

John Ousterhout

04/09/25

@ The Pragmatic Engineer

I encourage students to steal and cannibalize the best ideas from each other's projects during code reviews.

The Philosophy of Software Design – with John Ousterhout

Takeaways