Resources

 Designing Fault-Tolerant Software with Control System Transparency

GN&C Fault Protection Fundamentals by Robert Rasmussen, who works for the Jet Propulsion Laboratory, which is an organization that works closely with NASA on designing spacecraft. GN&C is guidance, navigation, and control. These are the main software systems here. This paper actually distills a ton of experience spent with really thinking through how to build really fault tolerant systems into some core principles.

Architecture Disributed Systems Video

Mar 5 2024

 Design Principles Behind Smalltalk

The purpose of the Smalltalk project is to provide computer support for the creative spirit in everyone. Our work flows from a vision that includes a creative individual and the best computing hardware available. We have chosen to concentrate on two principle areas of research: a language of description (programming language) that serves as an interface between the models in the human mind and those in computing hardware, and a language of interaction (user interface) that matches the human communication system to that of the computer. Our work has followed a two- to four-year cycle that can be seen to parallel the scientific method: Build an application program within the current system (make an observation) Based on that experience, redesign the language (formulate a theory) Build a new system based on the new design (make a prediction that can be tested) The Smalltalk-80 system marks our fifth time through this cycle. In this article, I present some of the general principles we have observed in the course of our work. While the presentation frequently touches on Smalltalk "motherhood", the principles themselves are more general and should prove useful in evaluating other systems and in guiding future work.

Design OOP Philosophy

Jan 2 2024

 12 Software Architecture Pitfalls and How to Avoid Them

Developing a successful software architecture is simple, but it’s not easy. Understanding QARs and then understanding and making the trade-offs that will maximally satisfy the QARs takes insight and experience, much of which has to be gathered through iterative experimentation on the architecture itself. The process itself is simple, but the trade-offs that need to be considered are often tough, and there are seldom easy answers.

Architecture Best Practices Design

Dec 18 2023

 Mental Models: The Best Way to Make Intelligent Decisions

A mental model is simply a compression of how something works. Any idea, belief, or concept can be distilled down into a workable model. While far from perfect, they are a useful way to change perspective, simplify complexity, and solve problems. Mental models help us understand the world. For example, velocity is a mental model that helps you understand that both speed and direction matter. Reciprocity is a mental model that helps you understand how going positive and going first gets the world to do most of the work for you. Margin of Safety is a mental model that helps you understand that things don’t always go as planned. Relativity is a mental model that shows us we have blind spots and how a different vantage point can change everything. The list goes on.

Philosophy

Nov 23 2023

 Granularity & Communication for Microservice Architectures

Architects struggle in modern distributed architectures with two Hard Parts: finding the appropriate service granularity and determining the correct communication styles between services. This talk introduces a new technique for performing tradeoff analysis for microservices architectures around both static and dynamic coupling. Static coupling helps determine the proper granularity by applying integrators and disintegrators. Dynamic coupling helps architects understand the interplay between communication (synchronous versus asynchronous), consistency (atomic versus eventual), and coordination (orchestration versus choreography), along with guidelines on when to choose particular communication styles. In this talk, Neal provides architects with the nomenclature and patterns to understand these difficult aspects of microservices and related architectures.

Architecture Disributed Systems Microservices Video

Oct 5 2023

 Cell-Based Architecture — Architecture Pattern

Cell-based architecture in computing involves designing systems that consist of interconnected cells, each cell capable of executing tasks independently. Like the cells in a biological organism, these computing cells have their own processing units, memory, and communication capabilities. They operate in parallel, exchanging information and collaborating to solve complex problems efficiently.

Architecture Design

Sep 4 2023

 How to do distributed locking

As part of the research for my book, I came across an algorithm called Redlock on the Redis website. The algorithm claims to implement fault-tolerant distributed locks (or rather, leases [1]) on top of Redis, and the page asks for feedback from people who are into distributed systems. The algorithm instinctively set off some alarm bells in the back of my mind, so I spent a bit of time thinking about it and writing up these notes.

Design Disributed Systems

Aug 20 2023

 The lost art of software design

“Big design up front is dumb. Doing no design up front is even dumber.” This quote epitomises what I’ve seen during our journey from “big design up front” in the 20th century, to “emergent design” and “evolutionary architecture” in the 21st. In their desire to become “agile”, many teams seem to have abandoned architectural thinking, upfront design, documentation, diagramming, and modelling. In many cases, this is a knee-jerk reaction to the heavy bloated processes of times past, and in others, it’s a misinterpretation and misapplication of the agile manifesto. As a result, many of the software design activities I witness these days are very high-level and superficial in nature. The resulting output, typically an ad hoc sketch on a whiteboard, is usually ambiguous and open to interpretation, leading to a situation where the underlying solution can’t be communicated, assessed, or reviewed. If you’re willing to consider that upfront design is about creating a sufficient starting point, rather than creating a perfect end-state, you soon realise that a large amount of the costly rework and “refactoring” seen on many software development teams can be avoided. Join me for a discussion about the lost art of software design, and how we can reintroduce it to help teams scale and move faster.

Design Video

Aug 13 2023