11:09
EM.413 System Architecture
Dan Sturtevant on software architecture
focused on software
Only 7% of projects are successful
on schedule, budget, good functionality, not abandoned
code has structure, but it’s not three dimensional
this makes it harder to understand the structural problems in code
Three dimensions are natural, two dimensions are efficient.
code is like taking knowledge and encapsulating it into functionality
emergent properties
usually bad
usually result in emergencies
define and enforce design rules
there’s often a difference between how the engineers think the code is structured and how it actually is
engineers disagree and code scanning shows a different result
Modular Design
Entropy happens to codebases to make them undesigned, less modular
Design Rules: The Power of Modularity by Carliss Baldwin and Kim Clark
if you have a technical system that’s highly modular is like creating an evolutionary system
similar to organs
DSM and network view can be isomorphic
DSM allows you to compress a lot of information a network view would be too complicated to view
can see API, shared code, hierarchy, complexity
dependencies across modules both above and below the diagonal shows bad hierarchy
see Joel Moses for work on network representations MIT
Question
Do you find that codebases that lean harder on Functional Programming concepts (like immutability, reduced side effects) produce more modular?
Systems want to be more tightly integrated if there are parts performing multiple functions
Hardware systems it’s more common to tightly integrate for operational efficiency
I suspect interfaces have more energy loss in hardware systems than in software systems
It’s not enough to say the baby is ugly, eventually you need to tell them how to get the baby a nose job.
modules could be mapped to files / functions
like type safety for architecture
->
Make your architecture type safe
restrict use of modules to the API
Apparently distributed organizations build more modular systems…
his company does this analysis on code
Silverthread
https://www.silverthreadinc.com/white-papers
can consider this for thesis, Dan Sturtevant would consider advising
Takeaways
architecture is meant to promote understandability and evolvability
architecture health is holistic, code health is reductive
both valuable
Dan Sturtevant wrote an article on Modular Design is required for Agile development
