Can you elaborate on the connection as you see it? I think of edge computing, SaaS, and microservices as independent concerns.

They are all outside of traditional mega data centers. :)

I think of the edge as a fancy term for services where minimizing I/O is one of the main goals. Which is sometimes, but not always the case with microservices. (Disclaimer: I'm not associated with this project in any way)

I am a maintainer at WasmEdge. :) The name “edge” signifies that it is lightweight. We think it is a lightweight and secure alternative to Linux containers.

The application use cases include containerization on edge devices, serverless functions on edge cloud, embedded functions for databases or SaaS, stream functions for data pipelines, or even smart contracts for blockchains.

All of the above are “edge” use cases in the sense that they are typically outside of mega data centers. :)

How do I use this on a bare metal Cortex-M with no filesystem or networking?

Edge typically means that the software is running neither on an end device (e.g. a consumers phone/PC/tablet/TV), nor on the very backend in a big datacenter (like AWS us-east-1 or another region), but somewhere in between. E.g. a "mini-datacenter" close to the user (CDN points-of-presence (POPs) are called edge locations", or some aggregation points in between (e.g. gateway devices in factories that proxy between on-site components and in-cloud components).

The term doesn't have a lot to do with how efficient or non-efficient the software that is run in those places is.

"Edge" seems to be used these days just to mean a cloud vendor with >>10 data centers.