Old technology is any tech that’s, well… old. Small technology is any tech that has a small footprint: doesn’t require a powerful machine to run, doesn’t have a lot of bloat, doesn’t have anti-features like spyware and tracking. Technology that is old enough is almost always small because, by modern standards, that’s all that was possible back then. Some small tech is old, some is modern. Embedded systems are an example of modern small tech development in many cases.