[badc0ffee]

There's always another 80s computer I'd never heard of...

The Tatung Einstein was released in 1984 in the UK, was kind of MSX-like architecturally, and used the same 3" (not 3.5") floppies as the Amstrad CPC.

I'm curious what US-based C64 devs would have used. Probably not this machine?

[egypturnash]

From what I’ve read it was not at all uncommon to have a MS-DOS machine that assembled your code much faster and spat it into the c64 over a parallel link.