Oh, good!

I tried to stick to documented history only, so I am not sure what there is to disagree with TBH, but, er, OK. :-)

The thing is that minicomputers sort of got squeezed out by history, and the final stages of that were as messy as the metaphor hints.

So on the one hand, micros expanded to occupy the niche, and some micros can actually run minicomputer OSes, so does that mean that those micros became minis?

This becomes a philosophical question. For comparison some people like to say "dinosaurs never died out, because birds are dinosaurs!" Well, kinda, yes. But birds are one small type of dino. There are no 4-legged birds, no birds with working forelimbs other than wings: no arms, or hands, or gripping claws, or walking forelimbs; no birds with teeth; no truly herbivorous birds; and so on. One small branch of the dino family survived, and prospered and thrived and is doing great, but it doesn't represent the profusion of types of dinosaur there were.

Well, yes, late minicomputers had networking, could drive fancy graphical terminals and so display graphics, and some were powered by CPUs that had been shrunk onto a single chip... but they evolved from a different line of devices and convergent evolution gave them some microcomputer-like aspects.

There were also PC-type devices like the Jarogate Sprite, with an x86 chip, a machine that ran Concurrent CP/M only, had a floppy drive and a hard disk, but could only be accessed over dumb terminals. It didn't have or support a display. You couldn't connect a keyboard to it. It was a small minicomputer built using PC tech.

Another example is Alpha Micro. Obscure now, so you've probably never heard of them. Here's the best site about them:

https://ampm.floodgap.com/

Alpha Micro made Motorola 680x0-powered computers, with a proprietary OS that was in effect a 3rd party clone of DEC mini OSes, especially TOPS-10 and RSTS/E. A notable feature was that the only removable media were tapes, but not computer tapes: VHS videocassettes. That's how software and updates were distributed: data, on a videocassette.

A small host machine with no keyboard, no display, no way to add them; a host that could only talk to terminals; a proprietary multiuser/multitasking OS and most apps written in compiled BASIC.

These are all attributes of a minicomputer. But it used microcomputer parts and processors.

Alpha Micro, Jarogate Sprite -- which is it: a mini or a micro?

Well, kinda, both...

A single-user minicomputer with a big hi-res graphics display, a local keyboard and mouse (probably attached over serial ports with a weird plug, because it evolved from a mini that only could talk to terminals)... available with a choice of CPUs, including proprietary, or 386s and 486s, or Motorola 680x0, but mostly fancy expensive RISC chips... but it acts like a mini, runs a mini-derived OS (usually UNIX)... and like a mini, it costs as much as a small house...

OTOH it's single user. Is that a mini or a workstation? Is a workstation a kind of microcomputer?

It's hard to say. Is a bird a dinosaur? It's hard to say.

But the key thing is that all the workstations are gone now. The last vestiges were late Sun workstations, most with Intel chips. All gone. IBM still makes POWER machines but not workstations. HP stopped when Itanium flopped.

Some of these companies still make server boxes with their RISC chips that evolved from minicomputer-type things. A server isn't a workstation, though. Workstations have big graphics displays, and late ones had fancy 3D cards to drive them, cards that cost as much as a small PC network on its own, and had more memory than that whole LAN put together.

Servers have cheap crappy PC-derived graphics chips that only show the firmware screen. You drive them over the network, possibly by some bodged-on "lights out management" card which pretends to be a serial terminal, captures output from the display, and then sends it over the network.

Ugly bodged hack of a tech, designed for PC servers that are at heart microcomputers with a frame buffer and a local keyboard, and that's the only way to access the firmware so the network-only server needs to fake and capture and redirect it.

Which makes that commodity tech, so you can bolt it onto proprietary servers that evolved from RISC workstations which evolved from minicomputers... so you use the ugly PC kludge in place of a device which, deep down in its firmware somewhere, actually would happily talk to a dumb serial terminal and doesn't need the ugly PC-originated hack.

The lines are blurred. It's not clear any more which is which.

IBM P series servers are POWER machines that natively run AIX. The POWER CPU line evolved from the RIOS/ROMP processor in the IBM RT-PC.

https://en.wikipedia.org/wiki/IBM_RT_PC

That's a deskside minicomputer with a processor complex made from 5 or 6 separate chips. But IBM marketed it as a workstation-cum-PC-replacement, and the Wikipedia editors even call its chip a microprocessor, which it definitely wasn't.

It's all rather confusing.