What about Macintosh computers hasn't changed in the last 25 years?

Are there any significant architectural (OS API or hardware architecture) similarities between the Apple Macintosh of 1984 and the Unix running Intel Macs of today?

Being a Windows developer, I know that there exists a clear history from 1981 to the present regarding “PC” hardware and the MS-DOS/Windows history, and that there is theoretical backward compatibility between Windows XP and the earliest MS-DOS version, and that the hardware interfaces, while much different, still are based around the same architecture and one could theoretically build a modern PC that had an ISA bus and took expansion cards from 1985 if you had enough resources.

In contrast, the Mac has undergone several drastic reforms, including two processor family switches and the switch to Unix.

Well, the snotty attitude on the part of the users is pretty much unchanged.

(I’m a Mac user, by the way)

Some of the original Mac API lives on in what Apple calls “Carbon” – a compatbility library that’s there to ease the porting of classic-style applications to MacOS X. It’s not used much for developing new applications.

Also, Carbon is lacking some “critical” routines that were in the original API (e.g. “InitWindows”), which in general means you can’t just take the source code of an old app and re-compile it, unchanged, for MacOS X. You’d have to do at least a little bit of re-writing.

Exactly. All the hardware standards I can think of have been replaced over the years: SCSI, ADB, NuBus …

Single Button Mouse.

You’re sort of onto something there. The mice that Apple sell tend to be single-button.

However, the original Mac had no support for multi-button mice, either in hardware or in the API. In contrast, MacOS X understands that you could have a multi-button mouse, and supports it both in hardware and in the API.

Do the recent versions still make you drag removable media to the trash can to eject them? That always seemed like a dubious analogy to me.

No, you click the “eject” button (looks like this, appropriately enough) in the directory browser, Finder. It appears directly next to removable media in the directory tree and sidebar.

You can if you want to; the trash can turns into an ‘eject’ symbol as you move the media icon over it. I usually right-click and select ‘eject’ from the context menu, or hit the little ‘eject’ symbol next to the drive in the Finder.

I don’t know if Macs still come with single-button mousen, but they can certainly use the two-button kind, and there are two-button mousen made by Apple.

I think you can still run a classic environment for backwards compatibility, but that’s more like an emulator, nowadays.

And there are arguably aspects of the look and feel that are still intact, if you want to count those. For instance, Mac keyboards still have a Command key (labeled with an Apple icon and/or a cloverleaf), and the keyboard shortcuts for things like cut, copy, and paste are still the same.

You could up through version 10.4. MacOS X 10.5 and later do not support the Classic runtime environment. (That’s ignoring emulators from third parties.)

Not for a long time.
Apple started shipping multi-button mice in 2005.

Four years is not what this forty-something-year old would call a long time.

But – correction noted.

Just to give an idea: even Emacs has moved from Carbon to Cocoa (if you use version 23 or up *).

  • In case anyone’s wondering about the version number, Gnu Emacs is currently enjoying its 25th year of continual development.

Apple Menu is still in the top left corner.
Most keyboard shortcuts are unchanged from those in the original ‘Human Interface Guidelines’.

Mac users stopped telling me that Intel chips were garbage. A few of them tell me they were garbage in the past , right up until 2006 when Intel suddenly started making great chips.

How does this answer the OP’s question?

Many of the Apple icons are still around, like the basic Apple logo’s outline, the wristwatch, the start-up smilie and the arrow cursor.

Steve Jobs is still making lots of money off them.
They still use a pretty similar GUI.
They’re still a premium brand.

More accurately, the trash can turns into an eject button as soon as you start to drag the icon of anything ejectable; it doesn’t wait until you actually get the icon over the trash can.

Also, in addition to 1) dragging the icon to the trash, 2) clicking the eject icon next to the drive in a Finder window, and 3) right-clicking and selecting “Eject”, you can also 4) click once on the drive to select it and then type Command-E.

with regard to the OP, I’m not quite sure how

and

are necessarily related. As far as I know, there is nothing in the current Mac architecture that could be called “backward compatible” with the 1984 Mac (the single-button mouse, for example, may still be around, but in 1984 the protocol of that mouse was ADB, now it’s USB; 1984 disk drives were SCSI, now they’re IDE or USB or FireWire).

Still, “If you had enough resources”, I’m sure you could make a modern Mac accept any expansion card you wanted. “If you had enough resources”, I’m sure you could get a 1984 Mac on the Internet. I don’t quite see how that gigantic “if” pertains to compatibility, backwards or forwards.

I mean, “If you had enough resources”, you could get a modern PC to read input from an abacus; does that mean that a modern PC is “backwards compatible” with an abacus?

Or, for the optical drive, you can hit the “eject” button on the keyboard.