How would Linux have been today if locked bootloaders were as common in the 90s as they are now on ARM devices?

You should go read Microsoft's attempt at excluding Linux/Unix from running on x86 using ACPI!

https://web.archive.org/web/20070202174648/http://www.iowaconsumercase.org/011607/3000/PX03020.pdf

:O The Archive! It's back online!! WOOOOO
Btw, in the end, they did this with their office format.
- Browser too, and the whole activeX, and DirectX api system to practically force windows only development.
Unix also including mac and bsds?
- BSDs mostly, Mac wasn't a Unix based system at the time. It also didn't run on x86.

The 90's? Locked bootloaders would've meant people woukdve simply bought different machines without a locked bootloader.

See the IBM/Phoenix BIOS war - it's essentially the same thing. IBM didn't want to license their BIOS to everyone, so Phoenix reverse engineered it. If I remember right, IBM was trying to lock everyone to using their OS.

its good to remember computers were used mostly by the computer people back then.

now with layman using theses devices en masse, things are a bit different. they dont need the nerds ro have a successful product anymore.
This! Manufacturers were trying to lock people into their systems, just by different means. Reverse engineering a piece of low-level software (BIOS) so that you could run high-level software written for that machine architecture on different hardware was the main battle of the day.
The ’90s*
Made me think of the first season of Halt and Catch Fire.
IBM built the original PC from off the shelf components and for some reason negotiated a non-exclusive license for MS-DOS with Microsoft. The only thing in the PC they held a copyright on was the BIOS ROM. A few companies tried making clones, IIRC Eagle Computer just brazenly dumped the IBM BIOS and used that and got sued out of existence. I believe it was Compaq that developed their own MS-DOS compatible BIOS from scratch that did not infringe so IBM had no case to sue. IBM got a competitor they didn't want, and the PC became a 40 year platform.
- Thanks, it's been a while.

Valid question. You can ask this about many things:

Would the Internet as we know it exist if Facebook, AOL, and Yahoo had united to create a walled garden?

Would Macbooks as we know them today exist without an open source ecosystem? Would the company Appke exist? Would there be an iPhone?

Would the web exist without Linux? Both developed at the same time, 1991 till now, and most stuff runs on Linux servers.

Would the people who build all the hardware and software even be interested in computers had they not played with (build) computers in the 90ies? What if we had given them an iPad aith CandyCrush that just works; and not BIOS codes, cables, extension cards and drivers?

What if we had given them an iPad aith CandyCrush that just works

We'll know the answer in just a few more years here. Whole generation growing up that way currently.
On the “web without Linux”, I imagine it probably would have been scattered across a few proprietary Nixes until FreeBSD emerged from the AT&T lawsuit, upon which FreeBSD would have become the dominant web server.

Things just weren't like that then. Otherwise all PC peripherals would be locked down too, so no device drivers. That was already a problem with cheap windows crap. But the better stuff was documented.

Maybe there would be no Linux but that isn't as bad as it sounds, since BSD Unix was being pried loose at the time, plus there were other kernels that had potential. And the consumer PCs we use now weren't really foreseen. We expected to run on workstation class hardware that was more serious (though more expensive) than PCs were at the time. They would have stayed less locked down.

Asded: PCs were an interesting target because there was a de facto open hardware standard, making the "PC compatible" industry possible. So again, without that, we would have used different hardware.

Seconding that's a not-how-things-were.

The lovely thing with legacy architectures (6502, 68k, x86, z80, etc.) that were in use during that time is that they were very very simple: all you needed to do was put executable code on a ROM at the correct memory address, and the system would boot it.

There wasn't anything required other than making sure the code was where the CPU would go looking for it, and then it'd handle it from there.

Sure, booting an OS meant that you needed whatever booted the CPU to then chain into the OS bootloader and provide all the things the OS was expecting (BIOS functions, etc.) but the actual bootstrap from 'off' to 'running code' was literally just an EPROM burner away.

It's a lot more complicated now, but users would, for the most part, not tolerate removing the ability to boot any OS they feel like, so there's enough pressure that locked shit won't migrate down to all consumer hardware.

There was still real competition in the x86 OS space back then, also. Like IBM had OS/2 and DOS 7, and made hardware, so they certainly wouldn't want it locked to a Microsoft OS.
- competition in the x86 OS space back then
  
  Oh yeah: there were a stuuuupid amount of OSes.
  
  On the DOS side you had MS, IBM, and Digital Research.
  
  You also had a bunch of commercial UNIXes: NextStep, Solaris, Xenix/SCO, etc. along with Linux and a variety of BSDs. There were also a ton of Sys4/5 implementations that were single-vendor specific so they could sell their hardware (which was x86 and not something more exotic) that have vanished to time because that business model only worked for a couple of years, if that.
  
  There was of course two different Windows (NT, 9x), OS/2 which of course could also run (some) Windows apps, and a whole host of oddballs like QNX and BeOS and Plan9 or even CP/M86.
  
  It was a lot less of a stodgy Linux-or-Windows monoculture, and I miss it.
I wonder what the newest PC motherboard with the BIOS ROM in a socketed DIP chip is.
- At least a decade old, if not more than.
  
  If you wanted to swap your vendor EFI image to something else, at this point it's all going to be via a SPI programmer, and if you own one of the two boards that it supports, coreboot/openboot.
  
  But, essentially, you can't swap because there's very little supported hardware, and thus are stuck with your vendor proprietary EFI.
  
  What's hilarious, I guess? is that the EFI setup is more or less it's own OS that can then chainboot an OS which is how the mid90s workstations (Sun, SGI, HP, etc.) worked.
but users would, for the most part, not tolerate removing the ability to boot any OS they feel like, so there's enough pressure that locked shit won't migrate down to all consumer hardware.

what makes you think that?
- The same reason people who drive 20 miles a day have worries about range on an EV that'll do 300, or why people espouse the freedom of Android but then use the default Google apps.
  
  People like the option of choice, even if they're not necessarily ever going to engage in making a different one.
  
  If there are two options for a computer, one is "will run everything" and the other is "will only run Windows" a good portion of people are still going to pick the first, even though very few of them will ever do anything else, simply because people really really like having the option of choice.