The Linux Kernel May Finally Phase Out Intel i486 CPU Support

[Chugworth]

About a year ago I was replacing a PBX, and I was poking around in the old one to gather information on its configuration, phone extensions, etc. It ran Linux, and to my surprise it was running on a 486 processor. This was a bit shocking to me since the system was first installed in the late 2000's when the 486 should have been dead. There's no telling how much they paid for that piece of junk. That old PBX was extremely slow just working in the command line. So I agree it's time to remove 486 support from the Linux kernel. That processor has no place in any Internet-connected device.

[schmidtbag]

Both 80386 and 80486 were kind of LTS releases. Manufacturing discontinued in 2007. Also not that many had even a IBM AT (80286) exactly 3 decades ago. E.g. when Wolfenstein 3D appeared (the state of the art FPS game 3 decades ago), the game had 80286 as a requirement, not 80386 or 80486. It didn't even require a modern protected mode multi-tasking OS.

I don't see how any of that changes things. The LTS support was most likely to accommodate businesses or industries where they can't upgrade the software.
I'm sure there isn't a single person, regardless of what they're doing with such a CPU, would see any noteworthy improvements since kernels as old as 4.0.

No longer maintaining these old platforms at the kernel level doesn't really have any impact on their day to day use. The important thing is that they can still work.

The stupid thing is this really should have been thought through before 6.0.

[hotaru]

Does any other major OS support 486? Maybe the BSDs?

FreeBSD still supports 386 and 486: https://www.freebsd.org/releases/13....are/#proc-i386

Almost all i386™-compatible processors with a floating point unit are supported. All Intel® processors beginning with the 80486 are supported, including the 80486, Pentium®, Pentium® Pro, Pentium® II, Pentium® III, Pentium® 4, and variants thereof, such as the Xeon™ and Celeron® processors. All i386™-compatible AMD processors are also supported, including the Am486®, Am5x86®, K5, AMD-K6® (and variants), AMD Athlon™ (including Athlon-MP, Athlon-XP, Athlon-4, and Athlon Thunderbird), and AMD Duron™ processors. The AMD Élan SC520 embedded processor is supported. The Transmeta Crusoe is recognized and supported, as are i386™-compatible processors from Cyrix and NexGen.

NetBSD still supports 486: https://www.netbsd.org/ports/i386/hardware.html

Any i486 or better CPU should work - genuine Intel or a compatible such as Cyrix, AMD, or NexGen.

OpenBSD doesn't, though: https://www.openbsd.org/i386.html

All CPUs compatible with the Intel Pentium or later, with Intel-compatible hardware floating point support should work.

[Mahboi]

Considering the kind of madmen I've seen requiring the continuation of support for pre-2005 cpus in 2022 in here, I am eagerly awaiting the Legend who will say that Linux is dead to him because his current 486 won't run on it anymore.

[archkde]

Is anybody even using the i486 support right now? I don't know a single distribution still supporting it. All seem to require Pentium at minimum (if they even have 32-bit x86 support at all).

[torsionbar28]

I never understood why people insist on supporting ancient hardware that stopped being relevant 3 decades ago....

A brief history lesson for you. The Pentium P5 wasn't released until March 1993, therefore the i486 was the literal state-of-the-art desktop CPU from intel 30 years ago, in 1992. How could it "stop being relevant", as you claim, when it was Intel's latest top of the line product? Your claim makes no sense. And as others have pointed out, it saw production use well into this century in various embedded and industrial systems. Linux is much more than an eye-candy desktop distro. It is used in a multitude of places you've likely never even heard of.

And just because intel stopped manufacturing i486 in 2007, doesn't mean folks stopped using them. In fact, the embedded and industrial markets typically run very long hardware refresh intervals. So its safe to assume industry was running i486 chips for many years after the official 2007 product eol. It is only now, here in 2022, where we can begin to have the discussion about removing support from the kernel.

Kids these days and their narrow distorted worldview, sheesh.

[RealNC]

I've seen some industrial boards running current-day manufactured 486 clones (they kinda look like Rpi boards with a 486 clone.) But, virtually all of them either run DOS or a 2.x Linux kernel anyway.

And retro computing hobbyists also just put things like Windows 95 on them or whatever.

I don't think there's any real use case for running a bleeding edge Linux on a 486.

[caligula]

A brief history lesson for you. The Pentium P5 wasn't released until March 1993, therefore the i486 was the literal state-of-the-art desktop CPU from intel 30 years ago, in 1992. How could it "stop being relevant", as you claim, when it was Intel's latest top of the line product?

80486 was also pretty common as a minimum requirement for games in late 1990s. E.g. the AAA game C&C Red Alert (1996) has a minimum requirement of 486DX2. The game was fully playable, but the loading time was a bit longer on these older systems (*). Larger maps had more issues with low RAM. If it was obsolete already in 1992, how come AAA game studios assumed it was still popular in gaming PCs?

* afterwards there have been some 3rd party optimizations. Even Doom runs about 33% faster now thanks to further optimized engines.

[pracedru]

Isn't MC 68000 still supported?

[stan]

486 computers are still being used and need to be maintained in the upstream Linux kernel so that these systems benefit from the latest optimizations and security fixes. There is no need to remove support for these systems. I never understood this destructive desire to break things that work.