Linux devs start removing support for 37-year-old Intel 486 CPU — head honcho Linus Torvalds says 'zero real reason' to continue support

Perhaps it is time to send your 37-year-old Intel 486 system into retirement, as far as modern Linux goes, as OS kernel developers appear to have started to dismantle support for this legendary CPU. Phoronix reports that the change seems to have been confirmed in patches destined for the Linux 7.1 kernel. So, those still cherishing their 486 PCs and using them to run a modern version of Linux should probably now make sure they run one of the existing Linux LTS kernels to squeeze a few more years from the platform. Alternatively, they could upgrade to a Pentium or even one of the best CPUs available in 2026.

The patching out of 486 support isn’t really a surprise. Firstly, it is ancient, with the first examples released in 1989, and modern Linux distros continue to grow more resource-hungry. Secondly, Linux creator Linus Torvalds hinted not long ago that 486 support may get the axe. The Linux mogul said that there was “zero real reason” to continue support for the 486 CPU. In fact, he indicated that continuing support for it was detrimental to upstream Linux kernel development efforts.

Developer Ingo Molnar will probably go down in history as the gallowsman, though. Molnar has authored a patch “that initially gets rid of the CONFIG_M486SX, CONFIG_M486, and CONFIG_MELAN Kconfig build option,” says Phoronix. Which is basically signaling in code that the 486 is on borrowed time.

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“In the x86 architecture we have various complicated hardware emulation facilities on x86-32 to support ancient 32-bit CPUs that very very few people are using with modern kernels,” commented Molnar in a note accompanying the patch. “This compatibility glue is sometimes even causing problems that people spend time to resolve, which time could be spent on other things.” Then he repeated some of Torvald’s remarks to remind readers of who signed the 486's death warrant.

Phronix notes that the patch should be merged in Linux 7.1, meaning users won’t be able to build an i486 kernel image. Then, barring an unexpected level of public uproar, the rest of the 486 support can be safely gutted.

We are sure that this isn’t the end of having fun or even being productive with old Intel 486 systems. For example, earlier this year, we covered the news of an open-source 486 motherboard being built from scratch and passing Linux, DOS, and Doom compatibility tests (and more).

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Mark Tyson is a news editor at Tom's Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.

21 Comments Comment from the forums

namtrooper81

Ah yes. The very first family pc I ever owned was a 486 dx100. A whole 100mhz.
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hwertz

After Atari 8-bits and an 8088 system (which frankly was a waste, the Atari had better software), my parents got a 386SX-16, and I ran Linux on that first. That is 16mhz, 0.016ghz. The 4MB RAM was VERY tight, and I upgraded before I ran X11 (on 4MB, I could start an xterm, start xeyes, and I was out of memory.).

Anyway, removing 486 support should allow a nice cleanup -- isn't there still a math coprocessor emulator in kernel? The 486sx was the last Intel system without an integrated FPU* so it won't need that any more.

*The 486sx 'had' one at least originally, in a case oe extreme binning it was a full 486 with the defective FPU disabled; when they made 486 motherboards with a FPU socket, this was actually just taking in a full 486DX and would disable the 486SX entirely and take over. *Pretty* weird.
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8086

The retro computing community will probably not be happy and some government organizations will also probably have issue with these changes as some of their older ISA cards will no longer work.
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hwertz

8086 said:
The retro computing community will probably not be happy and some government organizations will also probably have issue with these changes as some of their older ISA cards will no longer work.
They need to speak up! As support for some of the hardware I used back in the 1990s has been removed, they've put out feelers basically saying "if ANYONE is still using this, let us know", and in fact some vendor was still using a... I think it was a smart card reader?... that I think was redesigned to plug into a PCI slot, but using an ISA bridge and still just using the ISA driver. So they left it in.

I doubt they'll leave it in to benefit members of the retrocomputing community; but if organizations are actually legitimately using some hardware they will (probably) leave it in.
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bigdragon

What stops the Linux community from adding 486 support as a non-default option during the pre-compilation kernel config?

I don't mind them dropping support for 25+ years old hardware. I know that's because I'm biased in that the oldest system I still operate is from 2011 (only about 15-16 years old at this point) and therefore I'm unaffected. Still, the kernel config has so many configurable things. I prefer performance improvements rather than hanging on to really old legacy things.
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usertests

bigdragon said:
I don't mind them dropping support for 25+ years old hardware. I know that's because I'm biased in that the oldest system I still operate is from 2011 (only about 15-16 years old at this point) and therefore I'm unaffected.
i486 will be 37 years old on April 10. Your Sandy Bridge CPU will be fine for decades, and it could take a long time before e.g. Pentium III support is dropped.

Separately from Linux itself, there is an ongoing push to get rid of 32-bit systems. For example, Firefox plans to drop 32-bit x86 Linux support this year. Most people should be hopping onto Athlon 64 (2003), Prescott Pentium 4 (2004), or newer.
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BenMyers

Linux is not the only one dropping 486 support. Microsoft is no longer providing drivers or product activation for any version of Windows XP or earlier, which, of course, includes all the old versions of Windows that work with a 486. Anyone needing to set up an older version of Windows for a 486 is out of luck.

However, MS-DOS lives on and on, because it does not require activation.

A couple of years ago I delivered a Dell Optiplex running MS-DOS 6.22 with the FreeDOS version of HIMEM.SYS, detuned Intel 7th gen i5, and 2GB of memory to replace a failed Gateway 486 running some factory equipment via a serial port. Intel has engineered perfect compatibility with the old-time serial port in its newer chipsets, so the system worked pefectly with is DOS device control app.
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Geef

I have that exact chip sitting in a small box because it was the chip of my first PC. 80486 SX-33MHz
I had DOS 6.2 and Windows 3.11 for Workgroups.
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JamesJones44

The 486 is the one the few consumer processor families pre 2015 I never had. My parents had an old IBM XT and an 10 MHz, 1 MB of RAM 286. When I started building for myself I put together a 33 MHz 386 DX. I wanted to upgrade to a 486, but by the time I got around to upgrading I decided to splurge on a Pentium 75 instead of a 486 DX4 100 MHz

I'm honestly surprised support has stuck around this long, I can't remember the last time I encountered a 486 system.
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pjmelect

Why remove support for anything? It does not cost them anything to continue the support and I imagine that any space savings would be very small as a percentage of the total size of the distro.
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