These days, the i486 architecture is more of a relic from computer history books than something people use. To give you some perspective, we’re talking about CPUs from the 1990s. In other words, they’re really old.
But believe it or not, the Linux kernel still supports this ancient architecture. That said, this relic might finally be nearing its long-overdue retirement.
Just over a week ago, during a discussion about some kernel functionality on the kernel developers’ mailing list, Linus Torvalds wrapped up his message with the following:
I really get the feeling that it’s time to leave i486 support behind. There’s zero real reason for anybody to waste one second of development effort on this kind of issue.
And the answer wasn’t even late—it came before the next day. A long-time kernel developer, Ingo Molnar, posted a 15-patch RFC that would raise the hardware baseline for 32-bit x86 systems to processors equipped with a Time-Stamp Counter (TSC) and the CMPXCHG8B (“CX8”) instruction.
In plain English, that means bidding farewell to the 486 family and the earliest Pentium-class machines, so old they predate Windows 95.
Maintaining “compatibility glue” for chips that virtually nobody boots with today “is sometimes even causing problems that people spend time to resolve,” Molnar warned in the cover letter. So, a patch was submitted that removes or hard-wires several build-time options:
- CPU options: M486, M486SX, early M586, WinChip, Elan, and assorted quirks disappear.
- Platform support: Niche boards such as RDC321x and AMD’s 486-era Elan are scrubbed out.
- FPU emulation: The venerable
math-emu/library—and theno387boot flag—are deleted. - TSC and CX8: Both symbols become unconditional, erasing fallback paths for chips that lack them.
The cleanup expunges roughly 14,104 lines across 80 files, with a net addition of just 38 lines. Even after excluding the FPU emulator, the kernel still sheds over a thousand lines, a tidy saving for future maintainers.
If the patches are approved, this will be the first wholesale CPU drop-off since Linux 3.8 retired the i386 in 2012. Developers have floated the idea of jettisoning the i486 since at least 2022, but momentum finally coalesced after Torvald’s public nudge.
Lastly, who gets hurt? Practically speaking, very few, or to put it bluntly, no one. The last commercial i486 rolled off production lines in 2007, and modern kernels rarely run on such vintage silicon outside hobbyist retro-computing circles. For those edge-case users, older long-term-support kernels—or full-system emulators—remain viable escapes.
For more information, see Molnar’s proposal on the kernel mailing list.
