Hello Linux on the 486.  Will we miss you?

Hello Linux on the 486. Will we miss you?

A footnote in this week’s tech news came from Linus Torvalds, when he floated the idea of ‚Äč‚Äčabandoning support for the Intel 80486 architecture in a post on a Linux kernel mailing list. That an old and little-used architecture might be abandoned should come as no surprise, it’s been a decade since the same fate befell Linux’s first platform, the 80386. The 486 line may be long dead on the desktop, but as they’re not entirely gone from the embedded space and remains a favorite among the retro PC crowd, it’s worth taking a minute to examine what, if any, implications this move might have.

Is a 486 still a thing?

A whole 486 PC in a chip using only 1W, that would have been amazing in 1994!

Released in 1989, the Intel 80486 was a significantly improved version of their earlier 80386 line of 32-bit microprocessors with an on-chip cache, more efficient pipelining, and a built-in math co-processor. It had a 32-bit address space, but in practice the RAM and motherboard limitations of the 1990s meant that a typical 486 system would have RAM in megabyte quantities. There was a range of versions in clock speeds from 16 MHz to 100 MHz during its lifetime, and a low-end “SX” range with the coprocessor disabled. It would have been desirable as a processor to run Windows 3.1 on and it remained a competent platform for Windows 95, but by the late 90s its days on the desktop were over. Intel continued the line as an embedded processor line into the 2000s, finally pulling the plug in 2007. However, the story of the 486 was by no means over, as a number of competitors had produced their own version of the 486 throughout its active life. The non-Intel 486 chips have outlived the originals, and even today in 2022 there is more than one company making 486-compatible devices. RDC produces a line of RISC SoCs that run 486 code, and according to the ZF Micro Solutions website, they still boast an SoC that is a descendant of the Cyrix 486 series. There is some confusion online as to whether DM&P’s Vortex86 line are also 486 derivatives, but we understand that they are descendants of Rise Technology’s Pentium clone.

Where can a 486 hold?

A set of 486 chips from different manufacturers.
486s and compatible chips were produced by a variety of manufacturers. Winhistory, copyright free use.

It is likely that few engineers would choose these parts for a new x86 embedded design in 2022, not least because there is a much larger selection of devices on the market with Pentium-class or newer cores. We’ve encountered them on modules in industrial applications, and we’re guessing they’re still in production because somewhere there are long-running machine product lines that still use them. We’re quite fond of the RDC part as a complete 486 PC on a chip with only 1W of power consumption as our 90s selves would have drooled at the thought of a handheld 486 PC with long battery life, but here in 2022 we need a quick fix of portable 486 games, there are plenty of ARM boards that will run a software emulator fast enough to show no difference. So will the relatively small group of 486 users lack support for their platform in future Linux kernels? To answer that question, it’s worth thinking about what kind of software these machines are likely to run.

If there’s one thing industrial machinery operators value, it’s consistency. For them, the machine is an appliance rather than a computer, it must do their job continuously and flawlessly. To do that, it needs a rock-solid and stable software base rather than one that changes by the minute, so will an outdated industrial controller need access to the latest and greatest Linux distro? We probably don’t, in fact, we suspect it’s probably much more likely that an outdated x86-based industrial controller would use a DOS flavor. Meanwhile, the retrocomputing crowd is also more likely to be running a DOS or Windows version, so it’s hard to imagine many of them cramming the latest and greatest into a 486DX with 16 megabytes of memory.

Memory Lane isn’t so rosy when you remember how little RAM you had

The first Linux I ever tried was a Slackware version on a 486DX-33 sometime in 1994. At the time it would have been an extremely adventurous choice for an everyday OS, and while it was fine as an experiment, I continued to use AmigaOS, DOS and Windows for my everyday drivers. It would be about a decade later with a shiny new Core Duo laptop that I would switch to permanent dual-boot and eventually switch away from Windows altogether instead of just using Linux on servers, and since then several generations of PCs have continued the trend. If you used a real 486 back in the day, it’s tempting to think of it as still somehow a contender, but thinking about how many successive platforms have crossed my desk in the intervening years makes this venerable platform really is old. We’ve taken a look at the state of the 486 world in the paragraphs above, and we’re guessing that support for 486 processors will really be missed by very few people. How about you, do you drive a 486 for anything? Let us know in the comments.

Cover image: Oligopolism, CC0.

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