Linux Drops Support For 486 and Early Pentium Processors (zdnet.com) 55
An anonymous reader quotes a report from ZDNet: RIP, 486 processor. You've had a long run since Intel released you back in 1989. While Microsoft stopped supporting you with the release of Windows XP in 2001, Linux kept you alive and well for another 20+ years. But all good things must come to an end, and with the forthcoming release of the Linux 6.15 kernel, the 486 and the first Pentium processors will be sunsetted.
Why? Linus Torvalds wrote recently on the Linux Kernel Mailing List (LKML), "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." Senior Linux kernel developer Ingo Molnar put Torvalds' remark into context, writing, "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. This compatibility glue is sometimes even causing problems that people spend time to resolve, which time could be spent on other things." "This will be the first time Linux has dropped support for a major chip family since 2012, when Linux stopped supporting the 386 family," notes ZDNet's Steven Vaughan-Nichols. "Moving forward, the minimum supported x86 CPU will now be the original Pentium (P5) or newer, requiring the presence of the Time Stamp Counter (TSC) and the CMPXCHG8B (CX8) instruction. These features are absent in the older 486 and early 586 processors, such as the IDT WinChip and AMD Elan families."
That said, you can continue running Linux on Pentium CPUs, but you'll have to "run museum kernels," as Torvalds pointed out in 2022 when he first floated the idea of ending support for 486.
Why? Linus Torvalds wrote recently on the Linux Kernel Mailing List (LKML), "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." Senior Linux kernel developer Ingo Molnar put Torvalds' remark into context, writing, "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. This compatibility glue is sometimes even causing problems that people spend time to resolve, which time could be spent on other things." "This will be the first time Linux has dropped support for a major chip family since 2012, when Linux stopped supporting the 386 family," notes ZDNet's Steven Vaughan-Nichols. "Moving forward, the minimum supported x86 CPU will now be the original Pentium (P5) or newer, requiring the presence of the Time Stamp Counter (TSC) and the CMPXCHG8B (CX8) instruction. These features are absent in the older 486 and early 586 processors, such as the IDT WinChip and AMD Elan families."
That said, you can continue running Linux on Pentium CPUs, but you'll have to "run museum kernels," as Torvalds pointed out in 2022 when he first floated the idea of ending support for 486.
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https://www.vortex86.com/produ... [vortex86.com] "Linux : Up to kernel 4.14"
So already not supported with the current Linux kernel.
Uh no? (Score:1)
Look I love the DMP Electronics people but they don't update their website very much. There's no reason to update their website every time a new kernel comes out to say "Yes, it is still supported!"
Their systems are absolutely bog-standard PCs which is why they are still being made and purchased. I'm not going to compile the linux kernel for my HLV800 (DX-based system) for two reasons - one, I've got better things to do with my life than spend hours proving some random slashdotter wrong, the system was purc
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You can always run an older version of Linux on it. It's not like the new versions have features we need on the low-end hardware. Once the ability to optionally strip away features for embedded minimalist kernels was added we were pretty much good to go for another few decades on the i486 ports. That IPv6 and USB 3.0 made the cut is just gravy.
I wonder what the state of FUZIX is for i486. I see 8086 support on github. It might be a fun project to bring up 286+ 16-bit segmented protected mode or 386+ 32-bit
I get it. (Score:2)
I get it. Especially considering this is open source. But, how much effort was actually needed to sustain this?
Re:I get it. (Score:5, Insightful)
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You need to keep not only Intel's 486 models but 486 work-alikes from AMD and others. If a CPU is actively supported all of the variants need to be supported for the claim to be meaningful. Even if that's four different models that still four machines that are over three decades old.
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How much benefit? (Score:2)
I get it. Especially considering this is open source. But, how much effort was actually needed to sustain this?
That's half of the cost/benefit calculation. How much benefit is there? How many people running an operational 486 based system? A "museum display" can run an old kernel.
If there is an operational 486 system out there that system's devs can update the kernel themselves. The core kernel devs don't need to be involved. It's open source right? At some point it becomes the user's responsibility to make necessary changes or to pay others to make them for them. There is no guarantee that other volunteers will
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I get that. It's cool that they kept the support this long. I have a PC with a Cyrix MediaGX CPU, which is newer than a 486 and still the newest I can run on it is Debian 8, anything newer and the setup does not even start (not enough RAM or the CPU does not support some feature). I have not tried to compile the kernel or anything, I'm just using Debian 8 on that system.
I have a PC with 486, but would not think to try to run the latest kernel on it.
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I have a PC with 486, but would not think to try to run the latest kernel on it.
Do you still have a 486, have your turned it on lately? I turned a Pentium on for the first time in years and there was a pop followed by a burning smell. May your motherboard's capacitors be better than mine. :-)
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Yeah, last year. I installed Windows 3.1 on it and use it sometimes to play old games.
Bad caps are not difficult to replace, but I did not need to do it on that particular PC.
I also have a motherboard with a 286 (last tried to use it a few years ago), but do not have a suitable case for it.
Not even correct (Score:1)
It's not even true that you'll "have to run museum kernels" with no security support if you've got affected hardware.
There are LTS kernels from kernel.org with at least two years support from now, and distro kernels prior to V6.15 which will be supported with backported security fixes for 10+ years.
Linux laughs at Microsoft, Apple support lifetimes (Score:4, Interesting)
The Linux team is finally removing support for a 36-year-old processor ... and still supporting a 32-year-old processor. Meanwhile, the commercial OS people are over there killing support after seven or ten years. That shorter lifetime has not been necessarily bad for enterprise desktops in rich economise ... but an awful lot of the world falls outside that category. On top of that, Moore's law no longer delivers nearly as much year-over-year gain in performance, so it makes sense to keep hardware for longer and longer periods.
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If the world ever ends, it ain't gonna be old versions of Windows that you'll be booting up.
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Linux has removed support for processors a lot faster than that. Support for DSPs often doen't last very long, and Tilera TILE64 was possibly the architecture with the shortest-lived Linux kernel support, being added in 2.6.3 (2010) and removed in 4.16 (2018).
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How long did Windows and MacOS those architectures?
If you're going to make comparisons, they should hold up to scrutiny.
I assume I'm supposed to be outraged by this (Score:5, Insightful)
Look at all the junk ISA and Microchannel nonsense in the kernel. Get it out of there - and if these modules are actually maintained, then they can go up on GitHub and if people want this, they can get it there.
Re:I assume I'm supposed to be outraged by this (Score:5, Informative)
Amazingly, ISA disappeared much later than I thought. It seems there's a Skylake motherboard with an ISA slot out there. That architecture was only discontinued by intel 6 years ago.
Also, I believe the bus still internally survives in many boards that don't have a physical connector, and the LPC bus is ISA in a slightly newer form.
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It's very common for sensors to be on ISA, but that's really about it any more. It was common for a long time for mouse and keyboard, but I don't think even they are there now. If you put the sensors on some other bus, and there are several options, you could reasonably ditch ISA.
Hmm, wow, apropos of nothing except running sensors to see whether I was still using ISA, I seem to have a bunch of temp sensors in my system now. Besides the mainboard (which uses a nct6798, which it says is on ISA) there's the tw
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There are chips that do PCIe to ISA and USB to ISA. You can get adapters from Chinese manufacturers who are still supporting industrial users.
They still make 8086 machines and everything in-between over there. With such a huge global market, nothing is too niche for them. Need a replacement laser assembly for your Laserdisc player? An IDE SSD? Token ring USB adapter?
Re:I assume I'm supposed to be outraged by this (Score:4, Informative)
You might want to look into LPC bus - ISA is still alive and well!
https://www.youtube.com/watch?... [youtube.com]
The 486 was like epoch time. (Score:2, Interesting)
I remember the flame wars in the 80's about how the 486 shouldn't even be in the release kernel.
And how the 486 will outlive the free linux kernel.
Re: (Score:3, Interesting)
Not sure if this is joke or not, but the Linux kernel came out in 1991.
At the time, nobody did anything long with releases. At best, you had 80x86, which went back to 8088, MS/DOS and CP/M. It is still pretty amazing how long compatibility was kept since then.
BSD (Score:3)
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Came here to say the same, and AFAIK there are no planns for NetBSD to drop that support.
OpenBSD is there too, but seems the day may come for i386 (32 bit) removal, see:
https://www.openbsd.org/i386.html
Due to the increased usage of OpenBSD/amd64, as well as the age and practicality of most i386 hardware, only easy and critical security fixes are backported to i386.
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Re: BSD (Score:2)
If they drop the i386 userland support, it will be a calamity.
He'll abandon my good old NexGen 586 (Score:1, Offtopic)
when would 32 bit CPU support stop altogether? (Score:2)
So is it only ARMv7, 586 and 686 left in 32-bit CPUs?
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The Arm ones will still be something that needs to be maintained for a while. Arm7 chips are still made and usedm alas.
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Now thinking more about it, probably RISC-V and MIPS too.
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powerpc, m68k, mips and some others
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We could prop drop powerpc and m68k. But keep Risc-V in the roster.
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PowerPC and RISC-V
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Are there still 32-bit PPC cpus made and run under linux? Mips and RiscV definitely.
32-bit ARM is mostly microcontroller / embedded (Score:2)
So is it only ARMv7, 586 and 686 left in 32-bit CPUs?
The 32-bit ARM CPUs tend to be more microcontroller oriented, embedded oriented. Not so much desktop or server CPU oriented. More often using embedded Linux.
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I am aware that this is quite a niche application these days, and not Linux anyway.
(*) Although there is now the recent Moonshot Initiative [riscosopen.org] to port RISC OS to 64-bit, but it seems that would be a complete rewrite of the operating system in a higher level language than ARM Assembly.
Bad news for a few. (Score:2)
The ZF Micro "ZFx86" SoC lacks the needed instructions and thus will no longer be able to run new versions of Linux.
These are used in embedded systems, so impact is likely to be on some industrial controllers.
On the up side, the Vortex86 line is more common and will continue to function fine with new builds.
Torvalds' failure to adapt. (Score:3)
Instead of wasting human hours manually fixing the "compatibility glue" they should have written and trained AI to deeply understand all glue from the past and present and then used it to automatically keep the glue updated for all future versions without wasting human time.
These fools are stuck in the past. There is no reason not to support i486 forever.
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You forgot the /s.
(I hope.)
Embeded systems are the reason for old X86-32 (Score:2)
The lower end of Vortex's line of enbeded processors has processors that will be out of support after this. Lucky for them, the Linux for Public infrastructure will maintain some LTS for even longer (~ ten years)
Is the same reason that ISA, Microchannel, EISA, VESA and OG PCI support is still ahnging around in the kernel. Many PC/104 systems still being built today, some of those, with that stuff
Lucky for the X86-32 embeded world, the upper end of the Vortex range, and many Via processors still made today a
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And those Vortex processors support some rather modern hardware - they have SD card controllers that simulate a SATA host adapter (backwards compatible to ATA) so you can run a legacy OS without giving up modern easier to get hardware. Likewise they have DDR4 and USB support. They also have PCI, ISA and PCIe bus support.
They just can't implement the Pentium instruction set due to patents so they have a 486 core running at up to 1GHz or so.
They are extremely popular CPUs for embedded PCs - the screens you se
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Any Pentium patents expired more than ten years ago.
You bastards! (Score:2, Insightful)
Re: You bastards! (Score:2)
Nothing beats NetBSD on MicroVAX.
What is Pentium? (Score:2)
The Slashdot editor who posted this story obviously is confused about which CPUs are "Pentiums" and which are not.
Not enough (Score:1)
Even this is not enough, drop all support for 32-bit x86 and make the new minimum target amd64.