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Comment by znpy | Hacker News Reader

also, this video features a 486 cpu because linux dropped 386 support a while ago.

https://www.zdnet.com/article/good-bye-386-linux-to-drop-sup...

Anyone know what in particular the 486SX had that the 386 didn’t to make keeping only the former alive practical? Unfortunately the kernel mailing list link in the zdnet article appears to be rotted away.

I believe 386 did not have certain "atomic" instructions like CMPXCHG or XADD. So in order to support 386, the kernel had to have special versions of all locking primitives just for 386.

Basic multitasking (CMPXCHG) and cache management instructions.

Here's a working link: http://lkml.iu.edu/hypermail/linux/kernel/1212.1/01152.html

From that link:

  x86, 386 removal: Remove CONFIG_CMPXCHG
  x86, 386 removal: Remove CONFIG_XADD
  x86, 386 removal: Remove CONFIG_BSWAP
  x86, 386 removal: Remove CONFIG_INVLPG
  x86, 386 removal: Remove CONFIG_X86_WP_WORKS_OK
  x86, 386 removal: Remove CONFIG_X86_POPAD_OK

I was always under the impression that Linux 386 simply meant 32 bit support. So, no 386 support would mean no 32 bit support rather than the 386 specifically.

No, that's x86.

They dropped 386 support, but a 486 still works.

I have seen i386 being used in a couple of contexts. For example, Debian uses it to refer to the 32-bit port[1]. It also seemed to be used when various Linux distributions built Pentium optimized packages when that became a thing. In that case 386 would be used for earlier 32-bit processors and 686 would be used for later 32-bit processors. So the nomenclature is not always clear.

[1] https://www.debian.org/releases/stable/i386/

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