There's a misunderstanding here. Plan 9 is not patching itself in real time. It's a reboot. As mentioned, it's like kexec. And it works so simply because ... "everything is a filesystem" -- you can't separate out the ease of this from the namespace model. But, you may have noticed, most of us are not Plan 9 promoters :-) we just like it. [if you want to see a comparison of 5 versions of this 'kexec-like thing', look up "give your bootstrap the boot" paper at cluster 2004. Surprise! Plan 9 has the simplest and cleanest implementation.]
It's just a very fast way to reboot, and there are sharp edges, because historically lots of drivers don't handle it well, but if it works, it's great. If you want to see real time self patching to fix bugs, well, Linux has been doing this for years now. The hyperscalars use this capability to death because 15m of downtime for reboot, measured across their fleet, costs units of $1M at a time. So they hot-update the kernel. Linux risc-v kernels figure out what SoC they are on, then self-modify to optimize for that RISC-V part. Linux kernels do this on a smaller scale for other architectures, for security mitigation. Self-patching is old news. Self-patching scares me to death :-) On Thu, Jul 16, 2026 at 10:36 PM Aleksandar Kuktin <[email protected]> wrote: > >On Wed, 15 Jul 2026 17:19:21 -0400 > >Thaddeus Woskowiak <[email protected]> wrote: > > Copy /sys/src/9/pc/ether82563.c to somewhere in your home directory. > > > > [...lots of super-cool hacking...] > > > > Reboot and you should have a working system. > > You know, Plan 9 promoters would get a lot further if they showcased > these kinds of shenanigans front-and-center, instead of talking this > abstract talk of "everything is a filesystem". I don't think I've ever > previously encountered a system that can patch itself like this in > real-time. Though I could be mistaken, PC DOS is pretty capable when it > comes to real-time self-modification. And it would be nice if it could > patch the driver without (re)booting, although that requires hardware > support to work in the general case. > > -- > Svi moji e-mailovi su kriptografski potpisani. Proverite ih. > All of my e-mails are cryptographically signed. Verify them. > -- > You don't need an AI for a robot uprising. > Humans will do just fine. > -- ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T3991c01346348498-M3aa195a4d8cebc13ab7749c5 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
