David Cantrell 🏏

Back In The Day - early/mid 90s - I saw #SCO (or possibly #Novell) demo a version of #Unixware on some funky PC hardware where you could add and remove physical CPUs and memory on the fly. Does anyone remember what that hardware was?

And does anyone know when this feature will be added to #QEMU? It's just that my #FreeBSD testing VM has just started swapping, and I'd like to allocate more memory without having to stop it.

#retrocomputing

Mar 30 at 8:47pmWeb
Show threadpenguin42Mar 30
@DrHyde Qemu can hot add CPUs and RAM on the fly; removing them...sometimes works.
Show threadDavid Cantrell 🏏Mar 30
@penguin42 oooooooh nice. Of course, I doubt FreeBSD supports that anyway 🙂
Show threadpenguin42Mar 30
@DrHyde I suspect it does actually - I think it's a standard ACPI thing.
Hot unplug is tricikier for RAM because well, the OS has got to agree that it's not got anything in it 🙂
Show threadDavid Cantrell 🏏Mar 30
@penguin42 for now I shall put up with the swapping, but I'm definitely going to try that once this job is finished! Thanks!
Show threadSpace HoboMar 30
@DrHyde That sounds a lot like Tandem Computers: https://en.wikipedia.org/wiki/Tandem_Computers
Tandem Computers - Wikipedia

Show threadDavid Cantrell 🏏Mar 30
@spacehobo pretty sure it wasn't Tandem, they had their own OSes and I think they were MIPS-based at the time. My brain keeps saying "Apricot" but the interwebs don't throw up anything that looks right.
Show threadDave FischerMar 31
@DrHyde @spacehobo Some late 90s Suns could do this. I'd love to see a MIPS machine that could...
Show threadthe hatterMar 31
@DrHyde @spacehobo I definitely recall similar displays. Feels like maybe a fujitsu thing, or ibm or someone else with experience higher up the food chain but also a foot in enterprise x86. Think HP and dell could hot-add CPUs in some places, not sure about RAM.
Show threadDavid Cantrell 🏏Mar 31
@hatter @spacehobo hmmm Fujitsu is possible - cos they owned Apricot, and it's the sort of enterprisey thing they would do.
Show threadKaiMar 31
@DrHyde Does virtio_balloon https://man.freebsd.org/cgi/man.cgi?query=virtio_balloon&sektion=4&manpath=FreeBSD+15.0-RELEASE+and+Ports.quarterly not do what you want here?
virtio_balloon(4)

Show threadDavid Cantrell 🏏Mar 31
@socksinspace possibly, although the man page reads like you have to configure the VM to have all the memory first, then can release it back to the host, and request it again later. My problem was that I hadn't allocated enough in the first place, which is different. But then, perhaps the man page is just not well written. There's a first time for everything 😉
Show threadKaiMar 31

@DrHyde It seems like none of the options for changing memory in qemu cater to this usecase, dimms can actually be hotplugged, but slots need to be defined on startup, the issue with virtio-balloon is exactly what you have described, and virtio-mem is only supported on linux.

If i may make a silly suggestion: using a ramdisk on the host as swap in the vm might be the next best thing, disks should be hot-pluggable if i'm not too mistaken.

Show threadDavid Cantrell 🏏Mar 31
@socksinspace if that's silly then so am I because it's what I was going to try next!
Show threadIngvarMar 31
@DrHyde Huh. I have seen run-time hardware replacement of RAM, CPU, and bus cards on Data General kit, but that wasn't "PC" hardware, that was the machines designed to run Aviion (the DG Unixoid).