Can we get smaller VM hosts? I’ve seen some minimums at 512MB for a host. I need 8MB at most sometimes.

Update: Fourplex (this host) uses a 1GB minimum.

Running modern full-fat Linux on anything sub-512MB isn't a great experience unless you're willing to do a lot of tweaking, or running specialized distros like alpine. If dropping the whole "vm" thing is an option, you can go much lower -- I've been running perfectly usable alpine lxc system containers on as low as 32MB -- though container-based vps kind of fell out of favor in the last couple years, probably due to the issues that come with not having your "own" kernel in "your" vps. Virtuozzo/openvz was everywhere back then, now it's pretty much all kvm/vmware/hyperv.

What's the use case for a VM with 8MB memory?

A simple web server with some static content to server.

Running on what?... a quarter-century old linux kernel and busybox?

Newlib has been ported: https://github.com/ReturnInfinity/BareMetal-newlib4

Is there a system call reference somewhere?

The plan is to get existing *nix programs ported over, yes. That will require some more work (ideally a compatibility layer/library).

Working on that now ;)

Correct. BareMetal (the kernel) doesn't have context switching or userland. Think of the kernel as just a hardware abstraction layer.

It’s always fun to see this get brought up on Hacker News! I’m the developer behind BareMetal OS.

Keep in mind that this is all geared toward raw compute and throughput. No ring-3, no multitasking (we do support multiple cores though), and no higher-level abstractions like TCP/IP or full-featured file systems.

While it’s all coded in X86-64 assembly, a rewrite to ARM/RISC-V would be interesting once that hardware is standardized.

> ARM/RISC-V would be interesting once that hardware is standardized.

Could you elaborate on this? Both ARM and RISC-V have standardized their hardware feature and different target versions.

Is it more on the iterative angle given X86-64 now moves very slowly?

While the ISAs are (mostly) standardized, the broader hardware support is a mishmash.

ACPI is available, but not widely supported.

Some hardware uses DeviceTree.

Other hardware just expects you to know what devices are connected and how to interact with them.

What about SBSA, it's not universal but at least it's a target.

https://documentation-service.arm.com/static/60250c7395978b5...

Cool idea! I wonder if this may be useful for creating things like consoles, digital readouts etc. A very lightweight GUI library over this which writes directly to the video memory will do the job well.

I've been seeing this project since I graduated college in the early 2010s. Has this been confirmed to be used in production at any known organization or company?

The spirit of TempleOS is alive and well!

TempleOS is a very different beast—if anything, it’s closer to Lisp machines or the Canon Cat.

Keyboard is supported. NVMe, AHCI, ATA, and VirtIO for storage. A few gigabit network adapters from Intel, Realtek, and also VirtIO. A 10gbit intel network driver is currently being developed. Send works on it currently.

Interesting to see it written in higher-level languages!

Good point! I've added some text about wozmon to the README.

Yes - it uses the BareMetal OS kernel. I also wrote that.