Windows compatibility

[donno]

This issue intends to document and track compatibility on Microsoft Windows.

tl:dr: Running smolBSD on a Windows host is not too far away.

Identification

OS=$(uname -s|tr 'A-Z' 'a-z')

• For Git Bash, OS is set to mingw64_nt.<version>
• For Busybox for Windows, OS is set to windows_nt

For smoler/img.sh

OS=$(uname -s|tr 'A-Z' 'a-z')

case $OS in
linux|darwin) ;;
windows_nt|mingw64_nt*) OS=windows ;;
*)
	echo "unsupported platform"
	exit 1
	;;
esac

Orcas Installation

For Windows, the release of, Oras is provided via a ZIP file rater than a GZipped tar and the executable is named oras.exe rather than oras as common there.

install_oras()
{
	command -v oras >/dev/null && return
	version=$(curl -s https://api.github.com/repos/oras-project/oras/releases/latest | jq -r '.tag_name')
	[ "$OS" = "windows" ] && \
		( curl -fsSL --output bin/oras.zip "https://github.com/oras-project/oras/releases/download/${version}/oras_${version#v}_${OS}_${ARCH}.zip" && \
			unzip bin/oras.zip -d bin oras.exe && rm bin/oras.zip ) \
	||	curl -fsSL "https://github.com/oras-project/oras/releases/download/${version}/oras_${version#v}_${OS}_${ARCH}.tar.gz" | \
			tar xf - -C bin oras
}

This mostly works with both:

• Git Bash from Git for Windows as it ships with unzip and curl
• BusyBox for Windows, as it has an unzip applet and Microsoft have been shipping a copy of curl with Windows 10 for some time now.

What doesn't work is jq is not available so that is a prerequisite. I just happened to already have it available.

• This can be easily addressed by downloading it: curl -L --output bin/jq.exe https://github.com/jqlang/jq/releases/download/jq-1.8.1/jq-windows-amd64.exe

Image Pull

This is problematic because bsdshell-amd64:latest.img is not allowed via NTFS for the Win32 namespace/API, and when you try to pull the image down with oras you end up with images/bsdshell-amd64 that is zero bytes.

I haven't figured out a solution for this, it seems odd that the oras doesn't error or attempt to automatically sanitise the name when pulling an image on Windows nor does it seem to have any way to control this behaviour. For testing the rest of smolBSD, I pulled down the image in a container then renamed it.

Example

$ ./smoler.sh images
IMAGE                                    SIZE          CREATED        SIG
bsdshell-amd64_latest                    96.8M      01/01/1970        NOK

The _ before latest is due to changing the : in the filename to _

Fetching Kernel

No compatible make for performing kernfetch.
The simply work around I did to move on was manually fetch it with:

curl -L --output kernels/netbsd-SMOL https://smolbsd.org/assets/netbsd-SMOL

I haven't revisited this. Maybe the logic could be factored out to a separate script instead of being inlined in the Makefile.

Running image

This requires qemu-system-x86_64 be available via PATH.

• Configure the accelerator
  • -accel whpx
  • The change in startnb.sh would look like this:

Windows-NT|MINGW64_NT-*)
	accel="-accel whpx"
        cputype="kvm64-v1" # host not supported and max results in a trap.
	;;

• The use of cputype of max rather than host is because to use of -cpu host it requiring KVM or HVF - it doesn't seem to work with the Windows Hypervisor Platform accelerator (except on maybe aarch64/arm64 as the documentation shows it being used there.
• Tried cputype of max which but that resulted in fatal privileged instruction fault in supervisor mode and then a trap.

Due to the tweak above to the name, where its _ instead of :

/smoler.sh run bsdshell-amd64_latest

Output

➡️ using QEMU version 10.2.0 (v10.2.0-12105-g0f12d445bd)
➡️ using kernel kernels/netbsd-SMOL
➡️ using console: com
➡️ using disk image images/bsdshell-amd64_latest.img
🔚 ^D to stop the vm, ^A-X to kill it
WHPX: setting APIC emulation mode in the hypervisor
Windows Hypervisor Platform accelerator is operational
[   1.0000000] WARNING: system needs entropy for security; see entropy(7)
[   1.0000000] entropy: ready
[   1.0000000] [ Kernel symbol table missing! ]
[   1.0000000] smolBSD 11.0_BETA (SMOL)        Notice: this software is protected by copyright
[   1.0000000] Detecting hardware... (QBOOT    000000000000)
[   1.0000030]  done.
[   1.0646486] kernel boot time: 130ms
Created tmpfs /dev (1835008 byte, 3552 inodes)
[   1.6743150] /dev/dk0: file system not clean (fs_clean=0); please fsck(8)
Setting tty flags.
no viocon(4) support
add net default: gateway 10.0.2.2
net.inet.tcp.sendbuf_max: 262144 -> 16777216
net.inet.tcp.recvbuf_max: 262144 -> 16777216
kern.sbmax: 262144 -> 16777216
Starting local daemons:.
bsd@shell$ ping -c 3 google.com
PING google.com (142.250.124.100): 56 data bytes
64 bytes from 142.250.124.100: icmp_seq=0 ttl=255 time=11.124874 ms
64 bytes from 142.250.124.100: icmp_seq=1 ttl=255 time=11.030169 ms
64 bytes from 142.250.124.100: icmp_seq=2 ttl=255 time=12.020798 ms

----google.com PING Statistics----
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 11.030169/11.391947/12.020798/0.546656 ms
bsd@shell$

Summary

With some minor tweaks to the shell scripts, Windows can be supported through smoller.sh, with the two remaining known issues:

• Oras can't properly fetch/store the image on Windows as it contains a :
• Kernel can't be fetched through the normal methods.

I'm happy to put together a pull request with these changes even if it will remain a draft until a decision about what to do about Oras as that is the biggest show stopper. Would the maintainers of this project like to see one commit for "windows supports" or commit per section (for example, "support installing Oras on Windows" and "configure QEMU acceleration on Windows.")?

[donno]

Forgot to mention I hadn't looked the image building.

• Initial thing of note is mktemp from Git Bash and Busybox for Windows both error if the tmp directory is not created first.
• It requires bmake plus the various disk image tools, at which point may need to resort to needing WSL2 to build the images for smoller on Windows.

I've gone own the route of trying to build the Caddy (./smoler.sh build smolerfiles/Dockerfile.caddy) on Ubuntu in WSL2 (discovered that that needs startnb.sh to work. It may be useful to add a new flag to startnb.sh to disable acceleration to avoid needing nested virualisation as for building the loss in performance isn't such a problem), but the image isn't working when it is copied to Windows.

I did get stuck going down this path as the issue I ran into was:

   1.0000000] smolBSD 11.0_BETA (SMOL)        Notice: this software is protected by copyright
[   1.0000000] Detecting hardware... (QBOOT    000000000000)
[   1.0913579]  done.
[   1.0913579] unknown device major 0xffffffffffffffff
... <omitted repeated message> ...
[  21.5120096] unknown device major 0xffffffffffffffff
[  21.5120096] root device:
[  21.5832795] use one of: dk0 vioif0 ld0[a-p] wedge:CADDY=caddyroot halt reboot
[  21.5886181] root device:

Providing dk0 and continuing with the other inputs eventually does get it to build but then file system driver panics.

2026/05/06 00:00:13.853 WARN    admin   admin endpoint disabled
2026/05/06 00:00:13.889 INFO    tls.cache.maintenance   started background certificate maintenance      {"cache": "0x319274302f00"}
2026/05/06 00:00:13.962 WARN    http    HTTP/2 skipped because it requires TLS  {"network": "tcp", "addr": ":8880"}
2026/05/06 00:00:13.969 WARN    http    HTTP/3 skipped because it requires TLS  {"network": "tcp", "addr": ":8880"}
2026/05/06 00:00:13.974 INFO    http.log        server running  {"name": "static0", "protocols": ["h1", "h2", "h3"]}
Server address: [::]:8880
[  28.6654815] panic: ffs_newvnode: dup alloc ino=85112 on /: mode 100644/100644 gen 233243ba/233243ba size 0 blocks 2
[  28.6810475] rebooting...