Linux machine
A real x86 machine, emulated in the tab by v86: it boots the image, runs the software, and with the network relay switched on it also reaches the internet.
Distros that boot here
linux4.iso is a small Buildroot Linux: a real shell in about ten seconds, with udhcpc and wget. Alpine boots too and has apk, but it is slow here and asks you to log in as root (no password) before Net up.
Add your own image
Drop an ISO or IMG below. It goes to R2, shows up in the picker, and boots with the same machine.
Limits, honestly
v86 is an interpreter with a JIT: a text shell is quick, a desktop is slow, and anything needing hardware virtualisation will not run. That is the price of doing it in one tab.
Windows / DOS machine
No Windows licence ships with this lab. Upload a legal image — FreeDOS, ReactOS, a 95/98-era system or an ISO you own — and it boots in the same emulator.
What fits
FreeDOS (free), ReactOS (free, Windows-compatible), Windows 95/98-era images you own, small live ISOs. A modern Windows desktop needs a real machine or a cloud VM.
Boot from your own file
Builds
One shelf for everything you test: APK, IPA, EXE, AppImage, ISO. Stored in R2 with size and hash; images can boot straight into the machine.
Disk images
Every image in the lab storage, ready to boot.
Limits
Uploads stop at 100 MB per file, which is the Worker request limit, not a policy. Bigger images belong in R2 directly, with wrangler r2 object put.