USB Thumb Drive OS < 32 MB

[Harry Kuhman]

Harry, somewhere in my Internet wanderings, I came across a hacked version of Windows 3.1 that loads into a ramdisk entirely from a single floppy. There's not much there once it's running, but it runs.

Certainly one could run something like it from a 32MB device. The trick would be to get it to boot.

Hi eco2geek,
I hadn't heard of the Win 3.1 single floppy, but it is intereting. But if it really does run from a floppy (as opposed to loading itself into memory, which would be easier since then the information on the floppy could be compressed, giving yourself a bit more to work with), then it's important to remember that Win 3.1 has floppy support, but does not have USB support. That is why I tried to draw the fine line between actually running from the 32 meg USB device or just booting from the USB device into memory and running from memory. And yes, setting up these gizmos for booting is tricky, even when you have a computer bios with a boot from USB option, but people are managing to figure it out.

[eco2geek]

It creates a ramdisk and loads itself into memory, rather than running off the floppy.

As far as USB booting goes, there seems to be two competing formats, one that emulates a hard drive (USB-HDD) and one that emulates an Iomega zip drive (USB-ZIP). These formats seem to have something to do with the USB stick's geometry (link to Damn Small Linux article on setting your USB key's geometry).

There are also, of course, different bootloaders. Damn Small Linux has a script on the Live CD that installs itself to a USB key, using syslinux (it creates and boots from a FAT16 partition) and USB-ZIP geometry. Another cool-looking distro based on Kanotix named CPX-Mini installs GRUB to your USB key (it creates and boots from an ext2 partition) and uses USB-HDD geometry.

Unfortunately, CPX-Mini won't boot on my computer off the USB key, but Damn Small will. So my goal is to examine the Damn Small Linux script to see how they format and partition the key, then resize the partitions on the key to hold the larger CPX-Mini "KNOPPIX" loopback file. And use Syslinux instead of GRUB. Sort of piggybacking on the Damn Small Linux installation, if that makes sense.

As far as getting something bootable onto a 32MB USB key...here's a list of really tiny Linux distros, courtesy of MuLinux.