[userbinator]

Given that https://en.wikipedia.org/wiki/BartPE exists and can also create a "portable Windows" from the original files of an installation media for a normal version of Windows, is it possible to manually create one's own WinPE in the same way? i.e. is WinPE composed of only the same files that can be found on the installation disc, arranged in the right structure, or is there something more to it?

[ryanburk]

the tools needed to create WinPE - that shipped in the OEM preinstallation kits (OPK) - did do some work against the original files to make the magic happen. it was mainly around the special registry dB needed to get it to boot, not changing the files themselves. we also did a ton to try to slim it down, originally to get it to fit on a CDROM or RIS/PXE boot. well before USB sticks got larger than CDROMs.