I don't work in that department so I can't tell you the exact process, but this is how it was explained to me: The goal of escrow is to have people not only understand the toolchain and ensure that they can get it working at the time when the software is put into escrow and then document it, but to also periodically pull it out of the archives and verify it can still be built. As part of escrow, steps are taken to ensure that any additional necessary software and hardware is kept to support this. That's what you're paying for with something like NCC's escrow service. If you want I can actually just ask my colleagues tomorrow.