This is a lot like existing techniques, such as Gentoo's installation sandbox: first, a package is installed in a temporary file system, and changes made during the installation are then merged into the live filesystem (if installation was succesful, and none of the newly added files conflict with files already installed).

Furthermore, the FreeBSD manual recommends a similar procedure for automated building of package lists (lists of files installed by a package): create a regular port, install it into a temporary copy of a base filesystem, and use mtree to figure out what files were modified during the installation process. In this case no chroot environment is used, since ports are expected to honour the installation prefix (given in PREFIX).

So it's a pretty well-established technique; I'm not even sure using it to upgrade the base system is novel: as of late, FreeBSD provides binary updates to its operating system in addition to the traditional source upgrades (and binary releases), although I'm not sure how these packages are created.

OpenBSD is primarily used for firewalls. The purpose of a firewall is to do essentially nothing 'cept route and filter packets. As such, the cheapest least broken hardware is typically used. Some people (*cough* Steve Wozniak *cough*) even see embedded firewall devices that run OpenBSD. They run entirely off flash memory.

Yup. We do this at work (no link because I'm not spamming). We sell OpenBSD firewalls on minimal hardware (about the size of a broadband router, low power enough to be fanless), and then sell various services on top of that. You can do a surprising amount.

We use flash memory, and the space and rewrite cycle requirements for compiling on this are prohibitive.

Gerardo Santana worked on a project implementing binary patches for OpenBSD [sourceforge.net] at least since 2001. His code is quite reliable, IIRC he basically lacked the needed machines to create the patches for all the OBSD officially supported architectures.

The *BSDs package management is better than any other I've seen, and far better than Slackware's pkgs, which don't manage dependencies at all... OpenBSD just doesn't use packages for the base system (dist sets instead), and doesn't provide updated binaries (for manpower reasons), only source.

Maintenance actually gets easier, the more machines you have. If you need to build from ports for some reason, you only have to do it once, and can distribute the generated packages across as many systems as you want. Ditto for updating the base system, you just have to build it, then you can make dist sets to distribute.

You're not even a good troll.