Curtis Maurand via Dng <dng@???> wrote:

> That's how SCO did it. They moved everything and symlink'd everything. big PITA as I recall. I haven't looked at a SCO system in quite some time.

It’s a while since I worked on SCO as well.
What I recall about it was that when installing update packs etc, it didn’t copy all the new stuff into the standard directories - but used lots - and I mean LOTS - of symlinks. So updating any specific file was a case of the installer creating a directory tree for the package, then symlinking everything it affected.

Downside, a rather difficult system to navigate if you decided to dive in.
Upside, it could back out multiple updates since it kept a record of what had been in place before (I assume an inventory of all the symlinks it touched). You were limited to undoing updates in reverse order - so if you needed to remove one from several packs back, you’d have to rollback everything up to and including the one you want to remove, then re-apply the others you do want.

Might have been complicated, but it did work. We didn’t apply all that many update packs back then !


Simon