I remember my dad's RedHat came on 4 CDs: 2 Binary Discs, one Source Disc and one Documentation Disc.
If it worked the way I think, you could take it to a desert island and rebuild everything from source, with just those 4 CDs and an x86 computer.
Today a Debian mirror has 100+ GB of source packages and 600+ GB of binaries just for amd64.
But at least it's one place, heavily replicated. And IIRC it's supposed to work on a desert island.
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