Will existing updates and service packs remain available?

Just checking - I assume the answer is yes. My situation: While I have a new laptop with W7, I still use my old laptop as well. It is running XP, and since it only has 520 MB RAM (max capacity), it's not a candidate for W7. Being XP, every year or two I reload the OS to clean it up - or maybe I play with the partitions to try other OS's. I reload the OS from an original XP disk that is pre-servicepacks, then go through all the upgrades through SP1, 2 and 3. I assume (or at least hope) that these will be available online from MS forever. -Jim