They're ancient terms for ancient components.
Nowadays, if there's a distributor, it's electronic (HEI, usually), and there's not a whole lot you can do if it goes bad, except for replace the module. It's "easier" (i.e. less to do), but quite a bit more expensive.
The old Distributors are pretty simple. There are many parts that can (and should) be replaced periodically. Bill has things pretty well spelled out as to what all the little pieces-parts are.
The Generator is the old version of the alternator. They work differently (the alternator generates an AC current which is rectified into DC internally whereas the generator puts out a DC current right from the get-go) but do the same basic thing. The reason alternators are more prevlent nowadays is that you can get the same amount of charge whether you're sitting at idle or driving with the engine pegged out. With a generator, the higher the engine revs, the more juice your generator puts out... Which is where the regulator comes in. The regulator keeps your battery from overcharging when you've got the engine running at a higher RPM rate.
Most alternators are internally regulated as well, but some of the older ones use an external regulator like the generators did.
Have a peek at the shop manual, and if you'd like some pictures on how the thing works, I can take some tonight when I get home.
