Just thinking, with 64bit computing, we get over the 4gb ram limit (or is it 3gb).
Back in the day was the same wasn't it? 640k conventional, 384k extended. Don't know what came earlier, as my first machine was an 8086 already.
Then came dos extenders, DOS4G/W, and away we went.
Don't think I'll see more barriers broken in my lifetime, but hey who knows, 10 years from now, we'll see implanted mobile communication devices with 1 terabyte of data storage on carbon nano cubes or something.