The exact 640k quote from the talk:
"So that's a 1 MB address space. And in that original design I took the upper 340k and decided that a certain amount should be for video memory, a certain amount for the ROM and I/O, and that left 640k for general purpose memory. And that leads to today's situation where people talk about the 640k memory barrier; the limit of how much memory you can put to these machines. I have to say that in 1981, making those decisions, I felt like I was providing enough freedom for 10 years. . That is, a move from 64k to 640k felt like something that would last a great deal of time. Well, it didn't - it took about only 6 years before people started to see that as a real problem."
Slashdot Mirror
The exact 640k quote from the talk: "So that's a 1 MB address space. And in that original design I took the upper 340k and decided that a certain amount should be for video memory, a certain amount for the ROM and I/O, and that left 640k for general purpose memory. And that leads to today's situation where people talk about the 640k memory barrier; the limit of how much memory you can put to these machines. I have to say that in 1981, making those decisions, I felt like I was providing enough freedom for 10 years. . That is, a move from 64k to 640k felt like something that would last a great deal of time. Well, it didn't - it took about only 6 years before people started to see that as a real problem."
They actually did a "code audit" a while back. You can get details here: http://www.reactos.org/wiki/index.php/Audit.
Unfortunately, the build of ffmpeg we were using didn't allow theora encoding. We tried :(
There's also more talks at http://www.csclub.uwaterloo.ca/media/