“[RAM1993] I laid out memory so the bottom 640 K was general purpose RAM and the upper 384 I reserved for video and ROM, and things like that. That is why they talk about the 640 K limit. It is actually a limit, not of the software, in any way, shape, or form, it is the limit of the microprocessor. That thing generates addresses, 20-bits addresses, that only can address a megabyte of memory. And, therefore, all the applications are tied to that limit. It was ten times what we had before. But to my surprise, we ran out of that address base for applications within—oh five or six years people were complaining.”

Bill Gates Interview: Winner of the 1993 Price Waterhouse Leadership Award for Lifetime Achievement, Computerworld Smithsonian Awards, https://web.archive.org/web/20080501040344/http://americanhistory.si.edu/collections/comphist/gates.htm, May 10, 2008, National museum of American history - Smithsonian Institution, 1993, October 8, 2014 http://americanhistory.si.edu/collections/comphist/gates.htm, <br class="br">1990s