IBM 5150 maximum memory?

Jules wrote: Sure, but the MC68000 was *much* more expensive than an 8088 at that time, and required fewer support chips, because Intel had a bunch of peripheral chips that worked almost gluelessly on the 8088. I'm not sure whether the MC68008 was available then, but with the MC68000 the minimum memory configuration would have been 32KB rather than 16KB, and memory would have had to be expanded in increments of 18 chips. Most significantly, though was that IBM had already done 8086 designs, and the PC design more or less leveraged what they already had. I'm sure they would have liked to have put in a better processor, but since the PC was just supposed to be a quick-and-dirty hack to show that they could build a microcomputer, I don't think they were all that concerned about whether the decisions they made at the time would have unfortunate consequences later on (e.g., the stupid edge-triggered interrupts, where anyone with the slightest bit of experience would have known to use negative level triggered interrupts). They clearly didn't expect that the product they were designing for release in 1981 was going to set the standard for the most popular computer architecture on the planet for not just the next 27 years but for the forseeable future beyond that. Fortunately over time we have shed a lot of the legacy baggage, including the aforementioned interrupt stupidity. The x86 processor has even become more friendly to programmers, in the form of the 32-bit flat mode addressing of the 386 and later, and even more so in "long mode" on the x86-64. Eric