Int 13h buffer 64k boundaries

Chuck Guzis pointed out that the PC was built from 8 bit peripheral chips, which was where the 64KB problem came from. When I saw the design, I thought it was really cute how they were able to use one of the timer channels and one of the DMA channels to implement a DRAM refresh circuit almost "for free". Steve Jobs made fun of the design showing that just the CGA board had more chips in it than the whole Macintosh. Sure, PALs eliminate a lot of chips but so did 6845. Sadly, the PC AT was a lot less elegant. My impression was that they divided the project among separate groups who weren't perfectly coordinated. How many different ways does a single computer need to translate key scan codes to ASCII, for example? And there was a circuit with a bunch of TTLs just to generate the exact same signal that the clock chip was already generating. That didn't make sense until you found it came from an application note about the Multibus - if you have more than one processor than the signal is no longer the same. This allowed them to add the MASTER line in the ISA bus which would have been neat if it actually worked. -- Jecel