< performance on the /370). Since IBM used only the CPU and FPU, < the actual PC design is exact like a Mainframe without an IOC: < Just painfull slow. My pet peve is the IBM PC when launched was clocked at a rather poor 4.77mhz when most of the s100, multibus and generally everyone else that went with 16bits were looking for 8mhz or faster if possible. It saved a few dollars but not enough. At least DEC had a z80 in there to also do IO (instead of the IOC). < P.S.: The hate-segmentation-rantig against the x86 also drives < me mad - the segmentation sceme used is a very good compromise < between usability and performance. Loosing up to 15 Bytes < per segment isn't realy a drawback compared to granularities < of 4 or 8K today ... To me segmentation was just another bag on the side to get 16bits to address more. The other half is that MMU granularity makes sense for its time but with modern OSs eating megabytes for the kernel Even segments don't allow enough. Allison