Two years later, IBM began work on the model 5150 ... Any assembly-language program written as far back as 1978 for the Intel 8086 microprocessor will run, unmodified, on Intel’s latest Core ...

The honest answer is: We aren't. An 8086 from 1978 and a Core i7-8700K are both CPUs, just as a Model T and 2018 Toyota are both cars -- but they don't exactly share much beyond that most basic ...