A quick look at the pinouts of an Intel 8086 & 8088 processor reveals a 20 bit address bus. There was high demand for the ability to address 1 meg (2^20) of address space, and Intel delivered. However ...
Memory addressing in which each byte is referenced by a base number (the segment) plus an offset. An x86-based PC running in 16-bit mode (Real Mode and Virtual 8086 Mode) uses 64KB segments, and a ...