When the 8086 processor recovers from a hardware reset ... FFFF0 is really really really really close to the bottom of our memory map. Indeed, it is only 16 bytes away. So the first instruction ...

The memory map of the original 8086 computer with its base and extended memory made the original PC rather straightforward, but also posed countless issues for DOS-based applications as they tried ...

In the 8086 architecture, which is the architecture that DOS targeted, memory references are composed of two parts: a 2-byte segment “identifier” and a 2-byte offset within the segment.

This machine had 16KB of memory and ran at 800kHz ... and was ironically a successor to the first x86 CPU, called the 8086 Micro-processor, that had been made some years before.