Basic

segments

https://www.tek-tips.com/faqs.cfm?fid=290

"Basically, memory is one long string of bytes, and the actual address of the byte being referred to is calculated on-the-fly by the processor as (segment * 16 + offset)."

"Note that since segments overlap so much, you can usually take any segment:offset pointer, and add 1 to the segment while subtracting 16 from the offset, or subtract 1 from the segment while adding 16 to the offset."

https://hwiegman.home.xs4all.nl/gw-man/DEFSEG.html