As Michael explained - BYTE and WORD data types were used often back in the early days of programming.

I remember one of my early programs "Digital Address Book" - I designed the data records of that program to fit exactly into a floppy disk sector (256 bytes) - LOL - those were the days! ;-)
(I forget now how many sectors fit onto a formatted 5.25" disk back in the day but I remember being pleased with the idea of having 800+ addresses & contacts on a single disk. :-P )

...And most likely WHY most CAD programs >stick< with that 256 layer limitation still today is to be compatible with the "industry leader" AutoCAD et al...

If companies didn't care about maintaining compatibility with AutoCAD (and removing that "AutoCAD Compatible" bullet from their product promo materials), we would have probably seen packages with more than 256 layers years ago.

-Will