I remember when I was learning 8086 assembler (back in the days of MS/PC-DOS), and cringed when I noticed the segmented memory architecture -- had flashback of IBM-360/370 assembly code. Not that I'd hated it -- just cringed at the memories of results of mistakes when I'd accidentally trashed the contents of a base register and sent the program into parts unknown (if you were lucky you'd cause a memory fault immediately -- if you were unlucky your program would start dooing some really "interesting" stuff before bringing the system down). Did breathe a sigh of relief that segment registers on the 8086 weren't usable as general-purpose register (avoiding some of the problems I'd encountered with IBM-360).