#DOS/Windows, etc.
GDI does stand for "Graphics Device Interface." It's responsible for most all
imaging operations done in windows (managing windows, fonts, printing,
etc….).
System resources is a combination reference to the GDI stack as well as the
USER stack. I'm not entirely up on what the user stack does (as it causes less
problems for most people than the GDI does, there hasn't been a lot of talk in
the trade rags about it…), but I'd guess it handles tracking open files and
other system related stuff.
Both GDI & USER stacks are limited to 64K because the 8088's memory page
limitation is 64K. Windows originally was written run on 8088s and up. Just
like MessyDOS, Windows has all sorts of little holdovers for compatibility
purposes. It's getting pretty disgusting that MessySoft can get away with this
@#$% trashy programming, eh?