Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!snorkelwacker!apple!sun-barr!newstop!sun!amdahl!daf00 From: daf00@uts.amdahl.com (Dana Freiburger) Newsgroups: comp.arch Subject: Re: 64/32 bit processors - impending disaster? Message-ID: Date: 13 Feb 90 00:35:06 GMT References: <1990Feb12.182411.5982@ico.isc.com> Reply-To: daf00@amdahl.uts.amdahl.com (Dana Freiburger) Organization: Amdahl Corporation, Sunnyvale CA Lines: 12 Instead of 64 bit addressing, the ESA/370 architecture uses the advanced address-space facility to provide multiple address spaces 2G-byte in size. In effect, many 2G-byte spaces (31 bit addressing) versus one single giant address space (32+ bit addressing). I don't think IBM was worried about C programs when they designed ESA/370; IBM needed to provide a way for a program to have access to a larger concurrent address space than 370-XA allowed but with a level of compatibility with 370-XA. In this case, it's programs defining the architecture, not the architecture defining the programs.