> Yes, this is definitely good to see computer memory so cheep. There is
> a down side to this I fear, though. The 32 bit software and Os(s) would > only address 4G memory max, because that is the biggest integer possible > in a 32 bit binary system. The 64 bit processor can address > exponentially greater amounts of memory, because the number set in a > binary system that uses 64 bits integer will go up to > 18,446,744,073,709,551,615, (eg the top register of memory). This is a hard argument, Leland, because I'm reminded of Bill Gates saying users will never need more then, what was it, 64KB of RAM? That said, I'm sure we'll find ways to eat all the memory we're ever given, but as a practical matter, today I'd rather have 4GB of RAM then a 64 bit processor. <clipped> > This is dependent upon the hardware manufacturer providing > memory, CPUs, and other hardware that maintains compatibility with > applications that are 16 bit, or like VFP, that are 32 bit. At some point the industry > may break with this backwards compatibility, and once a clients buys > into new incompatible hardware, it may require that they purchase new > specialized computers designed specifically to run in 32 bit > emulation, along with the VM and application. This could be a very hard sell. I don't know this because I don't yearn for a 64 bit processor, but my guess is 64 bit machines will necessarily support both 32 and 64 bit modes to be practical and saleable. RE consideration of what it means to run 32 bit "emulation mode" on a 64 bit machine. Admittedly my internals background is big iron, but I can't imagine the PC is that much different on this matter, so I'll venture to say that running 32 bit software on a 64 bit machine boils down to a bit switch being set that controls how instructions are to be decoded (which is performed by a look-ahead/pre-processor before instructions are presented to the CPU). This being the case, I wouldn't expect any significant performance degradation by running 32 bit software on a 64 bit machine - that is, unless perhaps the CPU designers deigned to make that so. > A better solution would to be to get VFP into the hands of a > new vendor that would port her to a standardized 64 bit instruction set, and > otherwise bring VFP up to date, like making her better suited to run > over the internet and increase the maximum table size. Complete agreement <clipped> > With 8 bit, 16 bit, and 32 bit software, memory was limited requiring > the OS manage it very carefully. The day may be coming when > programmers would have virtually unlimited amounts of memory in which to work, so > I'll let your imagination fill in the blank on the possibilities and > changes that might occur in the way applications are > structured and how they might use the additional memory. As you've point out, 32 bit addressability limits RAM to 4gb, so either 64 bit or some other way of segmenting 4gb chunks is needed for, say, VM to manage larger amounts of RAM for 'x' number of 32 bit OS's. I don't know what techniques can/are being used, but I can imagine something right within VM doing it (i.e. VM managing 'n' number of 4gb real address spaces within a RAM farm of 100's of GB's) Bill <clipped> > LelandJ _______________________________________________ Post Messages to: [email protected] Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[EMAIL PROTECTED] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
