Foray into 64-bit computing
Posted by mop Thu, 12 Aug 2004 15:00:00 GMT
A summary of my experience to date with AMD’s 64-bit platform...
AMD has been developing 64-bit processors since 1999 or so, and released their first commercial chips in 2003. Large word systems have been around for some time (SPARC, MIPS, etc.), so why now and why AMD? Much of the recent interest in 64-bit systems is due to the scaling of commodity hardware - processors are fast and memory is cheap. In theory, fast hardware will diminish the overhead associated with larger data chunks and registers, and 64-bit systems can utilize large amounts of RAM. The new AMD processors are interesting because they are backward compatible with Intel 32-bit instruction sets (i.e. you can use binaries compiled for x86) and because the chips are priced to compete with 32-bit commodity hardware.
32-bit emulation
Is it marketing hype or is AMD64’s backwards compatibility a stroke of genius. Perhaps on a desktop, where you’re running a mix of compiled and commercial software it’ll be nice to have a choice. The reality is probably not that simple, but I suspect OSs will adapt. On servers, I suspect that most 64-bit systems will run in a pure 64-bit environment.
larger address space
The AMD address space is larger than conventional systems (40-bit, I think) allowing many gigabytes of RAM (terrabytes?) to be addresses without funky munging that is required in 32-bit systems. The 4GB address space of 32-bit systems is becoming a practical limit in today’s commodity systems. This, I think, is AMD64’s current sweet spot.
