On Wed, 2004-09-08 at 16:18 +0100, Paul Brook wrote: > On Wednesday 08 September 2004 15:42, Ron Johnson wrote: > > On Wed, 2004-09-08 at 15:03 +0100, Paul Brook wrote: > > > On Wednesday 08 September 2004 14:45, Ron Johnson wrote: > > > > In fact, it seems to me that *any* 32 bit processor (SPARC, HPPA, > > > > Power) that wants to be able to use more than 4GB of total RAM > > > > would have to use such a segmentation scheme. > > > > > > Err, all of the above have 64-bit variants. > > > > Yessss, but they didn't *start* with 64 bit variants. > > Actually Power did. It was designed as a 64-bit architecture that can also be > run/implemented with only 32-bits. http://www3.sk.sympatico.ca/jbayko/cpu5.html#Sec5Part4 "Part IV: IBM RS/6000 POWER chips (1990). . . ." "Thirty two 32-bit registers were defined for the POWER1 integer unit, which also included certain string operations, as well as all load/store operations." Blah blah blah POWER2 "It was superceded by the POWER3 (Early 1998), with eight functional units (two FPU, three integer (two single cycle, one multicycle), two load/store, and branch unit), but capable of operating at much higher clock speeds. In addition, a 64 bit version, the PowerPC A35 (Apache), was designed for the AS/400 E series" So, the first 64 bit POWER chips arrived 8 years after the 32 bit versions. > > > I don't know if the > > > 32-bit variants support more than 4GB ram, but I doubt it. > > > > Oh come on. You think the SPARC32s, Powers & PA-RISCs that ran > > big Solaris, AIX and HP-UX SMP boxen in big shops *never* had more > > than 4GB of RAM? > > > > I find it supremely hard to believe that Intel is the only company > > to have a 32 bit chip that can address more than 4GB of RAM. > > Well, sparc64 has been around an awful long time. Adding PAE-like hacks seems Since 1995. > a strange decision when you have backwards compatible 64-bit CPUs. There were largish SMP SPARC32 boxen for many years before the SPARC64 came into existence. I can't find any references on the web, but some of those big boxen had to have more than 4GB RAM. -- ----------------------------------------------------------------- Ron Johnson, Jr. Jefferson, LA USA PGP Key ID 8834C06B "Peace is a daily, a weekly, a monthly process, gradually changing opinions, slowly eroding old barriers, quietly building new structures." John F Kennedy
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