64 bit Intels?

Joe Griffin joe.griffin at mscsoftware.com
Mon Apr 22 09:52:02 EDT 2002


The Itanium is NOT 64 bit like a CRAY is 64 bit.
It is an LP64 (longs and pointers).

In FORTRAN: INTEGERs and REALs are still 32 bits.

In C, int are still 32 bits.

You are allowed larger addressing because
longs and pointers are 64 bits.

You may get 64 bit numberical accuracy
in FORTRAN by use of "DOUBLE PRECISSION" but
this capability is the same as on IA32 systems.
The item you gain is that you have a
bigger address space.

Regards,
Joe


Troy Baer wrote:
> On Fri, 19 Apr 2002, Todd Henderson wrote:
> 
>>We are currently specing out a new cluster and since we have a corp. agreement with one of the big pc vendors, I
>>thought I'd contact them.  They claim that the P4 Itanium is 64 bit, only in the 733 and 800 mhz speeds.  Is
>>Linux on Intel 64 bit for these processors?
> 
> 
> The Itanium isn't a P4 derivative; it's a totally different architecture
> that is in fact 64-bit.  Linux on them is 64-bit clean AFAIK.
> 
> 	--Troy



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