stan wrote:
> Alan Cox wrote:
>> On Mon, 27 Oct 2008 11:54:47 -0400
>> Matthew Flaschen <matthew.flaschen(a)gatech.edu> wrote:
>>
>>> Alan Cox wrote:
>>>
>>>> The moment you have more than about 900MB of RAM there are big
>>>> advantages
>>>> to running a 64bit kernel as it can keep all of physical and virtual
>>>> space mapped at the same time, which is a big performance win.
>>>>
>>>> Alan
> Wouldn't you need twice as much memory to have the same memory for
> applications if you are using double the word size?
This is incorrect in general. GNU/Linux 32-bit uses ILP32, meaning
integers, longs, and pointers all have 32 bits. GNU/Linux 64 uses LP64,
which means longs and pointers have 64 bits. Integers remain 32 bits,
and ASCII chars are still 8 bits (this is true of ILP64, another model,
as well). Please read
http://www.unix.org/whitepapers/64bit.html.