[Ham-Mac] LoTW and Mac OS X 10.6 Snow Leopard

[David Ferrington, M0XDF]

Hmmm, interesting, and of course the big thing about 64bit of memory  
addressing - thanks
73 de M0XDF
-- 
A society grows great when old men plant trees whose shade
they know they shall never sit in. -Greek proverb

On 2 Sep 2009, at 16:35, Jack Brindle wrote:

> Interestingly, maybe not. It seems the wider math for pointers (64
> bits vs 32 bits) tends to wipe out any speed advantage. Plus the
> kernel doesn't actually need to manage more than 4GB of memory. When
> you add to that the memory data paths may be 32 bits, which requires
> two fetches for 64 bit pointers, we can see the potential for slow-
> downs. It seems the extra registers in the CPU you get when the 64-bit
> flag is enabled may not counteract the rest of the system design. I
> bet down the road when we have 64 or 128 bit cpus and memory data
> paths things will scream.
>
> The Apple developer information for 32 vs 64 bits is rather
> interesting. 64 bits for apps that need it and large memory systems is
> worth while. For smaller systems it may not be. That's why they
> enabled it on big servers but not on consumer systems.
>
> On Sep 1, 2009, at 11:35 PM, David Ferrington, M0XDF wrote:
>
>> Because in theory, it will be much faster.
>> 73 de M0XDF
>> -- 
>> In theory, there is no difference between theory and practice,
>> but in practice there is.
>>
>>
>> On 2 Sep 2009, at 05:20, Jack Brindle wrote:
>>
>>> Why would you go to the 64 bit kernel?