At 4:47 PM -0700 6/18/2010, ah...clem wrote:
i've just been informed by a reliable source that OSX is a 32-bit
operating system,
Mac OS X has provided a 64-bit application environment for quite some
time, on hardware that could support it. Parts were there in Tiger,
then more in Leopard. But it wasn't until Snow Leopard's (OS X 10.6)
release that there was a pure 64-bit kernel.
Yes, OS X runs in mixed mode. The bitness of the kernel is
essentially independent of the bitness of the higher/app layers.
and because of that, no application can address more than 2GB of RAM.
"RAM". Are you talking about real memory or virtual?
In 32-bit mode, OS X provides each process with a 4 GB virtual
address space. Of course, not all that space is usable - some of it
is mapped to shared frameworks etc. Iffa you map less, you get more
VM to play in.
In 64-bit mode, OS X provides each process with up to 16 EB.
Due to physical memory controller limitations, the max real memory
space is 32 GB. Maybe someday Intel will do something about that...
if this is true, i am shocked. WTF is going on at apple?? hyping
64-bit hardware for the past seven years and loading it with a
32-bit OS??? can anyone confirm or refute this assertion?
The issue of 64-bitness in the kernel -- something which the app
never has access to anyway -- is more about the hardware itself.
It's tuff to sell a 64-bit kernel when so many peripherals don't work
in that hardware environment at all.
At 9:35 PM -0400 6/18/2010, iJohn wrote:
there aren't a heck of a lot of apps out there which would
ever actually test the 32-bit memory limits.
Quite true. The #1 benefit to a 64-bit system goes to the memory
manufacturers. They love the idea of selling you more memory, even
if 2/3 of it goes unused.
- Dan.
--
- Psychoceramic Emeritus; South Jersey, USA, Earth.
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