Mac files have two "forks" - the data fork and the resource fork. For
data files, the resource fork contains a File Creator code and a File
Type code that older MacOSes use to determine which application is used.
With MacOS X, that fork is still created, but the OS can also use
extensions.

In older MacOSes, memory allocation is done at the application level.
Mac OS X dynamically allocates memory to apps as necessary, the same as
any other Unix-based OS.



In article ,
Dave Peterson wrote:

From someone who almost cried when I tried to use a Mac (before Windows,
though), is that how mac's know what program the file is associated with?
(And
how much memory to allocate???)

Just curious (for no apparent reason).