Best way to have a byte array + NSZone questions

[Aurelien]

I have to access a raw byte array from within an object (it's a 
@protected instance variable). What's the best way to do that ? With 
NSData ?

When examining how to do it, I wondered what was the use of the 
NSXallocWithZone* methods, and what an NSZone object was. It's not 
documented in Apple's Foundation doc. Also when you NSXAlloc, you have 
to specify an NSZone pointer, but how do you get one ?

Also, generally speaking, I'd like to know if I'm not totally mistaken 
saying that simply, you have to send a retain message to an object when 
you don't want that object to be released when the object that created 
the given object is itself released. It means that the + <objectName> 
methods (those that statically return instances of a given class), 
return objects that could potentially be instantly released. Do you have 
to send a retain message to those objects right after getting them 
then ? What is the object that actually "owns" such statically created 
objects ?

Thanks for your help,

Aurélien