[Pythonmac-SIG] 64-bit code

[Jack Jansen]

On  17-Jun-2007, at 20:06 , Kevin Walzer wrote:
> OK, I guess this means that 32-bit isn't going away any time soon. The
> Carbon-dev list seems to think that this announcement means Carbon is
> going the way of Classic. At least some of the people on that list say
> that they will drop Mac support rather than port to Cocoa, because  
> they
> need 64-bit. That's not directly germane to my concerns, as I don't
> think I need 64-bit for what I do.

The last sentence is the pit you'll fall in. At least, it's the pit  
that I'm scared of falling in.

Even though my own code would benefit little from 64 bits, it depends  
on all sorts of third party libraries (mainly media stuff in my case,  
but the same holds for many other fields). As soon as such a library  
gets a twofold performance increase from switching to 64bits it's  
going to be very tempting for me to follow suit.

And this works iteratively: as soon as I switch to 64bits then people  
using my stuff will have to follow too. And even the tiniest  
application nowadays uses layer upon layer of third party software.  
Indeed, 32 bit support isn't going to go away in the next 2 years,  
but the bell has tolled. Compare what happened to Windows programs  
when they switched from win16 to win32: even though win16 programs  
could technically continue to be run for a pretty long time they were  
cut off from new developments and either were ported or died.

But, all that said, I'm not scared of the 32-64 transition. For my  
own code it'll probably be comparable to the PPC-Intel transition:  
more work than you hope for but nothing as drastic as the OS9-OSX  
switch or the 68K-PPC switch. The only thing I'm a bit scared of is  
Apple's own useful toolkits that depend on Carbon, specifically  
QuickTime and AppleEvents. I'm not too sure about AE, but for  
QuickTime I know that you have to leave QTKit and switch to the old  
QuickTime API's very often if you do more than play a simple video.  
So effectively this'll mean that the "single toolkit for everything"  
paradigm will break, because Oldstyle-C-Quicktime will (in 64 bit  
space) lose it's ability to tweak the rendering so it'll be an edit- 
only API and QTKit will have to be used for rendering.
--
Jack Jansen, <Jack.Jansen at cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma  
Goldman


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