[dvlug] 64 vs. 32 bit

[Rick Moen]

Quoting Grant Bowman (grantbow at ubuntu.com):

> Thanks for those important distinctions, Rick. Any thoughts as to why
> the 64 bit transition hasn't completed yet?  For Linux compatibility
> with proprietary Adobe Flash has been a problem in the past but to my
> knowledge this and other similar 64 bit compatibility issues seem to
> be resolved now for end users.

I don't fully know, except my SWAG (silly wild-assed guess) would be 
that a large part of it is proprietary AV codecs (and browser plugins).
That is, last I checked, quite a number of those were IA32-only because
the firms felt that to be a sufficient solution (even though ndiswrapper
can make that problem be smoothed over).

I know that a certain amount of laziness sets in, e.g., projects saying
'we're not bothering with an x64 build because we'd have to do
additional QA'.  That much is true in open source, too.

It should also be noted that x64 is not necessarily an advantage:
The extensions make possible somewhat cleaner code, offers more
registers, gives better access to large pools of memory on machines 
having over 4 GB physical RAM, and _potentially_ speeds things up.
However, on the other hand, there are also drawbacks, e.g., all your C
pointers automatically taking double the RAM upon malloc (and those and
other things that are suddenly double-sized become that much slower).

So, it remains a trade-off, albeit one where the advantages of x64
are slowly increasing over time.

However, until devices with significantly more than 4 GB physical RAM 
are more prominent than they are today, the most compelling advantage
(the better access to large pools of memory) doesn't really apply.