On Sun, 30 Jun 2019 21:11:27 +0100
The Natural Philosopher  wrote:

>On 30/06/2019 21:02, Richard Kettlewell wrote:
>> The Natural Philosopher  writes:
>>   
>>> On 30/06/2019 00:32, A. Dumas wrote:  
>>>> The work involved to maintain two concurrent releases (with a lot of
>>>> customisations) is their main reason apparently, yes, while the vast
>>>> majority of the install base (the Pis out there) isn't 64 bit compatible.
>>>> But their main software man also keeps saying: give me one good reason why
>>>> 64 bit is better than 32. See their blog on the new Buster release. Well,
>>>> it gets a bit embarrassing with lost optimisations when the current chip
is
>>>> armv8, for crying out loud. He says it doesn't make a difference but I
>>>> wonder.  
>>>
>>> Wasn't the drive to 64 bit more about accessing more RAM?  
>> 
>> More address space. CPUs with only 32-bit logical addressing can still
>> access more than 4GB physical RAM, but each process is still stuck in
>> 4GB (often less in practice).   
>
>I remember coding a 6809 with 256K of ROM and 16k of RAM. In assembler. 
>Page switching YUK!
>
>
>That’s a problem both for certain lagre
>> applications, and for security improvements like ASLR.
>> 
>> 64-bit GPRs are handy for some applications but rarely essential.
>> 
>> For both Intel and ARM the 64-bit instruction sets double the number of
>> architectural GPRs.   
>
>Ground penetrating radars?
>
>Particularly on Intel where the 32-bit situation is
>> pretty poor, that’s a big improvement for anyone writing in assembler.
>>   
>
>Yebbut thats not an itrinsic feature of 64 bit acrhitectures.
>
>Andf compilers *know* about that so its not JUST in assembler
>
>
>Anyway I think the opinion set is converging on the fact that more RAM 
>is more important than a 64 bit distro

The difference is not trivial if you are doing complex and high resolution
video and/or audio generation and processing. You are likely to be using
long ints and doubles in tight loops - and I'm not talking about just playing
MP3s.

On top of this I think there are extra features in the BCM2711 that the Pi
4 software doesn't use in order to maintain compatibility.

I don't buy the argument about confusing newbies with different OS versions -
especially when these users are most likely to get the thing as a complete
package


-- 
W J G

--- SoupGate-Win32 v1.05