Pi v3 on sale now

Well done, and thank you.

Gordon,

Thanks for the report. I have my RPI v3 on order....but may I ask a question.

Will C programs compiled on the RPi v3 work on the RPi 1 and 2, if they only use Linux calls? I'm thinking of CPU core differences making that questionable. At the moment, the standard NTP software I compile on the RPi B 2 appears to work on the RPi B. I'm also concerned about OS differences. Software compiled on the RPi 2 with Linux 4.0.8-v7+ (Wheezy?) works correctly 4.1.17-v7+ (Jessie?)

Thanks!

--
Cheers, 
David 
Web: http://www.satsignal.eu

Yes. Should all be backward compatible with the standard GCC flags. Even backwards from Jessie to Wheezy (so I'm told - not tried it yet) Wheezy to Jessie appears to work as I have tried that.

I'm currently compiling on a Piv 2 for stuff I'm testing on Pi v1's.

Gordon

Just as with the 2B model, the user programs will still all be in

32-bit ARMv6 code. Only the kernel on the 2B is ARMv7 so likely there will be a 64-bit ARMv8 kernel for the 3B.

"the possibility of 64-bit user programs" is considered as an option for the future. See the announcement page on raspberrypi.org

Note that running 64-bit code on a system with 1GB of RAM is not really an advantage.

On 29/02/2016 09:48, Gordon Henderson wrote: []

Thanks Gordon, and thanks Rob. Most helpful.

--
Cheers, 
David 
Web: http://www.satsignal.eu

The address bus was always 40 bit, I think? So 1 GB is not an issue. The speed advantage from recompiled code for ARMv8 would come from double the general purpose and floating point registers (might be 10%), double width FP/NEON registers (see

fewer conditinal instructions meaning simpler (=faster) architecture, hardware cryptography, and an otherwise extended instruction set. Source:

I think the address bus is 30 bit and therefore it is not very useful to address using 64-bit values (normally the reason to use 64-bit mode).