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Hello,

On Mar 6, 2007, at 01:55, jonathan michaels wrote:

> can i run sparc applications on a sparc64 built system.

Usually yes - if you have options COMPAT_NETBSD32 in your kernel config 
you can run 32bit sparc binaries on NetBSD/sparc64. Tools that muck 
around with kernel memory will not work though, use their 64bit 
equivalents.
Or, you can run a 32bit kernel on a 64bit machine, have a look at the 
GENERIC32 kernel config on arch/sparc64/conf.
That said - all UltraSPARC CPUs can run binaries compiled for SPARC V8 
CPUs, but only in user mode. Kernel mode is incompatible between 64bit 
and 32bit SPARC and most Ultras have hardware registers outside the 
lower 4GB physical address space so the kernel needs to be a 64bit 
binary in any case. On sparc64 you have the choice to build a kernel 
that natively runs 64bit userlands or one that natively runs 32bit 
userlands. On the former you can emulate enough ( that's what 
COMPAT_NETBSD32 is for ) to run most of the latter.

> i have many sparc ultraII cpu machines (ultra 60 and half dozen 
> creatord3d machines
> and netra but also some ss20's. is it possible to built a seamless
> network using a mix of machines  without reference to 64 bit/not 64 bit
> hardware and use just teh netbsd sparc port and forgoing some of teh
> 'specialties; that would be available from a a sparc64 hardware
> installed with sparc64 opsystem, much like the way people use thier 
> amd64
> based machines with freebsd 32 bit operating system and applications
> packages.

As long as you don't want to share binaries across all your machines 
there isn't much to consider. Some applications that benefit from 
having 64bit longs or sparc v9 instructions will take a (usually small) 
performance hit but that might be compensated by lower memory 
consumption to some degree.

have fun
Michael
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