Subject: Re: bootable cdrom
To: Sean Davis <dive@endersgame.net>
From: None <sigsegv@rambler.ru>
List: port-sparc64
Date: 02/12/2005 18:15:01
Sean Davis wrote:
>>1) Some packages are not 64-bit clean, so they need to be compiled and 
>>run as 32-bit executables
> 
> 
> Yeah, but I run with a minimal set of packages anyhow on that machine. My
> question was mainly: what are the pros and cons of sparc32 vs. sparc64
> NetBSD on a sparc64 machine. So far the only pro I see is the "some
> programmers are lazy" one :)

Well I may be wrong but here is what I think:

It makes sense to run 64-bit kernel + user applications only if you need
to address huge amounts of RAM. High end Sun servers support many
gigabytes of RAM, however NetBSD does not support such hardware

64-bit binaries are usually bigger than 32-bit, due to 64-bit pointers
and longs, etc. This takes up precious RAM and cache memory. On low
end Sun hardware, where you'll be lucky to have 1GB of RAM, I don't see 
any compelling reason to run 64-bit code

I don't know how this affects the kernel, i.e. maybe 32-bit kernel will 
not be able to support huge filesystems, spanning many terabytes.

Some integer arithmetic on long long datatypes may be faster in 64-bit 
mode, however I suspect compiling with gcc's -mcpu=ultrasparc may be 
able to produce 32-bit code which handles 64-bit integer arithmetic much 
more efficiently.