[rescue] (ot) 64 bit binaries

[James Lockwood]

On Mon, 3 Feb 2003, Kevin Loch wrote:

> Is there any benefit to compiling software as 64bit binaries
> with the new gcc?

Sometimes.

Plusses: easy to use more than 4GB of VM in a single process.  Makes huge
file I/O via mmap() a lot easier.  A lot of restrictive limits in stdio
were lifted.  Stack is nonexecutable by default (see the V9 ABI spec).

Minuses: some code & data get bigger.  Some compilers break (mostly older
versions of gcc).  Some sloppy code that depends on
sizeof(int)=sizeof(long)=sizeof(pointer) will break.  Fortunately the
Alpha blazed the 64 bit trail and convinced a lot of people to clean up
their code, but there are still many developers out there who believe "all
the world's an x86 box".

Running the 64 bit vs 32 bit kernel on UltraSparc has other tradeoffs, but
from your question I'm assuming that you're already running the 64 bit
kernel.  I would not be surprised to see the 32 bit UltraSparc kernel go
away a few revs down the road, Sun already makes machines that can only
boot 64.

The decision can be made app by app, and I thank Sun for that.

-James