[thelist] Determining Linux version of my host

[Rich Points]

Hi,
I'm installing the Zend Optimizer and when I go to download the source 
files I'm asked which version of Linux I'm using, I have no idea.  The 
choices are

linux-glibc21-i386 (4.96Mbytes)
Linux x86-64 (5.42Mbytes)
linux-glibc23-ppc64 (5.23Mbytes)

I wrote my host about this but they are slow to respond so I thought I'd 
try here.  I don't have shell access on this account.  Is there some 
kind of PHP I could stick in a page to find out this info?

Thanks
Rich