ruby -e "puts 'test'.hash"

Should this output the same integer value on all platforms where Ruby  
can run?

* Windows
ruby --version    #=> ruby 1.8.6 (2007-03-13 patchlevel 0) [i386- 
mswin32]
ruby -e "puts 'test'.hash"   #=> -914358341

* Mac 10.5
ruby --version    #=> ruby 1.8.6 (2007-03-13 patchlevel 0) [i686- 
darwin8.10.3]
ruby -e "puts 'test'.hash"    #=> -914358341

* Linux 2.6 Kernel
ruby --version    #=> ruby 1.8.6 (2007-06-07 patchlevel 36) [x86_64- 
linux]
ruby -e "puts 'test'.hash"    #=> 1233125307

ruby --version    #=> ruby 1.8.5 (2006-12-04 patchlevel 2) [x86_64- 
linux]
ruby -e "puts 'test'.hash"    #=> 1233125307


It appears not!  So, any suggestions on generating an ID number for an  
object that is unique yet consistent across different platforms?  I'd  
like to have some method that I could call on an object that would  
return a reproducible value that would uniquely identify that object.

Thoughts?

TwP