[ahoward@localhost ~]$ strace ruby -e' 1.times{ require "digest/md5.so" }' 2>&1 |grep open|grep md5
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY) = 3

   [ahoward@localhost ~]$ strace ruby -e' 2.times{ require "digest/md5.so" }' 2>&1 |grep open|grep md5
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY) = 3

   [ahoward@localhost ~]$ strace ruby -e' 3.times{ require "digest/md5.so" }' 2>&1 |grep open|grep md5
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY) = 3

   [ahoward@localhost ~]$ strace ruby -e' 4.times{ require "digest/md5.so" }' 2>&1 |grep open|grep md5
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY) = 3

   [ahoward@localhost ~]$ cat a.rb
   4.times{ require 'digest/md5' }

   [ahoward@localhost ~]$ strace ruby a.rb 2>&1 |grep open|grep md5
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3
   open("/usr/local/lib/ruby/1.8/i686-linux/digest/md5.so", O_RDONLY|O_LARGEFILE) = 3

why the difference?

-a
-- 
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