I have a C++ program that opens, gets a little data from, and closes about 5000 files. Now if I run the program when I first boot up, the running time is from about 10 seconds to a minute. Subsequently, the program runs in well inter one second. Buffering -- right? So I changed a parameter, so the program gets a different (albeit similar) 5000 files from a different directory. Running time on the first try: well under one second. How about that? [~]$ uname -a Linux xxxxx 2.6.18-194.32.1.el5 #1 SMP Wed Jan 5 17:53:09 EST 2011 i686 i686 i386 GNU/Linux Thanks for your comments. Mike.