One wonders, then, why the basic utils, like cp and mv don't deal with it better?
Cp deals with it. Info page for mv says that mv is using same code as "cp -a" when moving files from one file system to another. When moving files within single file system, the file actually stays where it was on the disk. Only pointer from directory structure is moved from one place to another (try it, if "a" is 10GB file, than "mv a b" will be almost instant).
-- Aleksandar Milivojevic <amilivojevic@xxxxxx> Pollard Banknote Limited Systems Administrator 1499 Buffalo Place Tel: (204) 474-2323 ext 276 Winnipeg, MB R3T 1L7