I have just finished recovering the data from a failing NT4 installation. The dd took _ages_ but reported no i/o errors, but booting failed with a checksum failure and investigation revealed there was a single bit error in a critical file which I subsequently replaced from a download of NT4 sp6a. A single bit error in one file obviously raises the possibility of more such errors... So I have a directory tree of NT4 files in the image I took of the original disk, mounted under Linux, and a flat directory containing the files from service pack 6a, and I want to compare them. There are heaps more files on the disk but these are the only ones I have the originals of. So the disk image fs looks like (for illustrative purposes only - actual filenames may not be correct): /WINDOWS/welcome.exe /WINDOWS/system32/mem.exe /WINDOWS/system32/WINSRV.dll /WINDOWS/file_that_does_not_exist_in_sp6a.dll and the sp6a directory looks like: /sp6a/WELCOME.EXE /sp6a/mem.exe /sp6a/winsrv.exe /sp6a/file_that_does_not_exist_on_installation.dll The files are possibly in different directories, and are possibly different cases. I could write some horribly inefficient shell script to just go through each file in the sp6a directory and find a file with the same name in the /WINDOWS tree and diff it, but maybe there is a better way? This would at least give me a very rough idea of how many errors I might be looking at. Thanks James