On Mon, 25 Aug 2003, chris wrote: DOS Format tries to READ every sector (in bunches of clusters) so it can tell which clusters are to be marked BAD. That is why it takes so long to format a disk under DOS. Starting with (I believe) 4.0, DOS added the volume serial number biz, and options to ease un-recovery of deleted files, as has been stated before. These include keeping a copy of the root dir and FAT around towards the end of the disk[partition], and a change in allocating directory entries (from overwriting the first "available" one to the first one that was not previously deleted; if available). The /U specifier to Format changes this back to the old behavior, meaning, just read all sectors, and dont try to keep the FAT and root dir around. There is some changing behavior between versions with regard to formatting a previously formatted drive... some versions will take on the previous format (and "skip" to using "new style" format), others really do the /U, even when a valid format is already there. cheers, Fred