On <03 Nov 94 11:07> [EMAIL PROTECTED] in response to Si' wrote: >> Out of interest, does *anyone* have any >> idea how MSDOS undeletes >> files? I can't see how it's able to do >> it, unless the second FAT is >> only updated on a new-file-write...
Fr> MessDos deletes files by marking the Fr> first letter in the filename Fr> is marked '?'. The DOS recognizes the Fr> allocations in the FAT related Fr> to all files marked '?' as free and Fr> uses them as at will. To undelete Fr> all you have to replace the '?' with Fr> some legal character. Then IF you'r Fr> lucky and MS/DOS have not used any of Fr> the sectors related to that Fr> file, voila, you have an undeleted file. I presume that appart from swapping the char over you'd also have to force a re-logging of the drive if it's a fixed disk? Really! shades of stolen ideas from CP/M file handling! That just marks erased files with an 0E5h in the user area directory field and frees the allocated blocks bit-map of allocated blocks (aka clusters) Just one question.... Why then do the 2 MS-DOS undelete utils I've used NOT restore atleast the remaining unchanged chars in the name instead of the junk that they do? Probably somthing to do with Microsofts brilliant programmers.... NOT! Cheers Johnathan. ___ Olms 1.60 [Evaluation] +-------------------------------------------------------------------+ | Standard disclaimer: The views of this user are strictly his own | | ===> Gated @ Centronics BBS [centron.com] +44-1473-273246] <=== | +-------------------------------------------------------------------+
