Path: utzoo!telecom-request Date: 6 May 91 20:14:29 GMT From: Toby Nixon Newsgroups: comp.dcom.telecom Subject: Re: Prodigy or Fraudigy ??? Message-ID: Organization: Hayes Microcomputer Products, Norcross, GA Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 339, Message 2 of 14 Lines: 26 In article , binder@decvax.dec.com (Simplicitas gratia simplicitatis) writes: > The formatting operation must by its very nature destroy the old data. > Formatting is a write operation that is done without reading to verify > position. It writes both the sector preambles and the data fields > instead of only the data fields. ... This is true, of course, for the initial low-level format of a disk. But a subsequent FORMAT command does nothing but rewrite the FAT and directories to show that the file spaces is all available. This is why a "deformat" program (e.g., Mace) that keeps a copy of the FAT and directories in inner cylinders can recover an accidentally-formatted hard disk by simply copying the saved information back to the outer cylinders. Nothing will recover from a low-level format, of course (although NSA and CIA supposedly have ways to even read this data by examining the residual magnetism in the media between tracks -- but I doubt it). Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net