Path: utzoo!attcan!uunet!mcvax!unido!nixpbe!ugun21!josef From: josef@ugun21.UUCP Newsgroups: comp.os.cpm Subject: Re: Recovering Erased CP/M Files Message-ID: <17700005@ugun21> Date: 25 Nov 88 07:43:00 GMT References: <6601@pucc.Princeton.EDU> Lines: 43 Nf-ID: #R:pucc.Princeton.EDU:-660100:ugun21:17700005:000:1327 Nf-From: ugun21.UUCP!josef Nov 25 08:43:00 1988 In his note, PKNIGHT@pucc.UUCP writes: > Is there any way to recover erased files on a CP/M disk? These are > WordStar files on a diskette formatted in a Kaypro machine. Ya bet there is! If You look at the CP/M disk directory entry format: uu ff ii ll ee nn aa mm ee ee xx tt ee 00 00 nn || | | || || || ^-- filename.ext --------------^ || ^^-- file size in sectors || ^^-- extent ^^-- user area number or -- 0e5h if erased aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa | | ^-- allocation group numbers --------------------^ Note: The only difference between an unused and a used entry is the user area field value. If the file is erased, it is e5, if not, it is 0 <= uu <= 15 (or so). (Of course, You must somehow take the free blocks into account) There are a number of (PD) programs floating around that do the desired unerasing. BEWARE: You must not do anything after having ERAsed the files. I have one, if You want to, I'll send it to You. Send me Your e-mail address! Josef Moellers paper mail: e-mail: c/o Nixdorf Computer AG USA: uunet!linus!nixbur!nixpbe!mollers.pad Abt. EG-3 !USA: mcvax!unido!nixpbe!mollers.pad Unterer Frankfurter Weg D-4790 Paderborn tel.: (+49) 5251 104691 Standard disclaimer: Blablabla opinion blablabla employer blablabla!