Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site zehntel.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!godot!harvard!seismo!hao!hplabs!intelca!qantel!dual!zehntel!zinfandel!dave From: dave@zinfandel.UUCP Newsgroups: net.micro.cbm Subject: For per at acf4 Message-ID: <1732@zehntel.UUCP> Date: Fri, 4-Jan-85 04:19:01 EST Article-I.D.: zehntel.1732 Posted: Fri Jan 4 04:19:01 1985 Date-Received: Sun, 6-Jan-85 01:09:27 EST Sender: berry@zehntel.UUCP Organization: Zehntel Automation Systems Inc, Walnut Creek CA Lines: 72 Nf-ID: #N:zinfandel:19800016:000:2259 Nf-From: zinfandel!dave Jan 2 10:10:00 1985 < > Sorry to bother the whole net (actually, you might be interested anyway), but I could not get this message through the mail. Date: 21 Dec 84 17:41:40 PST (Fri) From: zinfandel!ihnp4!cmcl2!MAILER-DAEMON (Mail Delivery Subsystem) Subject: Returned mail: User unknown Message-Id: <8412230536.AA01317@zinfandel.UUCP> Received: by ihnp4.ATT.UUCP; id AA24432; 22 Dec 84 11:12:35 CST (Sat) Received: by NYU-CMCL2.ARPA; Sat, 22 Dec 84 06:01:12 est Received: by zinfandel.UUCP (3.327/3.14) id AA01317; 22 Dec 84 21:36:21 PST (Sat) To: ihnp4!zehntel!zinfandel!dave Status: RO ----- Transcript of session follows ----- >>> RCPT To:<<< 550 ... User unknown 550 acf4!per... User unknown ----- Unsent message follows ----- Received: by NYU-CMCL2.ARPA; Sat, 22 Dec 84 06:01:12 est Received: by ihnp4.ATT.UUCP; id AA10899; 22 Dec 84 02:19:45 CST (Sat) Date: 21 Dec 84 17:41:40 PST (Fri) From: ihnp4!zinfandel!dave (Dave Funk) Subject: 1541 Scratch Proofing Message-Id: <8412220141.AA14198@zinfandel.UUCP> Received: by zinfandel.UUCP (3.327/3.14) id AA14198; 21 Dec 84 17:41:40 PST (Fri) To: zehntel!ihnp4!cmcl2!acf4!per About "scratch-proofing" files on the 1541.... Byte 2 (starting from byte 0) of the directory entry for a given file contains the file type. This information is on track 18, sector 0. To wit: $80 DELeted $81 SEQuential $82 PRoGram $83 USeR $84 RELative To scratch-proof a file, just change the '8' to a 'C'. This sets bit six in byte number two. Now when you cat the disk, you will see a '<' after the file type. If you try to scratch it, you will not get an error, but the file is NOT actually scratched. If you do another cat, it is still there just like it always was. The only way to scratch it now is 1) reset bit six or, 2) 'new' the disk. Pretty neat, huh? Now, how does one do this? I suppose you could figure out a way to send a command to the disk drive, but I just used a disk editor. RUN magazine published one a few months ago -- I used CLONE (a commercial disk copier/editor). If you need more details, just holler! Dave Funk Zehntel, Inc. 2625 Shadelands Drive Walnut Creek, CA 92598 (415) 932-6900 x309 ....!decvax!sytek!zehntel!dave ...."zehntel!dave"@BERKELEY