dmnhieu@watdragon.waterloo.edu (Duy-Minh NHIEU) (12/22/88)
Does any one know how to write protect a harddisk? Ie. you still can read but can not write to it? (Withou any hardware modification?) Please send reply to: dmnhieu@watdragon.uucp
simcha@humming.UUCP (Simcha Lerner) (12/23/88)
In article <10548@watdragon.waterloo.edu> dmnhieu@watdragon.waterloo.edu (Duy-Minh NHIEU) writes: >Does any one know how to write protect a harddisk? Ie. you still can read >but can not write to it? (Withou any hardware modification?) > >Please send reply to: dmnhieu@watdragon.uucp The easiest way to write protect a drive __VIA SOFTWARE__ is to write a TSR that monitors int 13 and intercepts all attempts to write to the hard drive. The tsr can either return an appropriate error or silently hide the fact that the write never took place, depending on your needs. CAVEAT EMPTOR: If you are concerned about viruses, many (most?) are smart enough to either access the hard drive controller directly, or at least call the original ROM entry point directly (without going through the interrupt vector table and therefore your tsr). A non-intrusive hardware solution is to install a short M to F ribbon cable between the hard drive and the cable from the controller. The line that enable writes can be switched, and this switch can be run outside the case (keep things short and low capacitance or you'll foul up timing). This is the only method that will protect against programs with malicious intent. The software approach is more appropriate to protecting the drive from accidental writes by user errors or "normal" program bugs. While I have seen this add-on hardware approach in use in the past, I do not know if anyone makes them or if you have to "roll your own." Does anyone out there know of a source that sells pre-made write-protect add-ons? Simcha Lerner harvard!humming!simcha BTW: for the record, since I have been asked almost every time I've posted anything, I'm a Mr., not a Ms. <insert generic cute disclaimer here>
henkp@nikhefk.UUCP (Henk Peek) (12/24/88)
In article <257@humming.UUCP> simcha@humming.UUCP (Simcha Lerner) writes: >In article <10548@watdragon.waterloo.edu> dmnhieu@watdragon.waterloo.edu (Duy-Minh NHIEU) writes: >>Does any one know how to write protect a hardisk? > >While I have seen this add-on hardware approach in use in the past, I >do not know if anyone makes them or if you have to "roll your own." >Does anyone out there know of a source that sells pre-made write-protect >add-ons? No, but when you have a hard disk drive with wirewarp jumpers, you can make your own very easy. Replace the drive select jumper by a 2 pole mini-PV connector. Twist the two wires and connect the other side with the write protect switch. Only one mini-PV connector with wires is not easy to get. When you have problems with the parts, ask and we can make a small serie but they are not free of charge. Henk Peek ..!uunet!mcvax!nikhefk!henkp.UUCP
waters@dover.uucp (Mike Waters) (12/25/88)
In article <10548@watdragon.waterloo.edu> dmnhieu@watdragon.waterloo.edu (Duy-Minh NHIEU) writes: >Does any one know how to write protect a harddisk? Ie. you still can read >but can not write to it? (Withou any hardware modification?) > >Please send reply to: dmnhieu@watdragon.uucp Our mailer is not working so I am posting this to you. There are several programs available which effectively intercept or disable the interrupt for writing to hard disk. The best is called WPHD.EXE, which reboots if a write is attempted. Unfortunately if you are looking for worm/virus protection any software solution can be defeated with a little effort. I suggest a switch in the power line to the HD. There is NO WAY to write to a disk without power! A really sophisticated approach would be to substitute a floppy drive for the C: drive and see if IT gets written to. About the only foolproof system I know of is to monitor the news/BBSs after getting a program and before trying it. If no-one gets "caught" then you probably won't ;-) -- Mike Waters AA4MW/7 * Motorola CAD Group * Witty remark goes *HERE* Mesa, AZ ...!sun!sunburn!dover!waters * OR moto@cad.Berkley.EDU *
len@csd4.milw.wisc.edu (Leonard P Levine) (12/27/88)
>In article <10548@watdragon.waterloo.edu> dmnhieu@watdragon.waterloo.edu (Duy-Minh NHIEU) writes: >Does any one know how to write protect a hardisk? >While I have seen this add-on hardware approach in use in the past, I >do not know if anyone makes them or if you have to "roll your own." >Does anyone out there know of a source that sells pre-made write-protect >add-ons? A company Director Tech. makes an add in that will protect a contiguous batch of tracks on a hard drive. It installs between the controller and the disk. They are at 906 University Place Evanston, IL 60201 (312) 491-2334 No affilliation, just a customer. It works. + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + | Leonard P. Levine e-mail len@evax.milw.wisc.edu | | Professor, Computer Science Office (414) 229-5170 | | University of Wisconsin-Milwaukee Home (414) 962-4719 | | Milwaukee, WI 53201 U.S.A. Modem (414) 962-6228 | + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +