Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!mips!pacbell.com!att!ucbvax!VTVM1.CC.VT.EDU!VALDIS From: VALDIS@VTVM1.CC.VT.EDU (Valdis Kletnieks) Newsgroups: comp.protocols.ibm Subject: (none) Message-ID: <9105191913.AA23799@lilac.berkeley.edu> Date: 19 May 91 19:06:20 GMT References: Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: BITNIC IBM-NETS List Organization: The Internet Lines: 22 On Sun, 19 May 91 14:53:23 EDT Jean-Serge Gagnon said: >I am looking for a way to hardware write protect a hard disk. I do not >have any specific machine in mind or any particular disk in mind. At the >University we have a concern for this and would like to be able, when it >is asked to add some sort of switch that would prevent writing on the >hard disk in much the same way as the write protect notch on a floppy. OK.. I'll bite. If you don't have a specific machine in mind, how are we out here on the network supposed to provide specific advice? After all, the details on how to do this are going to differ between a Mac disk and and an IBM PS/2 and a NeXT and so on.. The generic solution is to purchase the wiring schematics for your particular combination of hard disk and disk controller, find the circuit that supplies write voltage to the head assembly, and either cut it permanently or install a switch. Make sure to make it a debounced switch, as having transients applied to the head while it's passing over vital data could be bad news.. ;) Valdis Kletnieks Computer Systems Engineer Virginia Polytechnic Institute