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Article #5409Hard disk write protect
From: Kevin P. Kleinfelter
Date: Thu, 23 Jan 1986 14:56
Date: Thu, 23 Jan 1986 14:56
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1708 bytes
Recently there has been discussion of copy protection schemes trashing disks. Another case where disks can get trashed is when the programmer is developing software which may alter MS-DOS memory, and possibly causing invalid directory information to be written to the disk. On a floppy based system, these disasters are easy to avoid: you just put a write protect tab on the endangered diskette, and test away (or just make a quick backup). These approaches are inappropriate for a hard-disk based system. (There is no write protect notch, and a "quick" backup can take over an hour!) You can argue that booting your hard-disk PC from a floppy means that MSDOS doesn't know about the hard disk, and therefor won't update it erroneously, but if I am writing software which mucks about with memory and IO ports, I still might end up trashing my precious 20 megs. Why doesn't anyone sell a hard disk with a write protect switch on the front bezel? What would be involved in adding one? (I assume that there must be a write enable line from the controller to the disk. Would I simply need to install a SPST toggle switch in this line, or would it be more complex?) Disclaimer of responsibility: I am irresponsible.
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!watmath!clyde!cbosgd!gatech!gitpyr!kpk From: kpk@gitpyr.UUCP (Kevin P. Kleinfelter) Newsgroups: net.micro.pc Subject: Hard disk write protect Message-ID: <1283@gitpyr.UUCP> Date: Thu, 23-Jan-86 09:56:27 EST Article-I.D.: gitpyr.1283 Posted: Thu Jan 23 09:56:27 1986 Date-Received: Fri, 24-Jan-86 09:19:45 EST Distribution: na Organization: Georgia Institute of Technology Lines: 25