Thread View: alt.msdos.programmer
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Started by Robert Schmidt
Thu, 20 Aug 1992 14:28
Writing a boot password proggie, need tips
Author: Robert Schmidt
Date: Thu, 20 Aug 1992 14:28
Date: Thu, 20 Aug 1992 14:28
32 lines
2032 bytes
2032 bytes
I'm trying to make a boot sector program that requests a password from the user, and refuses to boot if the correct password is not corrected. I've figured out this: - I'll save the original boot sector at the last physical sector on the disk. Caveat: When I looked at this sector with DiskEdit I noticed some 'debris' from an earlier FORM-virus attack. How can I pick a safe sector? I thought about marking an unused sector bad, and use that... thoughts? - My boot program will relocate itself to 07c0h:0200h, that is, making room for loading the original boot sector, which must be put at 07c0h:0000h. Any hints on how to accomplish this? - I also want the harddisk to be unaccessible when the PC is booted with a DOS diskette in drive A:. I guess I will have to modify one/some of the values in the drive parameter table at the start of the boot sector program, but which value(s)? - When a boot has been successfully accomplished on C:, I need to put back the 'bad values' sometime, to make the HD unaccessible at next boot-up. A device driver in CONFIG.SYS sounds good enough. Ideas? If I ever finish this, I'll probably put it in the public domain, for you guys to pick from ftp's and bbs'es. Please reply via e-mail, it's easy to miss posts in News. -- Cheers from Robert Schmidt, aka Ztiff Zox, aka Buuud (IRC). E-mail to robert@solan.unit.no, snail-mail to Stud.techn. Robert Schmidt, Stud.post 170, Norwegian Institute of Technology, 7034 Trondheim, NORWAY Warlords: Now do you think my .sig is boring enough?
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