Path: utzoo!utgpu!watmath!att!dptg!rutgers!apple!usc!csun!srhqla!tcm
From: tcm@srhqla.SR.COM (Tim Meighan)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Preventing Floppy Boots
Message-ID: <1125@srhqla.SR.COM>
Date: 30 Aug 89 16:41:55 GMT
Reply-To: tcm@srhqla.SR.COM (Tim Meighan)
Distribution: na
Organization: Silent Radio, Los Angeles
Lines: 28

In article <1989Aug15.183532.27998@ee.rochester.edu>
jal@ee.rochester.edu writes:

>A friend of mine wants to write a program that would provide some
>small security by [preventing people from booting off a floppy drive.]
>This is for DOS and cannot involve significant hardware (like
>burning ROMS, cutting wires, etc).  Any thoughts would be appreciated.

Forget writing a program; unless you modify the EPROMs you can't stop the
firmware boot code from checking the A drive for a system (bootable) diskette.

But there is an easy fix.  Once the hard drive is set up and the computer 
is booting properly from it, open the case and unplug the A drive.  If the
A drive is dead, no floppy boots are possible.

If you only have one floppy drive, plug the "B" data cable into the drive
so that you still have the use of it (as drive B, naturally).

Of course, this doesn't protect you from those who have access to 
your computer while you aren't around and have enough savvy to open the
case and re-connect the A drive.  If this is the situation, though, you
are really vulnerable no matter what scheme you use, unless you bolt
the PC chasis to the desk and put a lock on the case.

Tim Meighan
SilentRadio

"It is a poor secret that has no agent."