Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!vax1.cc.lehigh.edu!cert.sei.cmu.edu!krvw From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) Newsgroups: comp.virus Subject: Re: PREVENTION of Drive A: boots - Suggestions Please (PC) Message-ID: <0011.9104261444.AA20785@ubu.cert.sei.cmu.edu> Date: 25 Apr 91 17:40:12 GMT Sender: Virus Discussion List Lines: 27 Approved: krvw@sei.cmu.edu | >b. Use of hardware modifications connected to a key switch mounted on | > the case which would be used to enable/disable floppy boots. | | Don't think this would work since all that is required to boot is for the | disk to be read. I do not think a switch could prevent selective reads witho ut | disbling any read. (unless you have a use for a write-only floppy). All you need is a switch the BIOS can read to disable trying the boot on A:. I mailed this to the original poster, but here's my idea. I suggested it to a vendor, but they haven't used it, or at least not yet. Have in the CMOS a "boot path" which works like the PATH variable, and specifies which devices are to be tried, in what order. This allows disable of floppy boot, as well as boot from B: if A: fails or if you have one 5-1/4 and one 3-1/2, etc. Use a password to allow access to change the configuration. If the password takes too much room, save three bytes of CRC20 plus a value for length range 1-15 characters. Length zero could mean "no password." - -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "Most of the VAX instructions are in microcode, but halt and no-op are in hardware for efficiency"