Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site psivax.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!psivax!al From: al@psivax.UUCP (Al Schwartz) Newsgroups: net.micro.pc Subject: Re: Dos Startup modification Message-ID: <319@psivax.UUCP> Date: Sun, 10-Feb-85 21:26:43 EST Article-I.D.: psivax.319 Posted: Sun Feb 10 21:26:43 1985 Date-Received: Wed, 13-Feb-85 02:32:21 EST References: <307@psivax.UUCP> <431@ahuta.UUCP> Reply-To: al@psivax.UUCP (Al Schwartz) Organization: Pacesetter Systems Inc., Sylmar, CA Lines: 31 Summary: In article <431@ahuta.UUCP> dmt@ahuta.UUCP (d.tutelman) writes: >As has already been pointed out, doing away with the startup test involves >burning new ROMs. I disagree with the comment about expense (unless you >buy an EPROM burner for this one-shot job), but it may be illegal. >In order to do it, you would need to copy the IBM BIOS ROM onto a >writeable medium (say, a floppy), edit it, and use the edited version >as input to an EPROM programmer. IBM has been sticky about people Let me know if there are EPROMS available to do this. I think that the ROMs that IBM uses have a strange pinout that CANNOT be emulated by standard EPROMS (27xx series). I guess one could build some adaptor boards but I would not consider this to be an elegant solution to the problem. I have heard that the BIOS ROM determines that the machine has been powered- up once already by examining two memory locations and checking them against the pattern 0x12 , 0x34. I forgot which locations have this (see the BIOS listing in the Tech. Ref. Manual for more details). If these locations contain the pattern then the BIOS skips the memory test. One could construct a circuit that decodes those memory locations to "fool" the BIOS into thinking that it tested the memory already. There still has to be software to write every memory location that you plan to use in order to set the parity bit at every memory location. This has to be done with the parity error interrupt ignored. I am still not sure if this will work though. Has anyone out there tried to do this? -- Yow! Am I having fun yet? Al Schwartz Pacesetter Systems Inc., Sylmar, CA {trwrb|allegra|burdvax|cbosgd|hplabs|ihnp4|sdcsvax|aero|uscvax|ucla-cs| bmcg|sdccsu3|csun|orstcs|akgua|randvax}!sdcrdcf!psivax!al or {seismo|citcsv|engvax|wlbr|zeus}!scgvaxd!psivax!al