Date: Thu, 26 Oct 1995 17:14:10 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, msmith@atrad.adelaide.edu.au Cc: hackers@FreeBSD.org, lenzi@cwbone.bsi.com.br, terry@lambert.org Subject: Re: boot disk.... Message-ID: <199510260714.RAA11866@godzilla.zeta.org.au>
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>> No. The (DOS) BPT reflects the BIOS geometry at the time the partition >Hang on a sec. When I say "BPT" I mean "BIOS Parameter Table", aka the >BIOS equipment list. Apologies for the TLA 8( The DOS BPT seems to be named the BPB (B = block). I often confuse this with the BPT. Now I don't know what you mean by the BPT. There is the BIOS disk parameters table pointed to by vector 0x1E, but that is only for floppies and changing it has little effect. >What I am asking is; if as a bootloader I establish that the drive is just >Too Damn Big, if I frob the advertised drive geometry, will the BIOS >honour that, or does it keep a private copy? I really don't give a damn >about DOS; it doesn't figure anywhere in my plans 8) I'm not sure about the BIOS, but for IDE drives the drive keeps a private copy and you can;t expect the BIOS to reprogram that for every i/o. It might work to change the hard disk parameters pointed to by the int 0x41 and/or int 0x46 vectors and then tell the BIOS to initialize the drive using int 0x13, ah = 9. Bruce
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