From owner-freebsd-hackers Sat Dec 15 4:14:45 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from scaup.prod.itd.earthlink.net (scaup.mail.pas.earthlink.net [207.217.120.49]) by hub.freebsd.org (Postfix) with ESMTP id 5EEC437B419 for ; Sat, 15 Dec 2001 04:14:42 -0800 (PST) Received: from pool0048.cvx22-bradley.dialup.earthlink.net ([209.179.198.48] helo=mindspring.com) by scaup.prod.itd.earthlink.net with esmtp (Exim 3.33 #1) id 16FDiD-00021Q-00; Sat, 15 Dec 2001 04:14:41 -0800 Message-ID: <3C1B3EB2.E6D1F0C0@mindspring.com> Date: Sat, 15 Dec 2001 04:14:42 -0800 From: Terry Lambert X-Mailer: Mozilla 4.7 [en]C-CCK-MCD {Sony} (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: Hiten Pandya Cc: hackers@freebsd.org Subject: Re: boot0 References: <20011215092344.54636.qmail@web21110.mail.yahoo.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Hiten Pandya wrote: > I found this piece of code in boot0.s, is it possible > if you could explain me a bit about it. > > .set NHRDRV,0x475 # Number of hard drives > > The hex value comes out to: 1141. > > Does that mean, that this is the amound of maximum > hard drives a user can have on FreeBSD? No. The BIOS bootstrap loaded passes the boot drive in the %DL; this gets pushed, and later poped for the byt compare; the compare is based on a storage location of a relative offset. Frankly, you don't need to understand this code if you are trying to get the boot loader to understand JFS; instead you want to add JFS support into boot1/2 via libstand in /usr/src/lib/libstand. See /usr/src/lib/libstand/ufs.c, and look at how the library is able to select the routines in ufs.c vs. cd9660.c. If you are serious about this, handle read-only non-root JFS mounts of Linux created disks, first, and then work up to read/write, root mount, and then booting (in that order). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message