Date: Wed, 10 Mar 2004 18:24:00 +0100 From: Erik Trulsson <ertr1013@student.uu.se> To: Jason Dictos <jason.dictos@yosemitetech.com> Cc: "''freebsd-questions@freebsd.org' '" <freebsd-questions@freebsd.org> Subject: Re: Using int 13 while BSD is running Message-ID: <20040310172400.GA53950@falcon.midgard.homeip.net> In-Reply-To: <E50A109EE98AA049BAA09D725DB0714F01AD3BB3@mail.tapeware.com> References: <E50A109EE98AA049BAA09D725DB0714F01AD3BB3@mail.tapeware.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 10, 2004 at 08:49:17AM -0800, Jason Dictos wrote: > > > > To Jason: take care not to *write* anything to the disk via int 13h. > > I still don't think I understand why you are using FreeBSD for this > specific purpose. Why if you just >spend time escaping from the OS? > > We actually _like_ protected mode, it allows us to be more flexible and our > code doesn't have to be bastardized with 16 dos compilers ;). However in dos > we have garanteed hard drive support via int13 (Well almost garanteed, but > if an os can boot of the computer, we can access the disk), and I'm looking > for the same sorta garantee in BSD. People will be using this with raid > controllers, scsi hard disks, and ide drives (Server recovery), so there > will be many times when the hardware running the hd requires specific > support, which BSD may or may not have, point is we dont' want to manage > that. > > Make sense? Just because you can boot from the disk does not mean that the BIOS can read the whole disk. As an example I have an old computer running FreeBSD with a 1GB disk. The BIOS in this computer cannot handle disks larger than 512MB (which was a quite common limitation in older BIOSs). I can however boot from this disk since all the files needed for booting reside below the 512MB mark. Once I have booted FreeBSD I can access the whole disk precisely because FreeBSD does *not* use the BIOS, but use its own routines. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040310172400.GA53950>