Date: Wed, 10 Mar 2004 09:32:03 -0800 From: Jason Dictos <jason.dictos@yosemitetech.com> To: 'Erik Trulsson' <ertr1013@student.uu.se>, 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: <E50A109EE98AA049BAA09D725DB0714F01AD3BB6@mail.tapeware.com>
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Point well taken. -Jason -----Original Message----- From: Erik Trulsson [mailto:ertr1013@student.uu.se] Sent: Wednesday, March 10, 2004 9:24 AM To: Jason Dictos Cc: 'Sergey 'DoubleF' Zaharchenko'; Dan Nelson; ''freebsd-questions@freebsd.org' ' Subject: Re: Using int 13 while BSD is running 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 ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
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