Date: Thu, 3 Dec 1998 13:13:48 +0200 (SAT) From: Robert Nordier <rnordier@nordier.com> To: joelh@gnu.org (Joel Ray Holveck) Cc: mike@smith.net.au, jkh@zippy.cdrom.com, Marius.Bendiksen@scancall.no, rnordier@nordier.com, hsw@email.generalresources.com, hsw@acm.org, abial@nask.pl, freebsd-current@FreeBSD.ORG Subject: Re: /boot/loader what to set rootdev to? Message-ID: <199812031114.NAA15654@ceia.nordier.com> In-Reply-To: <86g1ay6l8f.fsf@detlev.UUCP> from Joel Ray Holveck at "Dec 2, 98 07:57:20 pm"
next in thread | previous in thread | raw e-mail | index | archive | help
Joel Ray Holveck wrote:
> Mike said:
> > Yes, we have been over this before. Would you care to explain how you
> > plan to reinstate the vectors that the DOS7 kernel replaces so that
> > vm86 BIOS calls from the FreeBSD kernel will work?
> > Please understand that there are some really fundamental issues which
> > absolutely preclude starting FreeBSD once DOS has been started.
>
> We may have a different definition of "DOS7 kernel". I typically use
> that phrase to refer to IO.SYS alone. The vectors seem to be modified
> by HIMEM.SYS instead. By default, IO.SYS will load HIMEM.SYS and
> prevent the kernel from loading. However, the line "DOS=NOAUTO" in
> the config.sys will cause IO.SYS to skip that step. I have had
> success loading FreeBSD by using that line in the PIF's specified
> CONFIG.SYS myself.
As you go on to describe, it is *not* particularly difficult to
boot FreeBSD straight out of Windows. However, the reason we don't
want to actively support this is that it makes the kernel vm86
mechanism unreliable.
The choice is really a simple xor:
o Boot out of Windows
o Reliable kernel vm86 support
I researched the whole issue in really exhaustive detail, a year
or so ago, before off-list discussions with Mike Smith, which led
to the decision not to support any kind of FBSDBOOT approach in
the new boot code project.
What we can support with little trouble (if any Windows programmer
wants to step forward to do the actual Windows coding) is the following
completely safe method:
In Windows, have a FreeBSD control panel which allows you to
point and click on FreeBSD slice, and set any of the standard
boot block options like -s (single user) or -v (verbose). When
the user clicks "Go" (or whatever), the Windows application
communicates with the boot manager through an API, then does
a cold boot. The partition manager gets control, and passes
the selected parameters to the boot blocks, which may also pass
them on to /boot/loader, as required.
--
Robert Nordier
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199812031114.NAA15654>