Date: Sat, 6 Sep 1997 17:25:59 -0700 From: John-Mark Gurney <gurney_j@efn.org> To: Matthew Thyer <thyerm@box.net.au> Cc: Tom Bartol <bartol@salk.edu>, current@FreeBSD.ORG Subject: Re: modifying boot mgrs FROM FREEBSD Message-ID: <19970906172559.33659@hydrogen.nike.efn.org> In-Reply-To: <340F3E90.41C67EA6@box.net.au>; from Matthew Thyer on Fri, Sep 05, 1997 at 08:34:48AM %2B0930 References: <Pine.BSF.3.95.970806153805.1888E-100000@pauling.salk.edu> <340F3E90.41C67EA6@box.net.au>
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Matthew Thyer scribbled this message on Sep 5:
> I do this...
why not just use fbsdboot.{com,exe} from the cdrom or another location?
it will either boot a kernel off the dos partition or I think it will
even load a kernel off a ufs partition... seems that would be easier
than playing around with your boot blocks...
> Because I have a plug and pray sound card in a non plug and pray
> motherboard, I have to 'activate' the sound card from DOS with the
> "Intel Configuration Manager" before booting FreeBSD or the sound
> card will not be detected in the device probes. To do this I have
> set things up to default to booting my previous version of md-dos
> which has DWCFGMG.SYS in its config.sys (thus activating the card)
> then the autoexec.bat will re-write the boot block and reboot the
> machine thus booting into FreeBSD.
>
> I use the bootblock restore program from a utility called BOOTSAVE
> in DOS to manipulate the boot blocks and in FreeBSD on shutdown I
> use a script called "shutit" which is:
>
> dd if=/dos/boot.dos of=/dev/wd0 ibs=1 skip=4 count=512
> sleep 1
> shutdown -r now
>
> For those who dont know further details are:
>
> In my C:\MSDOS.W40 (msdos.sys in W95) in the [Options] section:
>
> BootMenu=1 ; show the W95 boot menu
> BootMenuDefault=8 ; default to previous version of ms-dos
> BootMenuDelay=5 ; give me 5 seconds to load W95 if I want
>
> then my C:\AUTOEXEC.BAT (autoexec.dos whilst in Win95 I think) I have:
>
> CHOICE /N /Ty,5 Rebooting to UNIX in 5 seconds (or press 'N' to stay
> with the DOG)
> IF ERRORLEVEL 2 GOTO SkipReboot
> ECHO Writing the FreeBSD bootblock and rebooting
> C:\UTILITY\BOOTSAVE\BOOTREST C:\BOOT.BSD
> REBOOT /F
> GOTO TheEnd
> :SkipReboot
> ECHO EGAD! You really want to use the DOG!
> :TheEnd
>
> You have to find a reboot utility also... its not standard with the DOG
> !
>
> It seems to work most times for me... Sometimes bootrest wont write the
> bootblock. But FreeBSD has never failed to put my /dos/boot.dos
> bootblock
> back (on shutit) and I've never had a disk corruption problem.
>
> Use at your own risk naturally.
>
> Tom Bartol wrote:
> >
> > Would it be too weird to do the following quick and dirty thing completely
> > without the need for any documentation on which boot manager you're using:
> >
> > 1) setup your boot manager from dos or wherever necessary to do the
> > initial install.
> >
> > 2) boot into freebsd or linux and use dd to read the boot blocks off the
> > disk and into a file.
> >
> > 3) boot back into whatever environment can be used to "tune" your boot
> > manager and do whatever "tuning" strikes your fancy.
> >
> > 4) boot back into freebsd or linux and use dd to read the modified boot
> > blocks into a second file.
> >
> > 5) use diff or cmp to find out what effect your "tuning" had on the boot
> > blocks and try to deduce the logic (i.e. reverse engineer) the mods.
> > Hopefully this will not be very complicated.
> >
> > 6) you might then be able to use patch on your snap-shot copy of the boot
> > blocks to "tune" it from within freebsd of linux. If you're really
> > confident of your work you can then use dd to write your "tuned" boot
> > blocks back to where they belong.
> >
> > Just a thought...
> >
> > Tom
> >
> > On Thu, 7 Aug 1997, George Michaelson wrote:
> >
> > > Four things:
> > >
> > > 1) at next boot, which of the menu of boot choices is to be the
> > > default ie under reboot, do you boot back into THIS unix or into
> > > W95, DOS, NetBSD, Linux etc
> > >
> > > 2) change the flag marking if the MBR is to be updated to reflect
> > > the current boot choice as the live preference. This is different
> > > to the above which states WHICH secondary boot is to be used, this
> > > marks if any alternate boot is actually taken because of keyboard
> > > selection, that the selection becomes the active default boot
> > >
> > > 3) change the textual stringprompts against each option
> > >
> > > 4) change which bootable partitions appear in the menu of choices
> > >
> > > -George
> > >
>
> --
> /=====================================================================\
> | Work: Matthew.Thyer@dsto.defence.gov.au | Home: thyerm@box.net.au |
> \=====================================================================/
> "If it is true that our Universe has a zero net value for all conserved
> quantities, then it may simply be a fluctuation of the vacuum of some
> larger space in which our Universe is imbedded. In answer to the
> question of why it happened, I offer the modest proposal that our
> Universe is simply one of those things which happen from time to time."
> E. P. Tryon from "Nature" Vol.246 Dec.14, 1973
--
John-Mark Gurney Modem/FAX: +1 541 683 6954
Cu Networking
Live in Peace, destroy Micro$oft, support free software, run FreeBSD
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