Grub Reinstall Problem!!!

[Phil Schaffner]

On Tue, 2004-06-01 at 01:41 -0400, Joe(theWordy)Philbrook wrote:
... snip ...
> 
> With grub, if I make a working boot floppy with "grub-install  /dev/fd0"
> then the one I had in /dev/hda is broken (infinte loop of the word grub
> being printed to the screen)  If I boot from the floppy and do a 
> "grub-install  /dev/hda" The mbr can boot again, but now the grub floppy
> boot is broke...
> 
> 1) is it possible to install the same grub to start from the mbr OR from
> a floppy depending on which bios finds first?

That's the way is should work.

Seems grub-install does cause such problems.  Doing it interactively MAY
help.  IIRC goes something like this if /boot is on /dev/hda3.

# grub
grub> root (hd0,2)
grub> setup (hd0)

The attached script will create DOS format GRUB floppy with a copy of
your current menu that can then be mounted and edited to customize.

> 
> 2) In case I must depend on the rescue mode sometime, Will it be able to
> find the right linux installation on a system with 
> FC2, FC1, MDK9.1, SuSE 7.3, Win98se, AND Dr Dos on it. Or would the
> following partition tables confuse it

Ya' got me.  Probably will be confused.  Please try it and let us
know. ;^)

> [root at localhost jtwdyp]# fdisk -l /dev/hda /dev/hdc
> 
> Disk /dev/hda: 40.0 GB, 40020664320 bytes
> 255 heads, 63 sectors/track, 4865 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/hda1   *           1         638     5124703+   c  W95 FAT32 (LBA)
> /dev/hda2             639        1217     4650817+   f  W95 Ext'd (LBA)
> /dev/hda3            1218        3162    15623212+  83  Linux
> /dev/hda4            3163        4865    13679347+  83  Linux
> /dev/hda5             639        1021     3076416    b  W95 FAT32
> /dev/hda6            1022        1148     1020096   83  Linux
> /dev/hda7            1149        1217      554211   82  Linux swap
> 

The above looks very strange.  The # of blocks in the extended partition
should be the sum of all those below it.

If you really want to confuse boot loaders and rescue disks try
something like this (-:

[root at tabb1 scr]# fdisk -l

Disk /dev/hde: 46.1 GB, 46115758080 bytes
16 heads, 63 sectors/track, 89355 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hde1   *           1       44673    22515066    7  HPFS/NTFS
/dev/hde2           44673       89346    22515097+   f  W95 Ext'd (LBA)
/dev/hde5           44673       64994    10241406    7  HPFS/NTFS
/dev/hde6           64994       89346    12273628+  83  Linux

Disk /dev/hdg: 120.0 GB, 120034123776 bytes
16 heads, 63 sectors/track, 232581 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdg1   *           1         249      125464+  83  Linux
/dev/hdg2             250        2234     1000440   82  Linux swap
/dev/hdg3            2235       33981    16000488   83  Linux
/dev/hdg4           33982      232581   100094400   83  Linux

Disk /dev/hdh: 46.1 GB, 46115758080 bytes
255 heads, 63 sectors/track, 5606 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdh1   *           1           7       56196   83  Linux
/dev/hdh2               8        2050    16410397+   c  W95 FAT32 (LBA)
/dev/hdh3            2051        3075     8233312+  83  Linux
/dev/hdh4            3076        5606    20330257+   5  Extended
/dev/hdh5            3076        3271     1574338+  83  Linux
/dev/hdh6            3272        5606    18755856   83  Linux

Disk /dev/sda: 18.3 GB, 18309995520 bytes
255 heads, 63 sectors/track, 2226 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          17      136521   83  Linux
/dev/sda2              18        2226    17743792+  83  Linux

Disk /dev/sdb: 18.3 GB, 18309995520 bytes
255 heads, 63 sectors/track, 2226 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1         197     1582371   82  Linux swap
/dev/sdb2             198        2226    16297942+  83  Linux


Getting BIOS and GRUB to agree is a bit tricky.

Phil

P.S.  Have you tried the GRUB "map" command on your DR-DOS problem to
fool it into thinking it's on the first disk?  Perhaps:

title DR-DOS on hdc
        map (hd0) (hd1)
        map (hd1) (hd0)
        rootnoverify (hd1,0)
        chainloader +1

Might also need "makeactive" after "rootnoverify".

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