On Sunday 30 April 2006 16:51, Mark Knecht wrote:
> 2) When I built the machine I had 512MB in the machine so a 1GB swap
> seemed fine. I have since updated to 1GB so the swap seemed a bit
> small anyway.
I've read somewhere that more than 1 GB swap would be wasted.
> 3) I will create two partitions early on the drive:
> c:\ -> approximately 1GB
> d:\ -> approximately 100MB
The former will have to be a primary if Windows is to boot it; where will
you put the latter?
> The only reason to create the d:\ partition would be to ensure that
> the /dev/sda# numbers do not change and thus cause any problems for my
> existing Linux installation.
It's easy enough to decrement the disk letters in /etc/fstab, and the disk
numbers in /boot/grub/grub.conf, don't you think?
> 4) I have already created /dev/sda9 and copied everything on
> /dev/sda1, my boot partition, there.
You may find that a partition that far up the disk can't be booted. It
depends on your BIOS, I think. Once the kernel image has been fetched from
your /boot partition, of course the BIOS is not used, but in the first step
it has to be. BIOSes used to be unable to boot a partition above cylinder
1023 but some (most? all?) now can. There's also the question of what
constitutes cylinder 1023, what with LBA etc.
> Since I am not changing the root partition it should remain /dev/sda3.
> Since grub will eventually go back on (hd0,0) after Windows is
> installed I assume that doesn't change either. However since the new
> /boot will be /dev/sda9 I'm thinking that grub.conf should change to
> point there. I'm guessing this is what it might need to look like:
> title 2.6.16-gentoo-r2
> root (hd0,0)
That's the first partition on the first disk, which won't be your /boot
partition. If you want grub installed in the MBR of the first disk, specify
> kernel (hd0,8)/boot/bzImage-2.6.16-gentoo-r2 root=/dev/sda3
That's fine, assuming that your BIOS boots sda before hda, which I suppose
it must or you'd have described it differently :-)
> I will change fstab to understand the changes when I'm reinstalling
> grub, I think. I am really not clear about how to point grub on
> /dev/sda1 to a /boot/grub directory sitting on /dev/sda9.
Your grub should be installed either in the MBR of the disk your BIOS boots
first, or in one of your ext2fs or ext3fs partitions which you should make
active (i.e. mark bootable). It's conventional and sensible for the latter
to be the partition that contains your /boot directory and the bootable
kernel image: in your case the alternatives are /dev/sda and /dev/sda9
If your /boot partition isn't the active primary partition on the first
disk, to get grub to boot from that partition you'll need some other boot
manager to point the BIOS to it; that's why most people install grub into
> Does all that make sense? It doesn't to me which worries me a bit, but
> hopefully I'll sort it out.
I think you're pretty nearly there, but with the provisos I've suggested.
> QUESTION: I am also unclear about marking partitions as 'bootable' in
> this configuration. Is a partition marked bootable because it has grub
> on it (my guess) or because it has the kernel residing on it? (Not my
The BIOS needs to know where to fetch the system boot code from.
Traditionally that meant the master boot record of the first physical disk.
The MBR is a small block of code at the beginning of the disk, outside all
the partitions. It's called "master" because each primary partition also
starts with a boot record, which can hold bootstrap code if you want it to
(that's what you do if you install grub into hd(0,0), say, i.e. /dev/sda1).
In this case, "traditionally" means "in the M$ FAT design", which all other
file systems on PCs have had to work with for compatibility. Just as 640KB
was supposedly all the memory anyone could want thirty years ago, so four
disk partitions were ditto, so the MBR only needed a two-bit pointer to the
partition the BIOS was to boot. That's why you can't boot a logical
partition directly. I believe there is a boot record in the primary
partition that's modified to become an extended partition, a container for
logical partitions, but I've never managed to make my systems boot through
it. And of course I'm as liable as anyone else to being wrong.
> Again, thanks in advance for any info you can provide on this.
I hope this has helped, not just added to the confusion :-)
> Fortunately I have many other machines here to work from while I go
> through this change over.
A boon, indeed.
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