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