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Re: GRUB and boot partition

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On 2017-12-29 06:46 AM, Pascal Hambourg wrote:
> Le 29/12/2017 à 11:02, deloptes a écrit :
>> microsoft gaofei wrote:
>>
>>> I'm thinking about a question ,how my hard disk admits so much data 
>>> ? If
>>> /boot partition is encrypted , then how does my hard disk admit GRUB ?
>>>
>>> sudo fdisk /dev/sda , and press o to create a DOS partition table . 
>>> This
>>> software starts on sector 2048 by default . So how does the 2048 
>>> sectors
>>> admit GRUB to achieve encrypted /boot  ?
>
> FWIW, here is what I replied to the OP's private mail :
>
> GRUB core image embeds all the required modules to read /boot/grub, 
> including crypto modules when /boot/grub is encrypted.
>
> 2048 512-byte sectors is 1 MiB. GRUB BIOS core image does not need so 
> much space. GRUB BIOS was developed at a time when partition alignment 
> was based on "cylinders", so the first partition usually started at 
> sector 63. GRUB BIOS core image was initially designed to fit in that 
> 30 KiB space. It has grown a bit over time and is sometimes slightly 
> bigger than 30 KiB, but 1 MiB is still plenty of space.
>
> A copy of GRUB BIOS core image is kept in /boot/grub/i386-pc/core.img, 
> so you can see its size.
>
>> you don't encrypt boot
>
> Why not ?
>
There's a lot of (not so) old information about /boot. I still have one 
machine with a separate /boot partition because when I first set it up, 
it was still required when using an mdadm RAID array.

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Re: GRUB and boot partition microsoft gaofei <wangziheng@outlook.com> - 2017-12-29 02:30 +0100
  Re: GRUB and boot partition deloptes <deloptes@gmail.com> - 2017-12-29 11:10 +0100
    Re: GRUB and boot partition Pascal Hambourg <pascal@plouf.fr.eu.org> - 2017-12-29 12:50 +0100
      Re: GRUB and boot partition Gary Dale <garydale@torfree.net> - 2017-12-29 23:30 +0100

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