Re: Question on what sectors grub2 uses?

[Michael D. Setzer II]

On 10 Mar 2012 at 22:41, Chris Murphy wrote:

Subject:                Re: Question on what sectors grub2 uses?
From:                   Chris Murphy <address@hidden>
Date sent:              Sat, 10 Mar 2012 22:41:53 -0700
To:                     address@hidden

> 
> On Mar 10, 2012, at 9:01 PM, Michael D. Setzer II wrote:
> 
> > Thanks to all the replies. Gives me some things to look into.
> > Also, brings up some questions,
> > 
> > With the older partitions showing that they start at 63?
> > If there are 63 sectors per track isn't that the last partition of
> > the previous track? Or did something change sector numbers starting
> > with 0? I know that sectors on the original disks and floppies
> > started at 1 and not zero? First computer had 8 sector 320K
> > floppies. 
> 
> All modern drives, 512 byte and 512e AF, use LBA. So track, cylinder,
> head doesn't really apply anymore.
> 
> And I did find out earlier that LBA 0 is the first sector, LBA 1 is
> the second sector, and so on.
> 
> > 
> > Now with the partition starting at 2048? Wouldn't that also be the
> > last sector of the first MB.
> 
> I don't understand.

In doing a test I found to get the same sector it took these 
commands.

dd if=/dev/sda of=mbrsx bs=512 skip=2048 count=1
dd if=/dev/sda1 of=sda1 bs=512 count=1

If I skip 2048 doesn't that make it sector 2049?


Looks like it is counting the sectors from 0?

>From sfdisk -lu /dev/sda
Units = sectors of 512 bytes, counting from 0




> 
> > Then there is were does the partition 
> > MBR go? 
> 
> LBA 0 is the MBR. The MBR contains the partition map, and the initial
> boot code. Wikipedia has pretty detailed information on the MBR.
> 
> Chris Murphy
> _______________________________________________
> Help-grub mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/help-grub


+----------------------------------------------------------+
  Michael D. Setzer II -  Computer Science Instructor      
  Guam Community College  Computer Center                  
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