Backup and Restor MBR

[Mike McCarty]

David-Paul Niner wrote:
> Quoting Mike McCarty <Mike.McCarty at sbcglobal.net>:
> 
>> Aaron Konstam wrote:
>>
>>> On Sun, 2006-12-10 at 07:01 +0530, Vivek J. Patankar wrote:
>>>
>>>> On 12/10/06, Hadders <fedora at workingwithit.com> wrote:
>>>>
>>>>> I'm going to install Vista (dual-boot) and was wondering if it was 
>>>>> easy
>>>>> to just back it up rather than running grub?
>>>>
>>>>
>>>> # dd if=/dev/hda of=/path/filename bs=512 count=1
>>>
>>>
>>> No, No, NO. The MBR is only the first 446 bytes of block 0. The rest is
>>> the partition table. I assume you don't want to rewrite the partition
>>> table.
>>
>>
>> The MBR is the Master Boot Record, which is 512 bytes long.
>> The MBR comprises three parts
>>
>> 1. Code
>> 2. Partition Table
>> 3. Boot Record Marker (AA 55)
>>
>> No part of the MBR may be read or written without reading
>> or writing all of it. Discs are, after all, BLOCK DEVICES
>> which cannot transfer any amount less than a block (sector).
>>
>> I don't like to presume about what other people do. (BTW, you
>> might investigate the difference in meaning between "assume",
>> and "presume".) If he states he wants to save and restore his
>> MBR, then I answer accordingly. If I have a question about what
>> his goals are, then I ask.
>>
>> If you are going to give such strong corrections and advice, you
>> ought at least to be correct.
>>
>> Saving the MBR should be done in its entirety. Whether one wants
>> to preserve the PT portion of the MBR when rewriting it on disc
>> later is a decision to be made at that time. Not saving the original
>> PT portion of the MBR is folly.
>>
>> Mike
>> -- 
>> p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
>> This message made from 100% recycled bits.
>> You have found the bank of Larn.
>> I can explain it for you, but I can't understand it for you.
>> I speak only for myself, and I am unanimous in that!
>>
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> 
> 
> It really depends on the platform you're using.  Here's a quick link  

I see now that I also need to reply here, as well as to the
copy which you sent me privately.

I've been formatting discs since about 1984 or so, on a variety
of platforms.

> that probably
> explains it well:
> 
> http://en.wikipedia.org/wiki/Master_boot_record

I am familiar with that.

> And don't be so quick to nit-pick over verbage, it comes across as 
> childish.

What I complained about is not words, but bad advice given based
on incorrect information.


When somebody states "No" four times in a row, and then gives incorrect
data and actually bad advice, he needs to have his wrist slapped. I
wasn't correcting *words*. I was correcting bad information and bad
advice.

Recommending not saving the entire MBR is BAD ADVICE, which he
based on INCORRECT INFORMATION.

Advising someone not to back up the entire MBR, based on the
misinformation that the PT is not part of it, is foolish.

Mike
-- 
p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
This message made from 100% recycled bits.
You have found the bank of Larn.
I can explain it for you, but I can't understand it for you.
I speak only for myself, and I am unanimous in that!