How do I . . .

[James Egan]

On Sat, 04 Nov 2006 11:43:19 -0500, kurt wismer <kurtw@sympatico.ca>
wrote:

>>
>> Are you saying windows alters the partition table of its own accord
>> sometimes, because that is apparently what happened, or do you mean it
>> sometimes overwrites whatever boot manager is in use with its own?
>
>apologies for my my flaky memory on this issue, i had to go and google
>it again for the specifics...
>
>as of win95 a drive id was introduced into the mbr that windows (not
>fdisk) places there on bootup (see this article by zvi
>http://groups.google.com/group/alt.c...7377e6dff955c)...


According to wiki, there is a 4 byte area available for the disk
signature before the 64 byte partition table at the end of the mbr.
It's used in connection with persistent mapping between partitions and
drive letters. This would explain the warnings he was getting without
shedding any light on what went wrong. I don't understand zvi's offset
220 (hex DC) remarks.


Jim.

[kurt wismer]

James Egan wrote:
> On Sat, 04 Nov 2006 11:43:19 -0500, kurt wismer <kurtw@sympatico.ca>
> wrote:
>
>>> Are you saying windows alters the partition table of its own accord
>>> sometimes, because that is apparently what happened, or do you mean it
>>> sometimes overwrites whatever boot manager is in use with its own?
>> apologies for my my flaky memory on this issue, i had to go and google
>> it again for the specifics...
>>
>> as of win95 a drive id was introduced into the mbr that windows (not
>> fdisk) places there on bootup (see this article by zvi
>> http://groups.google.com/group/alt.c...7377e6dff955c)...
>
>
> According to wiki, there is a 4 byte area available for the disk
> signature before the 64 byte partition table at the end of the mbr.
> It's used in connection with persistent mapping between partitions and
> drive letters. This would explain the warnings he was getting without
> shedding any light on what went wrong. I don't understand zvi's offset
> 220 (hex DC) remarks.

that's the location relative to the start of the sector rather than
relative to the start of the partition table...

and yes, it would explain the warnings without explaining the failure, i
still don't know what was going on with that failure... there doesn't
seem to be enough data yet... other people have said they can boot win98
machines with bartpe disks just fine so there must be some fact missing...

--
"it's not the right time to be sober
now the idiots have taken over
spreading like a social cancer,
is there an answer?"

[James Egan]

On Mon, 06 Nov 2006 07:57:13 -0500, kurt wismer <kurtw@sympatico.ca>
wrote:

>that's the location relative to the start of the sector rather than
>relative to the start of the partition table...
>

The disk signature is at 0x01B8 not 0x00DC so I don't know whether Zvi
was referring to something else.


>and yes, it would explain the warnings without explaining the failure, i
>still don't know what was going on with that failure... there doesn't
>seem to be enough data yet... other people have said they can boot win98
>machines with bartpe disks just fine so there must be some fact missing...

I think so too.


Jim.

[kurt wismer]

James Egan wrote:
> On Mon, 06 Nov 2006 07:57:13 -0500, kurt wismer <kurtw@sympatico.ca>
> wrote:
>
>> that's the location relative to the start of the sector rather than
>> relative to the start of the partition table...
>
> The disk signature is at 0x01B8 not 0x00DC so I don't know whether Zvi
> was referring to something else.

found this
http://groups.google.ca/group/comp.s...df2b5ad76f5660

apparently although the signature is now at 0x01b8, it used to be at
0x00dc for win9x...

--
"it's not the right time to be sober
now the idiots have taken over
spreading like a social cancer,
is there an answer?"

[James Egan]

On Tue, 07 Nov 2006 18:18:38 -0500, kurt wismer <kurtw@sympatico.ca>
wrote:

>>
>> The disk signature is at 0x01B8 not 0x00DC so I don't know whether Zvi
>> was referring to something else.
>
>found this
>http://groups.google.ca/group/comp.s...df2b5ad76f5660
>
>apparently although the signature is now at 0x01b8, it used to be at
>0x00dc for win9x...


So an alternative boot manager is at risk of being corrupted by win9x
writing it's disk signature in the middle of the loader code area. Par
for the course with Microsoft, I suppose. Installing win9x always used
to zap any existing boot manager without warning or asking. They
couldn't care less.


Jim.