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RE: windows 2000 could not start because the following file is mi ssing


From: tlaronde
Subject: RE: windows 2000 could not start because the following file is mi ssing or corrupt: <windows 2000 root>/system32/ntoskrnl.exe
Date: Tue, 22 Jul 2003 20:53:45 +0200 (MEST)
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Quoting Graeme Vetterlein <address@hidden>:

> > Please note that the following explanations are just _guesses_...
> 
> Thanks for the reply (even if it's just a guess :-) I suspect I need you
> to 
> give me a little background (FYI I have played around with FDISK
> partitions
> back in the days of MSDOS 3.0 ... but not a lot since :-)
> 
> (you may want to tell me to RTFM ... but please add a URL ..and your
> footnotes :-)
> 
>       1: There is a 'table' held with the MBR at the start of the DISK
>          this has (by convention) space for 4 entries (the primaries) 
>          ... then lots of stuff I don't understand about extended/logical.

The extended is just a primary partition "pointing" to other values and hence
making it possible to subdivide the disk more than for 4 partitions.

> 
>       2: The major/minor numbers for (in this case SCSI) disks is:
> 
>               /dev/sda (whole disk)   8,0
>               /dev/sda1                       8,1
>               /dev/sda2                       8,2
>               ...
>               /dev/sda15                      8,15

The numbers are kernel dependant, but the principle is the major number refers
to the driver (driving the device) and the minor to one instance of the driver.

> 
>       3: The disk itself is divided into partitions 
>       4: Within a partition you can add a single filesystem (or use it raw
> e.g. as swap_
>               (BTW you might be interested to know SVR4.2 AKA UnixWare
> allowed these FDISK
>                partitions to be further subdivided into partitions ...
> e.g.. edvtoc :-)

There is (also?) the BSD disklabels which solves the problem : one allocates a
"partition" to BSD which subdivides the partition allocated in many others 
(slices).
                
> 
> What I need to understand is the TERMINOLOGY used by various folks
> (grub,
> fdisk, M$ etc):
> 
> Entries in 'fdisk table'
> 
>       Q: Does each 'entry' have a 'slot' attribute such that entry No 3
> can be slot No 2?

This is the first time I see "slots" but since the slots are numbered from 0 to
3 I guess these refers to first, second, third and fourth entries in hte
partition table of the MBR.

>          Or does the entry No, imply 'slot No'? (I seem to recall it does)
> 
>       Q: If so, do we start at zero or one. Is it 0,1,2,3 or 1,2,3,4 ?

Seems to be 0
> 
>       Q: How are we referring to partitions on disk? Is the first (low
> cylinder Nos) called 0
>          next 1 etc. Alternatively do we call partition 0 the partition
> that is described by slot 0?

This _is_ the problem. It seems that some reorder the partition numbering
refering to the order of the first sector (in sector increasing order) while
some boot managers take them in the partition table order (at least your problem
seems to indicate that).

> 
>       Q: What does say /dev/sda1 refer to?
>               Fdisk entry No 1 (or number zero?)
>               Slot No 1 (0?)
>               Physical partition No 1 (low cylinder No)

The last.
> 
>       Q: What does grub reference (hd0, 2) refer to?
>               /dev/sd2 ?

/dev/sd3 (GRUB starts at 0, while Linux for example starts from 1)

>               Fdisk entry No 2 
>               Slot No 2
>               Physical partition No 2 (next to low cylinder No)
>               
>       Q: What does M$ use. Looks like partition(1) means '1st non empty
> slot in fdisk table' (number from 1)
>       (or 2nd entry, numbered from zero, with the dummy entry you
> suggest:-)

I do not know about M$ but the behavior seems to be specific to W2000. To have
a better view it would be necessary to have a copy of the MBR 512 bytes after
the installation of Windows (and before the installation of Linux), and the same
after the installation of Linux.

> 
>       Q: What does 'fix partition table' mean? why does it matter that
> slot order lines up with
>          physical partition order?
>               
> 
> > What would be interesting are the mbr of the second disk (if it is
> > identical to the MBR of the first disk with the initial 
> > partitioning of
> > Windows).
> 
> I have the 'cloned' disk prior to starting RedHat install (it's in a
> different box right now) if
> you tell me what kinds of dumps etc would be useful I can do that ...
> I'll
> have to do it from a CD 
> boot but that should be no problem.

OK, simply the copy of the first sector (the zeroth one) of the disk image for
the disk before Linux was installed, and the same after that is:

dd if=<disk_image> of=mbr.windows bs=512 count=1

dd if=/dev/sda of=mbr.linux bs=512 count=1

Cheers,




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