Data all gone

  • Thread starter Thread starter Irwin
  • Start date Start date
I

Irwin

Hello. I know better than to change something without a backup. I know
better. And yet... Did it anyhow, and now am suffering for it. I have
helped some people on this site, so now is my turn to ask for help.

On my son's XP SP2 machine, I wanted to split a logical partition in
two. There is the primary partition, and an extended partition with
logical drives. I used a Partition Magic 8 floppy, and shrank one of
the logical partitions, and created a new partition. Same thing I do
all the time on other machines. Did it just the other day. Anyhow,
shrank a logical partition and created an additional one in the
extended partition. Upon rebooting, the primary partition is toast.
Won't boot at all. I tried an XP boot floppy to all the partitions, but
it can't find any files on the primary partition. I tried a repair from
the setup CD using recovery console, but it wouldn't mount the
partition. I tried using ERD Commander, which told me all the hives
were gone, and all the files were gone, and it wouldn't repair it. Now,
there are lots of tools on the the recovery console and ERD Commander
that I don't know how to use, and haven't had the time at 10:30 pm to
research, so maybe there is something more to do with those.

Interestingly, all the partitions in the extended partition, including
the new ones, seem to be fine. Data partition is OK, gotta be glad of
that, that's for sure.

So what happened? Why did altering something in the extended partition
fry my primary partition? Why would it even touch it? I have always
wanted to know what is happening when Partition Magic and Drive Image
say "Saving System Information". What is that and what is it doing? I
guess it saved some system information to my primary drive. Did it
overwrite the FAT? Why would it do that? Unfortunate how these tools
work most of the time, but maybe 1-2% of the time in my hands they just
destroy everything.

Anyhow, given the time and my desire to move on, I then backed up the
hosed primary partition to one of the other partitions using Drive
Image (should have done it before, should have done it before, keep
saying it), and restored a backup of the c drive from several months
ago. This works fine, though all the modifications from his school's
requirements and probably a few data files here and there are gone.
Will take days to weeks to get everything back to normal.

So, my turn for help. What happened? Any way to mount that corrupted
image, or recover it and set it back up as a second primary partition?
Crow tastes bad, real bad. Thanks,

Irwin
 
What, no help for this problem? I will to reply to myself to bring it
to the top and perhaps rekindle some interest. Does anyone know:
1. What happened to my c drive?
2. What 'Saving system information is doing?"

Thanks,
Irwin
 
Sometimes PArtition Magic goes mad and break data. But i'm sorry i
cannot help you on this.
Maybe it's only the partition table that is corrupted ? (we can still
hope, can't we ?)

Regards
Nick
 
Irwin said:
What, no help for this problem? I will to reply to myself to bring it
to the top and perhaps rekindle some interest. Does anyone know:
1. What happened to my c drive?
2. What 'Saving system information is doing?"

Thanks,
Irwin
Click to expand...

I think you're probably scr*wed. I hope you can reconstruct most of
your information from other sources.
 
Previously Nick said:
Sometimes PArtition Magic goes mad and break data. But i'm sorry i
cannot help you on this.
Click to expand...

PM has had this problem for a long time. Their warning to backup
before changing anything is serious. Unfortunately the warning
to back up is in so many places today that it is hard to know
how serious the individual risk is.

Arno
 
Arno said:
PM has had this problem for a long time. Their warning to backup
before changing anything is serious. Unfortunately the warning
to back up is in so many places today that it is hard to know
how serious the individual risk is.

Arno
Click to expand...

FWIW, I can speak from experience on that one, too.
 
Actually, I take the warning to back up seriously. I was working on my
d: drive, so I backed up my d: drive before I did anything. I tried to
do the right thing. I never expected it to screw up my c: drive. I
worked on the d: drive, which ended up fine, but it screwed up my c:
drive. So what is the message? That it doesn't matter which partition
you are working on, it can screw up your primary partition? That is not
good.

New message: Before using Partition Magic to work on ANY partition, you
must back up your OS partition also, not just the partition you are
working on.

IMF
 
Irwin said:
Actually, I take the warning to back up seriously. I was working on my
d: drive, so I backed up my d: drive before I did anything. I tried to
do the right thing. I never expected it to screw up my c: drive. I
worked on the d: drive, which ended up fine, but it screwed up my c:
drive. So what is the message? That it doesn't matter which partition
you are working on, it can screw up your primary partition? That is not
good.

New message: Before using Partition Magic to work on ANY partition, you
must back up your OS partition also, not just the partition you are
working on.

IMF
Click to expand...

The message I took some time ago (the hard way) is not to use Partition
Magic.
 
Previously Irwin said:
Actually, I take the warning to back up seriously. I was working on my
d: drive, so I backed up my d: drive before I did anything. I tried to
do the right thing. I never expected it to screw up my c: drive. I
worked on the d: drive, which ended up fine, but it screwed up my c:
drive. So what is the message? That it doesn't matter which partition
you are working on, it can screw up your primary partition? That is not
good.
Click to expand...
New message: Before using Partition Magic to work on ANY partition, you
must back up your OS partition also, not just the partition you are
working on.
Click to expand...

No, that is the original message. Since you are doing a disk-global
operation, you allways need to back up the whole disk. And I am pretty
sure thah PM tells you to do just this.

Arno
 
The message I took some time ago (the hard way) is not to use Partition
Magic.
Click to expand...

I have recenlty made good experiences with GNU parted. It does not have
the PM "collect every operation into a complicated plan and then fail
to execute it somewhere in the middle" approach. It is a bit basic
in the interface thoiugh and there is no undo or safety questions.

I guess the warning about backing up goes for parted too.

But it works and it is free, so unlike PM you get actually
good value for your cash.

Arno
 
I am sure you are right, but why is it a disk-global operation? What
does that mean? Do you know what it is doing when it says 'saving
system information'? I take it that is the disk global thing you are
referring to, yes?

IMF
 
Previously Irwin said:
I am sure you are right, but why is it a disk-global operation? What
does that mean? Do you know what it is doing when it says 'saving
system information'? I take it that is the disk global thing you are
referring to, yes?
Click to expand...

The thing is that there is only one partition table on the disk. It
is organised as a chain of elementary tables, but it is in a sense
just one data structure representing all partitions on a disk. If you
change anything in that single table, all other information in it is
at risk. That means that modifying any single partition allways risks
the whole set of partitions on a disk.

Still, PM could be more careful. It is possible to keep partition
ooperations from affecting any partition information on partitions
before the modifyed one. My guess is that for some reason PM
allways rewrites the whole partition table and therefore risks
the whole disk structure on changes.

And no, I have no idea what PM does on 'saving system information'.

Arno
 
Arno said:
The thing is that there is only one partition table on the disk. It
is organised as a chain of elementary tables, but it is in a sense
just one data structure representing all partitions on a disk. If you
change anything in that single table, all other information in it is
at risk. That means that modifying any single partition allways risks
the whole set of partitions on a disk.

Still, PM could be more careful. It is possible to keep partition
ooperations from affecting any partition information on partitions
before the modifyed one. My guess is that for some reason PM
allways rewrites the whole partition table and therefore risks
the whole disk structure on changes.

And no, I have no idea what PM does on 'saving system information'.
Click to expand...

How large is the partition table? I was under the impression that it was
less than a single sector, so there's no way to rewrite only part of it.
 
Arno Wagner said:
The thing is that there is only one partition table on the disk.
Click to expand...

So what?
It is organised as a chain of elementary tables,
Click to expand...

No it is not, only the extended partition and the logicals in it are.
but it is in a sense
just one data structure representing all partitions on a disk. If you
change anything in that single table, all other information in it is
at risk.
Click to expand...

Nonsense, only that of the entry and substantial only if it is an extended partition.
That means that modifying any single partition allways risks
the whole set of partitions on a disk.
Nonsense.


Still, PM could be more careful. It is possible to keep partition
ooperations from affecting any partition information on partitions
before the modifyed one.
Click to expand...

Exactly, so now we know that you were just ranting, as usual.
 
Arno Wagner said:
I have recenlty made good experiences with GNU parted.
Click to expand...
It does not have
the PM "collect every operation into a complicated plan and then fail
to execute it somewhere in the middle" approach.
Click to expand...

Oh? How would you know? Are you the author?
It is a bit basic
in the interface thoiugh and there is no undo or safety questions.

I guess the warning about backing up goes for parted too.
Click to expand...
But it works
Click to expand...

So does PM, most(or is that some) of the time.
and it is free, so unlike PM you get actually good value for your cash.
Click to expand...

I consider that still bad value if it messes up my drive.
In which case I would hope it had never existed so I
wouldn't have been tempted to use it in the first place.
 
Previously J. Clarke said:
Arno Wagner wrote:
[...]

How large is the partition table? I was under the impression that it was
less than a single sector, so there's no way to rewrite only part of it.
Click to expand...

It is a bit obscure: There is room for 4 partitions in the partition
table space the boot/root sector od the disk. You can put primary or
extended partition entries in each. If it is an extended partition
entry, the the entry is actually a pointer to another sector, namely
the root (first) sector of the extended partition. That sector has in
turn a pointer to the root sector of the first partition in the
extended partition in its first (second?) entry. The other s are
unused.

For the partitions within the extended partition, there is one entry
in the root (first) sector of that partition and one entry that points
to the root sector of the next partition in the extended partition and
so on. The other two entries in these linked sectors are empty.

In a sense this whole obscure construct forms the "partition table".
I once traced this with a disk editor. That was a long time
ago, but I think it is still done this way.

Arno
 
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