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ABOUT PqRP - The PqRP de- mystified - PqRP FAQ - RFC

 
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Joep
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PostPosted: Sat Jul 26, 2003 3:01 am    Post subject: ABOUT PqRP - The PqRP de- mystified - PqRP FAQ - RFC Reply with quote

PowerQuest PqRP FAQ - July 25 2003 - Joep

[Feel free to re-distribute]

** About PqRP: **


* The problem:

As SOON as PartitionMagic (from now on: PM) starts it's operation on a
partition it will 'edit' the partition table and replace the byte that
descibes the type of partition (so FAT (06h), FAT32 (0Bh) etc ...) to byte
value 3Ch. PartitionMagic and all PQ products will display a 3Ch type
partition as PqRP or PQFlex type partition. A PqRP type partition can NOT be
accessed by Windows operating systems (Note: Linux can!). Only when PM
completed the operation it will replace the 3Ch value by the proper value
describing the partition type.

Therefore a PqRP type partition ONLY means that PM was performing a task on
this partition and it didn't get the chance to finish it. It does NOT say
anything regarding the amount of damage in the partition.

SOMETIMES (see section on 'PqRP.exe') changing the 3Ch value in the
partition table to the proper
partition type will help you gain access to the partition again. It highly
depends up on in which stage PM was, if contents of the partition are still
intact. For example PM starts by checking the partition (can sometimes be up
to 10% of total progress), and when it crashes during this stage, where no
'juggling' with data took place yet, editing the partition table alone may
be enough to gain access to the partition again.

Now the whole purpose of 'flagging' the partition this way is to prevent
tools like scandisk 'touching' this partition or to prevent you writing to
it. Running scandisk on a damaged partition may very well render recovery of
data impossible.


* The answer(s)

This group (comp.sys.ibm.pc.hardware.storage) is frequently visited by Svend
Olaf and he nailed down the PqRP problem pretty well (probably he's the
person who knows most about it aside from some PQ developers), he even
studied it to such a degree that he was able to write a tool (PqRP.exe) that
allows you to clasify the amount of damage within the PqRP partition.

His advise often is to leave the 'flag' as it is (3Ch - PqRP) and my guess
is that he advises this because of the same reason the PqRP mechanism exists
in the first place: as long as tools or Windows doesn't recognize a
partition they will not touch it i.e. will not make the damage worse than it
already is. This is good and solid advise!

PQ technical 1st line technical support does not have a clue what_so_ever of
what to do when the Ptedit trick (see below link for PQ KB article) doesn't
work, they just follow the same knowledge base article that is publically
available at the PQ support site (see below). They will refer you to the
manual where it is advised to create a backup before running PM. (NOTE: If
you DO edit the partition table for a FAT16 partition and you find a
'DYN_ROOT' when accessing it, I may be able to help to fix this - I have
written a tool that will fix this automatically - available up on request
only - I will first ask for a partinfo output, see below)

The only chance you have now:

- try the Ptedit trick (see link to PQ KB article below). Make sure to write
NOTHING to the partition, and prevent ALL programs from writing to or
touching the partition! Do NOT run Scandisk or NDD! Safest is to boot a DOS
diskette and try to READ the partition and verify you can access it, access
subfolders and maybe try to open a text file. Under NO circumstances write
to the partition until you have verified all is well! If data is only
partially available, copy the data you can access to ANOTHER physical disk
or removable disk.

- is getting Svend to help you, we all have been witnesses that he
frequently/always DOES recover PqRP partitions intact (at least of the
FAT/FAT32 type). Svend will ask for a findpart output (see below).

- or if you do not want to wait for that try a READ-ONLY commercial data
recovery tool to copy the data to ANOTHER disk. If such a tool succeeds in
recovering your files (verify them FIRST), you can then delete the PqRP
partition and recreate and reformat it. Concentrate on recovering user data
(copying an entire Windows installation and then expecting it to boot is
useles). If you decide to repartition the drive after you have recovered
your data and find PartitionMagic will not run because of partition table
errors see procedure below.

* Web addresses:

PowerQuest PqRP KB article :
http://www.powerquest.com/support/primus/id3851.cfm
PowerQuest's Ptedit program :
ftp://ftp.powerquest.com/pub/utilities/ptedit.zip
PowerQuest's Partinfo program :
ftp://ftp.powerquest.com/pub/utilities/partinfo.zip
Svend's PqRP program : http://inet.uni2.dk/~svolaf/utilities.htm
Svend's Findpart program : http://inet.uni2.dk/~svolaf/utilities.htm
Joep's website (for help with DYN_ROOT): http://www.diydatarecovery.nl


* Procedures:
======================================
PQ KB article:
Solution: Fixing a PQRP with PTEDIT
To fix a PQRP with PTEDIT:

1. Run PTEDIT.

2. Locate the PQRP (partition type 3C).
If the PQRP occurred on a logical partition, click "GoToEPBR" to locate
the correct partition.

3. Click in the "Type" field associated with the 3C partition.

4. Click "Set Type."
A list of available partition types is displayed.

5. Select the appropriate partition type (e.g., FAT32 if the partition type
was FAT32 before the PQRP, etc.).

6. Save the changes and exit.

If the system does not boot properly at this point, run a directory listing
(DIR) on the drive and make sure there are no "DYN_ROOT" entries. A
"DYN_ROOT" indicates that the original root directory has been relocated but
can, in most cases, be restored. If the directory listing appears as random
ASCII code or unrecognizable characters, the partition is likely corrupt and
cannot be recovered.

Note: If the root directory appears as a DYN_ROOT, do not SYS the drive.
Modifications made to the drive while in this state can reduce the
probability of recovery. Contact PowerQuest Technical Support for further
assistance.
======================================



======================================
Running partinfo:

1. Go to a true DOS prompt (not a Windows command prompt).

2. Change to the directory that contains PARTINFO.EXE. (For example, if you
want to run PARTINFO from the PartitionMagic rescue diskettes, insert the
first rescue diskette and change to the Adisgusted drive.)

3. Type PARTINFO > LPT1 (to send the results to the printer) or PARTINFO >
A:\PARTINFO.TXT (to save the output as a text file named PARTINFO.TXT to the
root directory), and then press Enter.
======================================


======================================
Running Findpart:

The report can be written to a file. Add the filename to the
command line. File extension must be .txt. To append to current
report file, use +<filename>.

Example: findpart all fp.txt [enter]
======================================


======================================
Running Svend's PqRP program

Usage: Pqrp <disknumber> [<logfile>] [files] [original]

Disks are numbered from 1. Log file extension must
be .txt. If 'files' is entered, a file listing is
printed to the file pqfiles.txt.

The 'original' option checks the partition at the
Pqrp location without adjustments.

This version works with disks with a 240 heads or
255 heads BIOS translation. Note that the settings
should not be changed after the disk has been
partitioned.

If the damage type is listed as 1, 2, 3 or 4 there is a good chance
that correctly editing the ID 3C partition table entry will recover
the partition. For damage types 3 and 4 it is not recognized what
happened, but the directory structure appears to be OK.

For damage types 5 and higher special tools are needed to recover all
files. Only the most common damage types are recognized in the current
version (was comment with version 1.1).
======================================


======================================
Running PartitionMagic while partition table errors are present

ONLY ignore partition table errors if it is your intention to delete the
partitions on the 'BAD' disk. Under NO other circumstances partition table
errors should be ignored!

PartitionMagic may fail to run if partition table errors are present (Disk
is shown as 'BAD'). You can tell PM to ignore partition table errors so you
can at least delete partitions from your harddisk (and by doing so getting
rid of partitions + partition table errors).

To do so run the DOS version of PartitionMagic with the /ipe switch:
pqmagic /ipe [enter].
======================================



* How to prevent dataloss as a result of a PqRP

- BACK UP YOUR DATA!
- Do NOT assume PM is hanging when it seems to have stopped displaying
progress! Toggle the NUMLOCK key and see if the LED toggles on and off, if
so leave PM and let it continue. (I have reproduced situations where it took
FIVE days to merge 2 partitions!)
- Do NOT perform resizes or merging when the partition(s) is/are almost
completely filled up!
- Do NOT merge a 'used' partition with an EMPTY one: instead delete the
empty partition and resize the used partition


* History:

July 24 - innitial version
July 25 - added info on PqRP tool / Mount PqRP partition from Linux
possibilty confirmed


* Final note(s):

- Suggestions for a PqRP FAQ are welcome
- remember you will hardly find notice posts how wonderful PM resized
partitions. Almost evry post you'll find will be about a problem of some
kind. This is NOT because PM tends to make partitions F.U.B.A.R., it is
because problems will cause people to seek help and post a message asking
for it. I no use PM for 4,5 years (frequently) and it has never let me down
(knock on wood). Also I have worked for PQ 3rd line support and often PqRPs
were caused by pure stupidity that some people are willing to admit, like
tripping over power cable - power cut - cat jumped on keyboard hitting
CTRL+ALT+DEL - PC fell from table etc.. (I am NOT joking or making this up!)


* Disclaimer: Use this information ON YOUR OWN RISK!


--
Kind regards,
Joep
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Adam Leinss
Guest





PostPosted: Sat Jul 26, 2003 5:16 am    Post subject: Re: ABOUT PqRP - The PqRP de- mystified - PqRP FAQ - RFC Reply with quote

"Joep" <joep@diydatarecovery.nl> wrote in
news:b29f1$3f21a8bd$3eddca68$11138@nf1.news-service.com:

Quote:
- Do NOT assume PM is hanging when it seems to have stopped
displaying progress! Toggle the NUMLOCK key and see if the LED
toggles on and off, if so leave PM and let it continue. (I have
reproduced situations where it took FIVE days to merge 2
partitions!)


I wonder if you wrote this with a straight face. 5 days? That's
normal? I would dump the software the first time it did that to me.

Adam
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DIY DataRecovery
Guest





PostPosted: Mon Aug 04, 2003 7:53 pm    Post subject: Re: ABOUT PqRP - The PqRP de- mystified - PqRP FAQ - RFC Reply with quote

Adam Leinss <aleinss@toughguy.net> wrote in message news:<Xns93C3C4072BED9aleinsstoughguynet@toughguy.net>...
Quote:
"Joep" <joep@diydatarecovery.nl> wrote in
news:b29f1$3f21a8bd$3eddca68$11138@nf1.news-service.com:

- Do NOT assume PM is hanging when it seems to have stopped
displaying progress! Toggle the NUMLOCK key and see if the LED
toggles on and off, if so leave PM and let it continue. (I have
reproduced situations where it took FIVE days to merge 2
partitions!)


I wonder if you wrote this with a straight face. 5 days? That's
normal? I would dump the software the first time it did that to me.

Adam

I did. This was a test in a scenario that irl should not occur and was
only intended to illustrate that PM can be still working although it
seems hanging.

Joep
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