Panasonic DMR-E100H HD / DVD Recorders

Hard Disks: Formats & Replacing

The information below applies specifically to the DMR-E100H, but as far as I know also applies more generally to all except possibly the most recent Panasonic HD / DVD Recorder models.

You can:

• Probably far too easily, format the hard disk (HD) thinking you were formatting the DVD-RAM!  I've made myself get into the habit of consciously checking that it really is the DVD at each confirmation message.
• Replace a faulty HD.
• If the fault allows, possibly rescue programmes off the old one by dubbing them to DVD-R or DVD-RAM.
• Dub rescued programmes back onto the new HD from DVD-RAM.

You can not:

• Dub rescued programmes back onto a new HD from DVD-R.
• Increase the HD capacity by putting in a larger HD.
• Read the disk format in a PC.

Here's why ...

Examining a low-level dump of the disk in a PC reveals that the tag  DVD_RTR_VMG0  occurs three times near the beginning of the format, each followed a little further on by a directory listing of the programmes on the disk.  Searching the internet for this tag found the following (now dead) patent link, suggesting that the HD format is related to DVD-RAM format, which is itself UDF:
      <a href="http://www.patentstorm.us/patents/6424797/description.html" title="www.patentstorm.us">Optical disc, recording device and reproducing device</a>

The practical consequence is that the format cannot be read by any driver or software commonly available for a PC.  Although one might have hoped that InCD from v4, Panasonic DVD-RAM, or other UDF drivers that can read DVD-RAMs, might have also been able to read one of these hard disks, in practice, they seem to have been programmed deliberately to ignore hard disks.

Although it would probably have been fairly simple to interrogate a newly-installed HD and format it to its actual capacity, the capacity to be formatted is hard-coded into the machine, so if you install a larger HD than the original, it will still only be formatted to the original's capacity!  This also means that probably you should never replace the HD with a smaller capacity than the original, as this might lead at best to errors, at worst to hardware damage.

Replace A Hard Disk

To replace the HD, if it's still under warranty, then obviously get it done professionally free of charge in the normal way, otherwise, if you can change a PC HD, you probably won't have any trouble doing this yourself.  Unless it's a recent model, it will almost certainly be a standard IDE drive, but in any case check by opening up the case.  Get a quiet replacement.  If it's IDE set the jumper(s) to Cable Select (CS).  Disconnect the power from the mains before you begin.  Everything else is pretty straightforward, though some of the screws are awkward to access.  Long tweezers &/or a magnetic screwdriver might prove useful for fishing out those that fall into the main PCB area.

After changing the HD, the machine will prompt to format it every time it's powered up until you either put back the original disk or agree to format the replacement.  Before you agree, it might be IMPORTANT to realise that if the prompt is accepted, then the new disk becomes the one that is recognised and subsequently reinstalling the original will result in a prompt to format that!  If you are already in this situation, then there is help further on.

Probable mechanism:  When the machine powers up, it interrogates the drive via the IDE interface and receives back an ID string.  You can see examples of these in Windows Explorer by right-clicking any HD and choosing Properties, Hardware.  When the machine formats a drive, it stores the drive's ID string in non-volatile memory (memory that preserves its contents without mains power).  It can therefore compare the value from the drive with that stored ...

• If they disagree, it knows the drive has been changed since the last format, and so prompts to format.
• If they agree, then it probably also checks somehow that the format is intact, in case the drive has been replaced with an identical model, though this is supposition on my part.

If you are trying to reinstall the original HD permanently, then you can get rid of the format prompt by fooling the machine.  If you have reinstalled the original merely to copy off programmes via DVD, then you can refuse the prompt to format.

Reinstate A Hard Disk Which The Recorder Prompts To Format

To reinstate an original HD permanently, you trick the machine into thinking that it has (re)formatted the disk, so that it writes the ID to non-volatile memory.  I am indebted for this to ...
     rtjoby, http://forums.afterdawn.com/thread_view.cfm/143317#834940
... which I confirm works, though it should be considered 'last gasp' rather than 'routine' procedure:

1. While the prompt to format is being displayed, CLEANLY pull out the power connector from the HD leaving the ribbon IDE data cable in place.
2. Press ENTER on the remote.  The unit will hang trying to format.  Let it hang for about 10-15 seconds.
3. Switch off the recorder at the wall.
4. Replace the HD power cable.
5. Switch the machine back on.  The HD, with your programmes intact, should now be recognised.

Copy Programmes From An Old Hard Disk To A Replacement

The following procedure can be used to copy programmes from the original HD to a replacement by temporarily bypassing the format prompt.  Only limited functionality is then available, but enough to dub recordings one at a time:

1. Disconnect the power, temporarily connect the new, replacement drive, reconnect the power, and format the disk.
2. Disconnect the power, reconnect the original drive, and reconnect the power.  The format prompt appears.
3. Wait until all activity, such as initialisation of the DVD drive, has ceased, and then press and hold STOP (black square) on the unit, the remote button is ignored, until, after some seconds, the prompt clears.
4. Using the remote as normal from now on, press ENTER on the owner confirmation message.
5. If there isn't one inserted already, insert a blank DVD-RAM disk.
6. Press DVD.
7. Press HDD.
8. Although you cannot record to the HD (it shows zero time free), and the FUNCTIONS button is disabled, you can now one by one copy programmes to DVD-RAM in the normal way by pressing DIRECT NAVIGATOR, selecting a programme, and then pressing DUBBING.  As usual, if High Speed mode is offered then the programme will fit on the DVD-RAM, but if flexible recording (FR) is offered, that means it will not.  Then you either have to accept the loss of quality that this option entails, or free up some additional DVD-RAM space.
9. Disconnect the power, reconnect the replacement drive, and reconnect the power.
10. Dub the programme(s) on the DVD-RAM(s) to HD using High Speed mode in the normal way.
11. Erase the DVD-RAM(s) and repeat the cycle from Step 2 until all your data is copied between the HDs.

Possible Symptom Of Defragmentation

I relate here an odd experience with my recorder in the possibility that it might help someone, or that someone might be able to give a fuller explanation

Having filled the original HD, as a stop-gap measure just before I went away, I took it out and replaced it with another of apparently the same size that I happened to have around.  After a year or so, this second hard disk started to show symptoms of failure, but only while recording  -  the recordings kept pausing and creating multiple files which didn't appear to contain anything.

I wasn't sure what the problem was, but it made me realise that if the machine went down, I'd lose everything I'd recorded on both hard disks, and that it would be better either to store the material on DVD-RAMs which my PC can read (but they're expensive, quite easily scratched, and I hadn't got enough of them) or to use the DVD-RAMs to copy them to my PC, reformat one of the HDs in a standard PC format, and then copy the files on to that.  I decided to try the latter.

When I'd copied everything off the replacement HD, I put the original back using the reinstatement procedure above, and the recording problems vanished, so naturally I thought the replacement HD must have been faulty, and counted myself lucky to have retrieved all the material off it (in fact off both of them).  However when I tried to format, surface check, etc, the supposedly faulty HD in my PC, there were none of the expected errors, and in fact it's now been in normal use for over a year with no obvious sign of failure as yet.

I have come to the conclusion that the original problem must have been:

1. Either disk defragmentation, which, if I'd been happy to lose the recordings, I could probably have cured just by reformatting the HD;
2. Or that the replacement HD, which was getting full, was perhaps ever so slightly smaller than the original, so the machine was trying to access areas that existed on the original disk but were beyond the capacity of the replacement.