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 not:
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 this patent link, suggesting that the HD format is related to
DVD-RAM format, which is itself UDF:
Optical disc, recording device and reproducing device
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.
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 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.
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 ...
... which I confirm works, though it should be considered 'last gasp' rather than 'routine' procedure:
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:
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: