Sorry about the long time answering - been away for the past few days.
Yes, the serial numbers start with H. Damn things are quite hard to read actually - in their infinite wisdom "Datasafe Media" painted over them. I scanned the serial to read it more easily and included pre and post processed images.
I should have included that my drive is the DVR-106D (not the 106, although I don't know exactly what the difference is), and it is firmware revision 1.05.
I tried the discs several times at both 2x and 4x but haven't bothered at 1x (I guess I will try that tonight if something decent comes on TV). Anyway, I didn't buy a 4x recorder to use it at 1x at an hour a throw...
Following my last post I did quite a lot of digging on the net, and spoke again to Pioneer UK technical support. It appears that Pioneer have tailored this drive almost on a brand by brand basis. The guy on the phone seemed to imply that Pioneer are trying to "protect their customers" from "poor quality" discs by making the drive not write to them!!?? He also said that some companies are using eachothers' media IDs in an attempt to get their discs to write quicker on some drives. This is definitely echoed by various people on the net (although of course that doesn't necessarily mean the info isnt all coming from the same source )
Also a few reports that the red top Datawrites are now discontinued (plus read about people bad experiences with firmware). Importantly, one guy on there says that the A05 will burn these fine - but the same discs in the 06 don't work.
Oddly though, I couldn't find any references to these discs being discontinued other than on forums - no manufacturers' press releases, etc.
Anyway, to cut through all the noise, it appears that some part of the following is responsible.
1. Either substandard discs escaped from the Princo factory
2. Or Pioneer caused the problems with its brand specific "burn-strategies" etc.
3. Or both are responsible for peoples problems
I have tried checking out the general level of success with the v1.06 firmware update for these drives, but (here we go again) - half the people say it fixed their problems, while the other half say it caused them. Quite a few happy 1.05 users upgraded to 1.06 and can no longer reliably burn discs (so BE WARNED - you can't generally revert to earlier firmware revisions unless you deliberately crash the drive into failsafe mode, so check this out carefully before you upgrade...). By the look of things, don't upgrade the firmware unless you need to - I am going to ask Pioneer about this too as there are definitely some new problems with the new firmware. There were also quite a few unhappy 1.05 users that then upgraded and found their problems were cured. Looks like the Pioneer firmware issue is a minefield - I won't post more links to it all here but you should be able to find plenty of material on the net.
I bought my redtops from Dabs.com. I checked their current stock (thinking that if these had been discontinued, maybe Dabs wouldnt have any left) but they say they have 939 packs in stock. An hour ago it was 942. So no help there (d'oh).
Oh, one other interesting thing - I couldn't get the "Nero CD/DVD Speed" tool (shipped with v18.104.22.168) to report the media ID for these discs. The other fields mostly appear, but the ID field is blank. Anyone else have this problem?
The only thing left that I can think of is for us to check the serial numbers of our Datawrite red 4x DVD-R discs, and maybe our DVR-106 drives too if anyone can be bothered to remove it from their machine. (I probably won't bother myself unless I get time to kill...).
If everyone who made coasters and everyone who burned these successfully could check the serial numbers on the inside rim, then maybe we could find out roughly the range of serial numbers for the bad discs. Then maybe we would have an answer.
(By the way, all the discs in the cake I opened have the same serial number, so it must be just a cake/batch number.)
So anyone out there who's used datawrite red tops, please let us know the outcome! (This should be interesting...)