I've been trying to get a verified dump of a Dreamcast disc with DCdumper for the past month or so with no luck.  I've tried with five different discs.  I have two compatible drives for GD-ROM HD area dumping: a TS-H192C and a TS-H352C.  Both reliably get matches on sections 1-39.  They will both match section 40 occasionally (sometimes takes a LOT of passes), but not yet so that I have been able to verify any dump against the database.  Also, I haven't been able to get the same hash on a section 40 match for the same disc twice.

From testing with my copy of Virtual On - Oratorio Tangram, I am certain that the drives are pulling good data from sections 1-39.  This disc has 58 tracks on the HD area and I have been able to match checksums on the first 57 from multiple dumps.  I've never been able to match the 58th.

I find it hard to believe that this is a problem with all five of my discs.  None of them have any significant scuffs or scratches, and Virtual On is pristine.  I've tried dumping with two separate PCs, with PowerShell and with the command prompt (not that I think either of these variables would matter).

Is this a common issue with Dreamcast dumping?  Is there anything else I can try?  Or should I really assume that both my drives are lemons?  How many drives should I expect to go through before I find one that'll do the job with section 40?

Dreamcast dumping is a bit like voodoo. One thing I've found is that it's often good to stop the dump if it goes around a few times without verifies - let the drive cool for an hour and go again. If you're dumping back to back to back, that might be part of the problem.

Some discs are known to be problematic with DC dumping, but based on the amount of verifies Virtual On shouldn't be one of them.

All my posts and submission data are released into Public Domain / CC0.

I'll give that a try.  Thanks for the tip.  I've certainly let the H352C run for many passes over long periods of time.  It's way slower and more finnicky about dumping than the H192C.

Dealing with this, it's amazing to me that there are as many Dreamcast dumps in the database as there are!

4 (edited by wiggy2k 2021-02-22 22:17:15)

i will expand on this in greater detail tomorrow whan i am not completely innebriated.

but the reason that people encounter more problems on "section 40" when using dcdumper.exe is because by default section 40 is 10 times larger than secions 1-39.

There are some command switches that can help, but, in short, yes, as you suspect. not all drives are created equal (whatever you do dont tell the lefties about that being a scientific fact)

I was thinking about next trying to just discard the -c446261 parameter and see if I can zero in on the part(s) of the discs that are causing matching problems.

Worthwhile?  I understand Section 40 is dumped as a 10x larger chunk of data because those last sections tend to be trouble on their own.

The idea behind dumping section 40 as one big chunk relates to the read momentum required to power through the trickier sectors. In other words if you slice it too thin you'll likely never be able to dump some sectors in their own small chunk. That's the theory anyway.

All my posts and submission data are released into Public Domain / CC0.