Backing up old optical game formats

Many older games released on optical media employed copy-protection measures that make it very difficult to back them up.  This is a listing of the scenes that rip and preserve them, with opinions about the merits of each courtesy of Rom Sheppard.

A work in progress:

3DO TOSEC-ISO A huge collection of verified dumps, certainly the most detailed 3DO set around ATM. Disc format is simple, so you are losing nothing compared to newer methods.
CD32/CDTV TOSEC-ISO Again a massive and almost complete collection
CD-i TOSEC-ISO In terms of regular discs, TOSEC-ISO again has the most exhaustive collection on the net. Regarding movie discs and CD-i Ready, Trurip, since the former were conciously not added to TOSEC-ISO, while the latter is a strange format not supported by other dumping systems. But they still haven’t appeared in public…looks likely to change soon though…
PSX Redump A huge and almost complete collection. Drawback that the relatively few Libcrypt games need additional files to support them properly, so I’d prefer Trurip for those.
PS2 Redump Only Redump handles this ATM
Gamecube Redump Only Redump handles this ATM
Xbox Redump Only Redump handles this ATM
DC TOSEC-ISO TOSEC-ISO has the most updated and complete collection of verified dumps. Trurip comes close (most dumps are identical since dumping method for GD-ROMs is the same and I share dumping info between TOSEC-ISO and Trurip, matter of naming choice only there) but it also supports MilCD (unhandled by other methods) and includes a few unverified dumps that won’t be added to TOSEC-ISO until verified. But Trurip tends to lag behind when it comes to new additions to the dat.
SegaCD Trurip Trurip…high quality and almost complete.
Saturn Redump Redump has a huge collection in all regions. Trurip might have won for higher overall quality if it wasn’t so lacking in the US set.
PCE Trurip Trurip all the way
PC-FX Trurip Trurip all the way
NEOGEO*CD Trurip Trurip is more accurate and thorough than anybody else.
Jaguar CD Trurip Trurip all the way
PC Redump Redump is massive…if you can find it anywhere…