Inquiry about bad dumps on the main site

[pak88]

I want to ask a few questions/have a discussion about the condition of isos/roms found on the main site. Not limiting this to any particular system.

1. I was wondering if the main site has any bad dumps/isos/roms and if so what ones are they? How many are there? Do some systems have more than others or is it limited to just some systems? (If anyone wants to, I would appreciate a list of all bad dumps/isos/roms found on the site or any info/links related to this)

2. Where do the isos/roms found on the main site come from? Are they a combination of scene releases and forum member uploads? Are these suppliers responsible for or related to any potential bad dumps/isos/roms?

3. What is a bad dump/iso/rom, what is wrong with them and what does this affect? Why do they exist? How can I identify bad dumps/isos/roms and are there any fixes/tools to make them good?

4. Now for something specific, I want to know more about multi-track games. I know that some multi-track games can have up to 18 tracks and they are more complex to deal with. Can a multi-track game be emulated "as is" or does it need to converted to something like a single-track game before it will work? Are multi-track games more prone to becoming bad dumps/isos/roms or are they harder to dump/rip?

Below are some discrepancies of isos/roms data. I have downloaded these games and was wondering if anyone can please explain to me what is wrong with them?
Are these examples of bad dumps/isos/roms?

In this case these multi-track games have a single iso file whose size equals it's first track size. Does this mean that they only have their first track and have the others removed?
http://www.emuparadise.me/Sony_Plays..._III_(E)/51874
http://redump.org/disc/2325/
http://www.emuparadise.me/Sony_Plays...e_IV_(E)/51875
http://redump.org/disc/549/

In this case these games have an iso file whose size is slightly larger than it's redump.org size. I can't figure this one out.
[url]http://www.emuparadise.me/Sony_Playstation_ISOs/Chrono_Cross_[Disc1of2]_[U]/36679
http://redump.org/disc/20/
[url]http://www.emuparadise.me/Sony_Playstation_ISOs/Chrono_Cross_[Disc2of2]_[U]/36680
http://redump.org/disc/21/
[url]http://www.emuparadise.me/Sony_Playstation_ISOs/Persona_-_Revelations_[NTSC-U]/37374
http://redump.org/disc/120/

In this case this multi-track game has a single iso file whose size equals it's total track size. Does this mean that it has all of it's tracks and has been converted into a single file?
[url]http://www.emuparadise.me/Sony_Playstation_ISOs/Lunar_Silver_Star_Story_Complete_(ccd)[Disc1of2]/37114
http://redump.org/disc/2676/
[url]http://www.emuparadise.me/Sony_Playstation_ISOs/Lunar_Silver_Star_Story_Complete_(ccd)[Disc2of2]/37115
http://redump.org/disc/2677/

5. Lastly, I want to know some more about revisions/update versions like Legend of Zelda, The - Ocarina of Time (USA) (Rev A) or Tales of Destiny 2 (Japan) (v1.01). I want to know what these affect like bug fixes, demos etc. I am aware that it's a case by case basis as each game is affected differently but it is hard to find what exactly is updated with a lot of games that get these revisions/update versions. On the contrary pc games get their patch/update information well publicized and almost all pc games get patches/updates compared to the few console games that get revisions/update versions. Is it more difficult or expensive to do revisions/update versions for console games compared to patches/updates for pc games? Why are revisions/update versions for console games never publicized much? Also I have been looking through the main site and I see Nintendo games have lots of revisions/update versions where as Sony games hardly have any. Does Sony not care about the quality of their games or simply spends less money to support their games as much as Nintendo?