game names and checksum

[sleipnir]

Hi

I know that for some older systems, groups like the Tosec created lists of known 'roms/disk images' for various systems. The naming conventions for the games are clear and their data is used by rom managing software (like Romcenter).
Is there a similar project for PSX games ?

Also, the lists also contain some 'checksum' information so you can verify your dump/rip is error free.
Is there also some kind of convention for PSX games so you can verify your rip is correct ?
When buying 2nd hand games there are sometimes scratches of the disks and it would be good to know if the disk is still in fine condition.

[Ultima]

Because of the very fact that scratches can occur, it's impossible to verify if an image is ripped correctly or not. A lot of image rippers fill unreadable scratches with 0s. Disc drives and emulators can overlook such errors as long as it's not too major. Because of this, varying images can still work. There is no naming convention that I know of for PlayStation games.

[Truth Unknown]

Closest to game Identification is the SxxS_###.## file in each disc. Thats about it.

[speedfreak]

The only thing so far for names is PS1 renamer at www.sonyindex.com/PS1_Renamer/index.htm but it doesn't do checksums

[sleipnir]

Thanks for the answers

ultima said:

Because of the very fact that scratches can occur, it's impossible to verify if an image is ripped correctly or not. A lot of image rippers fill unreadable scratches with 0s. Disc drives and emulators can overlook such errors as long as it's not too major. Because of this, varying images can still work.

The whole point would be to have a reference of good checksum made from known scratch free (like new) original disks.
a CD contains digital data, so if the disk is perfect, different rippers should give the same binary image file.
Then if you follow the same ripping method with same settings, you would know if your disk/image is perfect or not. It's only informational

The way bad disks/images are handled by rippers/emulators is another story...

[Ultima]

I know what the point was. My point is that that kind of information is near-useless because of the very fact that discs get scratched so easily, and the fact that having different hashes can mean next-to-nothing considering how minor differences are affect nothing (in most cases) with regards to readability, yet affect everything with regards to hash. If you have a million different images of the same disk (with different hashes), all of which work perfectly wherever you use it, what's the point of having one reference hash?

It was easier for cartridge-based games to have the same checksums because the data didn't vary so much (being stored in a cartridge and on a ROM chip greatly protected the data), so a good rip would normally end up the same. Because cartridges were essentially supposed to be the same, if something did come out with a different hash, it was very easy to say that the image was bad, since you can easily have a million other people who rip the cartridge and get the same hash as the reference checksum to attest to the correct one.

Don't get me wrong, I'm not saying the idea of having checksums for disc images is stupid or wrong (it'd be great if it could actually be used), I'm just saying that its utility is extremely limited considering the difference between disc images and cartridge images. With disc image ripping, getting different hashes is not uncommon. In fact, getting identical hashes can prove to be more common. In essence, how a disc is read/ripped has everything to do with why there isn't a database of hashes, and shouldn't be considered a different story on its own.

[patrickp]

Didn't some guy post here fairly recently saying he was setting up a database of Playstation game info, including checksums etc?

Ah, yes, here it is: PlayStation 1/2 Games Database.

[Ultima]

Yeah I originally linked to that in my first post in this thread, but decided it was irrelevant with regards to what sleipnir was looking for -- it doesn't list all that many games (only 200 or so), and doesn't have the hash either. If he were looking for a list of games, he could just check the master list or the Digital Press stuff site (both of which are linked to in the Things to Remember thread.

Edit: Oh crap lol, I didn't notice that the site actually lists the checksums as well -- I never actually bothered clicking the game links xD Still doesn't change my opinion on the matter, though

[sleipnir]

Cool

I knew this site but I didn't notice they were giving different hash for every game.
Just for fun, I calculated the checksums of one of my original (bought it brand new) and compared them with the ones from the site and they were identical.

Then I tried their .dat file in ClrMamePro, but unfortunately, the file names are all .cue and .bin (and mine are in ccd)

[Heihachi_73]

Resurfacing scratched CDs works most of the time depending on how deep the scratch is.

[lordflux]

I personally like the idea of having a list, or better yet a dat, of compiled checksums and hashes for PSOne games. I keep all of my discs in prime condition, but when I first tried out Castlevania: SOTN, I just knew that my disc must have been pressed improperly with the way it was stopping and skipping (but as everyone knows, it's actually an emulation issue). This also may cut down on people posting about compatibility issues that are actually caused by a bad rip.

[Sune]

The real problem is that different drives will produce a slightly different rip with the same disc, whether it has scratches or not.

Even if you ripped the same disc four times with the same drive, I don't think there's much of a chance of getting four 100% identical images.

[patrickp]

I don't know, Sune - I just checked the MD5s for several of my images against the ones posted on psxdb.com/psx, and they all match perfectly.

I think if different drives produce different images, it's because one or more of them isn't reading the disk properly.

Certainly, I've found that different drives produce different degrees of accuracy - I've got an old Plextor CD-RW that'll read flyshit, and that will sometimes produce a good image from disks that I can't get a good read from in other drives.

However, the DVD (ROM and RW drives) I usually use will read pretty much any Playstation disk in good nick successfully, using CloneCD.

RW drives, on the whole, seem to be better than ROM drives for reading accurately. The ripping application you use makes a lot of difference, too.

[heavensblade23]

Why wouldn't it be possible? There's a system for comparing hashes from audio CD rips (AccurateRip). I don't see why a data or mixed disc would be substantially different.

Not to mention TOSEC has released some ISO sets.