Proposal for a new file format "Super ADF" (for collections)

[LongLifeA1200]

Would you support such an idea?

A Super-ADF would contain a nominated primary/default ADF and append the differences of other versions.

[coldacid]

Excuse me while I put on my PM hat, but what's the use case here? Tell me why I as an Amiga user would want this, and why Toni or Frode would add it to UAE. What's the benefit, when managing individual ADFs for different versions of a disk isn't difficult? What would the performance look like? The user experience?

[Radertified]

Originally Posted by coldacid

what's the use case here?

Decluttering collections such as TOSEC would be one use case.

Remember a lot of [a]'s are just a few bytes changed. Why store 901,120 bytes for every single [a] when you can store a few extra bytes onto a main image instead and still have everything available?

[coldacid]

Originally Posted by Radertified

Decluttering collections such as TOSEC would be one use case.

Remember a lot of [a]'s are just a few bytes changed. Why store 901,120 bytes for every single [a] when you can store a few extra bytes onto a main image instead and still have everything available?

That sounds useful for collection managers, but I'm looking more from the perspective of the average user when I'm talking use cases. As a user of an emulated Amiga, I (read: some average joe, not actually me) just want to be able to download a game and play it on UAE, maybe install some programs on my emulated A1200, and not have to learn how to do something new just to be able to keep doing what I was doing before.


As a developer, this sounds pretty damn interesting, and I'd definitely tinker around with the concept, maybe provide some suggestions and perhaps even do some coding etc., but years of working on apps and websites for ordinary people have me always trying to look at things from the user perspective instead. I want to understand what someone who just throws an ADF at WinUAE would get from this, and if it would actually improve things for them, or make things more complicated instead.

[Radertified]

I don't think an average user would want this. As LongLifeA1200 said, it would be for collectors.

I guess Cloanto's RP9 format sort of implements this. It's just a zip and since zip will compress similar images down, it would be just as good. The added benefit is it also stores a metadata file and screenshots. I personally think this is what WinUAE should implement since it basically solves OP's problem and expands on it.

For anyone that has not experienced the RP9 format, there are some examples available for download at http://www.retroplatform.com/kb/15-122

[coldacid]

Zip doesn't actually "compress similar images down". Each individual file in a zip file is individually compressed, so you don't get the de-duplication that you would with RAR or 7Z solid archives. While I do like RP9, it wouldn't solve this particular issue.

[lesta_smsc]

So a base ADF with 'patches' as supplementary. I think MAME does something similar in ROM format?

[Radertified]

Originally Posted by coldacid

Zip doesn't actually "compress similar images down". Each individual file in a zip file is individually compressed, so you don't get the de-duplication that you would with RAR or 7Z solid archives. While I do like RP9, it wouldn't solve this particular issue.

Then we'll need a successor to RP9. RP10, which will use a better compression algorithm.