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RP9 File Format Information

 

TOPIC

Q: What are RP9 (.rp9) files?

 

DISCUSSION

A: RP9 (from RetroPlatform, the technology used in Amiga Forever and C64 Forever) is a packaging format largely compliant with the format endorsed by the W3C for web applications. It was designed for long-term preservation and one-click download and playback of "retrocomputing" content such as Amiga or C64 games and demoscene productions. RP9-enabled applications like Amiga Forever and C64 Forever support powerful content curation features to create and edit titles, which can be enjoyed "forever" in both personal and public use scenarios.

In its simplest technical form, an RP9 file is a ZIP archive compressed using the "deflate" method and containing an XML manifest (rp9-manifest.xml, as per RP9 XML Schema) and one or more preview (PNG) and media image files (e.g. ADF, D64, etc.)

Benefits of RP9 include:

  • All required media images are packed in a single RP9 file
  • XML manifest includes title description and configuration information
  • Title edits are applied to the title file itself (no external database needed)
  • Emulator-independent (configurations are described in terms of real hardware, and even "tweaks" are abstracted)
  • Titles are highly portable (separation between title-specific and host-specific options, e.g. for game controllers)
  • No dependency on external databases (although links to external resources are possible)
  • Natively compressed format (additional ZIP is not necessary)
  • Is recognizable as its own content type when downloading or opening (unlike the generic ZIP)
  • Preserves and respects original image files and names (original files can be extracted back from RP9)
  • May include visual preview images (PNG), help documents (text or PDF), box and media shots (PNG or JPEG), soundtrack and other related audio files
  • Supports streaming (titles can be played back in browser apps)

The MIME type of RP9 files is application/vnd.cloanto.rp9.

For the initial Amiga implementation, the preferred formats for disk images stored in RP9 files are ADF and HDF, for which disk change undo and save state is supported. ADZ, DMS and HDZ compressed disk images are converted to ADF or HDF by RetroPlatform Player instances, both to simplify playback support by simpler players, and because compressed formats carry an additional overhead which is redundant (RP9 is already compressed). CD images may be simple ISO files, or CUE-referenced ISO/BIN/WAV/MP3 file sets. Some other formats supported by the player may also be used, however undo and save state functionality may vary, and compatibility with third-party applications cannot be guaranteed.

To ease content grouping by authoring tools, format-specific file extensions (e.g. "example.mod", not "mod.example") are required for all embedded files (media, documents, images and audio, etc.)

Within the context of the RetroPlatform architecture, the main goal of RP9 is to introduce unity between "application" and "file" (i.e. one application = one file) and to simplify the download and organization of such applications without having to deal with ZIP archives or multiple files. RP9 files contain applications (e.g. disk images), optional application identifiers and configuration data and ancillary document and multimedia content (manuals, audio tracks, box shots, etc.)

The configuration data may contain a reference to a given RetroPlatform Library version, or other source of the configuration. Manual user additions and changes are also flagged as such. This makes it easier to automatically "clean up" RP9 files, applying new updates over old data, rather than vice versa, and respecting individual user changes, if so desired. If version data were missing, old RP9 files could contaminate the RP9 ecosystem, as emulation configuration improvements would not be as easily recognizable as such.

RP9 files do not require installation, and are independent of file name and location. We want users to be free to organize, rename and play RP9 files just like they can do with MP3 music and PDF documents. And, why not, even peek inside the archives.

Full support for RP9 was introduced in C64 Forever 2009 and Amiga Forever 2009, which were released in the first half of 2009. Support for embedded configuration data was introduced in the 2009.2 update. As of August 2009, several third-party developers were already working on quality-certified tools to support the RP9 format, and Cloanto's RetroPlatform team was working on improving the content of RetroPlatform Library based on the previously announced cataloging effort. The combination of RP9 authoring and conversion features (included in Amiga Forever and C64 Forever) and RetroPlatform Library, and similar third-party tools, are working towards making the vision of "one click to play, no configuration required" possible.

Here are some sample game files, ready for playback*:

If you are interested in offering RP9 files for download from your site, please contact us. Given the simplicity of RP9 you could be up and running in less than a day, at no cost. We mainly need to assign site-unique manifest data to you, and understand whether you require special support, for example by the Express Edition of Amiga Forever.

* After the War is Copyright © 1989 Dinamic SA, distributed under license. Aquanaut is Copyright © 1995 Phil Ruston, distributed under license. Breathless is Copyright © 1995 Fields of Vision, distributed under license. Death Trap is Copyright © 1990 Anco Software Ltd., distributed under license. Giddy II: Hero in an Egg Shell is Copyright © 1994 Phil Ruston, distributed under license. Metal Warrior is Copyright © 1993-2004 Covert BitOps, distributed under license. Operation Firestorm is Copyright © 1993 Phil Ruston, distributed under license. Super Scramble Simulator is Copyright © 1989 Magnetic Fields, distributed under license. The Persian Gulf Inferno is Copyright © 1989 Innerprise Software, Inc., distributed under license. Wrangler is Copyright © 1989 Magnetic Fields, distributed under license. RetroPlatform, RetroPlatform Player, RetroPlayer, Amiga Forever, the yellow daisy logo, C64 Forever, the blue daisy logo, RP9 and Workbench are either registered trademarks or trademarks of Cloanto Corporation in the United States and/or other countries.

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Article Information
Article ID: 15-122
Platform: All
Products: Amiga Forever, C64 Forever
Additional Keywords: file extension rp9
Last Update: 2016-12-30
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