Shared System Files on Chrome Devices

TOPIC

This article explains how third-party apps can access the shared system ROM and OS files provided by Amiga Forever Essentials for Chrome.

DISCUSSION

Amiga Forever Essentials for Chrome aims to both support the development of third-party emulation apps and to make it easier for users to enjoy such apps. In order to achieve this goal, legal and official ROM and OS files licensed for use in Chrome are made available, with a shared access mechanism for developers.

A self-describing JSON index file ("index.json") lists the available files and their properties. All items are inside the "shared" directory under the Amiga Forever Essentials "aemohkgcfhdkjpoonndfpaikgbpgcogm" Application ID namespace.

Additional information about the content of the JSON index:

• Amiga Forever Essentials ROM files are 512 KB, and may be XOR-encoded as illustrated in memory.c of the original UAE source code (October 1997 and later versions), in which case the "keyFile" property references the key
• The compatibility of each ROM and OS file is described using one or more RetroPlatform system tags, of which currently only "a-500" is guaranteed to be supported for the Chrome environment
• Different RetroPlatform disk image file types may be present, but only the "adf" disk image type is currently guaranteed to be included in Amiga Forever Essentials for Chrome
• The above means that it is safe to rely on the presence of ROMs for the "a-500" model and "adf" disk images
• ROMs and disk images have a "name" property for listing in drop-down menus and similar user interface options
• Bootable disk images have the "bootable" property set
• The EULA software license file is referenced by the "eula" property and is currently guaranteed to be present as "text/plain" ("type" property) and/or "text/html"

Sample URL to access the index: 

chrome-extension://aemohkgcfhdkjpoonndfpaikgbpgcogm/shared/index.json

Sample index data: 

 {
   "version": "1.0",
   "files": {
      "rom": [
         {
            "systems": [
               "a-500",
               "a-1000"
            ],
            "version": "120",
            "name": "Amiga 1.2",
            "romFile": "rom/amiga-os-120.rom",
            "keyFile": "rom/rom.key"
         },
         {
            "systems": [
               "a-500",
               "a-1000"
            ],
            "version": "130",
            "name": "Amiga 1.3",
            "romFile": "rom/amiga-os-130.rom",
            "keyFile": "rom/rom.key"
         },
         {
            "systems": [
               "a-500",
               "a-1000"
            ],
            "version": "204",
            "name": "Amiga 2.04",
            "romFile": "rom/amiga-os-204.rom",
            "keyFile": "rom/rom.key"
         }
      ],
      "adf": [
         {
            "name": "First Demos",
            "bootable": "true",
            "diskFile": "adf/af-demos-01.adf"
         },
         {
            "name": "Workbench 1.3",
            "bootable": "true",
            "diskFile": "adf/amiga-os-134-workbench.adf"
         }
      ],
      "eula": [
         {
            "type": "text/plain",
            "eulaFile": "eula.txt"
         }
      ]
   }
}}

Related Links

• Structure and Names of Emulation and System Files