Some of the metadata attributed to files on Acorn filing systems date from the 8-bit implementations of ADFS (and the earlier DFS) on the BBC Micro. These include the address to load the file in memory (RAM) whean read from disk, and the address at which the OS should start executing the file (if it is executable).
Key additions for RISC OS as used by the Archimedes include the three-byte file type that RISC OS uses to identify what programs should be used to open particular files (or whether they are executable themselves).
The inability to store the file type was the main issue with using DOS filing systems with an Archimedes, so this data will certainly be listed in the metadata file. I suspect it may include some or all of the information returned by the OS call OS_GBPB 12, which consists of the following data (at the given offsets):
- 0 Load address
- +4 Exec address
- +8 Length
- +12 Attributes (read, write permissions etc.)
- +16 Object type (e.g. file, directory)
- +20 Filetype (as described above)
- +24 Name (0 – terminated string)
Note: the ZIP file format has provision for storing RISC OS file types, which means that software for RISC OS machines is often stored in ZIP folders for distribution via non-RISC machines. The ZIP format stores all the metadata returned by OS_GBPB 12, as seen here.