Support for AppleSingle

[oliverschmidt]

AppleSingle file generation would allow to transport metadata like the code start address to tools that put the generated file onto a file system which maintains that metadata (like ProDOS).
As far as I know there's already a Cadius fork which accepts AppleSingle files. Other, similar tools do it as well. And the cc65 toolchain generates AppleSingle files by default.

[OlivierZARDINI]

Is it the more accurate information about AppleSingle file : https://web.archive.org/web/20180311140826/http://kaiser-edv.de/documents/AppleSingle_AppleDouble.pdf

Can you point me the Cadius fork that has integrated the support for AppleSingle files ?

[oliverschmidt]

Here you go: https://github.com/mach-kernel/cadius?tab=readme-ov-file#140

[fadden]

There are two versions of AppleSingle (v1 and v2). You should be using v2, which is described by the "foreign files" document. v1 is described by an Apple II file type note ($e0/0001).

See also https://github.com/fadden/CiderPress2/blob/main/DiskArc/Arc/AppleSingle-notes.md

[dfgordon]

Probably not important for Merlin, but:

The MS-DOS entry is not quite explained. There are only 8 bits in the attributes field of a FAT disk, but AppleSingle reserves 16. So which byte is the one that should be loaded with the attributes? I have in mind FAT12 floppies, but I think the same holds for FAT16 and FAT32 also.

[fadden]

Some of the most detailed info on AppleSingle is in the RFC. You can find a structure definition in the appendix, but it looks like the author is guessing:

   /* MS-DOS file attributes occupy 1 octet; since the Developer Note
    * is unspecific, I've placed them in the low order portion of the
    * field (based on example of other ASMacInfo & ASProdosInfo).
    */

   struct ASMsdosInfo      /* entry ID 12, MS-DOS file information */
   {
       uchar8 filler; /* filler, currently all bits 0 */
       uchar8 attr; /* _dos_getfileattr(), MS-DOS */
                                   /* interrupt 21h function 4300h */
   }; /* ASMsdosInfo */

   typedef struct ASMsdosInfo ASMsdosInfo;

   #define AS_DOS_NORMAL   0x00 /* normal file (all bits clear) */
   #define AS_DOS_READONLY 0x01 /* file is read-only */
   #define AS_DOS_HIDDEN   0x02 /* hidden file (not shown by DIR) */
   #define AS_DOS_SYSTEM   0x04 /* system file (not shown by DIR) */
   #define AS_DOS_VOLID    0x08 /* volume label (only in root dir) */
   #define AS_DOS_SUBDIR   0x10 /* file is a subdirectory */
   #define AS_DOS_ARCHIVE  0x20 /* new or modified (needs backup) */

I don't know if there's anything definitive.