For those who want some of the geeky details and links:I found this web page describing the _in-memory_ format of an Amiga keymap, in the form of a struct definition containing pointers to sub-tables: https://wiki.amigaos.net/wiki/Keymap_Library#Details_of_the_Keymap_StructureThe on-disk format wraps up that in-memory data layout into the same file format used by Amiga executables, containing a code hunk for the struct itself and its subsidiary tables, and a relocation hunk to fix up the internal pointers between those objects once the OS has decided where to load it. So I needed the format of the Amiga Hunk object/executable format too: http://amiga-dev.wikidot.com/file-format:hunkBut comparing those against existing keymap files, there was a missing piece. The 'struct KeyMap' described in the first page started 14 bytes after the beginning of the code hunk. What's in those first 14 bytes?I found the answer in the source code of the Scala keymap editor that I hadn't been able to build. Regardless of that, it was helpful anyway, because reading its source code told me that those 14 bytes are a linked-list node + metadata structure, containing zeroed-out 'pred' and 'succ' fields which I assume are filled in by the OS after loading into memory, and more importantly, a pointer to a NUL-terminated string _naming_ the keymap, which of course I needed to edit so that my new keymap had its own distinct name. https://github.com/weiju/fatma/blob/063185672474114c67a0505fc87a98193522d783/src/main/scala/org/dmpp/os/devices/KeymapWriter.scala#L198I didn't end up needing to write my own software tool to decode and encode keymap files (though it probably wouldn't have been too hard, given all that). The changes I wanted to make to the 'gb' keymap were small enough that I could just tweak the tables by hand with a hex editor. Changing the keymap name was the hardest part, because it changed the length of the hunks in the file, but still easy enough to do by hand for a one-off.Previous thread in which I describe bugs in Linux AFFS support and fixes I submitted to adflib and the Linux kernel: https://hachyderm.io/@simontatham/114040807878945101
