Flash and Storage question

256kB RAM 1024kB on-chip flash, 8MB external flash

could anybody explain:

1. what is "on-chip flash" for? Is it for firmware only?
   
2. there are modules Flash, Storage, StorageFile, fs.
   all can read/write... to which flash?
   
3. does block address space include both on-chip flash and external flash, kind of concatenates 1MB and 8MB, or they are separate?
   
4. I need to write text or binary files, they may be long size. Should I use StorageFile.write()?
   
5. what type of filesystem is it? FAT, VFAT?
   
6. I could not find how to get metadata of a file - size, create time, change time. I hope at least size should be somewhere.
   
7. can I create folders?
   

what is "on-chip flash" for? Is it for firmware only?

Right now, yes - at some point I'll enable the option to write files to internal flash though (which is faster)

there are modules Flash, Storage, StorageFile, fs. all can read/write... to which flash?

It depends. Storage -> external (at the moment), Flash -> anywhere, fs -> not enabled on Bangle.js

does block address space include both on-chip flash and external flash, kind of concatenates 1MB and 8MB, or they are separate?

They're separate

I need to write text or binary files, they may be long size. Should I use StorageFile.write()?
what type of filesystem is it? FAT, VFAT?

It's a custom filesystem designed to allow files to be written in one contiguous chunk (if needed). For text files that are being appended to, use StorageFile.write() - but for binary or if you know the file size up front you just want to write direct with Storage.

I could not find how to get metadata of a file - size, create time, change time. I hope at least size should be somewhere.

There is no metadata apart from size. storage.read("file").length is fine for size

can I create folders?

Nope

Thank you Gordon!