Local filesharing between linux and Windows

Very broadly, filesharing between linux and Windows can be local or network. Local filesharing concerns a single machine only. It is dual-boot, that is, linux and Windows both run on it but at different, mutually exclusive times. (Only one OS can run at a time on any machine, of course.) While running, each OS uses files that "belong" to the other in the sense that they were created by, are primarily for, or reside on a partition with a format (FAT, ext2, NTFS) associated with the other OS.

Mechanisms for local cross-platform filesharing

drivers to cross-read "foreign-formatted" partitions
 fat & ntfs drivers for linux
 ext2 drivers for Windows

readable-in-common removable media   
 floppies
 optical disks
 usb storage
 loopback devices and files

...

Loopback devices and files

Device vs file

Linux loopback device

File-based loopback device

Loopback encryption

Loopback-compatible encryption in Windows via FreeOTFE