In OX X Server 10.4, what does FTP support on-the-fly? (encrypt, decrypt, encode, decode, etc…) What is commonly done together and what is not supported?

encode — this has to do with the files with Resource forks (from mac OS 9 typically) which get encoded into a MacBinary file– with resource fork & data fork together

archive — taking a group of files and/or folders and archiving them into a single .tar file

compress — will add .gz to end and compress the file (does not preserve resource forks)

Commonly done together: archiving & compressing, to create a .tar.gz file

note you could also use MacBinary in combination with the others

WHAT IT DOES NOT SUPPORT:
encrypt
decrypt
uncompress