Recently, I had to create an orchestration that transfers files to the IBM mainframe running z/OS (also called sometimes MVS - Multiple Virtual Storage because of the legacy). The orchestration used dynamic FTP port to correlate incoming messages to the destination. During this exercise I learned something about FTPing to the mainframe with BizTalk adapter. First, flat files obviously must be passed in ASCII mode so the FTP server is able to convert them to EBCDIC format. Passed in binary mode files ......