Understanding File Transfers

IND$FILE Developed in the early 1980s to transfer files between an IBM mainframe and a system emulating a 3270 terminal. Variations of the IND$FILE program were developed for MVS/TSO,VM/CMS and CICS (both under MVS and DOS/VSE). is a proprietary transfer protocol that was developed by IBM.  In addition, this protocol was developed during the exclusively SNA SNA is a proprietary IBM architecture and set of implementing products for network computing within an enterprise. It existed prior to and became part of IBM's Systems Application Architecture (SAA). SNA itself contains several functional layers and includes an application program interface called the Virtual Telecommunications Access Method (Virtual Telecommunications Access Method), a communications protocol for the exchange of control information and data, and a data link layer, Synchronous Data Link Control (SDLC). SNA includes the concepts of nodes that can contain both physical units that provide certain setup functions and logical units, each associated with a particular network transaction. network era when communication was secure because IBM transferred files with other IBM SNA network clients.  The SNA network did not connect and could not be connected to any other network node.  The current environment is telnet Telnet is a text-based way of connecting to other computers and networks. It is one of the oldest forms of the Internet. When you telnet to another computer, it is like you are using a terminal of that system. Telnet operates in a client/server environment in which the computer you are using is the Client negotiates opening a session on another computer (the remote host or Server). over TCP/IP connections with TN3270 support which allows Internet access.

There are several programs that must reside on the IBM host for the file transfer process to work. The mainframe's operating environment must be MVS/CICS, DOS/VSE/CICS, VM/CMS or MVS/TSO.  In addition, to use the file transfer option, the IBM File Transfer program ( IND$FILE))must be installed on the mainframe. One of the following programs must be installed on the host depending upon the IBM operating system environment details.

NOTE: File transfers are always initiated from the PC side. This means that you cannot start a file transfer by typing a command at your host system prompt.  Also note that while the Windows environment allows you to multi-task (switch to another application) during the transfer, the host environment does not.