On 9/19/2012 5:39 AM, McKown, John wrote:
With TSO IND$FILE, you must encode and decode all your data into a 3270 data
stream. Which, due to TSO, is half duplex (like the old walkie talkies, only
one side talks at a time). You then IP connect your TN3270 emulator to a TN3270
server which encodes the 3270 data stream. Also, then IND$FILE transfer is
limited to the size of your TSO screen. I.e. send one screen of encoded data
(at most 80x24, or 1920, bytes for a -2; 27*132==3564 for a -5); wait and
decode the response (protocol overhead); wash, rinse, repeat until all data is
transferred. The protocol and data translation (if any) overhead on ftp is much
less.
The above is just my SWAG based on some knowledge of how IND$FILE works
internally.
You've described the old CUT-mode interface. Somewhere around the early 1980s,
DFT mode was introduced. It does not encode the data, use a screen to send it,
or any of that. It simply wraps the binary data in a 3270 structured field
envelope and sends it via the WSF (write-structured-field) command. Any 3270
emulator that still uses the CUT-mode interface for IND$FILE should be tossed on
the trash heap of history...
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
310-338-0400 x318
[email protected]
http://www.phoenixsoftware.com/
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