On Wed, 19 Sep 2012 07:39:13 -0500, McKown, John wrote:

>ftp does not go through as many transitions. Basically, there is an IP 
>connection to a server which write directly to a file. The only encode/decode 
>is if you do an ASCII translation. 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.
>

"...There are two forms of IND$FILE: DFT mode (which uses the structured 
fields) and CUT mode which uses 3270 Write commands..."  Gilbert Saint-Flour's 
IND$FILE-page @ http://gsf-soft.com/Documents/IND$FILE.html

Norbert Friemel

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