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On Fri, 11 Jan 2002, McCallion, Martin wrote: > > > It seems to me that the screen-at-a-time nature of 5250 would > > make it a very difficult task to port Lynx to the AS/400. > > > > Surely the thing to do would be to run it in QSHELL, since that's an > approximation of a Unix environment? That would handle the > line-at-a-time scrolling issues. It's not line-at-a-time scrolling issues that I feel would be an issue, it's the screen-at-a-time 5250 i/o. On a 5250 display, the AS/400 sends an entire screen to the terminal. The terminal displays the screen to the user, and allows the user to move around the screen, type in the input fields, etc... control does not go back to the AS/400 until you hit ENTER or a function key. In Lynx, when you press the down-arrow, the cursor moves to the next link on the page -- with 5250, this would not be possible. When you hit the space bar, it pages down -- this would not be possible. When you hit the 'G' key, it brings up a "URL to open:" prompt. This would not be possible (unless you hit ENTER after the G key). It makes no difference whether you're running QSHELL on the AS/400, or not. It's the way that 5250 terminals work that is the issue, so if you're accessing QSHELL from a 5250 terminal, you have the same exact restrictions. In fact, a normal program would work FAR better than QSHELL, since QSHELL's input comes from a single command line at the bottom of the screen, and that would really be non-intuitive in a web browser. Therefore, I was stating that you'd want to start from scratch if you wanted to make a 5250-based web browser. You'd want to make something that was specifically designed for 5250 displays. Instead of the various Lynx functions, such as "H)elp O)ptions P)rint G)o", you'd want to use F1, F2, etc. When those keys are pressed, it would automatically pass control to the program, which is much more intuitive. When rendering the HTML to display on the screen, you'd want to use a user-defined data stream. DSM might be an option for this. Sending the 5250 codes directly would also work... this would allow you to position input fields, display attributes, etc anywhere you wanted them, depending on the document instead of having to know the layout of the web page in advance :) As I said... all of this is possible. You could make something that's a lot like Lynx, which became a really nice utility. But it would be a lot of work.
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