Talk:VT52
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The terminal supported forward and reverse scrolling, allowing full-screen editing for the first time.
The critical feature was the ability to move the cursor position at all, not specifically being able to scroll the screen downwards. Yes, if you moved the cursor up whilst on the top line the entire screen did scroll but without this reverse scrolling it would still be possible to implement a full-screen editor by redrawing. On a slow line this would be cumbersome of course and the reverse scrolling was definitely important, but cursor movement was key.
(Further historical note: vt52 could not scroll part of the screen (unlike vt100) so when editing text in the middle of a document it was necessary to redraw everything below when lines were added/deleted. On very slow lines this redraw would sometimes only take place when the edit was completed; that is, added lines would temporarily overwrite what was on-screen.)
Ros0709 15:28, 28 February 2007 (UTC)
