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Re: x86 serial support


From: Omniflux
Subject: Re: x86 serial support
Date: Fri, 12 Aug 2005 16:18:49 -0600
User-agent: Mozilla Thunderbird 1.0 (Windows/20041206)

Marco Gerards wrote:

BTW, do you have any suggestion about the so-called "dumb terminal"?

The only thing I can think of is to disable the menu and replace clear
screen with a newline, which is what Legacy does IIRC.

Why can't we use a menu?  Is it really that slow to update the menu
over a serial console?

This is a communication problem caused by the fact that dumb terminal does not have a universally accepted definition. In this case, we are talking about a terminal without cursor control, such as a glass tty or teletype.

The following paragraph can be ignored if the above clarifies the issue. It contains examples for anyone else.

To implement a menu for this terminal would entail redrawing the screen each time something must be changed. This could be incredibly slow as many of these terminals have speeds of less then 110 bps. This also leaves the problem of marking the current menu selection, as we cannot use either color or reverse video. We would also be unable to reposition the cursor to (0,0) for the redraw, because we cannot be sure of the display size and thus the number of newlines which must be sent to move a line of text to that position. If the terminal is actually a display on paper terminal, we also have the problem of the waste of paper redisplaying the screen would create.

Why anyone would now be using such a terminal I do not know, but if we do not mention the proper way to use such a terminal, or not to use such a terminal at all, I'm sure someone will try it.

--
Omniflux





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