Re: flashing symptoms (magic cookies)

[Daniel Weaver]

At 04:14 PM 11/3/00 -0330, Neil Zanella wrote:
>On Fri, 3 Nov 2000, Daniel Weaver wrote:
>> At 03:47 PM 11/3/00 -0330, Neil Zanella wrote:
>> >
>> >Hello,
>> >
>> >I am using subwindows and subwindows of subwindows. When I refresh one
>> >bottom level subwindow and then anotherone the screen flashes a lot.
>> 
>> What kind of terminal are you using?  Terminals that have magic cookies
>> flash a lot.  There is not much that you can do about it.
>
>I am using xterm.

Then magic cookies are definitely not your problem.

> What are magic cookies?

Video attributes, such as bold, reverse and blink are usually implemented
in one of two ways.  The attributes are stored along with each byte, making
the video memory wider or the attributes take up a character cell on the
screen.  In the latter method the terminal would change attributes when
this special attribute character was hit and retain this attribute until
another special character was encountered.  This special character
became known as a magic cookie.

The reason magic cookies came to mind is that the cookie to turn on an
attribute usually gets written before the one to turn it off.  This makes
the screen flash with the new attribute from the current location to
the end on the screen.

> I have only heared that term in the context of http connections.

These are totally different.  An HTTP cookie is something the server
writes to your computer so it can remember something, such as preferences
or what you did last.


-----------------------------
Dan Weaver, ZNYX Networks
address@hidden