ALife sims and terminal refresh rates (was Stupid eBay user du jor)

27 Feb 2006

...
   19200,
assuming 10 bits per character (start, 8 data, 1 stop) is 1920 
 characters/second. Your screen has 1920 characters. So one full screen 
 per second, maximum  
 So not fast enough to get 2fps on an Alife simulator. Drat. 
Well, that depends if you have to update every chracter or not. If you 
only need to change a few locations, it would be a lot faster to send the 
cursor movement commands and just update those chracters.

...
   second. In
fact the PERQ easily beat it -- the peak speed, assuming all 
 you were doing was displaying things on the screen, was nearer 10 full 
 screens per second, and that's a full PERQ secreen, which displays 
 something like 80*66 characters.  
 Wow. Not bad. That said, the VRAM would have been memory-mapped, so I would
 have expected a decent write speed anyway. 
You misunderstood me. I wasn't talking about copying an area of memory 
the size of the screen bitmap into the video memory (which is part of the 
main memory anyway). I was talking about doing a raster operation -- 
something like XORing a given bitmap with the screen memory. Remember 
that even an insert-bitmap (i.e. to write a chracter bitmap to the 
screen) is non-trivial on a machine where the RAM is not bit addressable 
(the edges of the area you want to replace most likely are not word 
boundaries).

-tony

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ALife sims and terminal refresh rates (was Stupid eBay user du jor)