[Coco] Sort of on topic - key press lag time for older computers vs new

[RETRO Innovations]

On 1/10/2018 11:34 AM, John Guin wrote:
> Sad to not see any Tandy machines on this list: https://danluu.com/input-lag/
>
> He used a high speed camera to measure the time between pressing a key and the screen update.  Spoiler - the older machines win bigly.
>
> Enjoy!
> John
>
I would assume most 80's machines would see a latency of multiples of 
1/60s (16.6ms), since the keyboard scan routines and the video operate 
on that period (NTSC, PAL would be 20ms)  Assuming the interpreter loop 
is reasonably tight and can be discarded as a source of latency, it 
could take 16.6ms to read the key, and 16.6ms for the video to display.  
Thus, on balance, I would expect 33ms to be seen in the list by many 
home machines.  The 60ms for the Commodore PET 4016 seems a bit odd, as 
that machine is a very simple 6502-based machine with a dedicated monitor.

Jim

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