Subject: Computer Response Time
From: paul lamar
Date: 11/15/2015, 12:42 PM
To: A10-Me-Earthlink



Getting up too speed on my LinuxCNC installation and I ran across this well written explanation of why Windows does not work for machine control in pncconf.pdf. (attached)

The Maximite and DOS QB do not have this problem.

Way back in in 1975 when I wrote a hardware interrupt  driven multitasking OS for my Road Test system I figured this out. I designed a priority encoder for the hard ware interrupts using discrete integrated circuits. This was years ahead of it's time. Only in the past 20 years or so has this implemented in microcomputers like the PIC and ARM and I suspect it is yet to be implemented in Intel products. The pulse from the speed sensor had the highest priority in the Road Test system. I looked like an idiot Muslim in those days :-(

http://www.rotaryeng.net/RT1.pdf

"The servo period sets the heart beat of the system. Latency refers to the amount of time the computer can be longer then that period. Just like a rail road, LinuxCNC requires everything on a very tight and consistent time line or bad things happen. LinuxCNC requires and uses a real time operating system, which just means it has a low latency ( lateness ) response time when LinuxCNC requires its calculations and when doing LinuxCNCs calculations it cannot be interrupted by lower priority requests (such as user input to screen buttons or drawing etc)."


Paul Lamar


You wouldn't want to use Microsoft Windows anyway, you could only make malware !
   Chris. Hoskins


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