Re: Yet Another New Machine

On 06/11/2024 01:53, Jim Wilkins wrote:

"Bob La Londe"  wrote in message news:vgdohv$16n6e$1@dont-email.me...
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This can be an issue with Windows for example because it is not a real time operating system.  Or rather it does not by default give real time control to programs running under its overhead.  Not sure I said that right, but I am sure you get the idea.

It's been a while since I've done any Windows programming but the last main application was doing some data logging from force and torque equipment via the serial port and in order to get better timing response did set the thread as 'real time priority' in a Windows  data structure but the main thing that allowed decent timing at around 50Hz was to use the timeBeginPeriod () and timeEndPeriod () to set the system timer to 2ms.

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I quickly discovered Window's time slice multitasking and I/O port polling from a scope capture of a carefully timed I2C data stream generated by the printer port's control bits. Quick Basic running under the enhanced DOS behind Win98 and 2000 eliminated the gaps and polling, the only active interrupt in DOS updates the clock every 55mS, which I could detect and then have the CPU and I/O address space registers all to myself until the next predictable one.
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Windows still has an increasingly powerful DOS behind it, and it's needed for the fsutil.exe command that controls SSD garbage collection. This describes it in Windows 10/11:
https://www.easeus.com/resource/trim-ssd-windows-10.html
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The Shift, Ctrl and Alt keys set I/O address space register bits that allow a program to detect them, which was handy when the keyboard had been pushed almost out of reach by the circuit board being tested. Ctrl or Alt in the bottom row would advance the program. The F1-F12 keys return two bytes. I wrote an input function that correctly returned anything in the keyboard buffer, including ESCape, or that it was empty and the program could continue looping. It could also read a macro string of key commands.
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I dabbled in G code very little, mostly in the similar Gerber vector graphic language for photoplotting circuit board artworks, and the text language for transferring CAD electrical schematics to the PC board design program. The two disagreed on which end of a diode was pin 1, which caused puzzling problems to engineers who had used other board designers and gave me wizard status when I fixed them.
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Your college issues were worse than mine, at the end I arbitrarily needed 4 more credits, effectively 2 classes, in any subject to graduate and I signed up for 6 credit summer theatre as a carpenter. Instead of 2 hours 3 times a week it ran 12-14 hours a day, but was fun and I learned a lot about interacting with people who were very different from techies. The professors/directors were masters at coaxing yet another maximum effort from tired actors and dancers.
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OTOH as I neared graduation and the absolute need to continue to an advanced degree to be more than a pharmacy clerk the grad school draft deferment was cancelled. I think I made the best of it by enlisting for and completing the Army's longest and most difficult electronics school which enabled my subsequent career.
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In 8th grade I did take Geology, called Earth Science. It proved too difficult for most of the students, many who were children of Phillips Exeter Academy faculty and convinced of their intellectual superiority over us "townies" until I bested them in that class and even worse French.
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So is it a compiler?  ... No I think its best described as a specialized interpreter.

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I simply wondered if CAD systems typically generated readable and editable G code.
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I have not written an actual computer program in probably 20-25 years. It was a simple screen saver and program execution menu for PC-Dos 7.0. in order to prevent monitor burn in it would randomly flash the date and time around the screen.

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I may have mentioned that another programmer's screen saver randomly flashed "REPENT, THE END IS NEAR" as though it had been alerted by a sinner's presence. I worked on a machine sensitive enough to detect a human within about 20' but it only woke up and greeted them, which still bothered one woman.
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