race condition

[smercurio_fc]

---

@altenbach wrote:

---

@smercurio_fc wrote:
What you are seeing is not a race condition.

---

I thought that fits the definition of a race condition very well 🙂

---

That depends on how you define race condition. From my perspective a race condition is when you try to access something before it's been updated, a situation most prevalent with abuse of local variables.

Wikipedia has this:

A race condition or race hazard is a flaw in a system or process whereby the output and/or result of the process is unexpectedly and critically dependent on the sequence or timing of other events. The term originates with the idea of two signals racing each other to influence the output first.

Don't know. I guess you could argue that it does fit the more "general" definition. I'm not going to split hairs over it, though.

[krispiekream]

thank you so much for everyone's help here.
all of your advices helped me out about.
thanks Jarrod for the diagram post.

[krispiekream]

actually, i did it . and it still didnt work..

[smercurio_fc]

Please upload your code. Occurrences work, you may have just not wired something correctly.

[Ben]

smercurio wrote "The term originates with the idea of two signals racing each other to influence the output first."

That was my first exposure to the idea. Old mainframes used to use backplane wires wires of the same length to make sure the clock signals got to all of the boards (a CPU used about 100 circuit boards) at the same time. Fine tuning was possible but you had to make sure your scope probes were the same length. But in that case it was the first signal that won. In LV it is often the last that wins.

Ben

[smercurio_fc]

---

@Ben wrote:

smercurio wrote "The term originates with the idea of two signals racing each other to influence the output first."

That was my first exposure to the idea. Old mainframes used to use backplane wires wires of the same length to make sure the clock signals got to all of the boards (a CPU used about 100 circuit boards) at the same time. Fine tuning was possible but you had to make sure your scope probes were the same length. But in that case it was the first signal that won. In LV it is often the last that wins.

Ben

---

Hah! Good comparison. I just thought of a great LabVIEW game: The Race of the Wires. "Will the favorite, Blue, overpass the upstart, Purple, today? Place your bets to find out!"

[krispiekream]

it seems like it is working now since i moved REINITIALIZE ALL TO DEFAULT FROM

the sequence frame to the while loop.

Message Edited by krispiekream on 06-13-2008 01:19 PM

Message Edited by krispiekream on 06-13-2008 01:22 PM

[smercurio_fc]

That would have no impact, and is just a coincidence. You're not using the occurrences properly. The example that was shown had the Wait on Occurrence in a separate frame. There's a good reason for this:




Message Edited by smercurio_fc on 06-13-2008 01:27 PM

[smercurio_fc]

EDIT: Better picture with better comments:




Message Edited by smercurio_fc on 06-13-2008 01:30 PM

[Ray.R]

smercurio,

yes..  your last picture is more accurate..  less likely mind you, but still might.  That's the beauty of race conditions, no one knows for sure who will win!