3 ms·
>they totally do lie, for a number of reasons. A most common one is that multimeter presents much higher resistance [...] So yes, multimeters have their own lim
by jasode 3y ago
>they totally do lie, for a number of reasons. A most common one is that multimeter presents much higher resistance [...] So yes, multimeters have their own limitations,
Yes, I understand that any physical measurement tool in the universe has an error range whether it's a multimeter or an air pressure gauge. I have 3 air pressure gauges and yes -- all of them are are "lying" to me because they're all "wrong" by various percentages for various environmental reasons. Even the $150 Longacre elite air pressure gauge is lying to me about my car's actual tire pressure by the perspective you're using. The mistruth you're pointing out is from the perspective of the measurement tool (e.g. the multimeter has higher internal resistance.)
However, the "lie" perspective I was using was from the human-configured _target_ device itself -- for adversarial-or-performance-optimization reasons. The humans that configured the network nodes can deliberately make it not respond to ICMP packets which renders the traceroute statistics less than helpful (or "not real" as the author puts it). That's the angle the author was trying to explain in a confusing way. That's a different situation from the analogies that gp (kazinator) was using.
Your perspective is also correct but the physical limitations of measurement tools wasn't my point. The humans with "agency" in how to make their routers or servers respond to ICMP packets is a different kind of "lie" than batteries that haven't been shaken.
>Kinda like for traceroute :) so maybe the analogy is not that bad after all.
I use digital multimeters every day and reading "3v" from a 9-vote battery doesn't feel like a "lie" but a sort of "truth" based on the load factors you point out. However, pinging a system and getting timeouts feels more like a mistruth because the target system is often actually there but somebody didn't want to make it reply to those particular packets.
- theamk 3y agoI don't think the distinction between "physical limitation" vs "humans with agency" is quite as clear-cut as you think... After all, if one wanted my 9V batteries to be always clearly measurable they could make thicker electrodes and thinner electrolyte. Instead, the humans which designed batteries configured them to prioritized high capacity and low cost, "deliberately" making multimeters inaccurate. Or for a more extreme example: Apple chargers prominently say "20V" on them.. and yet if you get one and hook up a multimeter to it, you will only measure 6 volts (see "Charger Startup Process" in [0] to see why, spoiler: it needs special enable pulse as a safety measure). Will you call this "a lie"? Can we say "multimeters aren't real" because Apple power supplies require special pulse? Can we say "humans have deliberately made it not work with multimeters"? Instruments, be it traceroute or multimeters, have limitations; and users should know about them. Even if technology advances make tools less useful in some situations, there is no reason to disparage them. [0] http://www.righto.com/2013/06/teardown-and-exploration-of-magsafe.html http://www.righto.com/2013/06/teardown-and-exploration-of-ma...