4 ms·

What a quirky paper. I worked at a major winery that had dozens of tanks, up to 100,000 liters each. A single failure in a tank represented many millions of dol

What a quirky paper. I worked at a major winery that had dozens of tanks, up to 100,000 liters each. A single failure in a tank represented many millions of dollars. Our extremely expensive micro-oxygen pump used a standard 7-segment display combined with little red LEDs representing On/Off next to a list of tank numbers. The 7-segment display was used to read and to set the units (μg, mg , etc), amount, and rate of oxygen delivery. I never made the mistake of misconfiguring, but one of the senior Winemakers did resulting in some very angry customers, a 7 figure loss, and many contracts. I'm left with two opinions: 7-segment displays are not usually fail-safe, and have the potential to be fail-deadly (figure 1). In my entire life I've never had occasion to use a tool with a 7-segment readout, handheld or otherwise, that actually failed or that I misread due to ambiguity. So, I think a better conclusion would be don't use 7-segment displays in important places.

viraptor 6y ago
Alternatively, if the failure would cost you millions, stick in 2 of those displays which will cost you $1 each, so if they fail you're likely to notice.
- sneak 6y ago
  For a seven figure potential loss, this probably justifies a raspberry pi or two, on different UPSes, hooked up to backup sensors that can email a few different supervisors when the parameters exit the acceptable envelope.
skavi 6y ago
> In this paper, we raise design issues and present recommendations; for clarity we say “never” for design choices that are inappropriate for dependable or safety-critical applications. How does your conclusion differ from their initial recommendation?
gerardnll 6y ago
You didn't even read the introduction. > In this paper, we raise design issues and present recommendations; for clarity we say “never” for design choices that are inappropriate for dependable or safety-critical applications. For novelty and other non-dependable applications, obviously examination of cost and design trade-offs may lead to other decisions, and such decisions should be backed by competent empirical evaluation.

viraptor 6y ago

Alternatively, if the failure would cost you millions, stick in 2 of those displays which will cost you $1 each, so if they fail you're likely to notice.

sneak 6y ago
For a seven figure potential loss, this probably justifies a raspberry pi or two, on different UPSes, hooked up to backup sensors that can email a few different supervisors when the parameters exit the acceptable envelope.

skavi 6y ago

> In this paper, we raise design issues and present recommendations; for clarity we say “never” for design choices that are inappropriate for dependable or safety-critical applications. How does your conclusion differ from their initial recommendation?

gerardnll 6y ago

You didn't even read the introduction. > In this paper, we raise design issues and present recommendations; for clarity we say “never” for design choices that are inappropriate for dependable or safety-critical applications. For novelty and other non-dependable applications, obviously examination of cost and design trade-offs may lead to other decisions, and such decisions should be backed by competent empirical evaluation.