I seen this on another forum and thought I copy/paste it here ..... I'm curious to read some responses too.
"In the 'old days' of signaling, fail safe was one of the top design
priorities. I was wondering if today's 'modern technology' systems
have made any trade offs that result in a signaling system being not
so fail safe. I ask only cause I don't know.
As an example: In the old days the relays were mounted so that if
there was a failure gravity would pull the contacts to the 'stop'
state versus the 'clear' state. Todays relays are spring loaded, and
often mounted in ways that best suit the crowded cabinet. What if the
spring broke? What if a transistor shorted 'on' or 'off'? What if a
human programer wrote "if yes then" instead of "if no then" in his/her
code? I'm just curious to learn if there has been a little trade off
in fail safe to gain a lot more elsewhere."
"In the 'old days' of signaling, fail safe was one of the top design
priorities. I was wondering if today's 'modern technology' systems
have made any trade offs that result in a signaling system being not
so fail safe. I ask only cause I don't know.
As an example: In the old days the relays were mounted so that if
there was a failure gravity would pull the contacts to the 'stop'
state versus the 'clear' state. Todays relays are spring loaded, and
often mounted in ways that best suit the crowded cabinet. What if the
spring broke? What if a transistor shorted 'on' or 'off'? What if a
human programer wrote "if yes then" instead of "if no then" in his/her
code? I'm just curious to learn if there has been a little trade off
in fail safe to gain a lot more elsewhere."