5 ms·

I've been thinking about how pretty much no USA infrastructure of today is as reliable as of the last half of the 20th century. Just my imagination, or true? A

I've been thinking about how pretty much no USA infrastructure of today is as reliable as of the last half of the 20th century. Just my imagination, or true? And what does it mean?

lor_louis 3y ago
Redundancy was needed because individual nodes/machines were more prone to failure. As machines got more and more reliable, having highly redundant infrastructure was seen as an extra cost.
- kibwen 3y ago
  Efficiency or reliability: pick one.
- dymk 3y ago
  Do you work at a telecom or are you just guessing?
  - lor_louis 3y ago
    Used to work with telecom equipment in situations where high availability was required and equipment failure was expected.
- Animats 3y ago
  Yes. Electromechanical switching systems were substantially more reliable than their components. How this was done should be understood by anybody designing high-reliability systems today. "A History of Science and Engineering in the Bell System - Switching Technology 1925-1975" is a readable reference. The Internet Archive has it.[1] More hardcore: "No. 5 Crossbar"[2] The Connections Museum in Seattle still has a #5 Crossbar working.[3] Long distance used toll switches, "#4 Crossbar", and there were 202 of them. #4 and #5 Crossbar machines are collections of stateless microservices, implemented from electromechanical components. The terminology is used in the old books is completely different, but that's what they are. Each service always has at least two servers. The parts that do have state are distributed. The crossbar switches that make actual connections have state, but are dumb - they are told what to do by "markers", which are stateless but can read the state of the crossbars and of other components. Failure of a single crossbar unit can take down less than a hundred lines at most. Other than the crossbars to external lines, everything had alternate routes. Everything has fault detection, with lights and alarm bells. Error rates were fairly high. In the previous "step by step" system, a good central office misdirected about 1% of calls. With bad maintenance (and those things were high maintenance) that could get much worse. Crossbar was better, maybe 0.1% misdirected calls. Routing tables in crossbar were mostly static ROMs of one kind or another. Routing consisted of trying a predetermined set of routes, in order. Clunky, but reliable. Modern systems need a backdown to that mode. [1] https://archive.org/details/historyofenginee0000unse_q0d8 https://archive.org/details/historyofenginee0000unse_q0d8 [2] https://archive.org/details/bellsystem-no-5-crossbar-blr https://archive.org/details/bellsystem-no-5-crossbar-blr [3] http://www.telcomhistory.org/connections-museum-seattle-exhibits/mechanical-switching/ http://www.telcomhistory.org/connections-museum-seattle-exhi...
topkai22 3y ago
Airliners crash far less, road fatalities kept going down till 2010, so taking the broad view of were infrastructure is I’d say at least those got better. Anecdotally, I remember more electricity interruptions and plumbing issues when I was a kid, but that could be location dependent and I couldn’t quickly find good numbers going back that far. Edit: While the phone network didn’t necessarily go down, I frequently got “all circuits busy” when I was a kid. I don’t remember the last time that happened.
- watersb 3y ago
  And how often one of our five TV stations would be "Experiencing Technical Difficulties... Please Stand By".
- bronco21016 3y ago
  I wish we had metrics for utility companies. In my midwestern experience, things have gotten worse. I don’t remember any outages as a kid in the 90s that were over 24 hours aside from the major blackout in the early 2000s. As an adult I’ve experienced several outages greater than 24 hours in both summer and winter months. It’d be nice to be able to measure this.
  - Aloisius 3y ago
    I would caution comparing today against one's childhood memories. Children have few responsibilities and are shielded by their caretakers. They simply do not notice much of the things that happen.
    - vel0city 3y ago
      Right? As a kid we might not have questioned that sudden trip to Grandma's for the day.
- georgeplusplus 3y ago
  Not to come off pedantic but improvements in airplane and car design has nothing to do with infrastructure. I think the average person views infrastructure improvements as improvements in the roads, airports, or air traffic control.
onthecanposting 3y ago
Highway construction standards are much higher than they were 30-50 years ago, but it's a mixed bag. Administrative costs are significantly higher. Survey has dramatically improved with GPS. Highway engineering has not improved since about the 90s. Automated machine guidance has significantly improved the potential accuracy of grading operations in th last decade.
- georgeplusplus 3y ago
  >>>Highway construction standards are much higher than they were 30-50 years ago, The roads in many US cities arent built to those standards and are grandfathered from them. New York City highways areas horrible.
ksec 3y ago
It depends on you view this. If you measure by total bit / data / time per customer served divided by the total outage time I would think we are still very reliable in terms of telecoms. It is worth remember we are likely serving 1 to 100 million times of what we did on mobile network 30 years ago. Just purely in terms of total downtime itself we are less realible. Purely because of the complexity involves.

I've been thinking about how pretty much no USA infrastructure of today is as reliable as of the last half of the 20th century. Just my imagination, or true? And what does it mean?

lor_louis 3y ago

Redundancy was needed because individual nodes/machines were more prone to failure. As machines got more and more reliable, having highly redundant infrastructure was seen as an extra cost.

kibwen 3y ago
Efficiency or reliability: pick one.
dymk 3y ago
Do you work at a telecom or are you just guessing?
- lor_louis 3y ago
  Used to work with telecom equipment in situations where high availability was required and equipment failure was expected.
Animats 3y ago
Yes. Electromechanical switching systems were substantially more reliable than their components. How this was done should be understood by anybody designing high-reliability systems today. "A History of Science and Engineering in the Bell System - Switching Technology 1925-1975" is a readable reference. The Internet Archive has it.[1] More hardcore: "No. 5 Crossbar"[2] The Connections Museum in Seattle still has a #5 Crossbar working.[3] Long distance used toll switches, "#4 Crossbar", and there were 202 of them. #4 and #5 Crossbar machines are collections of stateless microservices, implemented from electromechanical components. The terminology is used in the old books is completely different, but that's what they are. Each service always has at least two servers. The parts that do have state are distributed. The crossbar switches that make actual connections have state, but are dumb - they are told what to do by "markers", which are stateless but can read the state of the crossbars and of other components. Failure of a single crossbar unit can take down less than a hundred lines at most. Other than the crossbars to external lines, everything had alternate routes. Everything has fault detection, with lights and alarm bells. Error rates were fairly high. In the previous "step by step" system, a good central office misdirected about 1% of calls. With bad maintenance (and those things were high maintenance) that could get much worse. Crossbar was better, maybe 0.1% misdirected calls. Routing tables in crossbar were mostly static ROMs of one kind or another. Routing consisted of trying a predetermined set of routes, in order. Clunky, but reliable. Modern systems need a backdown to that mode. [1] https://archive.org/details/historyofenginee0000unse_q0d8 https://archive.org/details/historyofenginee0000unse_q0d8 [2] https://archive.org/details/bellsystem-no-5-crossbar-blr https://archive.org/details/bellsystem-no-5-crossbar-blr [3] http://www.telcomhistory.org/connections-museum-seattle-exhibits/mechanical-switching/ http://www.telcomhistory.org/connections-museum-seattle-exhi...

topkai22 3y ago

Airliners crash far less, road fatalities kept going down till 2010, so taking the broad view of were infrastructure is I’d say at least those got better. Anecdotally, I remember more electricity interruptions and plumbing issues when I was a kid, but that could be location dependent and I couldn’t quickly find good numbers going back that far. Edit: While the phone network didn’t necessarily go down, I frequently got “all circuits busy” when I was a kid. I don’t remember the last time that happened.

watersb 3y ago
And how often one of our five TV stations would be "Experiencing Technical Difficulties... Please Stand By".
bronco21016 3y ago
I wish we had metrics for utility companies. In my midwestern experience, things have gotten worse. I don’t remember any outages as a kid in the 90s that were over 24 hours aside from the major blackout in the early 2000s. As an adult I’ve experienced several outages greater than 24 hours in both summer and winter months. It’d be nice to be able to measure this.
- Aloisius 3y ago
  I would caution comparing today against one's childhood memories. Children have few responsibilities and are shielded by their caretakers. They simply do not notice much of the things that happen.
  - vel0city 3y ago
    Right? As a kid we might not have questioned that sudden trip to Grandma's for the day.
georgeplusplus 3y ago
Not to come off pedantic but improvements in airplane and car design has nothing to do with infrastructure. I think the average person views infrastructure improvements as improvements in the roads, airports, or air traffic control.

onthecanposting 3y ago

Highway construction standards are much higher than they were 30-50 years ago, but it's a mixed bag. Administrative costs are significantly higher. Survey has dramatically improved with GPS. Highway engineering has not improved since about the 90s. Automated machine guidance has significantly improved the potential accuracy of grading operations in th last decade.

georgeplusplus 3y ago
>>>Highway construction standards are much higher than they were 30-50 years ago, The roads in many US cities arent built to those standards and are grandfathered from them. New York City highways areas horrible.

ksec 3y ago

It depends on you view this. If you measure by total bit / data / time per customer served divided by the total outage time I would think we are still very reliable in terms of telecoms. It is worth remember we are likely serving 1 to 100 million times of what we did on mobile network 30 years ago. Just purely in terms of total downtime itself we are less realible. Purely because of the complexity involves.