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Good. It is comforting to know that a conservative approach is taken with keeping those things running. If it does the job and you don't forsee it not doing t
by jlgreco 13y ago
Good. It is comforting to know that a conservative approach is taken with keeping those things running. If it does the job and you don't forsee it not doing the job anytime soon, then leave it alone.
- arethuza 13y agoI remember working, ~20 years ago, on a research project that involved creating a simulation of the device that was used at UK AGR nuclear plants to automatically shutdown plants in an emergency (I think it was called the RSSSE - Reactor Safety Shutdown Sequencing Equipment). The plants were designed in the 1960s and, for such a critical task, they wanted to be very conservative about the designs. So they didn't even use electronics - it was all relays and mechanical gearing!
- johnchristopher 13y agoWouldn't it be harder to maintain relays and moving gears than some electronics equipment for which maintenance checks only involve running software through the circuits and check if green lights are blinking on the other side ? My point is: isn't it far easier and more reliable to trust electronics than moving parts ? Moreover you can check out electronics as much as you want while mechanical parts would tend to degrade for each test. Disclaimer: I known next to nothing about nuclear plants and plant maintenance.
- arethuza 13y ago"isn't it far easier and more reliable to trust electronics than moving parts" Possibly now - but I can see that back in the 1960s they probably had a point.
- johnchristopher 13y agoTrue.
- kintamanimatt 13y agoIt may do the job, but if recruiting people to maintain a legacy system is damn near impossible, it is no longer appropriate for the job and should be replaced.
- kryten 13y agoUnless there is a tradeoff. The tradeoff here being that introducing immature equipment may result in a higher risk. Plus if it's an older PDP11, it's fully documented both hardware and software wise and is built out of flip chip modules which are essentially still replaceable and repairable to this day with a soldering iron and any half-decent EE. You can't even get half the parts in your PC from 5 years ago and there is no documentation bar some NDA smothered PDF which is mostly incorrect for most of the bits. It's the same reason I still have a 1972 oscilloscope...
- vidarh 13y agoIt just means the cost is a bit higher: You need to train people yourself. That didn't use to be such a novel idea.
- willvarfar 13y agoSurely its several orders of magnitude cheaper to hire someone, and them learn the system, than it is to pay for a rewrite?
- mseebach 13y agoOh yes. http://www.joelonsoftware.com/articles/fog0000000069.html http://www.joelonsoftware.com/articles/fog0000000069.html Also, if you think of PDP-11 programmers as embedded/hardware developers rather than "modern" "soft" developers, the challenge of finding developers becomes more approachable.