OSI was the right idea and way to go. Proprietary interests killed it. Thos who castigate the concept of OSI are fools.
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Now, Andy, see what you've done? The old pattern was still in memory, waiting to be matched. Rete lives: you supply the pattern, the match is detected, the rule fires, and the autIMMaton produces the predictable output.
Nice to know all that Fifth-Generation and Alvey money's produced at least one lasting on-line legacy ;-)
Stefek
What proprietary interests? The ISO OSI protocols were all being driven by the very same companies which were the only people who could be argued to have any proprietary interests. By making the standards process closed to anyone who couldn't pay thousands per year to be a member, the standards documents too expensive to be generally available to the public, the protocols overly complex and unchecked by any prior working/reference implementations, and their own implementations in the form of products extremely expensive, they killed it all by themselves. They were very thorough -- I can't think of anything else they could have done to be even more sure of killing it. I should know too -- I sat in some of the standards groups, and I did a couple of the implementations.
Without knowing exactly what you mean by "OSI" here, it's difficult to comment. The world is full of Open Systems which are Interworking extremely well, otherwise you couldn't read this news article. If you mean the OSI 7-layer model, well that's mirrored in just about all networking protocol stacks before and since the OSI ISO protocols. If you mean the OSI ISO protocols themselves, see the paragraph above.
Found it! It's at
Stefek
[...]
It's an interesting equation this. ISTM that dennis is proposing that all installations should be the equivalent of TT, where the fuse/MCB protection is there *only* to protect against overload or L-N shorts, and all other user protection is carried out by RCD. Look what happens with TT systems: only a very small percentage of installations have RCBOs on every circuit; most have at best two RCDs in series, and many still have a single RCD on the whole lot. This kind of goes against the spirit of discrimination.
If dennis is *not* proposing the use of RCDs, as is possibly implied by his quest to "limit the current to safe values" (I don't think he is from previous posts, but...) then how the heck is he proposing to limit the current in your example of a L-to-case fault? *All* earthed metalwork would at that point become live to some significant Voltage, and the fault would not clear. Anyone touching such a case would likely become the lowest impedance path to earth, and there is no way you can limit the current on the L to a value safe enough for someone to (effectively) grab hold of the L supply and come away unscathed.
An MCB is an inherently simpler device than an RCBO (less to go wrong) and is significantly cheaper (£4 versus £30 from Screwfix for Volex parts for example). Given that providing a low impedance earth is fairly easily possible in most situations (TN supplies) and that a low impedance earth is all that is required to clear earth faults quickly, where is the problem?
I'm not sure quite what kind of fault this "test box" is meant to detect. It's also going to need a return path to an isolator at the supply end, and sounds dreadfully complicated to me. Perhaps dennis is thinking of a US-style "arc fault circuit interruptor". This kind of device (installed at the CU) might actually detect loose connections, but AIUI they're not terribly reliable.
Hwyl!
M.
have.
Try adding in the toaster, iron, portable air conditioner, breadmaker, fridge, freezer, convection oven, microwave, fridge, freezer, hair drier ............
Then the little graphs don't quite add up.
Now we are into probabilities that the household won't have/use the appliances in a way that will cause an overload in one leg.
That is just a symptom of poor design. You see it everywhere that professionals are at work. Like heating systems that cycle all the time because someone fitted radiator valves rather than a control system.
The price you pay has little to do with the costs.
Any fault you want to put the effort into detecting.
The existing technology in wiring was first used in the ark. I am quite sure that a fresh look at the problems would find better solutions than we have now.
You seem to conveniently overlook the absence of frequent and regular outbreaks of fixed wiring fire in kitchens around the uk.
True. But it is amazing how much an EU initiative does kickstart things - like the insulation standards to meet Kyoto have driven things like the Clear Skies green power initiative or this heating renewal scheme for OAPs in Scotland. I fully admit the UK's wiring isn't a problem. Neither is Germany's or Scandanavia's. But the rest of Europe is nothing short of atrocious and everybody knows something needs doing - and soon.
But that wasn't the final choice. Look forward to late 1994 by which time there were several changes made - including the material I believe which I think you criticised elsewhere.
Ah - the 'good ole days' of standards :-)
That really has changed - and thank goodness it has ! I spent years in meetings on ISDN listening to embedded camps arguing about a feature no customer would ever see or care about. Nowadays in my field we currently have WiMax, Zigbee and UMA as well as extensions to 3G phones all being worked on at a pace that even ten years ago would have seemed unbelieveable. ADSL-2 was finished in months, not years, as were the new extensions to Bluetooth. And all are very high quality standards unlike some in the past which were at best average and at worst simply ignored.
The real difference has been the venture capitalists. Whereas before the telecomms bubble burst they would invest in any old tat that might be successful, nowadays they insist on startups being 'standards compliant', even if the standards don't exist yet. This forces frenetic activity from these companies in persuading the big, or at least influential companies (like BT), that a) they actually want a product something like the one proposed and b) this solution is the one that should be supported for standards work.
In the past it was these little companies that often delayed standards meetings because they were always looking for some niche whereas now they arrive from private pre-meetings because they are to small to be affected by anti-trust legislation and so have a common and agreed proposal. As the innovation usually comes from these companies the result is good fast standards.
But the downside is there are about 50 startups all aiming for 25% market share to break even - so most fail. But that's not the consumer's problem - they're on a win-win. Equipment that does what it says on the box at a competitive price from day one.
So is the IoM. I was in Malta a few weeks ago, hence the comment. What I was trying to point out is that the UK socket is used in lots of small countries like these whereas the US socket is used in lots of big countries.
When did Mr and Mrs Average UK Consumer 'tune the fuse'. It's 13A. Most probably don't even know it comes in different values.
In the UK of course not. But in Sweden or other countries where electric heating is the norm of course they will.
Because once the volume is there and these mini-CUs are cheap as chips, why wouldn't you ?
You appear to ignore the fact that they don't classify fires well enough to say they don't happen.
Or realise that overloads in cables cause the life of the cable to shorten..... we may not have had rings and large numbers of appliances around for long enough to show up yet. I hope you are correct and nobody gets hurt.
As I pointed out in another reply, most international standards bodies have been getting their act together a lot better in the last 5 years or so. If one wishes to credit the IETF with influencing this sea-change and proving it can be done faster then I wouldn't argue.
Token ring was one company not realising it wasn't the industry any more.
implementations,
Uh - I think I agree with you but don't see what you mean by the last sentence.
But as you say, without the 7 layer model a lot, though not all, of the networks we now take for granted, wouldn't function quite as they do now,
I wasn't aware it was dead. My phone worked last time I tried it.
TOTAL CRAP. I have sat on various national and IEC standards committees for 40 years and Peter Parry is correct. The objective of national and international standards is to agree on the lowest quality standard that the manufacturers can get away with. The whole exercise is primarily commercial. If you want to see a good example of standard nomenclature variations, just do an exercise on a US current rating for a given product and say a British one. We always used to describe it as "American Amps", these were roughly 1/2 the real current of British ones!
Regards Capitol
He has just
Yes. LIDL!!
Regards Capitol
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