In 3 years at my current company, we've maintained greater than 99.995% availability for fileservers, (thank you Netapp!), Exchange, and Active Directory. (excluding scheduled maintenance)
My numbers don't have to take into account anything that you mentioned, because I was just pointing out that the SLA guarantee is really meaningless, I wasn't comparing Office365 to locally installed applications.
Without some real world numbers, it's impossible to see how Office365 will affect my users since I don't yet know how many 9's of availability I can count on. When I host my own servers, I can get nearly any availability I want to pay for. If I use Office365, then all I can count on is a few thousand dollars if they don't meet their SLA, and that money doesn't come close to covering the cost to me if they have significant downtime.
If you need three nines ( and that includes not only work hours but evening and weekend hours when your workforce probably wasn't using Live365 anyways), maybe you shouldn't be on a cloud service.
Somehow Google maintains nearly 4 9's of service uptime on Google apps. My internet connection (dual-homed to independent, BGP so I can use either ISP) gave me 99.95% uptime last year (including maintenance windows).
I don't know what kind of workforce you have, but in my company I can count on people working from around 4am (from our East coast office) and ending around 11pm when people sign off for the night - this includes weekends (though obviously there are a lot fewer people working on a Saturday afternoon than a Monday afternoon).
All of our minor maintenance (where we expect little to no disruption in service) happens after 8pm. Major maintenance where some services are shut down completely happens between midnight and 4am.
Many people are quite happy with 99.9% availability...until that 0.1% hits them during peak working hours, then they ask how the hell can a server be down all day!? What do you mean they won't send someone out until tomorrow to repair it!? Then you have to point out that you asked for a redundant server (and/or premium same-day support contract) but it was rejected due to cost.
What kind of company do you work for where it's unlikely to have people working on nights and weekends?
And if it happens on the weekend, what is the "cost" of the 18 hour outage? Very nearly nothing in most cases.
Your imagined/calculated $80K "cost" is cut in half if the outage spills over into the weekend OR spillsover from the weekend into Monday...
Let's not forget the month over month savings from not having an IT infrastructure beyond a couple switches and an internet connection - that has to figure into your savings when weighed against the cost of an outage.
Your imaginary "company" has 100 employees who suddently become incapable of producing anything of value when their Live365 access is cut off? No cached documents, no local installs of Office? There's nothing they can do? Sounds like a company that shouldn't have been on a cloud-based solution, IMHO.
So you're telling me I get all of the cost savings from "not having an IT infrastructure beyond a couple switches and an internet connection", yet my company is stupid because I have no local installs of Office and can't get any work done without Live365?
That is to say, is your scenario that downtime of the cloud would result in the loss of a multi-million dollar contract in any way shape or form realistic?
Here's a more realistic scenario: 32 hour outage spanning 2 full business days. Company is paying $24/mo for 100 users = $2400 refund. (or, 18 hour intermittent outage, spanning 2 business days)
Company sent employees home with pay because without access to email, calendars, or documents they can't get any work done.
Each employee costs $50/hour average so 100 * $50 * 16 hours = $80,000.
So Microsoft paid out $2400 to "compensate" a company with a direct loss of $80K, plus indirect losses caused by the business being closed for 2 days (unable to process customer orders, etc)
Come on, guys. It's just a SLA. You get a full refund if it's more than 5% downtime (18.25 days). You get half off for 99% to 95% uptime , and 25% off for 99.9% to 99%. Do you really think they're expecting to give these refunds? No. But it's there in a contract just in case. I doubt many people will even get the 25% refund. 99.9% isn't by any means terrible.
Write an article when it actually goes down. The mindless/. MS bashing needs to stop.
Apparently they *do* expect to have to pay out on their SLA guarantee, otherwise they would have made it a 100% refund. Or even a 150% guarantee "We're so confident in our service that we will pay *you* half your monthly fee if we're down more than 5% of the time"
99.9% is reasonable for a cloud hosted app, but if they miss that target then they only pay me 25% of my monthly fee which doesn't really offset the cost to me if my entire workforce is idled for an hour because they can't reach their email, documents, etc.
I've written one or two Amazon reviews - normal reviews, quite positive, they were accepted.
Then I bought a DVD - a Nick Cave live in concert DVD - and I panned it. (There was a logo, "MC", on a black oval, BIG, and present ALL THE TIME through the whole video, in the top left - it ruined the DVD). I said - "don't buy it".
Amazon never posted that review.
I've thought for a long time that Amazon censors reviews - if it really pans the product, it doesn't get on the Amazon site. ALL the Amazon reviews are in that sense corrupt, because Amazon remove the really negative reviews. You only see the more positive reviews.
I've written about 2 dozen reviews on Amazon, two of them had a 1-star rating, two of them had a 2 star rating, and they were all published. One of my 1-star reviews was quite scathing, yet it's still there. I've seen lots of 1 star reviews for products (even ones that were not relevant to the product like "I bought a somewhat similar item from a different manufacturer and it broke in 2 days, SO STAY AWAY FROM THIS SHODDY PRODUCT!!!"... so I assumed Amazon doesn't check the content reviews at all.
Seriously dude, just get used to it. The ribbon has been out for 4 years now, for crying out loud. It is actually quite convenient if you take the time to familiarize yourself with it. Or you could just whine and never learn anything, I guess.
Yeah dammit! If I like the ribbon and find it easy to use, then you must too! Even if you don't like it, get used to it! There's no way that the previous UI was better! One size fits all and if you can't handle the ribbon, you're stupid.
(in reality, I don't like the ribbon and find it to be harder to use than the previous menus, I can never remember where things are - my artistically inclined wife, however, loves it - I guess she's more spatially/icon oriented and I'm more textually oriented. Fortunately, I can use Libreoffice for most of my Office document needs)
We tried some double conversion UPS's, but even they couldn't cope with the cheap gas powered generators. The UPS spent more time on battery power than on generator power and the battery kept discharging.
You seem to misunderstand double conversion. When doing double power conversion, your UPS is ALWAYS on batteries. Your AC input source, generator, grid, etc. ALWAYS recharge the batteries. So in double power conversion, your UPS won't trip between ON BATTERIES and ONLINE state since it is always on batteries.
Since your batteries are getting charged as fast as they get discharged, the power just goes through and amazingly, battery life is just as good or better.
Also, a higher end UPS with a true sin wave generator will make anything work flawlessly.
Well, it's not just me that doesn't understand how a double conversion UPS works, you should talk to the manufacturer whose stupid engineers put the "On Battery" indicator (with associated (and annoying) audio beep). I guess I just assumed that when we cut over to generator power and the UPS "On-Battery" light came on, that it meant that it was discharging the battery, especially when the UPS eventually shut down after it had run down the batteries.
Apparently those crazy guys at the factory think that if the UPS is not receiving input power (or if it's receiving power that it deems too dirty to use), then it discharges the battery.
I like your UPS better, the one that apparently ALWAYS charges the batteries, regardless of the quality of the input power.
True sine-wave only helps until the UPS is overloaded. In my case, the laser printer fuser pushed it over the edge. If I was on clean mains power, I think it would have been fine, when the fuser started warming up and the UPS found an overload, it would have just gone into bypass mode and everything would have run fine on mains power with the UPS bypassed. In my case, when the fuser started drawing more power, the generator couldn't increase its power output fast enough, so the UPS input voltage dropped, causing the UPS to switch over to battery power and since the UPS inverter couldn't handle the overload for more than a few seconds, it shut itself down.
You need to do double power conversion. That's what I do for my small data center in order to be able to use a cheap generator. It is much more cost effective while on generator. I only do double power conversion while on generator since my grid power stability is much above average.
I have the generator recharging the batteries so it doesn't directly feed the hardware. A 12 V DC to 110 V AC inverter feeds the hardware.
We tried some double conversion UPS's, but even they couldn't cope with the cheap gas powered generators. The UPS spent more time on battery power than on generator power and the battery kept discharging.
The UPS's worked ok with the Honda Inverter model.... until we tried to power a laser printer, the 2000kva UPS kept tripping off when the printer powered up to print -- The combined load from the computers plus the printer's fuser drew too much power. I suspect that a 3000kva UPS would have worked, but would have been outside of the range of the generator. (I know that you're not supposed to run a laser printer off of a UPS, but without a laser printer, the computers would have done little good so we had no choice)
Fortunately, it was the facility owner's responsibility to provide power, so they're the ones that ended up paying the rental cost for the 20KVA diesel generator. Rolling our own double-conversion system would have been outside the scope of our lease (assuming it had to be hardwired into the electrical system), and there was no reason for us to go to any great expense to accomodate crappy power.
Most switching power supplies immediately convert ac power into dc with a simple bridge rectifier before running it through the switching transistor at a very high kilohertz before going through the power supplies transformer. you could run a switching power supply on just about any frequency and even dc power
While you *could* design a switching power supply to run on nearly any voltage AC or DC, in practice, real-world computer power supplies tend to be pretty sensitive to power frequency and quality. I tried to run a small office off of a generator, and went through several generators including a Honda 2000W inverter model, a 10KVA gas generator (non-inverter), a 15KVA gas generator, and it wasn't until we got up to a 20KVA diesel generator that it gave stable enough power to run all of the computers. The diesel generator wasn't even stable enough until it had about a 50% load from turning on lights.
UPSes were no help, when we switched from mains power to generator, the UPSes tripped over to battery power on all but the diesel generator.
I'm not sure what your point is? Of course it uses VOLTAGE, that is how electronic devices work, they use ELECTRICITY. Hence the name ELECTRonic.
The point of the crystal is that its accuracy depends mostly on the physical properties of the crystal, not the input voltage. Ok, voltage DOES have some effect, but it's minimal, like in the order of 1 part per billion per 1V change.
and doesn't understand what happens when you're even a bunch of *degrees* out of sync, much less a few decihertz. We don't have *near* enough HVDC intertie to make this not matter, and I can't imaging how they think this is gonna work -- nothing at all on NERC's website to say what's *really* gonna happen, either.
Love all the warning, too.
I think the organization that's responsible for the reliability of the entire USA power grid has some idea of the need for frequency stabilization when connecting new power sources to the grid. Not that it's relevant for what they are proposing - power plants already know how to sync up their generators to the grid and they don't care if it's 60.001 Hz or 60.002 Hz, they'll take that into account.
The magnitude of this frequency deviation is tiny, 20 minutes/year is about.003% - the power grid can fluctuate much more than than on a daily basis, but until now, it's always been corrected to keep the overall frequency at 60 Hz.
The North American Electric Reliability Corp. runs the nation's interlocking web of transmission lines and power plants. A June 14 company presentation spelled out the potential effects of the change: East Coast clocks may run as much as 20 minutes fast over a year, but West Coast clocks are only likely to be off by 8 minutes. In Texas, it's only an expected speedup of 2 minutes.
My question is - will West Coast clocks run 8 minutes fast, or 8 minutes slow? My guess is that they'll be slow.
analog wall clock, thermostat, coffee maker, three alarm clocks in the bedroom, microwave, stove, a clock in my van,
and they all show different times, some are already off by 20 minutes.
this is 2011, every one of these devices should be able to connect to the internet and synchronize time just like my PC does (should) so I can be on my merry little way.
I bought a z-wave thermostat thinking it would get it's time from the controller automagically, not the case. royally pisses me off.
Do you really want to apply firmware upgrades to all of your devices everytime congress decides to change Daylight Savings time?
Would many people really take the time to program their wireless access point's WPA key into their coffee maker so it can sync the time?
Maybe extracting the time signal from Cellular GSM signals would be easier and nearly ubiquitous. Apparently the local cell phone tower knows what timezone I'm in, so there's be no need for devices to know, though I don't know how well that works on timezone borders.
Honest question. How hard/expensive is it to design an electronic timekeeping device that isn't directly based on electrical current? If the issue here is that some devices are poorly/cheaply made, it would seem, on the face of it, that these clocks should be designed better, rather than designing the electrical grid around the clocks. Bit of the tail wagging the dog?
Or is this just a straw man that the electric utilities want to put forward in order to accomplish a change that has a more insidious effect on consumers?
It's easy and relatively cheap to make new devices use their own time base, but there's a huge installed base of devices that do use powerline frequency because up until now, powerline frequency has been adjusted to keep it very close to 60 hertz. So it's not a matter of the tail wagging the dog - the grid intentionally guaranteed a stable time base so clockmakers took advantage of it. It's more like the dog decided that it doesn't want to wag the tail anymore so he's having it removed.
Were dinosaurs slow and lumbering, or quick and agile? It depends largely on whether they were cold or warm blooded. When dinosaurs were first discovered in the mid-19th century, paleontologists thought they were plodding beasts that had to rely on their environments to keep warm, like modern-day reptiles.
The writer is a moron.
No those paleontologists didn't fucking think that. The only damn reason the T. Rex in the American Museum of Natural History was mounted upright like that was because it was too damn heavy to mount with the backbone horizontal using the technology of the day.
Why the hell is there this general belief that people today are SOOO much smarter than people in the past?
I don't see the connection between the mounting position of a T.Rex and the speed or agileness of dinosaurs in general? The erect T-Rex doesn't look any more lumbering than a prone T-Rex to my untrained eye.
And is it really true that it takes modern structural materials to mount a t-rex horizontally? It seems like even in the early 1900's, they could have used a steel beam and cables to hang it if they really wanted to show it in a more horizontal position.
This reference says that scientists didn't discover until the 1970's that the upright position was not accurate, but it was because of biomechanics, not speed or agility.
Henry Fairfield Osborn, former president of the American Museum of Natural History (AMNH) in New York City, who believed the creature stood upright, further reinforced the notion after unveiling the first complete T. rex skeleton in 1915. It stood in this upright pose for nearly a century, until it was dismantled in 1992.[48] By 1970, scientists realized this pose was incorrect and could not have been maintained by a living animal, as it would have resulted in the dislocation or weakening of several joints, including the hips and the articulation between the head and the spinal column.[49]
Thats because they are a bad idea. The first time I saw the Palm Pilot, I said, "This will only be useful once its part of my cellphone". 10 years later it was ubiquitous.
Just because they are a bad idea for some people doesn't mean they are a bad idea for all people.
When I first saw a Palm Pilot, I said "Wow, you mean I can stop printing out my schedule, and I can carry an up to date address book with me!?" I was doing consulting at the time, with lots of client site visits and lots of meetings to keep track of.
Just because *you* found no use for it, doesn't mean that nobody did. Granted, my smartphone is much more useful, but the Palm Pilot was also quite useful - in some ways more usable than my smartphone since it did only a few things but did them pretty well.
Now I use a Netbook on the train on the way to work to read and reply to emails - the small formfactor makes it light and easy to carry with excellent battery life. It's great for travel since it's so light, but on a longer trip if I expect to be doing significant work, I still carry the 15" laptop, so it hasn't completely supplanted my laptop.
USB and Bluetooth implementations are much more involved than a simple voltage negotiation, yet you can buy a USB->Bluetooth adapter for 99 cent
I would hazard a guess that the bluetooth stack is running on the processor. It will not be a software defined radio, but the bluetooth chip in these cheap devices is very whimsy. The PC must do all the handshaking and encoding.
Voltage negotiation is irrelevant in this case. Bluetooth itself is wireless so it has none, and if you simply use or design a ttl compatible chip it will work perfectly off the 5V from USB without negotiation.
I wasn't implying that this does any sort of voltage negotiating, I was using it of an example of how far mass production can drive down prices - you get an entire USB client controller and some portion of a Bluetooth device for 99 cents, so it's not inconceivable that the much simpler voltage negotiation controller would cost less (at least on the laptop side. The power supply electronics might cost more since it needs to do voltage selection and switch relatively large currents).
In a "car" like this one with low friction tires and low friction drivetrain on a circular course, do you really get much better mileage with a lighter driver? For every bit of energy you spend pushing a heavier driver up a hill, you'll get nearly all of it back as you coast down the other side with the engine turned off.
The Apple Magsafe connector that many people here seem to be enamored with has 5 pins, and most of the complaints about fragility seem to be talking about the fragility of the power cord, not the connector itself. Besides, you don't *have* to have more than 2 pins... I don't know how negotiation works with this new standard, but for example, the power supply could supply 3V by default, then that device uses that 3V to power its negotiator and sends appropriate signals over the 2 power supply pins to request its desired voltage. After that, there doesn't need to be any more negotiation over the power pins. (though there could be further communication - the power adapter could say "Hey, my power source is a battery and it's running low, so I'd like you to drop down from 100W of power to 50W, ok?")
If all computers used the new standard, then the price of the power supply negotiation chipset would come down to be negligible, especially compared to the price of a laptop. The new standard would be used for many other things too -- like speakers, external hard drives, etc (i.e. anything that uses too much power to be powered from a USB port).
USB and Bluetooth implementations are much more involved than a simple voltage negotiation, yet you can buy a USB->Bluetooth adapter for 99 cents:
I once saw an eighty-year-old man parallel park by driving his car forward until he hit the car in front, angling the wheel, driving back till he hit the car in back, angling the wheel, and repeating this process as the two eighty-year-old women in the back seat appeared to be growing more and more concerned.
It's not just 80 year olds that park this way - I see this parking style often in the city where I live - parking is hard to come by and people will cram their car into impossibly small spaces.
Cambridge Design built an oxygen concentrator to replace oxygen tanks in battlefield medicine. This device is powered by a tiny diesel engine. I suspect that that engine is what's being used in this car, not the oxygen concentration device.
The article doesn't make it clear what role the oxygen concentrator plays, but it does sound like it's using a diesel powered engine:
Cambridge Design Partnership used elements from its own lightweight oxygen concentrator, as well as other in-house technologies, to create the unique car. The oxygen generator system was originially developed to treat injured soldiers, but in the car it is powered by an innovative micro-diesel-engine. The car also features low-friction tires to increase mileage.
...
We quickly realized that our R & D work for the MoD, creating an oxygen generator, was highly applicable to the Mileage Marathon Challenge. Both required an extremely efficient system that used very low power and could run off diesel. Now I just need to figure out how to make my own car get the same kind of mileage!”
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In 3 years at my current company, we've maintained greater than 99.995% availability for fileservers, (thank you Netapp!), Exchange, and Active Directory. (excluding scheduled maintenance)
My numbers don't have to take into account anything that you mentioned, because I was just pointing out that the SLA guarantee is really meaningless, I wasn't comparing Office365 to locally installed applications.
Without some real world numbers, it's impossible to see how Office365 will affect my users since I don't yet know how many 9's of availability I can count on. When I host my own servers, I can get nearly any availability I want to pay for. If I use Office365, then all I can count on is a few thousand dollars if they don't meet their SLA, and that money doesn't come close to covering the cost to me if they have significant downtime.
If you need three nines ( and that includes not only work hours but evening and weekend hours when your workforce probably wasn't using Live365 anyways), maybe you shouldn't be on a cloud service.
Somehow Google maintains nearly 4 9's of service uptime on Google apps. My internet connection (dual-homed to independent, BGP so I can use either ISP) gave me 99.95% uptime last year (including maintenance windows).
I don't know what kind of workforce you have, but in my company I can count on people working from around 4am (from our East coast office) and ending around 11pm when people sign off for the night - this includes weekends (though obviously there are a lot fewer people working on a Saturday afternoon than a Monday afternoon).
All of our minor maintenance (where we expect little to no disruption in service) happens after 8pm. Major maintenance where some services are shut down completely happens between midnight and 4am.
Many people are quite happy with 99.9% availability...until that 0.1% hits them during peak working hours, then they ask how the hell can a server be down all day!? What do you mean they won't send someone out until tomorrow to repair it!? Then you have to point out that you asked for a redundant server (and/or premium same-day support contract) but it was rejected due to cost.
What kind of company do you work for where it's unlikely to have people working on nights and weekends?
And if it happens on the weekend, what is the "cost" of the 18 hour outage? Very nearly nothing in most cases.
Your imagined/calculated $80K "cost" is cut in half if the outage spills over into the weekend OR spillsover from the weekend into Monday...
Let's not forget the month over month savings from not having an IT infrastructure beyond a couple switches and an internet connection - that has to figure into your savings when weighed against the cost of an outage.
Your imaginary "company" has 100 employees who suddently become incapable of producing anything of value when their Live365 access is cut off? No cached documents, no local installs of Office? There's nothing they can do? Sounds like a company that shouldn't have been on a cloud-based solution, IMHO.
So you're telling me I get all of the cost savings from "not having an IT infrastructure beyond a couple switches and an internet connection", yet my company is stupid because I have no local installs of Office and can't get any work done without Live365?
But would it really?
That is to say, is your scenario that downtime of the cloud would result in the loss of a multi-million dollar contract in any way shape or form realistic?
Here's a more realistic scenario: 32 hour outage spanning 2 full business days. Company is paying $24/mo for 100 users = $2400 refund. (or, 18 hour intermittent outage, spanning 2 business days)
Company sent employees home with pay because without access to email, calendars, or documents they can't get any work done.
Each employee costs $50/hour average so 100 * $50 * 16 hours = $80,000.
So Microsoft paid out $2400 to "compensate" a company with a direct loss of $80K, plus indirect losses caused by the business being closed for 2 days (unable to process customer orders, etc)
Come on, guys. It's just a SLA. You get a full refund if it's more than 5% downtime (18.25 days). You get half off for 99% to 95% uptime , and 25% off for 99.9% to 99%. Do you really think they're expecting to give these refunds? No. But it's there in a contract just in case. I doubt many people will even get the 25% refund. 99.9% isn't by any means terrible.
Write an article when it actually goes down. The mindless /. MS bashing needs to stop.
Apparently they *do* expect to have to pay out on their SLA guarantee, otherwise they would have made it a 100% refund. Or even a 150% guarantee "We're so confident in our service that we will pay *you* half your monthly fee if we're down more than 5% of the time"
99.9% is reasonable for a cloud hosted app, but if they miss that target then they only pay me 25% of my monthly fee which doesn't really offset the cost to me if my entire workforce is idled for an hour because they can't reach their email, documents, etc.
I've written one or two Amazon reviews - normal reviews, quite positive, they were accepted.
Then I bought a DVD - a Nick Cave live in concert DVD - and I panned it. (There was a logo, "MC", on a black oval, BIG, and present ALL THE TIME through the whole video, in the top left - it ruined the DVD). I said - "don't buy it".
Amazon never posted that review.
I've thought for a long time that Amazon censors reviews - if it really pans the product, it doesn't get on the Amazon site. ALL the Amazon reviews are in that sense corrupt, because Amazon remove the really negative reviews. You only see the more positive reviews.
I've written about 2 dozen reviews on Amazon, two of them had a 1-star rating, two of them had a 2 star rating, and they were all published. One of my 1-star reviews was quite scathing, yet it's still there. I've seen lots of 1 star reviews for products (even ones that were not relevant to the product like "I bought a somewhat similar item from a different manufacturer and it broke in 2 days, SO STAY AWAY FROM THIS SHODDY PRODUCT!!!"... so I assumed Amazon doesn't check the content reviews at all.
Seriously dude, just get used to it. The ribbon has been out for 4 years now, for crying out loud. It is actually quite convenient if you take the time to familiarize yourself with it. Or you could just whine and never learn anything, I guess.
Yeah dammit! If I like the ribbon and find it easy to use, then you must too! Even if you don't like it, get used to it! There's no way that the previous UI was better! One size fits all and if you can't handle the ribbon, you're stupid.
(in reality, I don't like the ribbon and find it to be harder to use than the previous menus, I can never remember where things are - my artistically inclined wife, however, loves it - I guess she's more spatially/icon oriented and I'm more textually oriented. Fortunately, I can use Libreoffice for most of my Office document needs)
We tried some double conversion UPS's, but even they couldn't cope with the cheap gas powered generators. The UPS spent more time on battery power than on generator power and the battery kept discharging.
You seem to misunderstand double conversion. When doing double power conversion, your UPS is ALWAYS on batteries. Your AC input source, generator, grid, etc. ALWAYS recharge the batteries. So in double power conversion, your UPS won't trip between ON BATTERIES and ONLINE state since it is always on batteries.
Since your batteries are getting charged as fast as they get discharged, the power just goes through and amazingly, battery life is just as good or better.
Also, a higher end UPS with a true sin wave generator will make anything work flawlessly.
Well, it's not just me that doesn't understand how a double conversion UPS works, you should talk to the manufacturer whose stupid engineers put the "On Battery" indicator (with associated (and annoying) audio beep). I guess I just assumed that when we cut over to generator power and the UPS "On-Battery" light came on, that it meant that it was discharging the battery, especially when the UPS eventually shut down after it had run down the batteries.
Apparently those crazy guys at the factory think that if the UPS is not receiving input power (or if it's receiving power that it deems too dirty to use), then it discharges the battery.
I like your UPS better, the one that apparently ALWAYS charges the batteries, regardless of the quality of the input power.
True sine-wave only helps until the UPS is overloaded. In my case, the laser printer fuser pushed it over the edge. If I was on clean mains power, I think it would have been fine, when the fuser started warming up and the UPS found an overload, it would have just gone into bypass mode and everything would have run fine on mains power with the UPS bypassed. In my case, when the fuser started drawing more power, the generator couldn't increase its power output fast enough, so the UPS input voltage dropped, causing the UPS to switch over to battery power and since the UPS inverter couldn't handle the overload for more than a few seconds, it shut itself down.
You need to do double power conversion. That's what I do for my small data center in order to be able to use a cheap generator. It is much more cost effective while on generator. I only do double power conversion while on generator since my grid power stability is much above average.
I have the generator recharging the batteries so it doesn't directly feed the hardware. A 12 V DC to 110 V AC inverter feeds the hardware.
http://en.wikipedia.org/wiki/Uninterruptible_power_supply#Double-conversion_.2F_online
We tried some double conversion UPS's, but even they couldn't cope with the cheap gas powered generators. The UPS spent more time on battery power than on generator power and the battery kept discharging.
The UPS's worked ok with the Honda Inverter model.... until we tried to power a laser printer, the 2000kva UPS kept tripping off when the printer powered up to print -- The combined load from the computers plus the printer's fuser drew too much power. I suspect that a 3000kva UPS would have worked, but would have been outside of the range of the generator. (I know that you're not supposed to run a laser printer off of a UPS, but without a laser printer, the computers would have done little good so we had no choice)
Fortunately, it was the facility owner's responsibility to provide power, so they're the ones that ended up paying the rental cost for the 20KVA diesel generator. Rolling our own double-conversion system would have been outside the scope of our lease (assuming it had to be hardwired into the electrical system), and there was no reason for us to go to any great expense to accomodate crappy power.
Most switching power supplies immediately convert ac power into dc with a simple bridge rectifier before running it through the switching transistor at a very high kilohertz before going through the power supplies transformer. you could run a switching power supply on just about any frequency and even dc power
While you *could* design a switching power supply to run on nearly any voltage AC or DC, in practice, real-world computer power supplies tend to be pretty sensitive to power frequency and quality. I tried to run a small office off of a generator, and went through several generators including a Honda 2000W inverter model, a 10KVA gas generator (non-inverter), a 15KVA gas generator, and it wasn't until we got up to a 20KVA diesel generator that it gave stable enough power to run all of the computers. The diesel generator wasn't even stable enough until it had about a 50% load from turning on lights.
UPSes were no help, when we switched from mains power to generator, the UPSes tripped over to battery power on all but the diesel generator.
Did you even read your link?
A Crystal oscillator takes in VOLTAGE to determine the signal.
http://www.zen22142.zen.co.uk/Circuits/Testgear/crystal.htm
I'm not sure what your point is? Of course it uses VOLTAGE, that is how electronic devices work, they use ELECTRICITY. Hence the name ELECTRonic.
The point of the crystal is that its accuracy depends mostly on the physical properties of the crystal, not the input voltage. Ok, voltage DOES have some effect, but it's minimal, like in the order of 1 part per billion per 1V change.
Clearly, whomever thought this was a Pretty Neat Idea hasn't read this:
http://yarchive.net/car/rv/generator_synchronization.html
and doesn't understand what happens when you're even a bunch of *degrees* out of sync, much less a few decihertz. We don't have *near* enough HVDC intertie to make this not matter, and I can't imaging how they think this is gonna work -- nothing at all on NERC's website to say what's *really* gonna happen, either.
Love all the warning, too.
I think the organization that's responsible for the reliability of the entire USA power grid has some idea of the need for frequency stabilization when connecting new power sources to the grid. Not that it's relevant for what they are proposing - power plants already know how to sync up their generators to the grid and they don't care if it's 60.001 Hz or 60.002 Hz, they'll take that into account.
The magnitude of this frequency deviation is tiny, 20 minutes/year is about .003% - the power grid can fluctuate much more than than on a daily basis, but until now, it's always been corrected to keep the overall frequency at 60 Hz.
what happens when my spindle speed can vary by 10%? do i need to put a tach on my mill?
If the powerline frequency deviated by 10%, many things would have problems... 20 minutes/year deviation is only around .003%.
From TFA:
The North American Electric Reliability Corp. runs the nation's interlocking web of transmission lines and power plants. A June 14 company presentation spelled out the potential effects of the change: East Coast clocks may run as much as 20 minutes fast over a year, but West Coast clocks are only likely to be off by 8 minutes. In Texas, it's only an expected speedup of 2 minutes.
My question is - will West Coast clocks run 8 minutes fast, or 8 minutes slow? My guess is that they'll be slow.
Hey, I've got 120 different clocks of my own.
analog wall clock,
thermostat,
coffee maker,
three alarm clocks in the bedroom,
microwave,
stove,
a clock in my van,
and they all show different times, some are already off by 20 minutes.
this is 2011, every one of these devices should be able to connect to the internet and synchronize time just like my PC does (should) so I can be on my merry little way.
I bought a z-wave thermostat thinking it would get it's time from the controller automagically, not the case. royally pisses me off.
Do you really want to apply firmware upgrades to all of your devices everytime congress decides to change Daylight Savings time?
Would many people really take the time to program their wireless access point's WPA key into their coffee maker so it can sync the time?
Maybe extracting the time signal from Cellular GSM signals would be easier and nearly ubiquitous. Apparently the local cell phone tower knows what timezone I'm in, so there's be no need for devices to know, though I don't know how well that works on timezone borders.
Honest question. How hard/expensive is it to design an electronic timekeeping device that isn't directly based on electrical current? If the issue here is that some devices are poorly/cheaply made, it would seem, on the face of it, that these clocks should be designed better, rather than designing the electrical grid around the clocks. Bit of the tail wagging the dog?
Or is this just a straw man that the electric utilities want to put forward in order to accomplish a change that has a more insidious effect on consumers?
It's easy and relatively cheap to make new devices use their own time base, but there's a huge installed base of devices that do use powerline frequency because up until now, powerline frequency has been adjusted to keep it very close to 60 hertz. So it's not a matter of the tail wagging the dog - the grid intentionally guaranteed a stable time base so clockmakers took advantage of it. It's more like the dog decided that it doesn't want to wag the tail anymore so he's having it removed.
Were dinosaurs slow and lumbering, or quick and agile? It depends largely on whether they were cold or warm blooded. When dinosaurs were first discovered in the mid-19th century, paleontologists thought they were plodding beasts that had to rely on their environments to keep warm, like modern-day reptiles.
The writer is a moron.
No those paleontologists didn't fucking think that. The only damn reason the T. Rex in the American Museum of Natural History was mounted upright like that was because it was too damn heavy to mount with the backbone horizontal using the technology of the day.
Why the hell is there this general belief that people today are SOOO much smarter than people in the past?
I don't see the connection between the mounting position of a T.Rex and the speed or agileness of dinosaurs in general? The erect T-Rex doesn't look any more lumbering than a prone T-Rex to my untrained eye.
And is it really true that it takes modern structural materials to mount a t-rex horizontally? It seems like even in the early 1900's, they could have used a steel beam and cables to hang it if they really wanted to show it in a more horizontal position.
This reference says that scientists didn't discover until the 1970's that the upright position was not accurate, but it was because of biomechanics, not speed or agility.
http://landbeforetime.wikia.com/wiki/Tyrannosaurus
Henry Fairfield Osborn, former president of the American Museum of Natural History (AMNH) in New York City, who believed the creature stood upright, further reinforced the notion after unveiling the first complete T. rex skeleton in 1915. It stood in this upright pose for nearly a century, until it was dismantled in 1992.[48] By 1970, scientists realized this pose was incorrect and could not have been maintained by a living animal, as it would have resulted in the dislocation or weakening of several joints, including the hips and the articulation between the head and the spinal column.[49]
Thats because they are a bad idea. The first time I saw the Palm Pilot, I said, "This will only be useful once its part of my cellphone". 10 years later it was ubiquitous.
Just because they are a bad idea for some people doesn't mean they are a bad idea for all people.
When I first saw a Palm Pilot, I said "Wow, you mean I can stop printing out my schedule, and I can carry an up to date address book with me!?" I was doing consulting at the time, with lots of client site visits and lots of meetings to keep track of.
Just because *you* found no use for it, doesn't mean that nobody did. Granted, my smartphone is much more useful, but the Palm Pilot was also quite useful - in some ways more usable than my smartphone since it did only a few things but did them pretty well.
Now I use a Netbook on the train on the way to work to read and reply to emails - the small formfactor makes it light and easy to carry with excellent battery life. It's great for travel since it's so light, but on a longer trip if I expect to be doing significant work, I still carry the 15" laptop, so it hasn't completely supplanted my laptop.
USB and Bluetooth implementations are much more involved than a simple voltage negotiation, yet you can buy a USB->Bluetooth adapter for 99 cent
I would hazard a guess that the bluetooth stack is running on the processor. It will not be a software defined radio, but the bluetooth chip in these cheap devices is very whimsy. The PC must do all the handshaking and encoding.
Voltage negotiation is irrelevant in this case. Bluetooth itself is wireless so it has none, and if you simply use or design a ttl compatible chip it will work perfectly off the 5V from USB without negotiation.
I wasn't implying that this does any sort of voltage negotiating, I was using it of an example of how far mass production can drive down prices - you get an entire USB client controller and some portion of a Bluetooth device for 99 cents, so it's not inconceivable that the much simpler voltage negotiation controller would cost less (at least on the laptop side. The power supply electronics might cost more since it needs to do voltage selection and switch relatively large currents).
In a "car" like this one with low friction tires and low friction drivetrain on a circular course, do you really get much better mileage with a lighter driver? For every bit of energy you spend pushing a heavier driver up a hill, you'll get nearly all of it back as you coast down the other side with the engine turned off.
The Apple Magsafe connector that many people here seem to be enamored with has 5 pins, and most of the complaints about fragility seem to be talking about the fragility of the power cord, not the connector itself. Besides, you don't *have* to have more than 2 pins... I don't know how negotiation works with this new standard, but for example, the power supply could supply 3V by default, then that device uses that 3V to power its negotiator and sends appropriate signals over the 2 power supply pins to request its desired voltage. After that, there doesn't need to be any more negotiation over the power pins. (though there could be further communication - the power adapter could say "Hey, my power source is a battery and it's running low, so I'd like you to drop down from 100W of power to 50W, ok?")
If all computers used the new standard, then the price of the power supply negotiation chipset would come down to be negligible, especially compared to the price of a laptop. The new standard would be used for many other things too -- like speakers, external hard drives, etc (i.e. anything that uses too much power to be powered from a USB port).
USB and Bluetooth implementations are much more involved than a simple voltage negotiation, yet you can buy a USB->Bluetooth adapter for 99 cents:
http://www.meritline.com/bluetooth-usb20-adapter---p-40150.aspx
http://tinyurl.com/6e42gxn
Why didn't you just post the lmgtfy link directly? http://lmgtfy.com/?q=define%3A+car
I'm not sure what point you're trying to make, your link shows a bunch of car ads and this definition:
car/kär/Noun
1. An automobile.
2. A vehicle that runs on rails, esp. a railroad car.
Here's one for you: http://lmgtfy.com/?q=tricycle
I once saw an eighty-year-old man parallel park by driving his car forward until he hit the car in front, angling the wheel, driving back till he hit the car in back, angling the wheel, and repeating this process as the two eighty-year-old women in the back seat appeared to be growing more and more concerned.
It's not just 80 year olds that park this way - I see this parking style often in the city where I live - parking is hard to come by and people will cram their car into impossibly small spaces.
Cambridge Design built an oxygen concentrator to replace oxygen tanks in battlefield medicine. This device is powered by a tiny diesel engine. I suspect that that engine is what's being used in this car, not the oxygen concentration device.
The article doesn't make it clear what role the oxygen concentrator plays, but it does sound like it's using a diesel powered engine:
Cambridge Design Partnership used elements from its own lightweight oxygen concentrator, as well as other in-house technologies, to create the unique car. The oxygen generator system was originially developed to treat injured soldiers, but in the car it is powered by an innovative micro-diesel-engine. The car also features low-friction tires to increase mileage.
We quickly realized that our R & D work for the MoD, creating an oxygen generator, was highly applicable to the Mileage Marathon Challenge. Both required an extremely efficient system that used very low power and could run off diesel. Now I just need to figure out how to make my own car get the same kind of mileage!”
That's no car, it's more like a motorized tricycle.