Ok, but you failed to look at what this function is used in the context of the zune.
In this case, everytime the current date is looked up, it needs to compute the is_leap_year function for every year since 1980, thus causing many of the cases from being used, ie, it's not always computing is_leap_year(CURRENT_YEAR).
This is why the average modulo cost is usefull, since the real cost of the date computation would be defined as sum(modulo_cost(is_leap_year(y)), y=1980..CURRENT_YEAR)) which we can evaluate as being close to (CURRENT_YEAR - 1980 + 1) * average_modulo cost. (+1 is used if 1980 is not precomputed)
In our case 2009 - 1980 + 1 = 30 30 * 1.26 = 37.8 => 38 modulo operations for obtaining the current date.
And, actually, since we recently went over a 100 year milestone, the average usage will be very close to a 1.26 value.
So, evaluation the average speed of the function in itself coult be pointless, as it's true that whatever you do will result in a 1, 2 or 3 modulo operations, but when you want to make a real usage of the function, and that you want to know which one to use between 2 functions, each using 1, 2 or 3 modulo operations, it's very usefull to be able to compare the real distribution of the values. In our case, it tells us that the date computation would takes 2.37 times less modulo operation (which will most probably be the controlling factor) with the former formula than with the proposed one.
Just for a single date computation this year it will use 29 calls to the is_leap_year function. No guesses on the total number of date computation being done per day has been done yet, which could be a fair amount.
I believed it was a joke.. We are speaking of embeded devices with a very limited amount of resources to spare, and it was already very well readable along with being written in the way it's usually described.
Haven't you learned that it's a leap year every 4 year first, then later on someone taught you it wasn't every 100 years even if divisble by 4, and then there's an exception if it's divisible by 400 where it's still a leap year, or they started in the reverse order?
Also, what if the chosen fractions (100 / 400) to split the time were not chosen to be a multiple of each other ? Reversing the equation would not work in that case.
That's why that's a full time average and not for specific years. Notice that your short them average (4 years to 99 years) gave 1.25 as the result, rather than 1.26 for a standard average.
Actually, it's far from being good. In 99% of the cases you will do 3 modulos operation, in 0.75% you will do 2 modulos and in 0.25% you will do 1 modulo, for an average modulo cost of 2.9875 per run.
With the initial solution, you have 1 modulo in 75% of the cases, 2 modulo in 24% of the cases, and 3 modulo in 1% of the cases, for a total average modulo cost of 1.26 per run.
No, but some of the settings are important to be left at their maximum value, since they give out cues on the events about to unfold which allow you to get yourself ready..
Factor in the price of gas, the environmental effect, distribution ineffectiveness (yes, people are driving those petroleum vans around, while those 600kV lines are doing a fine job of carying electricity around with minimal losses over thousands of kilometers), 20% or so effectiveness of the gas motor vs 90%+ of the electrical vehicule, effective torque of the electrical motor... and keep going. Yes, you'll want one too!
Wind turbine -- the efficiency of the turbine is not something as important since we are not running out of wind, what is of importance is the total cost for the lenght of time it can be used at a specific power output.
Solar panel ?
Hydroelectric power ?
Nuclear power ?
Geothermal power ?
That cover all the power plant types we have here, so we have no need to worry about the efficiency of the power plant in a fuel comparison:)
20A at 220V ? That means that running maybe 4 computers and a home cinema and nothing else works ? It's not even half of what my oven can use..
Actually, here at least, most house have a 200A 240V distribution panel. With the voltage losses in the lines from the transformator, and a buffer not to trigger the breaker, we are supposed to be able to use up to 44kW. So, if we were to use all of the power to charge this capacitor, it would take an hour and 11 minutes to charge up.
What would be the best thing is just to have a straight 10kV entry point for charging at a reduced rate rather than reducing it to 240V, or even a 600V/500A which is common here for farms or home enterprises (even garages), or, just fill it up at the gas/electricity station !
At least one ECC scheme (ECMQV) and some implementation techniques are covered by patents. Uncertainty about the availability of unencumbered ECC has limited the acceptance of ECC
The existence of open source solution does not mean you are free to use them: they can still be covered by patents that you will have to pay for.
Somewhere at the beginning of 2002, RSA labs. was already suggesting that 1024 bits keys was not big enough for root corporations and that they should already start using 2048 bits. Which makes it even worst...
If I remember right, a new computer in the ballpark of 300M would allegedgly be able to break a 1024bits key in a reasonable time by now. How much can a botnet represent ? Is it scaleable for this kind of work ?
Just don't break the seal and open it up the other way around. Have a toddler / pet kick up the keyboard until the I agree button is pressed, and there you go, no agreements between you and them.
My parrot is now very good at pressing the I agree button:)
It was called ITU G.992.5, offering double the bandwidth per frequency used VS ADSL2, based on the encoding of the signal, from the info gathered at that time. Also, for a small fee (14.99$ per month at that point, if they had allowed it) you could get double the bandwidth by using the 2 pairs of wire coming into your house/apartment, for a 48mbps speed.
They already deployed everything to offer 25Mbps to every house in all major cities, ready to offer multiple streams of high definition video on demand. The installation was done for my apartment 2 years ago, and it still isn't activated. The fastest I had been able to get unlocked was 8Mbps while they were offering only 5, from a third party ISP for that time, and now they've recently decided to unlock 16mbps.
Also, to answer a previous post, it's a very bad affirmation to say that everything which gets shaped is illegal traffic.
In my case, I've encountered problem downloading world of warcraft patch, since they use a distributed method for sending the patches. Creating an SSH connection to a server which wasn't hosted on bell, and directing all the traffic to this computer allowed me to go from 40KB/s to 850KB/s. After encountering this problem very often, I just started proxying everything by default through a vpn.
They could tap on the electrical line to read any disturbance, that might give out information. For the LCD, those ugly & cheap DVI or VGA cables are often not well shielded (same as the keyboard) and there are many more parts which could emit EMI to tap onto.
Actually, that depends where you live. Around here, it's 3.5, 4.5, 5.5, counting the kitchen / living room / bedroom as full and bathrooms as.5. If you have two bathrooms then you have a full number, but that's usually for higher numbers (6-7-8) of total rooms.
Here, a very nice 4.5 rooms apartment cost around 430$ (US equivalent at the current rate)
Slashdot Mirror
Ok, but you failed to look at what this function is used in the context of the zune.
In this case, everytime the current date is looked up, it needs to compute the is_leap_year function for every year since 1980, thus causing many of the cases from being used, ie, it's not always computing is_leap_year(CURRENT_YEAR).
This is why the average modulo cost is usefull, since the real cost of the date computation would be defined as sum(modulo_cost(is_leap_year(y)), y=1980..CURRENT_YEAR)) which we can evaluate as being close to (CURRENT_YEAR - 1980 + 1) * average_modulo cost. (+1 is used if 1980 is not precomputed)
In our case 2009 - 1980 + 1 = 30
30 * 1.26 = 37.8 => 38 modulo operations for obtaining the current date.
And, actually, since we recently went over a 100 year milestone, the average usage will be very close to a 1.26 value.
So, evaluation the average speed of the function in itself coult be pointless, as it's true that whatever you do will result in a 1, 2 or 3 modulo operations, but when you want to make a real usage of the function, and that you want to know which one to use between 2 functions, each using 1, 2 or 3 modulo operations, it's very usefull to be able to compare the real distribution of the values. In our case, it tells us that the date computation would takes 2.37 times less modulo operation (which will most probably be the controlling factor) with the former formula than with the proposed one.
How many calls to this function is used up ?
Guess ?
Just for a single date computation this year it will use 29 calls to the is_leap_year function. No guesses on the total number of date computation being done per day has been done yet, which could be a fair amount.
Insightful ?
I believed it was a joke.. We are speaking of embeded devices with a very limited amount of resources to spare, and it was already very well readable along with being written in the way it's usually described.
Haven't you learned that it's a leap year every 4 year first, then later on someone taught you it wasn't every 100 years even if divisble by 4, and then there's an exception if it's divisible by 400 where it's still a leap year, or they started in the reverse order?
Also, what if the chosen fractions (100 / 400) to split the time were not chosen to be a multiple of each other ? Reversing the equation would not work in that case.
That's why that's a full time average and not for specific years. Notice that your short them average (4 years to 99 years) gave 1.25 as the result, rather than 1.26 for a standard average.
I don't think it was worth pointing out ;)
Actually, it's far from being good. In 99% of the cases you will do 3 modulos operation, in 0.75% you will do 2 modulos and in 0.25% you will do 1 modulo, for an average modulo cost of 2.9875 per run.
With the initial solution, you have 1 modulo in 75% of the cases, 2 modulo in 24% of the cases, and 3 modulo in 1% of the cases, for a total average modulo cost of 1.26 per run.
I think your 20A is referring to the limit per outlet. How many breakers and at which strenght do you have in your distribution panel ?
No, but some of the settings are important to be left at their maximum value, since they give out cues on the events about to unfold which allow you to get yourself ready..
Factor in the price of gas, the environmental effect, distribution ineffectiveness (yes, people are driving those petroleum vans around, while those 600kV lines are doing a fine job of carying electricity around with minimal losses over thousands of kilometers), 20% or so effectiveness of the gas motor vs 90%+ of the electrical vehicule, effective torque of the electrical motor... and keep going. Yes, you'll want one too!
Wind turbine -- the efficiency of the turbine is not something as important since we are not running out of wind, what is of importance is the total cost for the lenght of time it can be used at a specific power output.
Solar panel ?
Hydroelectric power ?
Nuclear power ?
Geothermal power ?
That cover all the power plant types we have here, so we have no need to worry about the efficiency of the power plant in a fuel comparison :)
20A at 220V ? That means that running maybe 4 computers and a home cinema and nothing else works ? It's not even half of what my oven can use..
Actually, here at least, most house have a 200A 240V distribution panel. With the voltage losses in the lines from the transformator, and a buffer not to trigger the breaker, we are supposed to be able to use up to 44kW. So, if we were to use all of the power to charge this capacitor, it would take an hour and 11 minutes to charge up.
What would be the best thing is just to have a straight 10kV entry point for charging at a reduced rate rather than reducing it to 240V, or even a 600V/500A which is common here for farms or home enterprises (even garages), or, just fill it up at the gas/electricity station !
From the same page:
Patents
Main article: ECC patents
At least one ECC scheme (ECMQV) and some implementation techniques are covered by patents. Uncertainty about the availability of unencumbered ECC has limited the acceptance of ECC
The existence of open source solution does not mean you are free to use them: they can still be covered by patents that you will have to pay for.
Somewhere at the beginning of 2002, RSA labs. was already suggesting that 1024 bits keys was not big enough for root corporations and that they should already start using 2048 bits. Which makes it even worst...
If I remember right, a new computer in the ballpark of 300M would allegedgly be able to break a 1024bits key in a reasonable time by now. How much can a botnet represent ? Is it scaleable for this kind of work ?
Why not just use real bullets ? That would be a public service act!
Any proven benefits of GM foods ? Some companies make tons of cash out of it.. definitely a benefit for them!
Just don't break the seal and open it up the other way around. Have a toddler / pet kick up the keyboard until the I agree button is pressed, and there you go, no agreements between you and them.
My parrot is now very good at pressing the I agree button :)
It was called ITU G.992.5, offering double the bandwidth per frequency used VS ADSL2, based on the encoding of the signal, from the info gathered at that time. Also, for a small fee (14.99$ per month at that point, if they had allowed it) you could get double the bandwidth by using the 2 pairs of wire coming into your house/apartment, for a 48mbps speed.
yes, but how is it illegal to update my WoW game ?
They already deployed everything to offer 25Mbps to every house in all major cities, ready to offer multiple streams of high definition video on demand. The installation was done for my apartment 2 years ago, and it still isn't activated. The fastest I had been able to get unlocked was 8Mbps while they were offering only 5, from a third party ISP for that time, and now they've recently decided to unlock 16mbps.
Also, to answer a previous post, it's a very bad affirmation to say that everything which gets shaped is illegal traffic.
In my case, I've encountered problem downloading world of warcraft patch, since they use a distributed method for sending the patches. Creating an SSH connection to a server which wasn't hosted on bell, and directing all the traffic to this computer allowed me to go from 40KB/s to 850KB/s. After encountering this problem very often, I just started proxying everything by default through a vpn.
They can't use the term traffic limiting else it would not be an unlimited internet connection anymore ;)
They could tap on the electrical line to read any disturbance, that might give out information. For the LCD, those ugly & cheap DVI or VGA cables are often not well shielded (same as the keyboard) and there are many more parts which could emit EMI to tap onto.
Actually, pluging in the PSU or an LCD monitor increases the number of ways they could recover what you typed.
Actually, that depends where you live. Around here, it's 3.5, 4.5, 5.5, counting the kitchen / living room / bedroom as full and bathrooms as .5. If you have two bathrooms then you have a full number, but that's usually for higher numbers (6-7-8) of total rooms.
Here, a very nice 4.5 rooms apartment cost around 430$ (US equivalent at the current rate)
It might sound odd but some people still enjoy playing in those, without thinking about the loot :)
Or just use the year!
If you are out there relying on heaven help ... I believe it's too late :)