The reason is that any app developed for a phone that followed best practices will look and work acceptably on he tablets. If you did not try out multiple different screen sizes, resolutions, and dpis including some ridiculously large ones (like tablet sized screens) then you should have restricted your app to the appropriate screen size. If you did not do so, you will get many negative reviews from tablet owners, which will bury your app.
The OS does have support for different layouts for different screen sizes, which is often a good idea, as on larger screen sizes you may be able to combine two "screens" of your app into one screen, or make other tweaks to better utilize the space, perhaps moving things from the hidden menu into buttons on the screen.
If you find apps on the market that work poorly on a tablet, vote them down, and leave a comment. The developers will learn to either restrict the app to the sizes where it works well, or to fix the layout, or add a new layout for larger size screens.
AFAIK, there isn't any nation that spans a whole continent.
Well Australia nearly spans an entire continent. There are a few other countries owning to a couple of the islands of the continent, like the islands of Tasmania and New Guinea. But Australia does come very close.
Your DYNDns.com website does not make it particularly clear that you support DNSSEC on your domain registration product.
You provide the documentation for setting up DNSSec for a domain on http://www.dyndns.com/support/kb/implementing_dnssec.html, but you don't mention how to submit the information needed for DS records, so you can submit the DS records to the Registry for inclusion in the TLD zone. That page appears to not have been updated in a while, which is probably why it lacks that information.
I would also recommend that you mention DNSSec on this page, probably right after you talk about Glue Records, since DS records are similar in that they are added to the parent zone, and like glue records they are only needed if the domain is set up a specific way (namely set up to support DNSSec).
Very true. Unfortunately there is no easy way to check how big a problem something like that would be, since ISPs don't go publshing full information about peers, customers, and transit providers.
I do know that in the US there are several Tier-2 ISPs that are larger than many Tier-1 ISPs, and have settlement-free peering agreements with most of the tier-1 ISPs, plus are peered with many other Tier-2 ISPs. Thus they pay nothing to route packets to most of the internet. However, they do not have free routing to the entire internet, which is why they are not Tier-1.
One way this can happen is the Tier-2 ISP in question is not able to peer with one of the overseas Tier-1 providers, like Tata Communications, or DTAG, simply because they don't have a presence at any Exchange points where the Tier-1 in question operates as.
In order to get connectivity then they generally buy transit to that network from one of their peers. (Remember that a standard peering agreement with a tier-1 covers routing to that tier-1 network, and its customers, but does not normally cover routing to other tier-1 networks).
Provider "B" sells full transit to provider "A". "B" pays for packets sent to/received from providers "C" and "D", but is not buying full transit from them, so "C" will not deliver packets between "B" and "D", and "D" will not deliver packets between "B" and "C". (My understanding is that many Tier-2 providers have some "B" and "C" where this is the case).
If a user on provider "A" creates a multicast stream, that 100 customers of "C" and 200 customers of "D" want to see/hear, the following happens. "A" pays "B" for the sending one stream. "B" sends the stream to "C" and "D", and pays each for sending one stream.
In unicast "B" pays for sending 300 streams, but "A" pays him back for those plus markup, so he comes out ahead. With multicast "B" pays for sending two streams, but "A" only pays him for sending one stream. Depending on just how much "B" charges "A" for service, "B" could go from making significant money on the streams to losing money on them.
"B" would like to charge "A" for this, but "B" has no easy way to track this, since in the unicast world all "B" dd was count the bytes on the pipe between "A" and "B". Now "B" would need to flag the multicast packets from "A" and count them at the connections to "C" and "D" as well, which they are not equipped to do.
Lets say "B" sets things up so they can double bill if a packet went to each. "A" might be multi-homed, and wants to be able to know how much each provider will charge them, so as to route traffic to minimize costs. (this can make good sense if one or more of "A"'s providers has some form of variable pricing or overage fees). That is fairly easy in the unicast world. However, in the multi-cast world "A" has no way of knowing if a multicast packet sent to "B" will get billed twice or not, making it much harder to optimize things.
If one packet that becomes 100 is charged 100x, then they are not charging for bandwidth, since that would be a flat cost for an x Mbps pipe. Remember bandwidth is throughput, and is measured in bits per second.
If there is an allowance, then you are clearly referring to data utilization, (the integral of utilized throughput over a period of time) which is measured in bits or bytes.
------- Let me outline all this.
Consider the following ISPs. BV&V, and Zerivon are huge Tier-1 ISPs.
We have a Large ISP named InternetCo. InternetCo is a Tier-2 ISP.
InternetCo buys transit from both BV&V and Zerivon. InternetCo is also peered with several other ISPs, but their peering agreements cover local delivery and delivery to customers only, no transit to other networks is provided.
InternetCo sells transit to several ISPs. They sell based on data usage too.
PhoneCo is medium sized Tier-3 ISP, who buys transit from InternetCo. PhoneCo sells Internet service to its smaller divisions. The divisions sell to end-users and to small ISPs. The pipes between the divisions and the main PhoneCo network are oversubscribed. PhoneCo sells service based only on the size of the pipes.
CheapNet is a small ISP. They buy transit from a phoneCo division via a DSL line. Their DSL line is oversubscribed of course. They sell only one speed to customers at a flat rate sufficent to cover their flat rate from PhoneCo plus some profit.
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Ok. Now lets say some server in the Zerivon network is multicasting some work. Well InternetCo gets a single copy of each packet over the the connection from Zerivon and and makes a copy for each interested customer. PhoneCo gets a single copy of each packet that they send a copy to each division that is interested. The division sends a copy to CheapNet. Because of multicast, only one copy of each packet goes over the oversubscribed pipes. Everybody is happy with this situation.
Now, what happens if a CheapNet customer is sending a multicast stream out. One copy of each packet goes to CheapNet. CheapNet makes a copy for each interested customer, but they don't really care about that. They care only about the fact that they send at most one copy of the multicast packet to the PhoneCo division. The divison happens to have no interested customers, but there are interested customers upstream, so it sends one copy of each packet to PhoneCo. PhoneCo sends copies to interested divisions, and passes a Copy to InternetCo. InternetCo sends a copy to each interested customer, as well as to interested peers, and also to each of BV&V and Zerivon.
Intenernet Co does not like this. First of all, they feel that PhoneCo shouldhave to pay more for packets that result in 50 copies getiing sent to customers, and peers, than for a packet that goes to only one customer or peer. InternetCo though has no easy way to measure how many times each packet is split, so it really cannot charge PhoneCo appropriately. But even so that is not a big deal.
The big deal is that if this stream consisted of 20 GB of total data, PhoneCo payed sending 20 GB of data. However InternetCo payed sending 20GB of data to BV&V and payed for sending 20 GB of data to Zerivon.
If InternetCo is not charging PhoneCo at per gigabyte at the sum of the per gigabyte prices of BV&V and Zerivon, then InternetCo is losing money on this multicast stream. They will not tolerate that very well. While they might be able charge PhoneCo enough, other Tier-2 ISPs most certainly cannot. For example a Tier-2 that buys transit from 5 providers likely cannot charge its customers the sum of the per gigabyte prices of all 5.
--- The big problem here is sending multicast packets in the customer to providers direction. In that direction you can get problems like the one noted above.
However in the other direction (providers to customers) the ISPs are perfectly happy. They don't need to pay anything additional when they duplicate packets to send to their customers. If they charge customers per gigabyte, they are actually making more profit than usual with multicast, since they pay their provider (if any) only once, yet get payed for each of their customers interested in the stream.
Nonsense. SPDY may bypass HTTP proxy-based adblocking systems, but in browser systems still work.
Furthermore it is entirely possible to have a transparent SPDY proxy for ad-blocking if you want, but because only Google is using it, nobody bothers upgrading the exiting http-proxy based adblocking tools.
Of course, in reality proxy-based adblocking is very rare. Most users just use in-browser tools like AdBlock Plus for Firefox, or AdBlock Plus for Chrome, or Opera's built-in content filtering.
Combining multicast support which is certainly be bettter and more widely supported than it's today is. The reason is looming and it's HD-IPTV. Unicast HD-IPTV is a bandwith consumptive hog and the only practical way is to use multicast for it. That forces many organisations which did not previously bother configuring it reconsider and this will open doors to other applications using it too.
I strongly doubt that. Consider that AT&T uses multicast for their U-Verse service. The problem is that they provide no way to create your own multicast streams. They have no interest in allowing other applications to use it. Why would they? The multicast gives their service a serious cost advantage compared to other live streaming services. Because it is generally viewed as a separate TV service, most proposed net-neutrality regulations would not require them to open it up.
To the best of my knowledge there is no real standards for negotiating multi-cast between autonomous systems. Even if there were, the fact that the packets can multiply inside a network (when they reach a router with subscribers on more than one of the connected (sub)networks) makes setting up peering agreements difficult.
Transit agreements between ISPs generally assume that one packet sent in results in one packet leaving the network, or being delivered to a machine inside the network. With multicast between distinct autonomous systems, that one packet in could result in 100 packets being delivered to in network machines, and potentially one packet to each connected network. How should that be counted for billing?
If each resulting packet is counted, that would require network changes to track how many in-network machines it was delivered to. If it were counted as just the one packet for this network, plus one more packet for each connected peer or transit provider it reached, the required changes would be much smaller.
However in either case that would be really unfair to the sender of the packet, who has no way of knowing how many times an individual packet would be counted. It would also be rough on intermediate networks who may try to track usage and switch packets between multiple transit providers such as to minimize costs. They would only know that they sent one packet of some specific size to a given transit provider who may count it as many more packets.
The whole thing is very awkward. After all despite those issues, ISPs could benefit from the same number of users with the same style of usage resulting in many fewer total packets needing to be sent through the oversubscribed links from the core networks to last mile.
Now I understand that copyrights can be held pseudonymously; but how does this allow attribution as required by CC-BY-SA?
If a user posts something under a pseudonym, then attribution need only reference that pseudonym.
Is it enough for an author of a derivative work to reference the page on my site where the pseudonymous copyright holder grants the license?
Technically all a derivative work would need is enough information to clearly attribute the work. Even just the title of the work, name of your site, and the pseudonym the work was published under would qualify. (E.g. based on "the song" by sombody57 of example.com). It is debatable if a mere link to the source is sufficient, but the Wikimedia Foundation feels it is, so you would be in good company.
Does the end user need to be able to contact the copyright holder for additional rights?
No. There is no such requirement under copyright law. (You own copyright to work you publish completely anonymously (but good luck proving it is your work)). The CC-license
Is this a road through a minefield, so that I should just bite the bullet and, like Wikipedia, make a foundation to hold and license the copyright for collaborative works?
But the Wikimedia foundation does not hold copyright to the work. The copyright is held by the pseudonymous contributors.
Also, speaking of ball lenses... you can use your head as a ball lens to extend the range of your car's wireless entry key fob. If you find yourself just out of range of your keys, simply put the transmitter about an inch behind your head, directly *opposite* the car. Your head is mostly transparent to the RF, but has a slightly different index of refraction from air/vaccum, thus acts as a lens. And since your head is approximately spherical, it works well enough to make a practical convergent lens.
Really?!! Deliberately focusing radio waves via your head!?! Are you nuts!!?
Honestly though I would have assumed that the effect described was due to one of the other many unusual characteristics of RF that I never really payed attention to. The head as a lens would never have occurred to me.
I'd dispute that ruby is dying. Ruby is a well designed language, and works just fine. It will remain around, although when it reaches steady-state it will probably not be a particularly popular language anymore.
What is dying is Rails. Rails has been one of the largest driving forces for Ruby. And make no mistake, it is an excellent web MVC framework. Consider that most web MVC frameworks that have come since rails have incorporated at least one component of Rails. For example Microsoft's ASP.NET MVC comes with a routes system inspired by Rails, and has a definite convention over configuration design.
Rails is dying in large part because the MVC frameworks of other languages are now comparably easy to use, meaning that the advantages of using Rails frequently do not overcome the disadvantage of learning a new language, namely ruby.
These both require you to enter a number and the remaining menus change depending on the number you have entered, so unfortunately the way their service works, there is no way to continue, since they cannot predict the rest of the menu. Most other companies do not require such a number so early in the process, so you can at least jump directly to that stage, and often can jump directly to a representative.
What happens right now is that if the grid ran slightly fast for an hour, they then run the grid slightly slow for an hour so it averages to extremely close to 60.000Hz. (Yes, they try to average to more than 2 significant figures after the decimal!) The problem is that coordinating the grid to deliberately run at a different frequency for a while is a huge pain in the ass.
They are going to try out not making the deliberate corrections and see how much of a problem this really causes. If it does not cause too large a problem, (many household clocks already drift more than this will cause) it could save a lot of time and money.
By design arbitrary variations are supposed to work. After all Japan has 2 electric grids, one being 100V @ 50 Hz, and the other being 100V at @ 60 Hz. It is intended by design that US laptop power supplies work on both, since Japan uses the same socket design as the US.
Of course, some PSUs receive little or no testing except for 100-120V @ 60V and 220-240 V @ 50 Hz, so issues could occur. However, I have successfully run many electronics at ~120v @50Hz, by use of a stepdown transformer in Germany, and nothing ever gave me problems, although I did not test devices that used an LM8560, which would be problematic.
There are also quite a few old clocks out there that consist of simply an AC motor, relying on cycle frequency to remain reasonably accurate, with occasional manual correction.
We don't make many devices really reliant on the frequency anymore. All AC motors are reliant, but unless they are driving something timing dependent then the small variations we are discussing are not particularly problematic. For lightbulbs, and electric heaters, they really don't care, and could run just fine on 50Hz or 70Hz. Many electronics also don't care, since they convert to DC first.
There are some older devices still around that rely on the frequency like some old film projectors, but the small variances here are unlikely to cause notable issues.
Basically I think the main problems will be old clocks, and other devices that use incorporate a motor based clock, like traffic light controllers. I would be a bit concerned though about noise if the mains voltage happened to cross the modern TV refresh rate of 59.94Hz
Here is how education tends to work in the US. This is obviously a generalization, but It should give you a general idea.
1 Pre-primary education
Preschool (nursery school or prekindergarten) is technically optional program. It is most commonly one or two years. Part of the purpose is to get young children used to a classroom like setting, while not actually learning terribly much, but getting them accustomed to the process of learning, socialization, and other concepts.
2 Primary/Secondary Education In this section I'm going to describe primary and secondary education in the united states. There are many variations, and the line between primary and secondary is not particularly strict.
Different school districts, or private school systems divide things differently. I describe one system below, but there are many, many varaiations. This image does a reasonably good job at showing several common divisions. I'm going to describe the path second from the left, as the breaks in it correspond reasonable well to shifts in
2.1 Elementary School In the system I am describing Elementary School consists of Kindergarten and 1st through 5th grade.
Kindergarten generally the first compulsory year of schooling. It is not always full time. One common pattern is two days a week, plus one half-day. allowing for one teacher to have two distinct groups each week.
First grade is almost invariably full time, and things will remain this way through high school.
The primary focus of elementary school are the subjects of "reading", "writing", and "arithmetic". However, other subjects are present. There is often a physical education class ("gym"), and art and music classes are common. In the later grades science, history, or similar lessons occur. In my school, elementary students remained with the same teacher for all classes, with the exception of special classes like gym, art, and music, who had dedicated teachers, with each teacher's group having that that class at staggered dates and times, so that the specialty teachers taught groups of 30 or fewer at a time. Larger schools may do things differently.
2.2 Middle school In my example here, middle school involves 6th through 8th grade.
In in my school, this was the first time that you would have distinct teachers for each subject. The schedule was a grid, and you would have the same teacher each 8:15-9:00, or 9:05-10:50, etc time slot each day of the week. A tiny number of classes where not every day, in which case there was a pair of a two-day a week and a 3 day a weak class that would alternate days for the same timeslot. The year was also dvided nto two semesters, and you would be taing different coursed each semester, and even if they were in the same subject you may well have had a different teacher.
In Middle School the subjects become more diverse, including science, and social studies (a mixture of history, geography, and government). Toward the end of middle school was the first time I was allowed to make any decisions about which classes I would take, although the choices were very limited.
2.3 High School In this example, this encompases grades 9-12.
Classes were still scheduled in a grid, and there were two semesters pretty much just like like middle school. However, there was substantially more choice. While certain subjects were required certain years, the better students had the option of taking the honors or Advanced Placement courses, which are more difficult, but are expected by good colleges and universities.
The classes offered had a wider range. Foreign languages are often offered for the first time at this level, (although some large schools offer them in middle school). The classes are still limited. At many schools you will take only one year of physics and one year of chemistry, and only then if you are
Unfortunately, the state of electronic money in the US is rather sad.
First of all according to the survey by the Census Bureau 7.7% of US households do not have a bank account at all! Up to 25% of the population lives paycheck-to-paycheck, utilizing the services of Pawn Shops, non-bank check-cashing services, or payday loans (legal loan sharks).
Cash is accepted virtually everywhere. Paper Checks are also widely accepted, although are considered a bit risky by the merchants, more because of the likelihood of insufficient funds (and not being ale to track down the person if that happens) than fraud. If you do have insufficient funds, you will likely be hit by at least $100 in fees. ($25 from the merchant and $25 dollars from the bank for first presentation of the check, and both fees again when merchant
Credit Cards and Debt Cards are widely accepted, but not universally. If fraud occurs the merchant eats the loss, pretty much without exception. Merchants are also weary of people disputing the charges with their card company. If that occurs the credit card company tends to side with the consumer unless the merchant can show that the transaction was actually completed.
Online bill payment at the company's site is common for large companies, but smaller companies may not offer it, or may charge a fee to pay online. Except for the largest companies, if you pay online the payment is not counted as being payed when you finished entering your details, but only once the transaction is completed, so paying online at the due day may not qualify as paying on-time, (although oddly if you give them the same credit card information over the phone, they almost always count that as on-time.)
Wire transfer services are expensive. Fees of $20 or more to send a wire Transfer domestically are very common. At my credit union, receiving a wire transfer is a $5 fee, and I belive similar fees are also common.
The wire transfer system thus is not often used. Instead the ACH system is used. Most but not all employers offer direct deposit services, which use ACH to electronically post money into your account. Banks almost never charge a fee for that, but that is pretty much the only case in which consumers receive money via ACH. The more common use is to electronically present paper checks, for online bill payment via a bank, or for direct debit (where you authorize a company to directly charge your bank account.) There are no fees for the customer for those.
Online Bill payment through a bank does exist. However it does not work well. Payment is electronic (via ACH) only if your bank and the company have worked together to set that up. If not, when you use online bill payment the bank (or the company they contracted to provide the bill payment service) physically prints a paper check and mails it.
Many but not all companies with regular recurring bills offer a direct debit service (via ACH, as mentioned above), and indeed it is possible to pay nearly all your bills that way, except for one-off bills and perhaps a small number of recurring bills where the company does not offer direct debit.
Having integration between the bank and the company, such that you can view your bill electronically via the bank, and then pay the actual bill (useful for variable bills) is possible, but many banks and companies don't offer this. Even if both the bank and the company offer that, it may still not work, since there is no standard mechanism, so unless your bank (or its contractor) have specifically worked with the company to set up this integration, it will not happen.
For person to person electronic transfer of money there are few choices other than services like PayPal, or very recently a few services (such as Square) have started allowed individuals to accept credit cards.
Otherwise the only options for person-to-person payments is checks, or cash.
When's the last time you heard of a CS student calling the help desk for anything that could possibly solved without help desk involvement?
I'm sure it happens during the first semester until the students in question drop out of the program.
But you have a very good point. Most Linux users are people who are quite well aware how worthless the help-desk is, and will avoid contacting them when possible. If there is a Linux-specific support resource (offered by the CS department or similar) then people might try using it. I never did because I knew the Linux specific resources were focused on the department maintained Linux boxes.
Active Directory is just an X.500 directory that offers access via the Lightweight Directory Access Protocol (LDAP), combined with Kerberos and some dns management.
It is extremely well documented how to set up a similar Directory on Linux via an "LDAP server" (technically a Directory server that supports LDAP, but nobody gets the terminology right.)
It is also well documented how to set up Linux machines for LDAP with Kerberos authentication. So if you want to you can literally just have the Linux systems authenticate against AD. Sure all Linux systems also have local users accounts, but so does every Windows system. It is also possible to set up a Linux system as a Domain Controller, although admittedly I've not yet seen a setup that could interact with Microsoft domain controllers as part as an AD forest.
My university did the same thing. It was a Cisco captive portal system that also reconfigured the routers so your system's MAC would automatically be placed on the chosen VLAN (but most switches and all APs only offered one VLAN choice). It worked in Lynx, and just about anything else. After doing that you needed to "reboot", or more accurately drop your DHCP lease and acquire a new one.
The did drop you immediately on a page for downloading and installing their "helpful" bundle of completely non-required crapware, but the only people tricked into installing it are the ones who would benefit from it anyway.
For wireless, we did transition to using a secured wireless network using WPA-enterprise with PEAP (authentication using your Directory username and password which was used for all services, and to log into any University maintained machines), but for being somewhat obscure, it was surprising well supported by various devices, (except game consoles, which are better off wired anyway).
Google's engine does not distinguish between the various versions of HTML. As long as Google successfully detects the page as html (and it is quite good at determining that), you can use any feature from any version and Google could not care.
For what it is worth, this markup is also valid HTML 4, but HTML 4 simply does does not define the meaning of the "me" or "author" values of the rel attribute, while HTML 5 does define the meaning (although I have not actually verified that).
Slashdot Mirror
The reason is that any app developed for a phone that followed best practices will look and work acceptably on he tablets. If you did not try out multiple different screen sizes, resolutions, and dpis including some ridiculously large ones (like tablet sized screens) then you should have restricted your app to the appropriate screen size. If you did not do so, you will get many negative reviews from tablet owners, which will bury your app.
The OS does have support for different layouts for different screen sizes, which is often a good idea, as on larger screen sizes you may be able to combine two "screens" of your app into one screen, or make other tweaks to better utilize the space, perhaps moving things from the hidden menu into buttons on the screen.
If you find apps on the market that work poorly on a tablet, vote them down, and leave a comment. The developers will learn to either restrict the app to the sizes where it works well, or to fix the layout, or add a new layout for larger size screens.
AFAIK, there isn't any nation that spans a whole continent.
Well Australia nearly spans an entire continent. There are a few other countries owning to a couple of the islands of the continent, like the islands of Tasmania and New Guinea. But Australia does come very close.
Your DYNDns.com website does not make it particularly clear that you support DNSSEC on your domain registration product.
You provide the documentation for setting up DNSSec for a domain on http://www.dyndns.com/support/kb/implementing_dnssec.html, but you don't mention how to submit the information needed for DS records, so you can submit the DS records to the Registry for inclusion in the TLD zone. That page appears to not have been updated in a while, which is probably why it lacks that information.
I would also recommend that you mention DNSSec on this page, probably right after you talk about Glue Records, since DS records are similar in that they are added to the parent zone, and like glue records they are only needed if the domain is set up a specific way (namely set up to support DNSSec).
Very true. Unfortunately there is no easy way to check how big a problem something like that would be, since ISPs don't go publshing full information about peers, customers, and transit providers.
I do know that in the US there are several Tier-2 ISPs that are larger than many Tier-1 ISPs, and have settlement-free peering agreements with most of the tier-1 ISPs, plus are peered with many other Tier-2 ISPs. Thus they pay nothing to route packets to most of the internet. However, they do not have free routing to the entire internet, which is why they are not Tier-1.
One way this can happen is the Tier-2 ISP in question is not able to peer with one of the overseas Tier-1 providers, like Tata Communications, or DTAG, simply because they don't have a presence at any Exchange points where the Tier-1 in question operates as.
In order to get connectivity then they generally buy transit to that network from one of their peers. (Remember that a standard peering agreement with a tier-1 covers routing to that tier-1 network, and its customers, but does not normally cover routing to other tier-1 networks).
That is all true.
However, there is another problematic case.
Provider "B" sells full transit to provider "A". "B" pays for packets sent to/received from providers "C" and "D", but is not buying full transit from them, so "C" will not deliver packets between "B" and "D", and "D" will not deliver packets between "B" and "C". (My understanding is that many Tier-2 providers have some "B" and "C" where this is the case).
If a user on provider "A" creates a multicast stream, that 100 customers of "C" and 200 customers of "D" want to see/hear, the following happens. "A" pays "B" for the sending one stream. "B" sends the stream to "C" and "D", and pays each for sending one stream.
In unicast "B" pays for sending 300 streams, but "A" pays him back for those plus markup, so he comes out ahead. With multicast "B" pays for sending two streams, but "A" only pays him for sending one stream. Depending on just how much "B" charges "A" for service, "B" could go from making significant money on the streams to losing money on them.
"B" would like to charge "A" for this, but "B" has no easy way to track this, since in the unicast world all "B" dd was count the bytes on the pipe between "A" and "B". Now "B" would need to flag the multicast packets from "A" and count them at the connections to "C" and "D" as well, which they are not equipped to do.
Lets say "B" sets things up so they can double bill if a packet went to each. "A" might be multi-homed, and wants to be able to know how much each provider will charge them, so as to route traffic to minimize costs. (this can make good sense if one or more of "A"'s providers has some form of variable pricing or overage fees). That is fairly easy in the unicast world. However, in the multi-cast world "A" has no way of knowing if a multicast packet sent to "B" will get billed twice or not, making it much harder to optimize things.
If one packet that becomes 100 is charged 100x, then they are not charging for bandwidth, since that would be a flat cost for an x Mbps pipe. Remember bandwidth is throughput, and is measured in bits per second.
If there is an allowance, then you are clearly referring to data utilization, (the integral of utilized throughput over a period of time) which is measured in bits or bytes.
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Let me outline all this.
Consider the following ISPs. BV&V, and Zerivon are huge Tier-1 ISPs.
We have a Large ISP named InternetCo. InternetCo is a Tier-2 ISP.
InternetCo buys transit from both BV&V and Zerivon. InternetCo is also peered with several other ISPs, but their peering agreements cover local delivery and delivery to customers only, no transit to other networks is provided.
InternetCo sells transit to several ISPs. They sell based on data usage too.
PhoneCo is medium sized Tier-3 ISP, who buys transit from InternetCo. PhoneCo sells Internet service to its smaller divisions. The divisions sell to end-users and to small ISPs. The pipes between the divisions and the main PhoneCo network are oversubscribed. PhoneCo sells service based only on the size of the pipes.
CheapNet is a small ISP. They buy transit from a phoneCo division via a DSL line. Their DSL line is oversubscribed of course. They sell only one speed to customers at a flat rate sufficent to cover their flat rate from PhoneCo plus some profit.
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Ok. Now lets say some server in the Zerivon network is multicasting some work. Well InternetCo gets a single copy of each packet over the the connection from Zerivon and and makes a copy for each interested customer. PhoneCo gets a single copy of each packet that they send a copy to each division that is interested. The division sends a copy to CheapNet. Because of multicast, only one copy of each packet goes over the oversubscribed pipes. Everybody is happy with this situation.
Now, what happens if a CheapNet customer is sending a multicast stream out. One copy of each packet goes to CheapNet. CheapNet makes a copy for each interested customer, but they don't really care about that. They care only about the fact that they send at most one copy of the multicast packet to the PhoneCo division. The divison happens to have no interested customers, but there are interested customers upstream, so it sends one copy of each packet to PhoneCo. PhoneCo sends copies to interested divisions, and passes a Copy to InternetCo. InternetCo sends a copy to each interested customer, as well as to interested peers, and also to each of BV&V and Zerivon.
Intenernet Co does not like this. First of all, they feel that PhoneCo shouldhave to pay more for packets that result in 50 copies getiing sent to customers, and peers, than for a packet that goes to only one customer or peer. InternetCo though has no easy way to measure how many times each packet is split, so it really cannot charge PhoneCo appropriately. But even so that is not a big deal.
The big deal is that if this stream consisted of 20 GB of total data, PhoneCo payed sending 20 GB of data. However InternetCo payed sending 20GB of data to BV&V and payed for sending 20 GB of data to Zerivon.
If InternetCo is not charging PhoneCo at per gigabyte at the sum of the per gigabyte prices of BV&V and Zerivon, then InternetCo is losing money on this multicast stream. They will not tolerate that very well. While they might be able charge PhoneCo enough, other Tier-2 ISPs most certainly cannot. For example a Tier-2 that buys transit from 5 providers likely cannot charge its customers the sum of the per gigabyte prices of all 5.
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The big problem here is sending multicast packets in the customer to providers direction. In that direction you can get problems like the one noted above.
However in the other direction (providers to customers) the ISPs are perfectly happy. They don't need to pay anything additional when they duplicate packets to send to their customers. If they charge customers per gigabyte, they are actually making more profit than usual with multicast, since they pay their provider (if any) only once, yet get payed for each of their customers interested in the stream.
Nonsense. SPDY may bypass HTTP proxy-based adblocking systems, but in browser systems still work.
Furthermore it is entirely possible to have a transparent SPDY proxy for ad-blocking if you want, but because only Google is using it, nobody bothers upgrading the exiting http-proxy based adblocking tools.
Of course, in reality proxy-based adblocking is very rare. Most users just use in-browser tools like AdBlock Plus for Firefox, or AdBlock Plus for Chrome, or Opera's built-in content filtering.
Combining multicast support which is certainly be bettter and more widely supported than it's today is. The reason is looming and it's HD-IPTV. Unicast HD-IPTV is a bandwith consumptive hog and the only practical way is to use multicast for it. That forces many organisations which did not previously bother configuring it reconsider and this will open doors to other applications using it too.
I strongly doubt that. Consider that AT&T uses multicast for their U-Verse service. The problem is that they provide no way to create your own multicast streams. They have no interest in allowing other applications to use it. Why would they? The multicast gives their service a serious cost advantage compared to other live streaming services. Because it is generally viewed as a separate TV service, most proposed net-neutrality regulations would not require them to open it up.
To the best of my knowledge there is no real standards for negotiating multi-cast between autonomous systems. Even if there were, the fact that the packets can multiply inside a network (when they reach a router with subscribers on more than one of the connected (sub)networks) makes setting up peering agreements difficult.
Transit agreements between ISPs generally assume that one packet sent in results in one packet leaving the network, or being delivered to a machine inside the network. With multicast between distinct autonomous systems, that one packet in could result in 100 packets being delivered to in network machines, and potentially one packet to each connected network. How should that be counted for billing?
If each resulting packet is counted, that would require network changes to track how many in-network machines it was delivered to. If it were counted as just the one packet for this network, plus one more packet for each connected peer or transit provider it reached, the required changes would be much smaller.
However in either case that would be really unfair to the sender of the packet, who has no way of knowing how many times an individual packet would be counted. It would also be rough on intermediate networks who may try to track usage and switch packets between multiple transit providers such as to minimize costs. They would only know that they sent one packet of some specific size to a given transit provider who may count it as many more packets.
The whole thing is very awkward. After all despite those issues, ISPs could benefit from the same number of users with the same style of usage resulting in many fewer total packets needing to be sent through the oversubscribed links from the core networks to last mile.
Now I understand that copyrights can be held pseudonymously; but how does this allow attribution as required by CC-BY-SA?
If a user posts something under a pseudonym, then attribution need only reference that pseudonym.
Is it enough for an author of a derivative work to reference the page on my site where the pseudonymous copyright holder grants the license?
Technically all a derivative work would need is enough information to clearly attribute the work. Even just the title of the work, name of your site, and the pseudonym the work was published under would qualify. (E.g. based on "the song" by sombody57 of example.com). It is debatable if a mere link to the source is sufficient, but the Wikimedia Foundation feels it is, so you would be in good company.
Does the end user need to be able to contact the copyright holder for additional rights?
No. There is no such requirement under copyright law. (You own copyright to work you publish completely anonymously (but good luck proving it is your work)).
The CC-license
Is this a road through a minefield, so that I should just bite the bullet and, like Wikipedia, make a foundation to hold and license the copyright for collaborative works?
But the Wikimedia foundation does not hold copyright to the work. The copyright is held by the pseudonymous contributors.
In order for the waves to be going through my head, I'd need to take off my tinfoil hat (it's more of a helmet really) first, you insensitive clod. ;-)
She wouldn't touch the thing again.
Also, speaking of ball lenses... you can use your head as a ball lens to extend the range of your car's wireless entry key fob. If you find yourself just out of range of your keys, simply put the transmitter about an inch behind your head, directly *opposite* the car. Your head is mostly transparent to the RF, but has a slightly different index of refraction from air/vaccum, thus acts as a lens. And since your head is approximately spherical, it works well enough to make a practical convergent lens.
Really?!! Deliberately focusing radio waves via your head!?! Are you nuts!!?
Honestly though I would have assumed that the effect described was due to one of the other many unusual characteristics of RF that I never really payed attention to. The head as a lens would never have occurred to me.
I'd dispute that ruby is dying. Ruby is a well designed language, and works just fine. It will remain around, although when it reaches steady-state it will probably not be a particularly popular language anymore.
What is dying is Rails. Rails has been one of the largest driving forces for Ruby. And make no mistake, it is an excellent web MVC framework. Consider that most web MVC frameworks that have come since rails have incorporated at least one component of Rails. For example Microsoft's ASP.NET MVC comes with a routes system inspired by Rails, and has a definite convention over configuration design.
Rails is dying in large part because the MVC frameworks of other languages are now comparably easy to use, meaning that the advantages of using Rails frequently do not overcome the disadvantage of learning a new language, namely ruby.
These both require you to enter a number and the remaining menus change depending on the number you have entered, so unfortunately the way their service works, there is no way to continue, since they cannot predict the rest of the menu. Most other companies do not require such a number so early in the process, so you can at least jump directly to that stage, and often can jump directly to a representative.
They need to match phases. That is a given.
What happens right now is that if the grid ran slightly fast for an hour, they then run the grid slightly slow for an hour so it averages to extremely close to 60.000Hz. (Yes, they try to average to more than 2 significant figures after the decimal!) The problem is that coordinating the grid to deliberately run at a different frequency for a while is a huge pain in the ass.
They are going to try out not making the deliberate corrections and see how much of a problem this really causes. If it does not cause too large a problem, (many household clocks already drift more than this will cause) it could save a lot of time and money.
By design arbitrary variations are supposed to work. After all Japan has 2 electric grids, one being 100V @ 50 Hz, and the other being 100V at @ 60 Hz. It is intended by design that US laptop power supplies work on both, since Japan uses the same socket design as the US.
Of course, some PSUs receive little or no testing except for 100-120V @ 60V and 220-240 V @ 50 Hz, so issues could occur. However, I have successfully run many electronics at ~120v @50Hz, by use of a stepdown transformer in Germany, and nothing ever gave me problems, although I did not test devices that used an LM8560, which would be problematic.
There are also quite a few old clocks out there that consist of simply an AC motor, relying on cycle frequency to remain reasonably accurate, with occasional manual correction.
We don't make many devices really reliant on the frequency anymore. All AC motors are reliant, but unless they are driving something timing dependent then the small variations we are discussing are not particularly problematic. For lightbulbs, and electric heaters, they really don't care, and could run just fine on 50Hz or 70Hz. Many electronics also don't care, since they convert to DC first.
There are some older devices still around that rely on the frequency like some old film projectors, but the small variances here are unlikely to cause notable issues.
Basically I think the main problems will be old clocks, and other devices that use incorporate a motor based clock, like traffic light controllers. I would be a bit concerned though about noise if the mains voltage happened to cross the modern TV refresh rate of 59.94Hz
Here is how education tends to work in the US. This is obviously a generalization, but It should give you a general idea.
1 Pre-primary education
Preschool (nursery school or prekindergarten) is technically optional program. It is most commonly one or two years. Part of the purpose is to get young children used to a classroom like setting, while not actually learning terribly much, but getting them accustomed to the process of learning, socialization, and other concepts.
2 Primary/Secondary Education
In this section I'm going to describe primary and secondary education in the united states. There are many variations, and the line between primary and secondary is not particularly strict.
Different school districts, or private school systems divide things differently. I describe one system below, but there are many, many varaiations. This image does a reasonably good job at showing several common divisions. I'm going to describe the path second from the left, as the breaks in it correspond reasonable well to shifts in
2.1 Elementary School
In the system I am describing Elementary School consists of Kindergarten and 1st through 5th grade.
Kindergarten generally the first compulsory year of schooling. It is not always full time. One common pattern is two days a week, plus one half-day. allowing for one teacher to have two distinct groups each week.
First grade is almost invariably full time, and things will remain this way through high school.
The primary focus of elementary school are the subjects of "reading", "writing", and "arithmetic". However, other subjects are present. There is often a physical education class ("gym"), and art and music classes are common. In the later grades science, history, or similar lessons occur. In my school, elementary students remained with the same teacher for all classes, with the exception of special classes like gym, art, and music, who had dedicated teachers, with each teacher's group having that that class at staggered dates and times, so that the specialty teachers taught groups of 30 or fewer at a time. Larger schools may do things differently.
2.2 Middle school
In my example here, middle school involves 6th through 8th grade.
In in my school, this was the first time that you would have distinct teachers for each subject. The schedule was a grid, and you would have the same teacher each 8:15-9:00, or 9:05-10:50, etc time slot each day of the week. A tiny number of classes where not every day, in which case there was a pair of a two-day a week and a 3 day a weak class that would alternate days for the same timeslot. The year was also dvided nto two semesters, and you would be taing different coursed each semester, and even if they were in the same subject you may well have had a different teacher.
In Middle School the subjects become more diverse, including science, and social studies (a mixture of history, geography, and government). Toward the end of middle school was the first time I was allowed to make any decisions about which classes I would take, although the choices were very limited.
2.3 High School
In this example, this encompases grades 9-12.
Classes were still scheduled in a grid, and there were two semesters pretty much just like like middle school. However, there was substantially more choice. While certain subjects were required certain years, the better students had the option of taking the honors or Advanced Placement courses, which are more difficult, but are expected by good colleges and universities.
The classes offered had a wider range. Foreign languages are often offered for the first time at this level, (although some large schools offer them in middle school). The classes are still limited. At many schools you will take only one year of physics and one year of chemistry, and only then if you are
Unfortunately, the state of electronic money in the US is rather sad.
First of all according to the survey by the Census Bureau 7.7% of US households do not have a bank account at all! Up to 25% of the population lives paycheck-to-paycheck, utilizing the services of Pawn Shops, non-bank check-cashing services, or payday loans (legal loan sharks).
Cash is accepted virtually everywhere. Paper Checks are also widely accepted, although are considered a bit risky by the merchants, more because of the likelihood of insufficient funds (and not being ale to track down the person if that happens) than fraud. If you do have insufficient funds, you will likely be hit by at least $100 in fees. ($25 from the merchant and $25 dollars from the bank for first presentation of the check, and both fees again when merchant
Credit Cards and Debt Cards are widely accepted, but not universally. If fraud occurs the merchant eats the loss, pretty much without exception. Merchants are also weary of people disputing the charges with their card company. If that occurs the credit card company tends to side with the consumer unless the merchant can show that the transaction was actually completed.
Online bill payment at the company's site is common for large companies, but smaller companies may not offer it, or may charge a fee to pay online. Except for the largest companies, if you pay online the payment is not counted as being payed when you finished entering your details, but only once the transaction is completed, so paying online at the due day may not qualify as paying on-time, (although oddly if you give them the same credit card information over the phone, they almost always count that as on-time.)
Wire transfer services are expensive. Fees of $20 or more to send a wire Transfer domestically are very common.
At my credit union, receiving a wire transfer is a $5 fee, and I belive similar fees are also common.
The wire transfer system thus is not often used. Instead the ACH system is used. Most but not all employers offer direct deposit services, which use ACH to electronically post money into your account. Banks almost never charge a fee for that, but that is pretty much the only case in which consumers receive money via ACH. The more common use is to electronically present paper checks, for online bill payment via a bank, or for direct debit (where you authorize a company to directly charge your bank account.) There are no fees for the customer for those.
Online Bill payment through a bank does exist. However it does not work well. Payment is electronic (via ACH) only if your bank and the company have worked together to set that up. If not, when you use online bill payment the bank (or the company they contracted to provide the bill payment service) physically prints a paper check and mails it.
Many but not all companies with regular recurring bills offer a direct debit service (via ACH, as mentioned above), and indeed it is possible to pay nearly all your bills that way, except for one-off bills and perhaps a small number of recurring bills where the company does not offer direct debit.
Having integration between the bank and the company, such that you can view your bill electronically via the bank, and then pay the actual bill (useful for variable bills) is possible, but many banks and companies don't offer this. Even if both the bank and the company offer that, it may still not work, since there is no standard mechanism, so unless your bank (or its contractor) have specifically worked with the company to set up this integration, it will not happen.
For person to person electronic transfer of money there are few choices other than services like PayPal, or very recently a few services (such as Square) have started allowed individuals to accept credit cards.
Otherwise the only options for person-to-person payments is checks, or cash.
When's the last time you heard of a CS student calling the help desk for anything that could possibly solved without help desk involvement?
I'm sure it happens during the first semester until the students in question drop out of the program.
But you have a very good point. Most Linux users are people who are quite well aware how worthless the help-desk is, and will avoid contacting them when possible. If there is a Linux-specific support resource (offered by the CS department or similar) then people might try using it. I never did because I knew the Linux specific resources were focused on the department maintained Linux boxes.
Active Directory is just an X.500 directory that offers access via the Lightweight Directory Access Protocol (LDAP), combined with Kerberos and some dns management.
It is extremely well documented how to set up a similar Directory on Linux via an "LDAP server" (technically a Directory server that supports LDAP, but nobody gets the terminology right.)
It is also well documented how to set up Linux machines for LDAP with Kerberos authentication. So if you want to you can literally just have the Linux systems authenticate against AD. Sure all Linux systems also have local users accounts, but so does every Windows system. It is also possible to set up a Linux system as a Domain Controller, although admittedly I've not yet seen a setup that could interact with Microsoft domain controllers as part as an AD forest.
My university did the same thing. It was a Cisco captive portal system that also reconfigured the routers so your system's MAC would automatically be placed on the chosen VLAN (but most switches and all APs only offered one VLAN choice). It worked in Lynx, and just about anything else. After doing that you needed to "reboot", or more accurately drop your DHCP lease and acquire a new one.
The did drop you immediately on a page for downloading and installing their "helpful" bundle of completely non-required crapware, but the only people tricked into installing it are the ones who would benefit from it anyway.
For wireless, we did transition to using a secured wireless network using WPA-enterprise with PEAP (authentication using your Directory username and password which was used for all services, and to log into any University maintained machines), but for being somewhat obscure, it was surprising well supported by various devices, (except game consoles, which are better off wired anyway).
Correct me if I'm wrong
This is the Internet. Someone will correct you even if you're right.
Correction: Oh. Wait.... Never mind.
His book on Dependency Injection is one of the few recent computer books I had to go through carefully, and with notepad and highlighter in hand
Is that a good thing? Personally, If I am going through a book closely with a notepad and highlighter, I am either:
Google's engine does not distinguish between the various versions of HTML. As long as Google successfully detects the page as html (and it is quite good at determining that), you can use any feature from any version and Google could not care.
For what it is worth, this markup is also valid HTML 4, but HTML 4 simply does does not define the meaning of the "me" or "author" values of the rel attribute, while HTML 5 does define the meaning (although I have not actually verified that).
Ahhh..... Oh my god! My eyes! You bastard. That kitten sleeping in a cereal bowl so greatly offends me.
Somebody stole the poor thing's soul by taking a photograph of it....
</humor> (This is SGML, with the start tag optional).
Sorry. I think there is no safe image anymore in Tennessee.