If we say salat 5 times regularly and spend the rest of time studying, is the time spend studying considered ibadah?

Question: Is there any Quranic verse or hadith according to which if we say our mandatory prayers (farz prayers) of 5 times regularly, (and do not say the "nafl" (which are not mandatory) prayers) and spend the rest of the time studying as a student and resting as required (for the well being of our body), is that time spent studying also considered ibadah (worship of Allah) by Allah?
Answer: Considering Ibadah (عبادة).It is better to understand its meaning first.Ibadah which we mean Worship to God has a root word in Arabic (عبد) which means a Slave or a Servant.Now a servant is bound to do what his Master says ,So ibadah does not only mean to pray 5 times or fasting but there are many ways to do it. What ever Allah Subhan O Taala has ordered us to do or not to do and then we are living in accordance to it then this is also a form of Ibadah.
Allah Subhan o Taala has said in Quran(24:37)
[Are] men whom neither commerce nor sale distracts from the remembrance of Allah and performance of prayer and giving of zakah. They fear a Day in which the hearts and eyes will [fearfully] turn about
About those people who are in commerce or sale or doing any bussiness but their hearts are not free from the remembarance of Allah All mighty so if they are earning Halal and with their hearts sticked to the remembrance of Allah then they are doing Ibadah ,By making beautiful and pure intentions to please Allah Swt in any case or in any ways it is also a form of Ibadah,and supplication is also Ibadah.the Prophet  Muhammad peace be upon him said: "The supplication is the essence of worship."(Tirmidhi)
If a person is studying with intention to seek knowledge beneficial to all or to earn halal and to spend money for Allah's cause too and  and heart is filled with remembrance of Allah Swt then its also a form of Ibadah.
Apart from Mandatory prayers (Fardh),There are also Sunnah Prayers ,Sunnat Mu'akkadah prayers that the Prophet Muhammad peace be upon him observed regularly and strongly encouraged his followers to do so and Sunnat Ghair-il-Mu'akkadah prayers that the Prophet Muhammad peace be upon him did not perform regularly.Sunnah leads to Jannah.Leaving Suunah on a regular basis is also considered bad.The one who neglects an act that is an obligatory Sunnah will be punished; the one who neglects a mustahabb Sunnah will not be punished.Sunnat Muakkadah should not be left without any solid excuse. Nafl prayers are optional Prayers with which one can attain more closeness to Allah Swt.With the management of time if one is praying nafl also it is much rewarding and getting closer to Allah Swt but it is optional.
Abu Qatada, a Companion of the Messenger of Allah (ﷺ), said:
I entered the mosque, when the Messenger of Allah (ﷺ) had been sitting among people, and I also sat down among them. Upon this the Messenger of Allah (ﷺ) said: What prevented you from offering two rak'ahs (of Nafl prayer) before sitting down? I said: Messenger of Allah, I saw you sitting and people sitting (around you and I, therefore, sat in your company). He (the Holy Prophet) then said: When anyone among you enters the mosque, he should not sit till he has observed two rak'ahs.(Sahih Muslim)
Answer: First of all the Niyya (intention or motive) is important as we know:

It is narrated on the authority of Amirul Mu'minin, Abu Hafs 'Umar bin
  al-Khattab ( may Allah be pleased with him) who said: I heard the
  Messenger of Allah (ﷺ) say: "Actions are (judged) by motives (niyyah),
  so each man will have what he intended. Thus, he whose migration
  (hijrah) was to Allah and His Messenger, his migration is to Allah and
  His Messenger; but he whose migration was for some worldly thing he
  might gain, or for a wife he might marry, his migration is to that for
  which he migrated." [Bukhari & Muslim]

so if you do some useless studies or study something which is not allowed or have the wrong intention all what you do will be in vain. As Allah said in Surat al-Furqan (25:23)

Then We shall turn . to what they had done and render it vain like scattered dust.

On the other Hand studying/learning/getting more knowledge is one of the best 'ibadat as you may find in Surat Taha (20:114) as a kind of dua'

..."O my Lord, give me more of knowledge."

There is also one Hadith that shows, if you only do what you have to do (mandatory worship) and do nothing bad you may go to Jannah (Paradise):

On the authority of Abu Abdullah Jabir bin Abdullah al-Ansaree (may
  Allah be pleased with him) that: A man questioned the Messenger of
  Allah (peace and blessings of Allah be upon him) and said, "Do you
  think that if I perform the obligatory prayers, fast in Ramadhan,
  treat as lawful that which is halal, and treat as forbidden that which
  is haram, and do not increase upon that [in voluntary good deeds],
  then I shall enter Paradise?" He (peace and blessings of Allah be upon
  him) replied, "Yes." [This is the part of the hadith quoted by Imam an-Nawawi see also Sahih Muslim]

And i guess this one fits what you where looking for:

It was narrated that Abu Dharr said: "The Messenger of Allah said to
  me: 'O Abu Dharr! For you to come out in the morning and learn one
  Verse from the Book of Allah is better for you than praying one
  hundred Rak'ah, and for you to come out and learn a matter of
  knowledge, whether it is acted upon or not, is better for you than
  praying one thousand Rak'ah.'" [Sunan Ibn Majah
  ]

And if you like to read it in Arabic there is this Fatwa saying "seeking knowledge is (much) better then all kinds of optional worship طلب العلم أفضل من جميع  نوافل العبادات ".
Therefore you should have as an intention to learn and study for Allah's sake or to become a positive/productive ... part to the Muslim community and work hard on it!


How do I make soft chapattis?

Question: I have been trying to make chapattis (an Indian flat unleavened bread, somewhat like a wheat tortilla), using the following recipe for the dough: 300ml water, 250g whole wheat flour, 250g white wheat flour, pinch of salt. The dough rolls out fine, but the cooked chapattis turn out rather hard and/or rubbery instead of nice and soft. Any ideas why, and what I can do to improve the result?
Comment: Perfect example of a "good" recipe question.  I can't answer this one myself, but I sincerely hope you get some good ones!
Comment: Here's Manjula's Roti recipe: http://www.manjulaskitchen.com/2007/03/21/roti-chapati-flat-indian-bread/
Answer: Yogurt and milk might work, but those ingredients are not in authentic chapati.  When I hear the words "hard" and "rubbery" in reference to pan-fried bread, I'm almost certain that the problem is that they are cooking for too long on too low of heat. Increase the heat on your pan (it should be very hot) and cook the chapati very briefly on each side. This will still give them a nicely browned exterior, without turning them into sheets of rubber.
Answer: Oh well, I make chapatis everyday, even when I bake a Pizza or a cake.
The dough for making chapatis and stuffed and plain parantha and even poori is same. Until and unless you are trying some thing fancy like bhature you just need water and wheat flour.
As I am used to kneading dough w/out any measurement I cant suggest you measurements. I knead the dough till the time its firm enough to stand in a round shape. More over I take a ball of dough and throw it on granite counter with some force it doesn't loose its shape.
Now the temperature of griddle matters a lot. I keep it on a medium heat for chapatis and high for paranthas.
Roll out a chapati and place it on preheated griddle. You may need some flour while rolling out the chapati. Leave it on griddle for 10-15 seconds. Turn the side and leave for another 15-20 seconds. Turn side third time and you should see the chapati puffing up with steam. With this dough you can make chapatis, plain paranthas, stuffed paranthas and poori.
On a very special occasion my Mom used to knead the dough with milk and or ghee, a kind of clarified butter. Dough kneaded using milk and ghee is normally used for purees.
Apart from all the technicalities you may have practice a while. It took me a month to roll out a perfect round fluffy and soft chapati. Best of luck :)
Answer: Besides the tips above, you have to fold the chapatis a couple of times and flatten it. Like this :

This creates layers. Use a bit of ghee/pure ghee while folding.
 If you do this once or twice it and if the chapati is thin enough (2mm-3mm) it puffs up into a fluffy ball when you put it on the flame/pan.
Comment: That will NOT result in "Chapatis". It will result in "Parathas". Chapatis are NOT supposed to contain oil in layers.
Answer: One trick is to add a small amount of oil while kneading the dough. It makes the chapattis nice and soft.
Also, the more you knead the dough, the better the chapattis.
Answer: I don't know that unleavened bread is ever going to be super-soft, but are you simply cooking in a griddle as in the recipe Pointy linked? You can get them to really puff up if you expose them to direct heat. I'd try using two burners, one with a pan as before and one simply bare and over medium-high heat (experiment on this). After you brown both sides, use tongs to put the chapati directly on the burner -- it will inflate almost instantly, after which you can remove it from the fire. I've gotten quite good texture with this method.
Answer:
Add good amount of milk or fresh yoghurt  in place of
  water. It makes chapati soft

Please see About.com Indian Food Section @
Making Soft Chapatis (Indian flatbread)
Comment: Well, milk is several things:  high in protein and fat, and more basic (pH) than water.  I don't know which, but there are plenty of reasons it could result in a softer dough.
Comment: This should be the official cooking website for geeks :D
Comment: And what would be the scientific basis for this technique (assuming it works, which I am skeptical of)?
Comment: I have tried it it works. Don't know scientific reasons!
Comment: Well I'm not wrong. Please see this link guys
http://indianfood.about.com/od/breadrecipes/ig/How-to-Make-Chapatis/
Answer: I've been taught to roll them out three times. Roll out, spread with vegetable oil, fold into a bun, let rest while you do the same to the rest, then roll out again, spread with oil, fold back into bun, let rest. The last time you roll it out it is ready. Put in a medium-hot pan with oil and never let it sit. Keep spinning it with your fingers. Turn over and remove from the fire.
Answer: Adding some oil while preparing dough. And leave it for half an hour.
To get a softer and tastier chappathi.
Answer: Adding to the other answers, leave it for an hour or so, wrapped in a moist cloth. This would enhance the gluten formation.
Answer: Its all about how you add/maintain/remove moisture during the whole process of making a chapati.
I am not sure how anyone can measure the amount of water for the dough.
Use a little oil while kneading the dough, and add as much water as possible without losing the consistency you want.
Also, leave the freshly kneaded dough to settle for sometime (~15mins) by sprinkling some water all over the dough and cover it. The kneaded dough will absorb much more water during this time.
Once you have the rolled chapati off the tava, place it in a covered container/box.
Answer: I see there are several advices for preparing dough and rolling Roti posted on this site but I think an important trick while heating or cooking it is missing. So, I am adding an answer regarding heating/cooking it properly to avoid Roti becoming hard from my own experience for a week.
Note that this is not about making soft Bhakhri but it's for Roti.
Make sure that dough is soft. (Add little more water and after preparing, leave it for 3 to 5 minutes if dough is not soft enough). Also make sure that Rolled Roti is thin enough.
Heating or Cooking tip:
The key is: Roti becomes soft if it inflates completely.

If you have just ignited gas stove, give some time to heatup tava. (Note that Metal Tava is suitable for Roti whereas Clay Tava is suitable for Bhakhari)
Set the flow of gas fire to minimum before throwing rolled Roti on it.
When rolled Roti is ready, drag it form rolling board/disk and drop on tava flipping it. (That means the face which is in front of you after rolling should be flipped and thrown on to the tava and now after throwing on Tava, opposite side should be in front of you)
Wait only for 15 seconds and flip  the side of Roti on Tava. (You'll very small inflated grains on cooked side)
After flipping Roti, make the new side of Roti stayed and cooked in Tava for about 45 seconds. (Do not flip the side). Then increase the fire to maximum limit.
Now, take Roti away from Tava and take Tava out of burner. Throw Roti directly on fire flipping it. That means you will flip the side before putting your Roti on fire.
After throwing Roti directly on fire, you should see Roti starts inflating and it should inflated completely within 5 seconds. Now (even if Roti doesn't inflate in your case) immediately flip the side again to cook the opposite side just for another 2 to 3 seconds and take Roti out of fire. Done!
Here the timing of 5 seconds when Roti flattens completely is very important since it makes Roti smooth. If you make delay then it will make roti hard.

I will try to capture video next time I prepare Roti and will attach pictures or gif.

How do I make soft chapattis?


How to reduce amount of language proofreading of my revised paper?

Question: I'm a non-native author and I have a revised paper that has been edited for good English before the first review. Now I made major changes, but still a large part of my essay remained as before. What is the best way to get my revised paper edited for English and flow without having to get charged for the whole (relatively long) paper again? Was someone in a similar situation?
Comment: Is it possible to get the same proofreader as for the first round?
Comment: You probably don't even need to send the paper to a professional proof-reading service again.
Answer: I am a native English speaker, this is based off my experiences proofreading papers for others in my lab who are not native speakers.
Changing even a small section of a paper can have repercussions throughout the rest of the paper in unexpected ways. Also, as important as it is that the English in the changed sections is correct it is also important that those changed sections flow appropriately with the rest of the paper.
To help with both of these issues it is best to have the entire paper proofread again. Even as a native-English speaker, I have others proofread my paper after revisions because of the above issues. It can be helpful to somehow mark the changed sections and request that the proofreader be aware that those areas were changed.
Answer: ESL here and this is how I usually deal with similar situations.
Go back to the same editor for a reduced rate
It will not hurt to ask. Highlight the parts that you changed, and send over with an inquiry if he/she is willing to look at it again, with heavier grammatical checks in the highlighted sections and then overall flow, at a reduced rate.
Form a weekly writing group
This is a pretty stressful method but it's one of the best decisions I have made. Form a writing group with 2-3 colleagues. We model after this article. All my partners are native speakers, and I often get English-related advices and even edits from them.
You may feel inadequate (I did at the beginning), but don't. Being an ESL has its appeal. If I can understand their work, it's very likely that native audience will also understand their work. In a way, I am their coal mine canary.
Answer: I agree with Nahkki that changing parts of the paper influences the remaining paper as well. The reason is that when reading / reviewing a paper you can easily spot different writing styles (especially if you have parts coming from native and non-native speakers). Having different styles within a single paper distorts reading and makes a bad impression. In your case, I would suggest to let proof read the whole paper again.
However, in general, I suggest to write papers with co-authors who are either native speakers or know how to write. Only this way, you can actually learn how to write, which is an important skill often underrated. I cannot see how you can learn writing scientific articles without having the opportunity to talk and discuss why some sentences or paragraphs are written in "native" way. So, my advise is to get people working with you and learn from them.


seeking feedback for course from learners

Question: Our users view courses by launching them from our Learning Management System (LMS). It opens in a new window. We call it course player.
The window has main sections as shown:

The course tree is to navigate through the course. And the course display area is the content.
The course duration usually ranges 2 hours to 24 hours.
The users are mainly engineers who can be designers, reviewers, program managers. Also, engineering students, who just joined the organization or under some academic program get access to our content within the university.
Problem
We do not have any mechanism to capture the feedback from the users while they are taking the course or when they are done with the course. To capture the feedback in a subtle way is what I am trying to work.
My objective is

When and how often to ask for feedback during the course. With this, I mean what is the most appropriate time to ask for feedback. Certainly, at the end is an ideal opportunity to throw feedback question. But in our scenario, sometimes users take the course for a specific portion of the course and close the player.

Proposal
My Idea is shown below, with red circles as triggers causing the pop-up of feedback panel. That is when the user

has made a progress of x% of course (is it a good idea?)
closes the player (Wouldn't it be intimidating next time the user closes the player?)
clicks the button provided just below tree (it's the most direct and loud way of asking feedback. I am not happy with this, but would like to see your opinion)

Consider an example, the course is 4 hours, and the user has spent already 1 hour browsing the course. And has made a progress of 30% completion. Is it time to ask for feedback?

How many questions to ask the users. My proposal is to keep the feedback as Subjective and try to assess their emotional level in terms of asking about the experience by rating, as shown below. I am keeping it very minimalistic coz number of questions may annoy users. A better way would be to collect detailed feedback via a survey asking multiple questions.

Any other question that can be useful.
Comment: Is the question not clear enough?
Answer: My preference would be to let the user drive it. Put a link in an appropriate place called "How are you getting on?" Which launches your feedback module, this way users do not feel harassed in the same we try an gather feedback from website visitors.
Answer: i think you should ask for feedback on completion of nth sub segments like after completing 5 sessions. this will give user a small break from the activity and will not bother them in their learning process.
and according to my suggestion, you should ask one question each time - can go for maximum 2 questions.
Comment: Ok, I think its good idea, after 5 sessions, triggering a feedback panel makes sense.


What is the purpose of the block time/ difficulty in mining?

Question: I understand the point of mining is to decentralize away from allowing one entity to add to the ledger. What I don't understand is why it's necessary for miners to compete over who gets to add to the ledger. Why can't a random miner just be selected instantly and therefore bypass any block time? It would be just as random. What am I missing here?
Answer:
Why can't a random miner just be selected instantly and therefore bypass any block time?

The problem is: how do you select a miner in a truly random way? If the mining process was just a simple random election, who gets to enter in that lottery? How would you stop someone from just running a million fake nodes, in order to increase their chance of being selected?
These are the sort of problems that are solved by Bitcoin's proof-of-work mining. In a proof-of-work scheme, a miner must expend computational resources in order to 'enter the lottery', there are no 'free tickets', if you will.
Proof-of-work also provides a mechanism of security: in order to change the blockchain history, an attacker would need to redo all of the work from the point of change onwards. To do so, they would need more computational power than the rest of the network (51% or more). A simple 'random election' would not include this 'real world resource expenditure', or the type of security it provides.
Comment: A simple random number generator can make it truly random. And there are already a bunch of people running tons of nodes to increase their chances of being selected. Sure they're limited to how many due to computing power, but it doesn't matter because everyone is limited. If there was no limit, then everyone has fair chance of creating a million nodes, so it's still the same odds.
Comment: After researching more last night, I believe the reason for block time is so that all miners receive the previous verified block before the next block comes in. If it was instant, people might be mining blocks without the most recent ledger and this could result in dead blocks. There needs to be time between blocks so all miner's ledgers are up to date
Comment: But as far as proof-of-work goes, thats definitely a point I didn't take into consideration. That's a big aspect too! It definitely needs to be really difficult to re-mine blocks.
Comment: @dcporter7 look up a 'Sybil attack', if mining were a random-number-generator-election, then a Sybil attack would be possible. Proof-of-work sort of creates a 'Sybil-proof' system. When I mentioned 'running a million fake nodes', this is the issue I was referencing. Running a POW miner requires resource expenditure in a way that defeats Sybil attacks, which is important in creating a fair mining protocol.


Relocated to USA. How to get credit card without existing credit history / score?

Question: I recently relocated to USA and have no Credit Score.
Is Secure Credit Card is the only option for me to start building my credit score?
Also please recommend which other credit cards are available for people like me to build credit score
Comment: Related: http://money.stackexchange.com/questions/1190/i-just-moved-to-the-united-states-what-should-i-do-to-develop-a-good-credit-rat
Answer:
If you have an AMEX from another country, you can get an AMEX in the US.  American Express has a separate system that is not as strongly country-dependent as, say, VISA and MasterCard.
Equifax operates in both Canada and the United States, so if you're from Canada you can ask the bank to get your credit score through Equifax.  Not a lot of people know about this but it can be done, so be persistent if they say it can't.  This may be possible with other credit reporting agencies as well.
If you have proof of income and some cash, most banks will let you get a card.  They let teenagers with no credit get a card!
Answer: Secured credit cards are usually not very cost effective for building credit.
Find a local credit union, of medium to large size. A credit union is like a bank, but operates under slightly different rules, and is non-profit. Locally based credit unions often have more flexibility when it comes to offering you loans and credit.
If you just need a card that you can use for daily and online purchases, get a debit card from your credit union. Most CU's will offer a small personal line of credit to protect you from overdraft and overdraft fees when using the debit card. This will not build much credit, but it can help protect you from accidents when using the debit card.
To have a good credit score, you need a long history of paying loans on-time.
A great way to build credit long term is through cash-secured loans from your local credit union. You essentially take out a loan against your own money. You can typically set up automatic payments, so you never miss a payment deadline. The loan term (length of time to pay it off) should be fairly long, so that more history is built.
One of the best ways to build credit is getting a mortgage & paying it on-time, every month.
With little credit history, you won't get a good interest rate on that mortgage, at first. Once you have built a better score, refinance the mortgage for a better rate, better terms, etc.
Once again: go to a local credit union, they can help you navigate most of this.
Answer: Most banks will give you a credit card if you open an account with sufficient funds. It especially helps if you have have a job that direct deposits into your account.
Answer: I think your options are to get a secured card like you said or possibly get a credit card from a local bank that you can build a relationship with.  Sometimes local banks are more willing to work with you as a person instead of the National Banks that look at you like an account number.
Answer: If you have had an American Express card abroad, you can try and get a US Amex on the strength of it, otherwise you're looking at a secured card if you really want a credit card. That's basically what I did. Of course the downside with Amex is that it's not accepted everywhere.
I'm not a big fan of people co-signing for credit cards (or loans for that matter). I'd also talk to the local credit union(s) and see what they have available.
Answer: If the country you came from has an HSBC, you can ask HSBC to use your credit rating from that country to give you an  HSBC Mastercard in the US.
This might only be a service for HSBC Premier but it's worth checking.  I moved from UK to US and got $10,000 credit limit immediately based on my UK credit rating.
Answer: My local bank (on which I had had my pay direct-deposited for a while when I applied) rejected me for a credit card, but a major national institution accepted me after an online application. I had expected the opposite, but this is what happened.
I got a tiny amount of credit at first and had to be careful for a while not to go over the limit, but I immediately set up "automatic full payment" from my checking account and started getting automatic increases regularly. It only takes a year or so to have a very good score if you use your card and always pay it in full.
This was before the new "consumer protection" laws when it was easier to get credit, so you might have to get a secured card. It might be a $25 investment or so, but if you ever get a real loan (like a mortgage or even for a car) it's more than worth it. Even just the cashback you'll get once you upgrade to a real card will pay back those $25 fast.
Also, it might depend on how it's set up, but being an authorised user on someone else's account might not contribute to your history.
Answer: If you have family or friends in the US, you can ask them to add you as an additional card holder on their credit card account. I have done it for a friend, and he was able to obtain his own credit card after a year on my card. Otherwise, look for a credit union that will be a bit more flexible than a bank.


Significance of Nissl bodies

Question: What is the significance of Nissl bodies? How are Nissl bodies different from any other RER seen in any other cell of the body?
Comment: Hi there, I think this is a homework question. Please add a refference and try to solve it on you own first. Otherwise you may not get answer.
Comment: https://en.wikipedia.org/wiki/Nissl_body this might be a good start.
Answer: I am going to try answer this question.
The origine of this name came from article writen by Franz Niessl (18660-1919) and published in 1894. HE found this substance after he visualized it by nissl stainning method invented by him.
This basophilic substance was just only find in dendrites of neurons, not axones. It is composed by RNA polyribosomes.
Basicly i am tring to tell you that Niessle body is just older name from old ages of histology.
Niessel body is not diffrent with others rought endoplasmatic reticulum(RER). It same pourpose as normal RER.

Significance of Nissl bodies


Application used MapKit crash on iOS6

Question: I have a strange problem with google map in my application dedicated for iPad (with iOS6). I've made a horizontal scroll view, filled with two views. One is a detail information view (some text, nothing special), and the second view is a view controller with google map. This is the universal scheme in my application (scrollview build from two views) for a few different purposes. The problem occurs when I've started to test the app on a real iPad with iOS6. The application crash when it should view a scroll view. But not immediatly. At start, scroll view is viewed properly. Then I want to build a new scroll view with new datas. It also goes fine, and scroll view is viewed properly. After a few operation like that I've start to receiveing more and more error logs like this:
failed to make complete framebuffer object 8cdd
After a few runs of scrollView, the application crash without any additional errors. Code editor points on main.m file, and the following line:
int retVal = UIApplicationMain(argc, argv, nil, nil);
Please direct me to find what am I doing wrong. Where is the viewDidLoad method from my view controller responsible for viewing the google map:
-(void)viewDidLoad {
mapView.mapType = MKMapTypeSatellite;
mapView.showsUserLocation = YES;

/* ANNOTATION (pin) */

CLLocationCoordinate2D annotationCoord;

annotationCoord.latitude = [self.restaurant.latitude doubleValue];
annotationCoord.longitude = [self.restaurant.longitude doubleValue];

// a pin with the info.

MKPointAnnotation *annotationPoint = [[MKPointAnnotation alloc] init];

annotationPoint.coordinate = annotationCoord;
annotationPoint.title = self.restaurant.name;

// add annotation to the map

    [mapView performSelectorOnMainThread:@selector(addAnnotation:)
                                  withObject:annotationPoint
                                  waitUntilDone:YES];

[annotationPoint release];

MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance (annotationCoord, 500, 500);
[self.mapView setRegion:region animated:YES];

[super viewDidLoad];
}

and no mater how I push the view controller with google map to the view. It always crash my app :(. I`ve tried like this:
[scrollView addSubview:self.googleMapViewController.view];

or that:
[[self navigationController] pushViewController:self.googleMapViewController animated:YES];

When I run the application on simulator, there`s everything all right. I'm using XCode 4.5.1.
Answer: I had the same problem in one of my projects. It was caused by a memory leak. Map views consume alot of memory if you don't delete them. It doesn't appear on simulator because a computer can use much more memory.
Just make sure to get rid of the map views when you no longer need them.
I also recommend running the app with Instruments (Leaks) - it is an extremely useful tool in such cases.

Application used MapKit crash on iOS6


What could cause a tubs drain to gurgle when the toilet is flushed?

Question: One day after I used a bacterial enzyme degreaser/ septic treatment to clear slow draining bathtub drains I can hear gurgling in my master bath tub drain when someone flushes the toilet in the other second floor bathroom.  This morning the downstairs toilet was blowing bubbles when flushed.  I have used this product before without this happening.
Comment: Possible [duplicate](http://diy.stackexchange.com/questions/29276/what-causes-tub-drain-to-gurgle-when-toilet-flushed)
Comment: Do you have a septic or sewer system?
Answer: The gurgling typically happens with a vent pipe blockage. Without a source of air to follow behind the rushing water, a vacuum is created that will result in gurgling. You may be seeing that now if the vent pipe is partially blocked and there isn't enough air to support the faster flow. It may be necessary to snake out the vent pipe from the roof and/or run some water to clear out any debris that has collected inside.
Bubbles in a toilet below the water source (upstairs toilet) may be a sign of a blockage further down the drain. If that's the case, you may need your main drain line snaked and the plumber may need to run a scope down the line to find the location and cause of the blockage. It's possible that the enzyme pushed a clog further down the line, or the slow drains may indicate your septic system has started to backup into the house and needs to be serviced.
Answer: BMitch's answer is more likely to be your problem but ...
One other possibility: the trap is dry due to lack of use.  It doesn't sound like your situation but if you have a tub, as an example, that isn't used often, the trap can dry out.  Once it dries out, you'll hear a lot more noise from the plumbing. Simply put a quart of water down any infrequently used drains once a month to prevent this noise and to prevent sewer gas from entering through the dry trap.


What are the rules in the UK about attaching a GoPro camera to the outside of an aircraft?

Question: Is it fully legal to have a GoPro attached to the outside of the aircraft during flight, in the UK? I've heard mixed answers, but I don't want to try it until I've got confirmation.
Comment: For those voting to close as duplicate, please note that the other question asks about FAA regulation. This question is specific to the UK where the UK-CAA is the regulating authority. So this is in fact a different question.
Comment: Great question. I've wondered about this for a while, but @bjb568's referenced answer is a complete answer to this question.
Comment: The discussion is the same in Germany. One party says that attaching a camera to your aircraft is an alteration which render's the aircraft without certification. Another party says it's fine, because it's not permanent. You will however have another issue, which is: What happens when the camera detaches and damages property or pedestrians on the ground? Your insurance will most likely not cover this....
Comment: Related: http://aviation.stackexchange.com/questions/96/can-i-attach-a-camera-to-the-outside-of-my-aircraft
Comment: On its way to damaging people and property on the ground, a detaching camera could also wreak havoc on the aircraft itself.
Answer: Flyer magazine had an article on this recently. I've not been able to find the full article on their website, but I have found this which at least partially answers your question.
https://www.flyer.co.uk/gopro-camera-mounts-to-be-approved-by-engineer/
From the article, which was published in Feb 2016:

Mounting a camera is a modification, and requires either inspection from a Part66 licensed aircraft engineer, or via the CAA as a minor modification.
To approve any installation the engineer will need to complete a maintenance release checklist and complete the aircraft logbook entry.
If your aircraft is overseen by the British Microlight Aircraft Association or Light Aircraft Association, then their restrictions apply (but it doesn't say what those are).

It also references CAP1369, which is the CAA document covering mounted cameras. I'm including a link to that here.
CAA CAP1369
Comment: welcome to aviation.se Please do not post only a link, the page could disappear any time. Instead, write in your answer the part that is relevant to the question.
Answer: The Certificate of Airworthiness may be invalidated with an external attachment to the aircraft.  The aircraft operator will need to inquire to the CAA what applies for the type in question.  This is the operators best course of action to get an answer on airworthiness questions.
However it may just require pilot approval, but it depends, there are however precedence in photography fields already pertaining to external fasteners and equipment. But contacting the CAA is the best way to clear this up.


Changing behaviour of .NET 3.5 bootstrapper generated by WIX

Question: I've got following problem:
I have built an installer with WIX. This installer contains a bootstrapper for .NET framework 3.5. First time installing the bootstrapper works like a charm. .NET framework 3.5 is installed. But for example after uninstalling and reinstalling the bootstrapper doesn't recognize that .NET framework 3.5 is already installed.
I found out following reason:
According to the bootstrapper log it checks this registry value:

Reading value 'Install' of registry key 'HKLM\Software\Microsoft\NET
  Framework Setup\NDP \v3.5\1033' Unable to read registry value

It searches for a localized version of the .NET framework (1033=German)
In my case I only have the English version of the framework installed (1031=English)
So I've only got 1031 as a subkey.
So my question is if it is possible to change the check from

'HKLM\Software\Microsoft\NET Framework Setup\NDP\v3.5\1033'
  to
  'HKLM\Software\Microsoft\NET Framework Setup\NDP\v3.5\'

There is also a value named 'installed' and for the bootstrapper it doesn't matter which language for the framework is installed.
Thanks in advance for your help
Comment: How was the bootstrapper created?
Answer: If you are using burn as a boot-strapper you should use the DetectCondition attribute on the ExePackage element which will not run the .net framework installer if it detects is already installed.


How can we purify our soul, and why is it important?

Question: How can we purify our soul? Why is it important in Islam?
Answer: The subject or theme of the Quran is "Man". God has  described all the prerequisites to become successful in both the worlds. That's the reason, God has given man the consciousness and the understanding of right and wrong or good and bad, that has been built in our emotion or psyche that distinguishes human beings from animals. But we need to enhance this attribute constantly then only we can retain it otherwise we may lose this quality and will become even inferior to animals whereas we were supposed to be the noblest of civilised beings.

"We have certainly created man in the best of stature;
  Then We return him to the lowest of the low, "(Quran 95 :3/4)

Purification of the soul is called Tazkiya Nafs in arabic which is not one time job ..we have to practice and apply it constantly. We need to understand what is Purification of the Soul and why its so important that Prophet pbub prime responsibility to purify the soul before teaching them the command of the Quran.Purification of the soul is a prerequisite for closeness to God. Indeed, the whole point of morality and spirituality is to purify one's soul.

"Indeed he succeeds who purifies his ownself (i.e. obeys and performs all that Allah ordered, by following the true Faith of Islamic Monotheism and by doing righteous good deeds)".
" And indeed he fails who corrupts his ownself (i.e. disobeys what Allah has ordered by rejecting the true Faith of Islamic Monotheism or by following polytheism, etc. or by doing every kind of evil wicked deeds)".  [ Quran 91 : 9/10]

So in chapter Shams, God swear by His creation eleven times, after so much emphasis, God declares that the person who purifies his soul will be successful, and whoever pollutes and corrupts his soul will fail. On the Day of Judgment, there will be two groups of people: those who are prosperous and happy because they purified their soul, and those who are in an unfortunate position because they were careless and negligent of their soul.. Thats the reason purifyingthe soul is the important task in islam.
Answer: Purifying our soul (Ruh in Arabic) is the most important thing for a Muslim. Without a pure heart, no one can enter paradise.
Allah says in Quran 26: 88-89
<code>The Day [Judgement Day] when neither wealth nor children will benefit [anyone].
But only one who comes to Allah with a sound [pure] heart.
</code>
Quran and Hadiths command us to clean our hearts from ill-feelings, ill-thoughts and from diseases like arrogance, envy, hatred etc.


Japan public transport directions

Question: Google Maps seems not complete enough for finding transit directions in Japan. Any better or official website or app for this?
Comment: Any limits to Language (English / Japanese) or to Phone (iPhone / Android) / PC?
Comment: I was looking for an English solution. But your answer below cover many options. Great answer!
Comment: The biggest problem you will have is an internet connection. Assuming you don't have wireless internet and as long as you have done your searches before you leave the internet at the hotel / café / airport, you will be fine. Otherwise, almost all apps require an internet connection. Also as @fkraiem mentioned, HyperDia (and Google Maps for the most part) will not be very up to date on service disruptions or localised temporary schedule changes (for things like holidays and special events).
Answer: HyperDia is an alternative to Google Maps for planning transit journeys in Japan.
From Wikivoyage:

For sorting through transport schedules and fares, Hitachi's Hyperdia is an invaluable companion; it computes to-the-minute directions including connecting trains, as well as buses and planes

From a happy user on reddit:

The best Hyperdia routes never show on Google Maps
Over and over, I'm looking for routes from the place I'm going to be in Japan to nearby destinations, and Google Maps always routes a big U-shape out and back in using different trains, but Hyperdia gives a direct route. Does anybody else notice this? Maybe it's just the local trains around this area that confuse Google. The train lines and stations are all on Google Maps, it just never seems to pick the most direct route as any of the choices listed.
Comment: I also use Hyperdia, but one must be aware that it is not perfect. The only buses it includes are buses to/from airports, and even for those it explicitly says it is not reliable. Local and intercity buses are not included at all. Further, one must pay attention to the "validity limit" for timetables, which is displayed at the bottom of the search results page. Finally, be aware that Hyperdia typically does not know about temporary timetable changes, which do occur every now and then.
Answer: Jorudan is a popular site in Japan, which also has an English interface.
Train, highway bus, and plane info is available.
Answer: There are numerous options available for transit directions in Japan however how many of them you can use will be limited by your language ability and your choice of device.
Mainstream Apps
Yahoo! Travel (Site - Japanese) iPhone [J], Android [J]
Internet connection required.
The site and apps themselves are all in Japanese however input can be made in English (your results will be displayed in Japanese). Timetable searching. After searching, 20 of your most recent search results are available offline (requires reconnection to the internet for a new search).
NAVITIME (Site - Japanese) iPhone [E, J], Android [E, J]
Internet connection required.
The site is in Japanese however the apps are available in either Japanese or English. Currently (2016 April) heavily promoted in Japan. Timetable searching and (with the paid service) can reroute you in the case of a service disruption.
乗換案内 (Site - Japanese, English) iPhone [J], Android [J]
Internet connection required.
As mentioned by @Kent, there is 乗換案内 by Jorudan. These is also an English mobile website if you have internet access and a Japanese mobile. Timetable searching.
駅すぱあと (Site - Japanese) iPhone [J], Android [J], PC[J]
Internet connection required for mobile apps. Desktop App requires internet access for timetable searches.
The site and apps are in Japanese. Instead of an online app, has a desktop app instead. This is by far the most comprehensive of the apps mentioned however the UI can be a bit difficult to use initially. Provides maps of lines of all rail providers across Japan as well as timetable searching.
Hyperdia (Site - Japanese, English) iPhone [E, J], Android [E, J]
Internet connection required.
Produced by Hitachi Systems. Both websites offer free searches however both the iPhone and Android app require a paid subsciption. The Android app costs US$2.99/Month or US$25.99/Year for both English/Japanese access. The iPhone app costs $1.99/Month for Japanese only, US$2.99/Month for English/Japanese, $16.99/Year for Japanese only and $25.99 /Year for English/Japanese. The iPhone app can be operated by voice. Both apps can search for Japan Rail pass usage areas / timetables. Timetable searching.
Google Maps (Site - Japanese, English) iPhone [E, J], Android [E, J]
Internet connection required.
For completeness sake I will include this one. Offers both English and Japanese searching directly as well as a map of the area (it is a map app after all). Doesn't normally show service disruptions in a timely manner. Some searches may give abstract results especially when searching in English (for example searching for a somewhat rare place name may give results of stores in otherwise unrelated parts of Japan (and sometimes the world)).

Special Mention
駅.Locky (Site - Japanese) iPhone [J], Android [J]
Internet connection required for updates and initial installation only.
駅.Locky was designed and built by graduate students from Nagoya University. It is a crowd-sourced rail time-keeping app which whilst may not be able to tell you directions, it will be able to tell you the time (to the second) of the next train (in fact all trains throughout the day for the lines you have downloaded). The app only has a Japanese version.

Notes
All apps mentioned have at least a free version or trial although many have additional services for a fee. Also that all Mainstream Apps will feature (usually toggleable) Train, Bus, Shinkansen, Plane and Ferry services when you perform a search. There are many more services than the ones mentioned here.
Comment: A great answer!
Comment: I would also suggest Japan Direct (https://itunes.apple.com/app/id1383391252?ls=1&mt=8) available in English and French for iOS, fully free.
Answer: I've found a combination of Hyperdia and Google maps to be the best bet. Hyperdia tells you what route is best a lot of the time, but google maps suggests better stations and, I found, gives excellent route direction. It helped a lot when I was lost in the Nagoya subway system.

Japan public transport directions


Oyster card—London only?

Question: I vaguely remember using an "Oyster card" somewhere other than London.  But perhaps I am misremembering.  Is there another place that uses that term for transit?
Answer: A Google search for "Oyster Card" excluding "London" suggests there is no such place.
What you remember is possibly Hong Kong's Octopus card, whose success later inspired the Oyster card.
Comment: Or the Dutch OV kaart, (OV pass) which is a later version and for all public transport in the country.
Comment: Damn. What about vegetarian cards, then?
Comment: Well, it wasn't the first time I was in London.  So it was probably London.  Last time I was in Hong Kong was in the 1970s.  I don't think they were using RFID then.

Oyster card—London only?


How exactly did Obito escape from Itachi's Amaterasu?

Question: Itachi attacked Obito with Amaterasu through Sasuke's eyes, when Sasuke saw Obito's Sharingan. As soon as Obito was engulfed by the flames, he went into the dark region of the room and got rid of the lethal flame. How did he do it? Did he achieve that with Kamui?
Comment: I think its not revealed yet! :S
Comment: Is it possible that the amaterasu never actually touched Obito, since he can move parts of his body into dark space? Maybe he only wanted to make Itachi believe that the amaterasu hit him?
Answer: I've been thinking about this question, and I've found a theory, which would explain a few things:
I'm almost 100% sure that the Amaterasu had hit Obito, as in the anime we can hear the damage being received. As from that moment, we can't talk about the Transportation Technique, because the Amaterasu lasts until his target is completely gone.
So that would reach the 5 minute limit and Obito would have been dead, just as it would've been the same result in the fight with Konan: those paper bombs kept coming, and they would've reach the 5 minutes limit, IF, and here it comes my theory. Obito escaped with the same technique both times, the Izanagi.
Since he had a lot of Sharingan eyes in reserve, he could have easily replaced the eye he had just used, just as he did after fighting Konan. AND he could have implied this, by the lines (if I recall well), "Even Itachi didn't know everything about me". That he could use Izanagi, or that he has those Sharingan reserves (since Itachi never knew about the eyes collected by Tobi, or Tobi's expertise in using this rare and forbidden jutsu).
Comment: good theory though!!!!!! but i can think of another theory,for instance,he made zetsu's clone to mimic like him(Tobi) and made him interrogate with Sasuke during it's first face to face conversation.We know that Tobi is a cautious guy(recalling his fight against Minato) and he thinks twice before taking any step....... anyway good theory and good effort......unfortunately we dont have any concrete proof though
Comment: yeah,this one is interesting too,but I couldn't believe, that even Obito would be able to mimic his sharingan into a Zetsu, because Itachi's Amaterasu reacted with Obito's sharingan, that would mean,that Obito transplanted his eye to Zetsu,si I can't imagine someone being able to "replicate" a sharingan in a host body:-??...yet,is interesting...It's kinda we're thinking the same way:)...you would be my "naruto soul-mate"? xD
Comment: isn't shinra tensei able to deflect the amaterasu fire. don't rem if obito had rinnegan or not but if he did then he must have used that instead.
Comment: @Rinneg4n i beleive what i meant was that since Zetsu can transform anything by touching a person,he converted himself into Tobi,and then he apprached in front of Sasuke. Tobi needn't have to transplant any sharingan or anything on Tobi's eyes.Recall the fight between Kisame and Bee.Zetsu came and transformed his body completely just by touching Kisame.
Comment: @Rikudu Sennin I think you can accept my asnwer,if you eould like
Answer: At that time, Obito/Tobi doesn't have Rinnegan. The Rinnegan was in Nagato's possession. At that time the only Sharingan that had evolved into the Rinnegan was that of Uchiha Madara. Obito's was just a Mangekyou Sharingan. Therefore it definitely was not Shinra Tensei.
A possible explanation to how he get rid of the Amaterasu is that he used Izanagi using one of the Sharingans he collected. But it can't be said for 100% as it was never revealed in manga nor anime.
Since the Amaterasu hit him on his whole bod,
he surely didn't do the same thing he did when he fought Danzo's bodyguard Fuu and Torune (pulling off his arm that is). Therefore I can say for 95% that it was Izanagi.
Answer: he used Kamui. the third databook brought up the question of how he survived and talked about his ability to slip through things
Comment: This looks like the real answer, but it'd be better if you could also [edit] and mention the full title of the databook and quote some references related to this? Thanks!
Answer: I don't think zetsu had anything to do with it. And personally, I don't think he used the izanagi either. I think he used the same thing he uses to make things pass through him to escape it. Yes, the Amaterasu flames don't burn out until their target it burnt to a crisp, but think about it. Fire is energy, no matter what  how it is formed, and chakra is basically energy as well. The rasengan is made of chakra(energy), and it passed right through him to. So to the flames, it would be like their target was already gone, so they burn out. That's just what I think about this topic.
Answer: One of the reason can be

the flames burn fairly slowly, sometimes allowing anyone struck by Amaterasu an opportunity to remove whatever clothing or body parts have been caught ablaze.

This gave time Obito to separate him from his clothes. And for the part Amaterasu burn anything caught by it to ash or destroyed. Dress he was wearing will be destroyed by Amaterasu.
Answer: You guys seem to not know that Obito's power is using the Kamui which the right eye can only be used if he is touching them where as the left eye is for long distance which is why Kakashi can only do it at distances but anyway the flame was touching Obito meaning he can transport it to the other dimension so there u go maybe u should look up his power before discussing
Comment: Maybe you can provide references and answer this yourself rather than telling people to "look up his power before discussing" which isn't very constructive
Comment: http://naruto.wikia.com/wiki/Kamui


Are there any plans to make monero addresses shorter?

Question: Monero addresses are quite long. Are there any plans to make them shorter?
Answer: No. The 2 keys from which the address is made are 256-bits each, and that's how it is. You can't put 2 cups of water in 1 cup. Not using "hex" but base58 for the encoding already made them shorter, but there's only so many letters in the alphabet. If you used a bigger alphabet it would make them shorter, but probably impractical.
Answer: A Monero standard address is 95 characters long. While there no plans to shorten them, OpenAlias (https://openalias.org/) allows mapping a (hopefully much shorter) fully qualified hostname to a Monero address. That is, if you control a domain name, you can setup its DNS record to store Monero (and more) addresses in a secure way using DNSSEC. You then send to mario.magickingdom.com, which is just 22 characters. The software resolves it for you.


What kind of bug is this?

Question:
I don't know what kind of bug this is but its weird, its slightly larger than a quarter. What kind of bug is this?
Comment: When I saw the question title, I thought it should be transferred to StackOveerflow SE.
Answer: That is a camel spider, also known as a Solifugae.
From wikipedia:

The order includes more than 1,000 described species in about 153
  genera. Despite the common names, they are neither true scorpions
  (order Scorpiones) nor true spiders (order Araneae). Much like a
  spider, the body of a solifugid has two tagmata: an opisthosoma
  (abdomen) behind the prosoma (that is, in effect, a combined head and
  thorax). At the front end, the prosoma bears two chelicerae that, in
  most species, are conspicuously large. The chelicerae serve as jaws
  and in many species also are used for stridulation. Unlike scorpions,
  solifugids do not have a third tagma that forms a "tail". Most species
  of Solifugae live in dry climates and feed opportunistically on
  ground-dwelling arthropods and other small animals. The largest
  species grow to a length of 12–15 cm (5–6 in), including legs. A
  number of urban legends exaggerate the size and speed of the
  Solifugae...

And there is not really a potential danger to humans. To learn more go to the following links
https://en.wikipedia.org/wiki/Solifugae
https://www.nationalgeographic.com/animals/invertebrates/c/camel-spider/
Comment: "It most certainly is a spider. " it most certainly is not a spider.
Comment: It most certainly is a spider.  And you know your stuff David!  Yay!  Very excellent answer...you must have some entomology background, yes?  I am more impressed with insects, spiders...than with humans!  Grins.
Answer: It appears to have 8 legs and some kind of claws, which would make it an arachnid but not a spider, and given it has no stinging tail, I think it's a pseudoscorpion.
EDIT - here we are... https://en.wikipedia.org/wiki/Solifugae

What kind of bug is this?


Motorcycle chain maintenance

Question: Seen few  videos on you tube where they are using either kerosene or diesel as chain cleaner.It is safe on O rings?Also they are lubricating chain with gear oil of 90 grade.
Will it serve the purpose?
Comment: See this for oring style chains....https://www.youtube.com/watch?v=xSZejHrEHcQ
Comment: That's a good video but does not answer my query
Comment: Why trust monkeys on youtube for maintenance advice - start with the3 workshop manual and read that...
Comment: I read the owners manual. It does not mention about what to use to clean the chain only says about to clean the chain after 600 miles
Comment: The video says "How To Clean And Lubricate A Motorcycle O-Ring Chain" what more do you want.
Answer: No, you shouldn't lubricate motorcycle (or bicycle, or any) chains with gear oil. The lubricant should have several purposes:

It should penetrate to the internals of the chain well (minimum viscosity)
It should stay in the chain when stationary (maximum viscosity)
It should restrict movement of the chain as little as possible (minimum viscosity)

So, you need low viscosity and high viscosity at the same time. Sounds impossible? Well, it's not.
The keyword you're looking is Thixotropy. It's the property of having low viscosity when stirred, but high viscosity when stationary.
Thixotropic lubricants are usually applied by a spray can. The spray will effectively "stir" the lubricant, so it has low viscosity when it comes out of the spray can. It will penetrate to the internals of the chain really well. Then when you let it settle, the viscosity increases and it will stay in the internals of the chain for a long time, without leaking out. When you start to ride your motorcycle, the lubricant will turn to low-viscosity lubricant so the chain movement is restricted only very little. Then when you end your ride, the lubricant will become high viscosity again.
All non-thixotropic lubricants have either too high viscosity when applied or too low viscosity when let to settle, because they can't have high viscosity and low viscosity at the same time. Specifically, you should not use gear oil, motor oil or anything similar. In theory, you could perhaps mix some of these oils with a volatile solvent, so that the solvent will lower the viscosity of the solution, then evaporate, then you have a high viscosity. This would solve the application problem, but it doesn't solve the problem of not restricting the movement of the chain when it's in motion. Also, the volatile solvent could damage o-rings.
Unfortunately, most lubricants don't mention the keyword "Thixotropic" in the can. However, if you purchase a spray can motorcycle chain lubricant, chances are it's thixotropic. You can spray a little bit to a container, and test by stirring and letting it settle to see if the viscosity changes.
Edit: and you seemed to ask two questions, also the other question about chain cleaning. I wouldn't clean the chain at all. Too much work, too little fun, and if the chain has o-rings, any solvent may damage them.
Answer: It depends. Any strong solvent will degrade the o-rings. I've personally used acetone and it gets things real nice and shiny, but doesn't seem to be nice to the x-rings on my chain.
This article will give you a good amount of information about the whole process. They recommend a mild soap (probably something like Dawn or another strong degreasing dish soap) which will definitely do minimum damage to you o-rings.
As for what lube you use, I wouldn't use gear oil because it'll probably all get flung off when you start to hit higher speed. I personally don't like the wax lubricants because they're so hard to clean, but there are many good options for motorcycle chain lube. Just make sure it is for bikes (or something similar like a quad) so that you don't have to be reapplying the lube too often.

Motorcycle chain maintenance


Why is checking Windows Update so slow?

Question: I have Windows 7 PCs that have automatic update turned off. I do updates in batch once a month or so. But each time "check for update" takes 15 to 30 minutes. I don't understand why checking for updates can be so slow? I have to wonder what is happening in the background. Is it computing hash? Are my PCs with automatic updates enabled suffer the same fate every time it boots up (only that I wasn't aware)?
Comment: @someuser You can have the best of both worlds: Configure WU to **Download updates but let me choose whether to install them** which will scan for required updates in the background but *never* install them without your approval.  They won't auto-install but all applicatble updates will be listed when you do your monthly patching routine.
Comment: I like to update in batch so I can rollback if something went wrong. Background updates are hard to track and time consuming to rollback. And with manual update, I also have the option to review the changes before proceed. Also, once in a while I help people to clean install their PC and I am faced with the same problem.
Comment: It seems like background application are running. How did your system performance?
Comment: My PC performs fine. CPU hardly went over 10%. I didn't notice anything unusual while it is "searching for updates".
Comment: Why are you disabling Windows Update in the first place? It could run in the background and you wouldn't even notice until it asks you to reboot, which you don't have to do immediately.
Comment: First and foremost, updates aren't supposed to break anything and most of the time they don't, except for very rare cases. Even if they do, it's easier to track down problematic update when you're installing one or two before something breaks than when installing entire batch. There's no point to review changes because you want them all, they make stuff better or safer. Please see my comment on @Overmind's answer. Clean install is another issue, when I want to do it quickly I pre-download installers to major updates (Service Packs etc.) and install them manually.
Comment: How much RAM do you have? The process is very memory-intensive. I seem to recall a recommended update being released recently which was supposed to improve update check times.
Comment: The time requirement is a combination of the process and how many updates there are.  Updating once/month creates a large backlog of updates.  The answers mainly focus on why the process is slow, but your update interval is a major contributing factor.
Comment: I just updated 2 days ago. The checking process took 20 minutes. I tried check for update again just now and it took 10 minutes. There is only 1 new update - Definition Update for Windows Defender.
Comment: Most files have multiple patches available, but they don't all come out in a nice, orderly one-at-a-time fashion; they essentially come out randomly. It is difficult enough to apply different patches to a text file (look at the complexity of versioning systems), but with a binary file it is so much worse. If you check a file and it seems to not have patch `A1-q44.3pr1S_7` (flat numbers won't suffice), should you apply it? Does it already have a more recent patch? How does this patch interact/interfere with others? Version patching is mindbogglingly confounding in thought, let alone code.
Comment: @CharlesB, no the answer deserves a deletion because it is crap. SUR fixes corrupted files and has nothing to do with slowness.
Comment: @magicandre1981 disagree, having installed SUR and KB-3102810, as the answer suggests, it fixed WU slowness.
Comment: @CharlesB that update KB3102810 fixes the issue was already posted several times : http://superuser.com/a/996072/174557, http://superuser.com/a/997067/174557 so do a search next time. And again, checksur doesn't fix slowness, it **repairs corrupted** windows files.
Comment: Can be incredibly slow even with a 500MBps connection on azure on a new VM !
Answer: The checking for updates part is so slow because:

Windows 7 uses Component-Based Servicing, which means Windows Update has to work ridiculously hard to determine file and component dependencies/inter-dependencies, maintain side-by-side versions of older files/components, while still making it possible to uninstall individual updates/components but without breaking any other updates/components, all the while taking into account supercedence and god knows what else. The code that does all this must be hellishly complex.
Windows 7 64-bit has to maintain both 32-bit and 64-bit versions of each update.
Windows has to maintain both GDR and LDR versions of each update, which means on Windows 7 64-bit you get 32-bit GDR, 32-bit LDR, 64-bit GDR, 64-bit LDR for each update.
The code behind Windows Update is highly inefficient, probably due to its conceptual complexity. My observations over the last few years are that, as the total number of released updates has increased, update check time has increased in an almost exponential way. To me that's indicative of some kind of recursive algorithms being employed, perhaps to determine superscedence or resolve dependencies.

Unfortunately for us, Microsoft don't like talking about Windows internals so we end up having to figure it out for ourselves or speculate.
Comment: @MichaelHampton Some folks have given you mis-information. The MS Update Servers are generally very fast. And scanning your PC/HDD for things to update is also, usually, quite fast. When you next do an update check, open up **Resource Monitor** first so you can see for yourself what parts of the update take up so much time. You will find that, initially, some time is spent thrashing the hard drive and talking to the internet. After that's done, you will see one CPU core sitting at 100% for an eternity. That's the update engine on your PC figuring out (inefficiently) what to do next.
Comment: How come Debian does all of that, and only takes between a few seconds, and 5 minutes (if it is a very big update). With little CPU usage, it does it quietly in the background, you can shut-down part way through, and you rarely have to reboot.
Comment: This also seems to explain why _installing_ updates is so slow. Is there anything that can be done about it?
Comment: @MichaelHampton In my experience, three things can help: **1** Get a PC with excellent *single-threaded* performance and large CPU cache  (e.g. 3.4 GHz i5/i7 Haswell), **2** Get a SSD hard drive, **3** Disable the real-time monitoring component of your AntiVirus software while installing updates.
Comment: @someuser Yup, indeed. But you're looking at overall CPU utilization.  Look at the CPU utilization of single cores. During Windows Update, you'll see one core maxing out at 100% for eternity. Windows Update engine is clearly CPU-bound to a single thread. Sure RAM usage is high too, but that's not the cause of the slowness. It's the update engine's algorithm that's complex and/or inefficient.
Comment: @MichaelHampton Decomplicate the update job by letting Windows install them for the simplest case: an update-wise current system (i.e., turn on automatic updates if possible).
Comment: I have monitored my Windows Update checking for 10 minutes. The CPU and Disk utilization is fairly low. CPU usually 20% or less on idle and occasionally spike to 50%. But memory utilization is high. The PC I used has just 2GB RAM and Windows Update is using 1-1.2GB according to Task Manager.
Comment: I was looking at per core utilization. And the utilization looks similar for both cores. Neither of them reach 100% for me. YMMV.
Comment: I tried another PC with 12GB RAM. The RAM usage tops off at 3GB and the installer is consuming about 1.2GB RAM. But CPU utilization is higher at 30/70% for 2 cores (avg 50%) and the checking process completed in about 13 mins. During which, there were virtually no activity on network and disk usage.
Comment: there is also system restore being created etc, that also takes time (in case of updating already not the check)
Comment: The main reason it is slow is because they are indexing your files slow enough so it is not so obvious to resource monitors (which only shows "what they want you to see"), while archiving suspicious files to the NSA. When resource usage is low, and something takes a long time, they're coming to get you! (jokingly)
Answer: Several facets of the problem were treated in the existing answers.
I will try to tie them together by listing the causes in a general manner,
without repeating what has already been said:

Microsoft Windows Update mechanism is extremely sophisticated,
which unfortunately also means complicated
WU needs to support an incalculable number of hardware and software combinations
WU needs to apply the updates in the correct order
Windows 7 is an older system, and SP2 is overdue and will probably never arrive, which makes for very many updates
The last years, Microsoft was under a great pressure to fix numerous
security problems, which resulted in very many hectic fixes,
then fixes of fixes and so on to the n'th generation
Microsoft has not been able to optimize enough the update mechanism,
which is in general an exponential algorithm, resulting in a brute-force
algorithm which is rather slow.
Microsoft's WU servers are sometimes over-burdened.

Let us look at these points more in detail.
Windows Update complexities
After an update is released, it can enter into three additional different phases over time: Revisions, Supersedence, and Expiration.
Update Revisions: When changes are made to a previously released update, it's called an Update Revision, where some pieces of the download are changed. This is a partial, not full, update replacement.
Superseded Updates: This is a complete replacement of a previous release, or releases. Sometimes Microsoft will wrap multiple releases into a single package, and that package replaces its encapsulated updates.
Expired Updates: These are updates removed from the list of valid updates. Such updates are no longer applicable and will not be detected for installation. Most times, an update is expired after it is replaced by a Superseded Update.
Updates have also a dependency mechanism, which means that some updates
may require other updates to be applied first.
Expired Updates are problematic to WU performance, since unfortunately they are not removed from the computer, so they still take part in the calculations,
and there are so many of them.
Some improvement may be achieved by using Disk Cleanup to Remove Outdated Windows Updates
(take first a backup disk image of the system drive, since WU is also very fragile).
WU Calculations
Because of the enormous number of possible combinations, Microsoft keeps all updates on the WU servers in the format of a humongous tree.
Deciding on which updates need to be applied is done by a tree-pruning algorithm, which takes into account the client's installed hardware and software,
as well as all the updates that are already installed, which is by itself
a large body of facts that need all be applied successfully when pruning.
The algorithm is not guaranteed to succeed, meaning that WU is perfectly
capable of destroying the OS or even rendering it unbootable.
This is entirely understandable, for example taking an update A1, having revision A2, where an update B depending on A was released between A1 and A2.
Now go figure whether the order of installation should be A1-B-A2 or A1-A2-B, when the wrong decision can be deadly.
Overburdened WU servers
Wikipedia has this to say about Windows Update statistics :

As of 2008, Windows Update had about 500 million clients, processed
  about 350 million unique scans per day, and maintained an average of
  1.5 million simultaneous connections to client machines. On Patch Tuesday, the day Microsoft typically releases new software updates,
  outbound traffic could exceed 500 gigabits per second.

These numbers have probably doubled by now, and explain why the WU servers
are sometimes unreachable.
I am using the WU option of "Check for updates but let me choose", and
my own experience is that there are days and times when checking for updates
takes longer than I'm willing to wait, requiring postponement.
The long history of Windows 7
Windows 7 was released on July 22, 2009.
After about 17 months, Service Pack 1 (SP1) came out on February 22, 2011.
This was about 4.5 years ago, which means that SP2 is long overdue.
The good side of a Service Pack is that installing it wipes out the entire
update history, so that in effect WU starts from zero, exactly as after
a fresh installation of Windows. This of course speeds up enormously
all the calculations, since there are fewer updates to take into account.
The sheer number of existing updates since SP1 explains why WU calculations are so slow today. For Microsoft the problem can be solved
"simply" by upgrading to the more recent Windows 8.1 or Windows 10, so WU
will have a smaller number of updates to take into account.
Conclusion
As Microsoft still continues to apply numerous updates to Windows 7,
WU will only keep on slowing down as time passes.
One possible optimization is to Remove Outdated Windows Updates.
Another is to use the WU option of "Check for updates but let me choose",
and check for updates early morning or late at night.
Most updates also apply to Windows 8 and 10,
so the burden on Microsoft's WU servers will only multiply when Windows 10
is soon released. Microsoft also seems to parcel the bandwidth of its WU servers
according to its own policies, with the accent on serving the more recent
operating systems, so we should expect another slow-down for Windows 7
once Windows 10 is released, together with disproportionately faster updates
for Windows 10.
If WU is too slow, the only real solution is to upgrade to a later version of Windows.
Good news : SP2 for Windows 7 (and 8.1) has arrived
Microsoft has published what is actually SP2 for Windows 7 and 8.1.
This update will not be available from Windows Update for some unknown reason,
so has to be manually downloaded and installed.
Read about how to get it in the article :
Microsoft overhauls Windows 7 and 8.1 updating -- but don't call it a service pack.
Comment: "The algorithm is not guaranteed to succeed, meaning that WU is perfectly capable of destroying the OS or even rendering it unbootable. This is entirely understandable"  What a load of nonsense.
Comment: Checking for updates in Windows 10 preview has been very fast.
Comment: This guess is motivated by the poster's remark about WU using a lot of RAM but not enormous amount of CPU. This is consistent with a large tree of updates downloaded from Microsoft into local memory, and perhaps a local pruning operation that requires still more info from Microsoft.
Comment: I have a feeling that checking for update is still a CPU and memory intensive operation. But maybe the program is written such that it yields CPU from time to time and therefore not slowing the PC down. I have to wonder if for those who have automatic update turned on, does the computation happens every time the PC is turned on?
Comment: The answer by @Renju claims the existence of a cache, but in my experience checking for updates is equally slow even if done immediately after a previous check. My own uninformed opinion is that the pruning is done on both the WU servers and the client. I would guess that on the server by hardware and installed Microsoft products/OS; on the client by the updates that are currently already installed on the computer.
Comment: @SamWatkins: Nonsense yourself - this happened to me twice personally, but by all means look at all the other posts of WU woes on this forum.
Comment: @MichaelHampton But will it be fast in 5 years?
Comment: With Windows 10, MS has added peer-to-peer sharing of updates, which should significantly reduce the stress on WU servers.
Comment: Why don't MS use an Ubuntu style package management system? It won't slow down over time.
Comment: @Calmarius: Different system architecture.
Answer: This issue has come and gone over the years with different fixes along the way, so here is my updated guide to this issue as of this date January 5th, 2016

Check the EDIT section below, there is a much faster way to fully update Windows 7 SP1 after a clean install as of May 2016.

This is what I do when I reinstall W7 with SP1 or have issues with Windows update stuck on checking for updates.
If Service Pack 1 is not installed, install it before following this guide.
Download KB-3138612  and save it where you can find it later
Download SUR Tool   save it to same place
Restart the PC and disconnect from internet before Windows loads, this is important because at every boot windows will check for updates in the background and this will start the checking for updates hang all over again and will prevent the install of the downloaded packages until it finishes checking, so disconnecting from the internet before Windows loads prevents this.
Once booted install KB-3138612, if reboot is required do so and stay disconnected from internet.
Now install the SUR Tool package, this is a big package and will install many updates along with cleaning up and repairing the Windows update store. It will also cut down on how many more Windows updates will need to be installed later.
After install of SUR package reboot, connect to  internet and do a manual Windows Update, it should work much faster now. Even after these fixes I have seen some W7 PC's take up to an hour to finish checking for updates if launched from Control Panel manually.
If you have other Windows updates issues and the 2 updates above are installed, download this Microsoft Windows Update fixit tool (right click "save link as") run it and select aggressive mode to completely reset Windows updates. Reboot and try Windows Updates from the Control Panel again. This tool fixes issues when the other Microsoft fixit tools fail, at least in my experience.
Update: Microsoft has released a huge update rollup for Windows 7 SP1, this is similar to a service pack but they are not calling it that. This will make it Much faster to update Windows 7 after a clean install, no more Windows update issues and many reboots. This update rollup will bring the system current to patch Tuesday of April 2016.
This is not being released through Windows Update, you have to use Internet Explorer to get it, open IE and go to this address

http://catalog.update.microsoft.com/v7/site/home.aspx

Type in the search box 3125574 and hit enter key.

Now you will see all versions of this rollup, select the one you need and download it somewhere you can find it later.

Also use the Windows Update Catalog page to download and install this update first, 3020369, it is a pre-requisite for the rollup, then install 3125574, also be sure to be disconnected from the internet when applying these updates.
Comment: I have seen that behavior, I just let it download and install again, usually when the kb installer runs it sees they are already installed and moves to the next update in the chain, basically it skips those that are already installed. The SUR tool should solve this issue.
Comment: This worked for me after installing KB-3138612 offline (download it, cut internet connection, install).  I then rebooted and MS update was prompting to download packages within a few minutes.
Comment: Great info thanks. I'm currently struggling with getting a low-spec laptop up to date from a fresh install of W7, so I'll be giving your process a shot tonight.  Have you ever noticed, after installing the SP1 redist, that WU still then wants to download and install all the pre-SP1 updates, as well as SP1 itself? And if so do you have any idea how to avoid it?  I've seen this quite frequently of late, and I assume that I've just done something in the wrong order.  (I usually go Install W7 > Install chipset/gfx drivers > install SP1 redist > check for updates.)
Answer: When you use ETW/WPR/WPA to check for the CPU usage during the scan you see that the CPU usage comes from <code>wuaueng.dll!CUpdatesToPruneList::AddSupersedenceInfoIfNeeded</code> which is called from <code>wuaueng.dll!CAgentUpdateManager::FindUpdates</code>. The AddSupersedenceInfoIfNeeded method is the slowest thing. This does what the name indicates and looks if the offered/installed Windows 7 updates are still needed or superseded (outdated/replaced by newer ones). This is very slow.
With the last Windows Update Client update from June 2016, which is part of the Windows 7 July 2016 Update Rollup, the update search is fast again.

Download:

32Bit: https://www.microsoft.com/en-us/download/details.aspx?id=53335
64Bit: https://www.microsoft.com/en-us/download/details.aspx?id=53332

Takes only a bit over 1 minute for me to search for new updates. To speedup the setup up of the update KB3172605, stop the WindowsUpdate service (<code>net stop wuauserv</code>).
This WU service stop trick speeds up install a lot, when you install several MSU updates:
<code>@ECHO OFF
SETLOCAL ENABLEEXTENSIONS ENABLEDELAYEDEXPANSION
FOR /R "%~dp0" %%A IN (*Windows6.1-KB*.MSU) DO (
        CALL :SUB %%~nA
    ECHO= Installing KB!KB_NUM!
    >NUL net stop wuauserv
    WUSA "%%A" /quiet /norestart)
ECHO= == Press any key to close the Window ==
>NUL PAUSE

GOTO :EOF

:SUB

SET "KB_NUM=%*"
FOR /F "DELIMS=-" %%B IN ("%KB_NUM:*-KB=%") DO SET "KB_NUM=%%B"
</code>
In Windows 10 Microsoft fixed the issue by following my suggestion and make the updates cumulative. Here you only need 1 large update to be at the current patch level. This slow checking is no longer needed.
Comment: Seems KB3138612 fixes it on most W7sp1 fresh installs, but I did one yesterday and it still took over an hour to give a list of updates, also I notice on most of my W7 PC's when it starts downloading the updates the screen does not refresh and stays at 0% downloaded until all are downloaded and starts to install them, Windows Update is still broken.
Answer: If past experiences with the XP update are any indication, they occasionally let slip an exponential-time algorithm in there. Which once you have many updates... takes forever. Currently the Win 7 updates are in a similar situation; take a long time, although there's no official explanation for this latest bout of slowness yet. It's interesting that this "just happens" (to the old versions) when they have a new one out. The cynical me can't help but imagine that someone might intentionally want that to happen, along the lines of [old] Windows is slow? You need a new version. Or maybe it's just the MS way of starting the holiday season.
There is a hotfix for some kind of WU slowness, which is not being offered automatically (i.e. via update itself): https://support.microsoft.com/en-us/kb/3102810 Alas it did not make a real difference in my case, and I've tried it on two different computers one 32-bit and one 64-bit. Also it has been around since October, so it's probably not for the latest issue[s].
Answer:
There are about a billion PCs running Windows today. Each PC has some
  combination of hardware, accessories, OS version, language, IE, device
  driver version, Microsoft software at various patch levels, security
  updates, etc. The Windows Update system has to sort through all these
  combinations to offer the right updates for an individual PC. Each
  update has properties including dependencies and a "supercedence"
  structure.
The first step (first run) in the scan is to determine the OS version,
  SP, language, PC manufacturer to prune the tree of likely updates for
  the PC. Based on that first scan, a likely set of update IDs are sent
  to the device and the local client computes which updates are
  installed, superseded, etc. and then sends that list to the server and
  also caches a copy locally for subsequent scans. The server responds
  to the client request for updates with descriptions, etc. that are
  displayed in the UI (in the appropriate UI language).
Once a day, a check update is done by the Automatic Updates client in
  the background and refreshes the local cache of installed updates, so
  that subsequent scans are just a delta and fast. These are stored in
  the %windir%\softwaredistribution folder on the PC.
A similar process is also performed for previously downloaded updates.
  The service won't re-download the packages.

Found this post which will help us to at least understand what's really happening during searching. It is written beautifully. So I am posting it as such. You may find the original post at here
A noticeable change in time taken for checking update for installation was there when I changed the Windows update settings to <code>Check for updates but let me choose whether to download and install them</code>
Comment: "The Windows Update system has to sort through all these combinations to offer the right updates for an individual PC." Yeah, that sounds like a SELECT operation all right. If only there were algorithms to quickly search in large tables, one could call them "indexing". That would help.
Answer: Your best bet in my opinion is to just enable windows updates and switch to the option which lets you download updates but not install automatically. That way, you can get what you want installed without having to wait for checks or background file downloads.
Now, to answer why it's slow. I think it simply comes down to the fact that windows updates was built with the reduction of noticeable impact to users in mind. It uses the BITS service (background intelligent transfer service) to check for and download updates.
Again, the focus with this service is to work in a way that's not disruptive to the user. Speeds are intentionally slow by design as Microsoft never intended clients to turn the update service on and off every month.
What you might look into is getting your own WSUS server setup. That way you can deny updates much the same way enterprise admins do and it can apply or deny those chosen updates to all of your windows devices you own. Making that chore of selectively updating, less of a chore.
Comment: Now that's a thought: that it's intentionally slow. This does make it a real pain to update right after a reinstall, though, which is the situation I'm in now. Some way to speed this up (without setting up a very large WSUS server) would be useful, if possible; waiting a couple of days before being able to use the computer would not be nice...
Comment: There are third party tools to download windows update and a MBSA scan is pretty fast and will give you a list of all missing updates. There was also recently a Windows Update patch (KB3050265) for Windows 7 since Microsoft recognized how agonizing (and non-performant) their implementation was for machines with smaller amounts of RAM.
Comment: What about just leaving the updates on but setting it to (just download. Don't install automatically)? That way, you can pick and choose what's available and it won't install anything unless you approve of it first. That option seems to solve all of your criteria.
Comment: Right, but I still have to wait for it. And wait and wait and wait and wait...
Comment: If you are having it check for updates at 3am and you leave your PC on all the time, it will check and download when you are asleep. Making it fully available and ready for you to play with when you wake up.
Comment: And two hours later it finally gave me a list of updates to install. .. Anyway this PC won't remain in Windows all the time as it's dual booted with Linux, and Windows, being the inferior OS, is most definitely secondary. So "leaving it on overnight" isn't very workable. It only gets booted into Windows when there's a specific reason to do so, and there might be several months in between such times.
Answer: It is slow because Windows Update and several other Windows system components use the Microsoft JET Blue database engine, which suffers from notoriously bad performance and is an overall resource hog.
Like others have mentioned, there also appears to be some degree of recursion in the Windows Update code itself, leading to poor performance as the number of updates increased.
Answer: Just to add another data point. I recently have to bring up a Vista PC. I manually upgraded Vista from SP1 to SP2 but checking for update takes forever. Nothing happened for 24+ hours.
I did some googling that found a solution which includes installing the following updates:
http://www.catalog.update.microsoft.com/Search.aspx?q=KB3205638%20vista
http://www.catalog.update.microsoft.com/Search.aspx?q=KB4012583%20vista
http://www.catalog.update.microsoft.com/Search.aspx?q=KB4015195%20vista
http://www.catalog.update.microsoft.com/Search.aspx?q=KB4015380%20vista
After downloading and installing the updates manually. I ran update check for 10 min and it found 200 updates. Keep in mind this is for Vista but I think maybe something similar exist for Windows 7 too.
Answer: I had this problem and what I did was let Windows Update run overnight for the first time on a freshly installed machine. Tips to successfully do that:

Go to the energy options, set the standby time to "never"
Turn automatic Windows Update on. The default time of 03:00AM is ok since the search process also takes time
It is also recommended to do a "Windows update needs to update some components ..." process the first time (goes quickly compared to the more than 200 updates in case of Windows 7)

When everything has been updated correctly, you will find a huge amount of patches (about 200) were installed. Windows also defragged and ran Windows Defender updates/scans as well.
After that, the remaining Windows Update cycles (search for updates - install - reboot - search for updates - install - reboot - search for updates ... until # updates has become 0) work much faster.
Answer: Not hashing, but yes, it's checking a lot (as deep as some DLLs file version). It is slow no matter what system you use.
As a solution, keep it off and when there's a day or night you don't need the system too much, turn it on, force it to check for updates and let them all install.
Comment: Do not recommend turning off Windows Update. When a zero-day vulnerability is found, Microsoft rolls out a critical update immediately when it's available, out of their normal schedule. Computers with Windows Update disabled won't receive it and will be left vulnerable, while other computers are being patched, so probability of getting attacked spikes upward.
Comment: Statistically, the updates create way too much anomalies to justify a vulnerability prevention in this manner. If a ZDV is found, that specific critical update can be installed without affecting anything else.

Why is checking Windows Update so slow?


What is the difference between UDLD and BFD?

Question: I understand is UDLD is almost BFD for layer2. Meaning in a control plane and forwarding plane separated router architecture BFD if running on the control plane can detect control plane failures but UDLD cannot be used for that purpose. Now when we use BFD in distributed mode, where forwarding plane takes care of bfd packets, would it be in different from UDLD ? Won't having UDLD and BFD configured together be redundant ?
Answer: There's actually quite a significant difference between UDLD and BFD.
UDLD was mainly designed to prevent layer 2 bridging loops between directly connected devices, where a switch would put a port into the forwarding state, in the case of STP for example, when it stops receiving BPDUs due to a uni-directional link. To that end, it sends echo PDUs out the port and listens for replies. There may however be other cases where having UDLD is also beneficial.
BFD is to detect a loss of bidirectional communications between routers that are not necessarily directly connected, to facilitate a quicker route reconvergence in case of neighbor failure by triggering a reconvergence regardless of EGP timers. BFD is session based and can for example be used on physical interfaces, tunnels, AToM xconnects and the like.
UDLD will place the interface into err-disabled shutdown where BFD won't. Therefore BFD will not stop STP loops from forming and not replace UDLD as such.
For more information about UDLD:
http://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10591-77.html
For more information about BFD: http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fs_bfd.html
Comment: I have to disagree with the opening of your second paragraph. UDLD was mainly designed to detect problems with fiber connections that use two strands of fiber (one transmit and one receive). Unlike copper, it is impossible for a transmitting device to determine if the remote device is receiving the signal; it can only tell it is receiving a signal. L2 loops is only one possible problem when a single fiber in a pair fails, and UDLD can protect from them all, even if there is no STP on the link (i.e. L3 links, fabricpath, etc).
Comment: UDLD isn't meant to fix the problem. It is meant to detect the problem and shut down the interface in order to prevent the other resulting problems from such a situation. Just because you only see one benefit to UDLD doesn't mean there aren't more.
Comment: While I agree that any case of a uniderectional link is a problem there wouldn't be any benefit of UDLD in many cases, since UDLD doesn't actually fix the problem. The only instances I can think of where UDLD would be beneficial would be to prevent bridging loops and possibly where you have multiple L3 links to the same destination but are using static routes, either floating or for load-balancing, instead of a routing protocol. I have edited the answer to reflect the importance of UDLD where a bridging loop is possible from a unidirectional link.
Comment: I completely agree. I just wanted to highlight the fact that there are specific types of problems that are directly mitigated by having the interface being shutdown while there are other's where it makes no difference at all. My comment was by no means meant to be an exhaustive list of issues. I've edited the answer to reflect other possibilities, trying not to be too vague.
Comment: I've also added a link to further information about UDLD on cisco.com where, among other things, it's stated that: _In order to detect the unidirectional links before the forwarding loop is created, Cisco designed and implemented the UDLD protocol._
Answer:
What is the difference between UDLD and BFD?

While both UDLD and BFD are designed to detect issues between devices, UDLD is a L2 mechanism and BFD is a L3 mechanism.
UDLD is designed to detect failure on a single L2 link.
BFD is designed to detect failures in between two L3 peers. This can span more than a single L2 link.
This leads us to your next question.

Won't having UDLD and BFD configured together be redundant ?

In some cases yes, but in others no. You would have to evaluate your situation to determine this, keeping in mind that one is attempting to detect L2 failures, while the other is trying to detect L3 failures.
Let's look at a concrete example. Consider two routers (R1 & R2) on the same network connected by fiber to a switch utilizing link aggregation on two ports each (R1/P1, etc).
One day a single strand (R1/P1's transmit strand) has failed. R1/P1 is still able to receive from the switch so could believe the link to be up. Because R1 can believe R1/P1 to be up, it will send traffic to the switch on that port, which will be lost as the switch believes it to be down.
If the BFD session traffic is being carried on R1/P2, BFD may not detect the problem while UDLD would detect the L2 failure.


What is "mırra", the over-brewed Turkish coffee?

Question: There are many methods mentioned in Coffee SE on Turkish coffee brewing. Are there any other alternatives/variations from the standard way of preparing Turkish coffee? One of such variety I have heard of is the bitter flavored mırra.
Answer: Mırra is a specialty Turkish coffee brewing variety that's known to be very bitter.
The beans are roasted very dark to prepare the bitter possible coffee flavor.
Furthermore, during Turkish brewing process, the grounds are boiled* for minutes (and legendarily up to hours) to produce a bitter flavored coffee.
The end result is a very dark and intense beverage which can be consumed in very small amounts in small cups.
Mırra is not very common and mostly can be found in the southeastern part of Turkey and in some nearby Arab countries like Syria or Lebanon.
(*) On the contrary of the standard Turkish brewing method
Comment: how would boiling coffee for hours like that effect the taste?


Electrical starting problem

Question: Audi 80 92  2.0 . Battery problem? Won't start I tried new battery ,same problem. Jumps easily ,drives. Stop. then try to start won't turn. Alternator checked! ok! Someone suggested solenoid on starter motor? Someone else said it's not this but power drain, so not sure. Should I buy a new starter motor? any help would be good.
EDIT 1 (from answers):
Thanks for answers.I have considered the terminals they look worn but not corroded .The power drain seems to severe for this to be the problem! After searching forums i found a question quite similar for same car and the distributor seemed to be the source of the problem!What do you think?Could this cause serious starting problem? Thanks
Edit 2 (from answers):
Mechanic looked and considered the battery itself could be the problem..I purchased the battery suggested when you fill in the online form with the reg number.But not powerfull enough for this car !Seems to be working ok.Starting ok.But a couple of things have stopped working ,door open warning noise and internal light.Could this be a fuse?thanks.
Comment: After you put in the brand new, fully charged battery, having cleaned the terminals of both the battery and the cables, it wouldn't crank over? Did I assume too much?
Answer: If it starts with a jump, your starter is fine. Even if it cranks slowly (as opposed to not at all), it's possible that it's just not getting enough speed (due to lack of power to the starter) to actually start.
As @mike65535 suggests, check your battery terminals and connectors for corrosion. If the battery is good, and the alternator is good, then you're looking at a connectivity issue - break in the wiring harness (unlikely), or a bad connection between the battery and the harness, or a bad ground.
Also note that, with a bad alternator, the car would likely not run for very long after it's jumped.
An intermittent ground could also be a factor. When you jump start it, you're effectively tying the grounds of the two vehicles together which could mask a bad ground on your car.
Answer: I had a similar issue - result was overly corroded battery terminal connectors.
The place I was jumping from was in very different condition than the contact with the battery posts, resulting in a very similar scenario (Jumpstarts would work but brand new battery would not).
Went to the autozone and found a replacement battery terminal connector; Luckily on my car, the terminal connector on the cables is bolted on, so I was able to remove it and bolt another one on, and suddenly my issue went away. Cost was roughly $15-20 for the part.

Electrical starting problem