"Show more" vs. "See more"

Question: Which is considered more appropriate for a button, loading more items on a webpage? "Show more" ("Load more") sounds like a command to the system, but "See more" ("View more") is an actual action a user is going to perform. Obviously, both of them are understandable, as they are frequently used on websites. But which of them is more appropriate from the user experience perspective?
Comment: I don't believe one is more appropriate than the other, as long as you keep it consistent to the other actions in your webpage (all talking to the system or all talking to the user?)
Comment: Like Luciano said (and Ray completed with a more extended answer), consistency is the key. Other than that, if you're curious you can just run an A/B test
Answer: For any kind of writing or presentation, unless you want to confuse the readers, always use a consistent point of view.
Even if it doesn't confuse them, and they don't even realize what's happening, they will feel slightly uncomfortable and the writing will seem awkward.
This is almost never how you want people to feel when they read your work.
Here's an extract from something I wrote 10 years ago:

According to author James Alan Gardner, "viewpoint is essential in winning the reader's confidence".
He is talking about writing fiction here, but the principle is just as important for essays, textbooks, web pages, or other works of non-fiction.
Writing that doesn't present a consistent point of view can be very disconcerting and confusing for the reader, even when, or perhaps especially when, the reader doesn't realize what the problem is.
…
Many web site home pages use a very direct and impersonal third-person presentation of information:

XYZ Corporation manufactures widgets for the high-tech restaurateur.
XYZ has branches in 42 countries and employs over 15,000 people.

and of links to other pages:

XYZ Catalog and price list.
XYZ Employment opportunities.

Other sites have home pages with a more friendly first-person presentation:

At XYZ Corporation, we manufacture widgets for the high-tech restaurateur.
We are more than 15,000 people working in 42 countries around the world.
We have an extensive catalog and affordable price list.
We offer excellent employment opportunities.

Others have a more personal first-person presentation that conversationally involves the second person:

XYZ Corporation manufactures widgets for high-tech restaurateurs like you.
Did you know that XYZ employs over 15,000 people worldwide?
You can visit XYZ at branches in 42 countries.
You can look at the XYZ catalog and price list here.
If you'd like to work with us, go here.

And still others reverse the relationship by presenting an even more personal second-person viewpoint, pretending to actually be the second person and making you first-person:

Show me your catalog and price list.
I'm considering working for XYZ.

Depending upon its intended use, one viewpoint may be more appropriate than any other; there is no point of view that is always right or wrong.
What is important though, is sticking with the chosen viewpoint.
Ideally, all pages at the same sibling level will present the same point of view.
And, unless a section is clearly marked as different, certainly within any one page a consistent point of view must be maintained.
— Style: Maintain a consistent point of view

And do read Jim's much longer article: A Seminar on Writing Prose
Answer: "Show more" and "See more" both assume the user is sighted. "Load more" sounds like a system command, but it isn't so "system-ese" that an average user would find it off-putting. It's used by top ecommerce sites and recommended by Nielsen-Norman Group.

"Show more" vs. "See more"


Light fork recommendations?

Question: I just built my first bike up, it's a total frankenbike and it's a lot of fun, but I'd like, just for fun, to see how light I can make it as I do mostly use it for practical commuting. The frame is a vintage carbon MTB frame so I'm already pretty ahead, but I had to use a steel fork for the time being. I need it to accept a 26" wheel, with a threadless straight steerer, 1-1/8" with horizontal pull rim brakes if possible. I don't necessarily need to go full carbon, especially since I don't seem to find any forks that are both carbon and rim brake compatible, but just something that's fair
Comment: Welcome to Bicycles SE.  As an exchange site, it is not like a traditional forum, and it is not designed to give product recommendations as personal subjectivity ventures in.  It is more geared toward solving problems that bike owners/riders have with their equipment or with various issues with bicycling in general.
Comment: What is "vintage carbon"?  Could you please add in a clear well-lit photo ideally from the right-hand side of the bike?
Comment: If it weren't for the 26-inch wheel requirement and preference for rim brakes, I would point you at Cannondale's Lefty Ocho. Removing almost half the fork from the equation does a remarkably good job of cutting down on weight. They definitely don't support rim brakes though, and AFAICT they've only ever been made for 29-inch wheels. That said, seriously consider switching to a disc brake on the front (or on both wheels), that will open up a lot of possibilities in what fork you can use (including forks for different wheel sizes), and the weight penalty is negligible.
Answer: If you want suspension, you will not find a light 26" fork with posts for brakes new. Best you will do new is low or maybe mid range. You only realistic option is a used fork (or donor bike). Good news is you can often pick up something like SID for next to nothing, although it will need servicing and may be too worn out to be worth fixing.
However, I presume you are after a rigid fork. The crown to axle becomes the main measurement for a frame designed for suspension. Fortunately, this means you will likely find a 650B to 700C fork with close to the correct measurements. Unfortunately, this means that the brake posts will be in the wrong place. You may be able to find brakes that are adjustable enough to make this work, running the 26", or you could run mullet (larger front that rear wheel).
Consider going to disc front brake. The weight penalty is minimal, and it opens a much bigger range of fork options, and no need to run mullet if you go to a 650B or 700C fork.
Answer: The specific combination of low-weight, 26", and rim brake actually has a market: trials bikes. You'll get something overkill sturdy and plenty of tyre clearance, which strictly speaking makes little sense for "practical commuting", but it'll certainly work. Tapered steerers are the norm now but straight models still available too.
As usual, if you want carbon, you'll have to dish out a lot of money – e.g. a Hashtagg Carbon costs £330. Aluminium is much more affordable, e.g. Jitsie Varial 400 for £170. That's not cheap for a rigid fork, but it'll last forever and is still very light.
Especially if you intend to ride at least some off-road, I definitely wouldn't insist on 26" and rim brakes. Discs are better for almost all use cases, and I'm sure you'll find something used with Shimano hydraulics for a good price/value. A 27.5" front will most likely work just fine on that bike as long as it doesn't have too long travel. Light 27.5" air suspension forks are available for cross-country, but they're expensive and require a lot of maintenance. If you want suspension on a commuter bike then a cheap coil fork makes more sense, but these are much heavier.
Perhaps you'll also find a 26" short-travel fork in the dirt-jump category.

Light fork recommendations?


"Research and development of something" or "Research and development on something"

Question: "we perform research on technology", and "we perform development of technology". But when we perform "research and development", should "of" or "on" be used?
Comment: _We perform technological research and development._
Comment: If two terms joined by ***and*** would normally take different prepositions, the idiomatic standard in English is that *we use the preposition that suits the **second** term*. So in your case it should be *research and development **of** [whatever]* - or for different pairings, *funding and research **into** [some project]* and *research and funding **for** [the project]*.
Answer:
These Google ngrams show that both 'on' and 'of', and additionally 'in', are used; 'on' lags behind the others, probably because 'development on ...' sounds incongruous.
False positives abound, especially with locative 'in', but the domain usage also exists:

Learn about working at National Institute for Research and Development
  in Informatics (ICI).  [LinkedIn_ICI]

......................................................
With 'of', there seems to have been a dropping of the normal rule that relevant prepositions always need to be inserted (one would expect say research on/in and development of); this is a typical example:

Research and development of medical products: opportunities and
  challenges [The Academy of Medical Sciences]

......................................................
Likewise with 'on', with not even a proximity argument:

The research and development on a single compound pharmaceutical from
  a herbal medicine requires inputs of hundreds of millions of dollars
  and typically ... [ScienceDirect]

.....

This debate pack is prepared for a general debate on research and
  development on tackling infectious diseases. [UK Parliament Research
  Briefings]

.....

Institute of Research and Development on Photovoltaic Energy [Nature
  Index_IRDEP]

......................................................
While the 'of' variant lends itself more naturally to things that are developed and the 'in' variant to conceptual fields or other domains (eg industries), the last three examples show that the prepositional complement of 'on' is not narrowly scoped; products (things made), or more or less abstract concerns / concepts are referents with complements filling this slot.
Answer: R&D of would apply to something already defined - 'research and development of electric cars' for example.
R&D on is more suitable to abstract concepts - 'she is engaged in research and development on the potential of electric cars'.


Is there anything to do to get more gold fish from cats?

Question: Is there anything that you can do to affect how often you receive gold fish as a gift from your cats or is it completely random?  What I've tried so far is save up for the living room expansion so that I have more cats visiting at once which I would hope means more chances for gold fish.  However, I feel like I'm getting even less gold fish than before I saved up for the room.
Answer: The only thing you can do is get better food and items. The cat stay more time in your yard and that means more chances or getting gold fish. Usually, when a cat can give you more than 50 normal fish, the next time he can give you gold fish. Also, there are rare cats that usually give you more gold fish than others.
Just try to have the best food and items.


Is it a problem to use the test dataset for the hyperparameter tuning, when I want to compare 2 classification algorithms on the 10 different dataset?

Question: I know that we should use the validation set to perform hyperparameter tuning and that test dataset is not anymore really the test if it is used for hyperparameter tuning. But is this a problem if i want to compare the performance of 2 algorithms (e.g., Random Forest and XGBoost) across 10 different datasets, where each time I am using the test data for tuning. I believe that if they are trained and tested under the same conditions, the final performance analysis should be actually true representation which algorithm is better performing on these datasets. Or am i mistaken?
Comment: It's not totally clear to me what your proposed procedure is. Could you try to clarify a bit?
Comment: I have two classifiers, A and B, and I want to determine which performs better across 10 datasets. To avoid overfitting I do hyperparameter tuning of A and B -> where A and B are trained with the training data and but performance is evaluated on test data (common approach is to use validation set in model tuning...). After the best set of hyperparameters is found, I test it on test data. This is done for model A and B for each dataset and I compare final results. If A is better than B in this approach, would it be also better if I would use validation set instead of test set in tuning phase?
Answer: Seems like there is something flawed in the procedure here. If you use the test data set for tuning, then what do you use for testing performance?
In general, the models should not get any information from the test set. If models are exposed to the test set you will generally tend to conclude the more flexible model has better performance when it may tend to overfit the training data and underperform simpler models if the test set is isolated during the model fitting procedure.
Comment: Thank you for the answer. In my case I have Random Forest and XGBoost. If e.g., the Random Forest performs better using this approach, does it mean that it would perform also better if I use validation set for tuning and leave the test set only for the testing phase? The purpose is only to compare these two classifiers and since they undergo the same training and testing conditions, why the results are not relevant? Thanks!
Comment: The only way to know for sure is to run the data pipeline and look at the results. Can you describe your data pipeline more. It sounds like you only have a training set and a validation set? Are you doing any preprocessing steps? If so please describe that process.


Impedance matching L Network

Question: I'm trying to understand exactly what an L-section Network does. I understand it tries to eliminate the imaginary part of the impedance and match the real part. However I do not understand what excatly both components do and why the inductor(in my example, more specifically in a Highpass Downward L-match) has to be a shunt inductor and the capacitor has to be in series? Thank you for any help.
Comment: Simply put, the impedance ratio creates an attenuator by rising f causing Xc to decrease while XL increases passing high f voltage to a damping resistor load
Comment: Thanks, what is meant by Xc and XL?
Comment: Reactive impedance, look it up
Answer:
I'm trying to understand exactly what an L-section Network does.

What you are describing in your question is a loss-less, high-pass, L-pad impedance matching circuit as per this example: -

The L-pad is used to match a lower impedance on the left with a higher impedance on the right. Either end can be source of course. In other words; you can match a higher source impedance to a lower load impedance or vice versa.
The formulas for L and C are dependant on the operating frequency of interest (\$\omega\$), the input impedance (\$R_{IN}\$) and the output impedance (\$R_L\$): -
$$C = \dfrac{1}{\omega\cdot R_{IN}}\cdot\sqrt{\dfrac{1}{\frac{R_L}{R_{IN}}+1}}$$
$$L = R_{IN}\cdot R_L\cdot C$$
Here you can find a calculator that saves you crunching the numbers by hand: -

That website also provides proofs for the formulas.

why the inductor(in my example, more specifically in a Highpass
Downward L-match) has to be a shunt inductor and the capacitor has to
be in series?

Well, you can make a low-pass version like this: -

Both work the same; at the frequency of interest, you can provide loss-less impedance matching as opposed to a wideband lossy impedance matcher like this: -

I understand it tries to eliminate the imaginary part of the impedance
and match the real part.

It provides loss-less impedance matching i.e. it makes the input impedance looks resistive and the output impedance looks resistive at the desired operating frequency. Either side of the mid-operating frequency, it's not quote perfect, but, it's good enough for most signals just like an antenna is not quite perfect either side of it's target mid-point frequency.
Comment: Ah I am new here and didn't understand one could/should do that. i'm sorry
Comment: Thank you very much. I see that a different arrangements have a different effect. Do you know why that is? Like what the singular component does to achieve these different results?
Comment: @SimonGerber there is no superficial or obvious explanation to this other than following the theory of examining the input and output impedances mathematically and finding the value of \$\omega\$ where both are resistive. If you find one, you find the other of course. But, the different effects can only be realized by following the math (as detailed in the websites I linked).
Comment: @SimonGerber if you have your answer you should [take the 2 minute tour](https://electronics.stackexchange.com/tour) to understand what motivates people to give free answers then, when you understand that, you can formally accept my answer unless you have something you still don't understand and need clarification via a comment.

Impedance matching L Network


USB ports charge but do not recognize anything I plug in / Windows 7 64

Question: So I've been having this issue for some time. I have 1 port that recognizes only my keyboard and mouse (Logitech). The other ports charge items but does not recognize them. I have done the following:
Flashed the Bios (Acer Predator G3610)
Used both USBDeview and USBOblivion
Reinstalled the chipset software
unplugged devices and restarted the computer
unplugged the USB ports from the motherboard
Everything that I could find online to do I have tried and it's making me a little crazy.
It's running Windows 7 x64.
Crazy part is when I plug in a wired keyboard to the one port that works, the keyboard works. If I plug in anything else (ie printer, iphone, tablet, thumb drive) it doesn't recognize it. Any ideas on how to fix this would be great. Thanks
Answer: USBDevView can show you if there was an unusual entry in the list of all USB devices ever connected. This list can also be accessed from the Registry. You might have an invalid item on the list causing the issue. Back up the Registry before removing an entry, though.


How to move data from the cloned external drive to the newly installed ssd?

Question: So here is my situation:
I want to upgrade my MacBook Pro mid 2010 to Samsung ssd 850 Evo. I used carbon copy cloner to clone my Mac to an external drive (WD My passport for Mac). Then I installed the Samsung ssd in my Mac. And now I'm trying to get the data back from the external drive to my newly installed ssd but having difficulties. What's the best way to do that?
Comment: Could you please explain the difficulties you are having as it's hard to help explain the best way to do this, without explaining what the problem is that you are encountering, it should be as simple as doing what you did before.
Comment: Did you actually install a OS X on the new drive, or you trying to get the OS X from the external drive? Normaly the CCC would make a bootable disk, so all you have to do is hold the option key during start up that will let you select where from to boot.
Comment: also did you read this https://bombich.com/kb/ccc3/restoring-disk-image
Answer: If I am understanding correctly it sounds like he cloned is old internal drive to an external drive, installed an SSD in the Mac and now wants to copy his files back.
If the new drive has Mac OS installed on it (if not probably best to install it. COMMAND-R and select internet recovery) you can just use Migration Assistant to copy your user files and (optionally) apps to the internal drive. Run Migration assistant and it will have an option for restoring from a local drive. Just select your CCC backup.
If the new drive has nothing on it, reboot the Mac while holding OPTION and select the external drive to boot from. Then use CCC to clone the boot drive to the internal drive. Doing it this way you won't get your recovery partition and might end up with other boot issues. Go back and use the first procedure.
Comment: Making CCC clone a second time will actually add the Recovery Partition - assuming there is one on the original… You have to remember to do it twice when making the first clone, too. 2nd clone takes 5 mins, as there's nothing new to add, of course.
Comment: So by just running CCC a second time and not specifying anything different (EG just "re-cloning" the drive) CCC will create the recovery partition?
Comment: It will spring a dialog telling you there isn't one & would you like to create one, as a separate step - but in effect, yes. You don't even have to do the 2nd clone after that [I did because I'd left a couple of days between events]. I'm guessing it's because 1st time it doesn't recognise the 'to-be clone' as a boot drive, 2nd time it does.
Comment: Great tip, never knew that, thx!
Comment: Welcome - I discovered it purely by accident when I needed to clone to do an SSD firmware update & just needed to add a couple of days extra data to the clone
Answer: I am assuming you are just turning on the Macbook? Have you tried holding down the Option key as stated here: https://support.apple.com/en-us/HT204417 and choosing the drive to boot from in the Startup Manager? And do you have an external drive also plugged in? Or just the new one? The computer may be trying to find the old boot drive? You don't say what is happening.
As stated in the comment you did not provide us with what the difficulties are.
After it boots the first time you can set the default startup disk. I would have preferred to use a comment for this but I don't have enough rep for that.


What is the pressure exerted by air column on closed glass vessel?

Question: Lets say we have a glass vessel initially open to atmosphere.I can understand that the pressure inside will be equal to atmospheric pressure.,But now the vessel is closed. Now will the pressure inside exerted by the little air present equal the atmospheric pressure? If yes then how? How can little air column exert such a large air pressure?
Answer: The trapped air is compressed - it was squashed in there by air pressure in the first place. When you closed the lid, you kept it in its compressed state.
Think about those films you see of them squeezing people into the Tokyo Underground carriages. When the doors slide closed, the people are still squashed, aren't they?
Answer: Air pressure is the force that the air exerts on the container per unit area.  You have to think about how this force on the container is being exerted.  This force is being exerted through the air molecules bouncing off of the container walls, both inside and out.  The pressure on the walls of the container is then going to depend on the rate at which the air molecules collide with the container wall and how much energy the have (in a simplified view of things).  The amount air that is trapped in the container is certainly much less than the amount of air outside the container, but it can bounce between the walls quickly since the total volume on the inside is much less. Also, the amount of energy that they have is the same as that of the air outside in equilibrium (also I'm assuming that you didn't actively remove any of the air, so the air density is the same as well).  So, they will be able to bounce off of the container walls at the same rate, exhibiting the same force per unit area as the air outside.  Hence, the pressures are equal.


Can a virus from a VirtualBox VM affect the host computer?

Question: Can a virus from a VirtualBox VM affect the host computer?
Answer: Very good question.
The main reason a virus could propagate from VM to host Operating System is via the network. Once you start using bridged networking between the host and guest things get more risky. Your machine and the VM are seen as 2 nodes on the same subnet. A worm which sees these 2 nodes has the possibility of propagation if such a vulnerability is found.
Comment: @arathorn, there are no votes given for upvoting ;)
Comment: @John T: But not good enough to actually upvote for once? ;)
Comment: I wasn't stumped :)
Answer: Yes, if you have shared folders...
Either shared folders through the VM, or standard networking.
I am not sure, and have not seen any viruses in quite a while that spread like this and edit files over a network, but it is possible.
Just because it is a VM does not mean it is safe, you just have to treat it like another physical machine on your network.
So, if you have anti virus on your host machine (and others on your network) you are as safe as you are going to be, but again... treat any VM like any other physical machine.
The only safe way to run a VM is to disable networking features (or VLAN separate it completely from your network... and not have any sort of management interface on that VLAN.) and all the host/guest integration that involve sharing files.
Comment: When you wrote *"have not seen any viruses in quite a while that spread like this and edit files over a network"* six years ago, that might have been very true. Meanwhile we know that ransomware [is here to stay](http://www.networkworld.com/article/2931814/security0/intel-security-scares-ransomware-script-kiddie-out-of-business.html) and is surely [targeting network drives](https://www.us-cert.gov/ncas/alerts/TA13-309A) too. So, indeed: yes.
Answer: Unless there's a security flaw in Virtualbox that allows you to break out of the VM (and you've not patched), then no. However, it's worth remembering that if there's any network connection between the two, there's the possibility of it moving to the host, as it would move between normal machines on the same network.
Edit: In terms of checking for connections, the simplest way is to nmap the host from the guest. Use the -PN switch, incase your host blocks ping. If there is any response, then you've got a connection there. Even if you don't, there's still the possibility of a connection through another machine, if that one is connected to both the host and the guest.
Comment: @EBGreen. No he is trying to recreate xkcd. http://xkcd.com/350/
Comment: how can I check for any connection between the host and vm ?
Comment: Are you trying to write a virus?
Comment: EBGreen, I am talking about my VM, how can I change the settings so it doesn't talk between the two!  I want to install something but I'm weary of it.
Comment: There are *always* security flaws that aren't patched.
Answer: technically, the answer is yes and with virtualization growing increasingly popular, expect more attacks on hosts through the guest OS in the forseeable future.
Answer: In response the John T's post about bridging - There is nothing required the host to be addressed. In our setups the host never has an assigned ip and therefore has no network connection. When updates are needed all virtuals are suspended, the host is temporarily assigned an IP, updates are performed, host IP is removed, then virtuals can be resumed.
Since we keep the host fairly bare and do all work in the virtuals, very few host updates are needed, kernel, X and virtualization code mainly.
Answer: I can confirm that it is possible for the host to get affected while browsing in the guest.
I have Windows 7 as the host and Ubuntu 12.04 as the guest system. I also have ESET Smart Security in Windows 7.
I was working on the guest system and suddenly wanted to browse. I opened Firefox in the guest system and while searching clicked on an ad. That ad seemed to be malware as ESET (in the host) popped up a warning saying something has been blocked from installing.
So, an ad clicked at guest seemed to affect host. Though it was blocked, hopefully, by the host antivirus. I was thinking that shared folder was the only link untill now. But a simple network connection via NAT allows for a virus to spread between systems.
Hope this clears the air a bit. This is just my experience yesterday, as I don't know the full technical details of how it is possible.
Comment: Happened to me as well.
Answer: A little late to the answer party, but affect can have multiple meanings.  The virus can be contained and have no risk of spreading from the VM.  However, it can still consume resources such as CPU, RAM, disk, and the network of the host machine.
Comment: Reading up on usage of the word affect & effect was interesting. I could imagine disk resources being eaten up if given a generously sized dynamic virtual disk. Interesting. Given that there is no networking between the Guest and OS I would assume that the worst that would happen is VirtualBox crashes or becomes unresponsive, maybe even the host OS becomes unresponsive if too much disk space gets eaten up. Huh.
Answer: technically yes because the VM saves the files to the host PC so its risky and it depends on the virus
Comment: This answer does not add any new information that wasn't already stated in an existing answer.


Can DPM 2007 back up virtualized Domain Controllers?

Question: I'm reading this article on caveats and best-practices for running DCs in VMs. It states that the only way to back up a virtualized DC would be to use Windows Server Backup on the guest, due to interactions with Active Directory, and USN rollback, and yadda yadda. Is this accurate? My organization uses DPM 2007 for backups, with system states and full disk backups (from within the guest server, not the VHD from the host) going on each virtual DC daily. If using DPM is supported, what are the correct practices to back up and restore virtual DCs?
Answer: A brief and very simplified explanation:
When "restoring", using a snapshot, the active directory database on the DC in question will not update its own invocation ID, leaving other DC's unaware of the fact that it has been restored.
Since the information about object "up-to-dateness" in an active directory partition in correlation to its replication partners depend on self-contained information (in the form of database and object USN's), the Domain Controller can not possibly be aware that it has been restored either, and so you run the risk of leaving objects on the DC in a stale state.
This is not just yadda yadda, blah blah blah, this is serious stuff, you might end up destroying more than you rebuild.
The issue of USN rollbacks due to unsupported recovery methods like snapshot reverts is covered extensively in this KB-article: http://support.microsoft.com/kb/875495. Here is an example from the real world
The bottom line is:
Snapshots are not valid as AD DS backups!
If you intend to back up your Domain Controller for active directory disaster recovery purposes (which I can only recommend), be sure to back up the system state of the VM, not the VHD. I haven't used DPM myself, but as I understand you can have DPM automatically retrieve the system state backup from wbadmin on the VM
Comment: If I only back up the System State, and the whole VM itself is shot, how would I go about getting it back up and running again? Just make a fresh VM image with a new Windows install and restore the system state?
Comment: As long as the VM has the same HW configuration and OS, yes.
Comment: I see. Another option I've heard is to restore the last full-system backup, boot into DSRM, then restore the system state. Is this valid too? Which is the "correct" method?


Time it takes to Transfer btc from exchange to another wallet?

Question: I recently sent a small amount of btc from the exchange to my other bitcoin wallet and it hasn't shown up yet, can anyone give me info regarding delays and how long such a transfer can take?
Comment: the transfer in the bitcoin network is one thing. exchanges are adding usually high network-fees for your withdrawal. but Some exchange services sometimes take a lot of time for start a withdrawal-transaction.
Answer: Transactions are sent instantly, but may not be confirmed for a long time, depending on the fee you paid. See this answer for more info on confirmations and fees: Why is my transaction not getting confirmed and what can I do about it?
Comment: "depending on the fee you paid" he sent funds >from< an exchange. very few exchanges allows the user to set the network-fee for their withdrawals.
Comment: @anion "depending on the fee that **was paid**" then, a little bit picky don't you think :)
Answer: BTC transactions require at least 6 confirmations. Since BTC block time = 10 mins, then you need to wait for at least 1 hour for Bitcoin transaction
(And also it is possible, that your transaction couldn't get to the nearest block because of a low tx fee.
More tx fee => more chance to get in a block.
And each block restricted in size by 1 MB, so it can have a limited number of transactions. It's actually a big scalability problem with btc.
So, if your tx doesn't get to the nearest block, then it waits in the pool for the next one and so on. Pool size depends on the mining node, as well expiration time. In most cases after 2-3 days staying in the pool tx become expired. And even if tx becomes expired, your BTC will just remain on your exchange, as if nothing happens. But usually, exchanges put on transactions quite a big fee, so this situation almost impossible)
Comment: Transactions do not require 6 confirmations, that is just a recommendation for security, but even 0-conf transactions are still valid transactions


How to export an Access database and import to MySQL?

Question: I am working on a Java project that sources data from an MS Access database, but I want to use MySQL because I have found it to be very easy to manage. How can I export an Access database that has tables of 8 MB and more, and move the data to MySQL?
Comment: To expand on @Dekel's answer, there's a video of the process [here](https://www.youtube.com/watch?v=m9LxGF3Qc90).
Answer: You can use ODBC to connect from MSAccess to MySQL.
Here is an example.
What you should actually do is:

Configure a new ODBC DNS connection (this might help)
Inside access - click on the table you would like to export, click on the file menu, then go to export and choose the name for the export
Select the ODBC connection you just created from the list of files of type.

MSAccess will connect to your MySQL server and export the data in that table to your MySQL database.
Comment: Just a head's up about DBA.SE. Link only answers are normally frowned upon (link rot). Maybe you could expand on this answer - provide the steps? Also, please use the formatting tools provided - in this case the link tool allowing one to embed the link in a relevant word (Edited).
Comment: @Vérace, thanks for that. As for the steps - they are very easy to produce based on the link, so I thought it will not make sense to just copy what's written there.
Comment: Well, just a summary should do - it's just as I said though, link rot does occur.
Comment: Ok, made some changes. I think now it's better :)
Answer: The best way to do that is:

Export Access data to xml
Go to phpmyadmin Import that xml file.

Note: if the xml file size is bigger than max upload size import through command line / bash or Terminal
Comment: Can i have this xml file in general format for learning purpose.?


what are the holomorphic curves in $T^{*}S^3$ with boundary on the zero section?

Question: How would I characterize such things? Is the minimal spanning (real) surface of a (real) curve in $S^3$ contained entirely in that $S^3$?
Answer: I presume you are choosing an almost complex structure on $T^*S^3$ that is compatible with the canonical symplectic form? (This includes the complex structure coming from the holomorphic structure on the affine quadric.)
In that case, you need to specify a bit more about what kinds of curves you are looking for. If the curves only have boundary components and all these boundary components are mapped to the 0 section, then they are all constant. Indeed, the canonical symplectic form is exact (with primitive by the canonical 1-form on $T^*S^3$), and this primitive vanishes on the $0$-section. Therefore, the symplectic area of any holomorphic curve is $0$. Since the symplectic form is compatible with the almost complex structure, we also have that this area
\[
\int u^*\omega = \int |du|^2 d vol.
\]
In order to get non-trivial holomorphic curves, you need to allow punctures. This picture becomes technical fairly quickly, so before I explain more, you should specify what you are looking for exactly.

Update with punctured holomorphic curves: You can think of the above as some kind of analogue of looking for holomorphic sections of a bundle. There are plenty of bundles without sections, but that have meromorphic sections. Punctured curves are then some analogue of meromorphic sections.
More precisely, you want to think of $T^*S^3$ as being composed of a compact piece, whose boundary is the unit cotangent bundle (with its canonical contact structure - denote this by $Y = S^3 \times S^2$ since $S^3$ is paralellizable), and a piece that looks like $\mathbb{R}^+ \times Y$. If you choose a contact form on $Y$, you can now ask to have an almost complex structure in this region $\mathbb{R}^+ \times Y$ that is invariant under the $\mathbb{R}$ action and that sends the generator of this action to the Reeb vector field on $Y$. Now, with a suitable notion of energy, curves defined on punctured domains can converge to periodic orbits of this Reeb vector field as they go to infinity (see the Hofer-Kriener survey paper I mentioned or take a look at the difficult papers by Bourgeois-Eliashberg-Hofer-Wysocki-Zehnder on compactness or by Eliashberg-Givental-Hofer on SFT).
This family of ideas allows one to study string topology... see for instance Cieliebak-Latschev (it has something like string topology in the title) or Seidel's paper on "a biased view of symplectic cohomology".
Comment: I came to the conclusion you describe shortly after asking this question. I would like to hear what you have to say about the case with punctures if you would, however.
Comment: I recommend a nice survey article (though a little obsolete) by Hofer and Kriener. I'll update what I wrote with a few more details.


Can I install Ngnix on a server that is already on Apache?

Question: I have a dedicated server that is running on Apache, I heard Nginx is uses less resources and gives 10 times better results on the same hardware.
Is it possible for me to replace Apache with Nginx? Will it effect any data or settings of my server?
Answer: This depends on your server configuration (virtual hosts, rewrite, etc..). You need to configure nginx in the same way you configured apache (after finding the equivalent directives in nginx).
If you failed to do so, you may end up by having your website(s) not running as expected or not running at all.
Answer: Yes you can install nginx on a server at the same time as having apache installed. You can also have them both running at the same time - The only restriction is that they cannot both be listening to the same port.
Yes you can replace apache with nginx, just as you could replace it with almost any webserver.
No your data will not be affected (assuming you mean your application's data)
Yes the settings of your server will be affected - the config files for apache cannot be read by nginx.
If you want to try out nginx, the simplest way to do so is simply to install it to a different port. E:g. find the listen directive and put:
<code>listen 81;
</code>
It will then run alongside your existing apache install - you can load http://example.com (apache) and http://example.com:81 (nginx) to check for errors etc. If you are happy that things are working, you can then turn off apache, change it to listen on port 80 and there should be no noticeable impact (except perhaps better performance) to visitors to your web.
Answer:
Is it possible for me to replace Apache with Nginx?

Short answer: Yes!

Will it effect any data or settings of my server?

Short answer: No!
With careful planning and testing, you can migrate all the settings to Nginx. The data wouldn't be affected, though.
In Apache there are certain things are handled much easier such as rewrites. In Nginx, rewrites need to be manually created.


About SKU in magento

Question: I want to know if i created one simple product with e.g sku:YJR
then i have to create the same product as bundle product with same sku, then it create any problem in future, if not then what's the rightway ?
Any guidence is accepted.
Thanks in advance.
Comment: Questions abut Magento should be asked on [magento.se]
Comment: I'm voting to close this question as off-topic because it is a question about business operations, specifically store/inventory management and therefore might be more applicable over in magento.stackexchange
Answer: Firstly I would like to tell you something about : SKU
SKU StockKeeping Unit, is a unique identification code, usually alphanumeric. It allows a particular product to be tracked for inventory purposes. Typically, an SKU (pronounced with the individual letters or as SKYEW) is associated with any purchasable item in a store or catalog. You can choose any format you like for SKU but usually there is some system for choosing numbers, for example, a woman's blouse of a particular style and size might have an SKU of "3726-8," meaning "Style 3726, size 8."
SKU is unique identification code.You can not create a product a with already existed SKU its not possible.
Hope this one is useful for you
Comment: Thanks for the descriptive answer.

About SKU in magento


Is there any difference between "time line" and "timeline"?

Question: Whenever I type "timeline," without a space, it gets red squiggly line. But when I search to Google, the word actually exists. Is there any difference? And please give some other compound words that can be written in many ways? Adding a dash and a space and without any.
Comment: Don't trust automatic grammar or spelling checkers very much, they're not very good.
Answer: Timeline means the linear portrayal of chronological events. Time line is incorrect in this context (although I suppose the words could show up in some other sentence with an unrelated meaning, e.g., "the runner crossed the time line").
in to and into are commonly confused as well, since the word in is used last in so many two-word idiomatic phrases.  Explanation: http://writingexplained.org/into-vs-in-to-difference
Answer: Based on an article at The MLA Style Center (which uses definitions from Merriam-Webster), a "time line" is a dated list of significant events that have happened in the past, while a "timeline" is a schedule or timetable of planned events.


Is there any difference between Bounded and Totally bounded?

Question:
Is there any difference between bounded and totally bounded? (in a metric space)
Answer: The real line $\Bbb R$ endowed with the metric $d(x,y)=\min(1,|x-y|)$ is a bounded metric space that isn't totally bounded.
Answer: Just to throw one more answer into the mix, any infinite set with the discrete metric is bounded but not totally bounded (I like @Gedgar's answer better, but just for some variety...)
Answer: A major theorem in metric space theory is that a metric space is compact if and only if it is complete and totally bounded. In $\mathbb{R}^{n}$ with the usual metric ( for $n < \infty$), bounded and totally bounded are the same, which is essentially the content of the Heine Borel theorem. In fact, the unit ball of a Banach space is compact if and only if the space is finite dimensional.
Answer: Every totally bounded set is bounded.  But not conversely.  The unit ball in Hilbert space is bounded, but not totally bounded.
Comment: Maybe you mean an infinite dimensional Hilbert space?


How can I report to Drupal what is the translation in a language of a string passed to t()?

Question: I'm using Drupal 7. I see that the t() function is responsible for translating terms. Where do I go to find the list of translatable terms? For example, suppose I have t('hello world') in my code.  What file do I edit to tell Drupal 7 that the French version of "hello world" is bonjour toute le monde?
Answer:
You could browse to the Translate interface page
(/admin/config/regional/translate/translate).
You could use a .po file and import it (en/admin/config/regional/translate/import).

You'll have to enable the Locale module for this (it's in core).
More information is available on Translating a site interface to different languages.
Comment: I just want to notify that you string would be available only if it appear in the foreign language at least one time. For example, you are looking for `hello world` but if you didn't see it in the french part of your website you'll not able to find it in the admin.
Comment: The easiest way would be to export your terms first (/admin/config/regional/translate/export). That way you'll have a .po file that you can edit. If you translate one term you'll have the complete syntax.
Comment: Thanks, how do I create a .po file for my Hello World example?


Is there a reason drill bits are stored pointy side up?

Question: The title says it all... Is it for marketing purposes, or is there an actual reason bits are typically stored sharp side up?
Answer: In older days a drill bit set would normally be kept in a metal box called a drill index. Here is a picture of a typical drill index.

The hinge out carriers for the drill bits were made of metal and it is a possibility that the nice sharp ground edges on the drill flutes could be worn if the fluted end of the bit was shoved down into the holes.
More of the modern drill kit boxes use a different style. They are made of plastic and often have a squeeze in holder for the smooth shank part of the drill bit. It is much harder to get the fluted end it snap in to this type of holder and the sharp edges would cut up the plastic.

So there you have two plausible answers to your question. Only other thing I can say is that the fluted ends all look cool when packaged in a size sequenced set. Why not show them off?
Comment: As long as the index was made from a softer metal than the bits, there should be no fear of bit damage. And plastic indexes could surely be designed to accept bits tip down.
Comment: Softer metal on the index than the bits = drill index being worn down over repeated drill bit insertions upside down. I think it started this way out of practicality and stayed that way out of convention mostly for display/marketing purposes. I like being able to see the tips and flutes of the bits I'm buying to know they're not completely dull before I buy them and I expect others do too.
Comment: @Tester101 - My old old metal drill index boxes have steel carriers for the drill bits. I have indeed seen others that have the carriers made out of aluminum so that would be much softer. Although along with that I've also seen those get bent out of shape much easier.


Covered call buy back

Question: I sold a covered call for $1000. If I buy it back for $5000 before the expiration  date, will the $4000 considered a short term loss and will it offset my short term gain and long term gain? I do not mind keeping the underlying stock.
Answer: If you buy the call back before expiration, the $4,000 will be considered a short term loss regardless of the length of time that the option position was open (short sales are treated as short-term even if they were open for more than one year).
It might have been a good idea to either cover the short call before it appreciated so much or to have rolled it up and out for a small loss or even a credit but as it is, I am not a fan of realizing option losses while carrying paper gains because the market has a perverse way of making you pay for that.  I would sooner adjust the position, book gains and carry paper losses.
Comment: Thank you. Also, once I buy back and use that loss for my 2020 gains, can I immediately go ahead and sell new covered calls for the same security for same or another expiration date.
Comment: When it comes to options, there's a lot of ambiguity in US tax law.  AFAIC, if you sell a call on the same underlying within 30 days before and after realizing a loss on an existing call, it's a wash sale since the calls are substantially identical.  You should verify this yourself before doing so.  A wash sale has no consequence if the entire position is closed before the end of the year and you remain out of it for 30 days.  This is one of the reasons that I previously mentioned rolling for a small loss or a credit before the option gets away from you.

Covered call buy back


How to change temperature and humidity sensor of XH-M452 thermostat?

Question: there is a thermostat for incubator for poultry. People generally using this model XH-M452. But this thermostat has a problem, in high humidity environment temperature and humidity sensor of XH m452 not working good. when I opened the case of sensor I saw, AHT21 sensor was inside. Aht21 is I2C interface. I wonder how can I change hdc1080 instead of aht. Both sensor are using I2C interface but I think HDC1080 address is 0x42 but address of AHT21 is 0x38
Comment: Usually `xxx21` sensors (e.g. sht21, htu21) are interchangeable. You can check their addresses out to see if you could use them instead.
Comment: BTW, the temperature and humidity are related and formulas are available in some datasheets to correct them. It seems the maker has overlooked it.
Answer: The problem is not only about the chips having different I2C addresses.
The chips also have different commands how to start measurements and how to read the results.
You need to do two separate things.
First thing is to emulate the original sensor, and it does not matter how you implement it and how you fake the results.
Second thing is to get the needed measurement data from somewhere, no matter from where, but it can come from a different type of sensor.
It might be easier to simply replace the original MCU with your own to run your own software, or do a similar clone of the product. Maybe with Arduino and relays and displays and buttons.


How to specify which functions/methods should be covered by a test, using Karma, Jasmine, and Istanbul

Question: I am trying to figure out how to restrict my tests, so that the coverage reporter only considers a function covered when a test was written specifically for that function.
The following example from the PHPUnit doc shows pretty good what I try to achieve:

The @covers annotation can be used in the test code to specify which
  method(s) a test method wants to test:

/**
 * @covers BankAccount::getBalance
 */
public function testBalanceIsInitiallyZero()
{
    $this->assertEquals(0, $this->ba->getBalance());
}

If the test above would be executed, only the function getBalance will be marked as covered, and none other.
Now some actual code sample from my JavaScript tests. This test shows the unwanted behaviour that I try to get rid of:
it('Test get date range', function()
{
    expect(dateService.getDateRange('2001-01-01', '2001-01-07')).toEqual(7);
});

This test will mark the function getDateRange as covered, but also any other function that is called from inside getDateRange. Because of this quirk the actual code coverage for my project is probably a lot lower than the reported code coverage.
How can I stop this behaviour? Is there a way to make Karma/Jasmine/Istanbul behave the way I want it, or do I need to switch to another framework for JavaScript testing?
Comment: What comes to mind is to use dependency injection and mocks to reduce the number of calls to actual production-code.
Comment: I agree with henrikmerlander. Besides, if you're using real function calls instead of mocks inside the tested method indirectly you're testing that function as well
Comment: really good question. For example, testing with phpunit, we have /**  @coverage **/ phpdoc tag ;)
Answer: I don't see any particular reason for what you're asking. I'd say if your test causes a nested function to be called, then the function is covered too. You are indeed indirectly testing that piece of code, so why shouldn't that be included in the code coverage metrics? If the inner function contains a bug, your test could catch it even if it's not testing that directly.
You can annotate your code with special comments to tell Istanbul to ignore certain paths:
https://github.com/gotwarlost/istanbul/blob/master/ignoring-code-for-coverage.md
but that's more for the opposite I think, not to decrease coverage if you know you don't want a particular execution path to be covered, maybe because it would be too hard to write a test case for it.
Also, if you care about your "low level" functions tested in isolation, then make sure your code is structured in a modular way so that you can test those by themselves first. You can also set up different test run configurations, so you can have a suite that tests only the basic logic and reports the coverage for that.
As suggested in the comments, mocking and dependency injections can help to make your tests more focused, but you basically always want to have some high level tests where you check the integrations of these parts together. If you mock everything then you never test the actual pieces working together.


How to identify associated widget when list item is clicked?

Question: I have been able to create a ListActivity that displays a header and a footer, and sandwiched between these a custom layout that contains on each row three checkboxes and a Contact name (reading from the Contacts database). I use a SimpleCursorAdapter to display this info. My problem has been getting the OnListItemClicked()* to fire. I click in the ListView (on the checkboxes AND on the name of the Contact) and my breakpoint is never reached. So: What must I do to get that to fire. I AM setting it, like so:
lv.SetOnListItemClicked(etc);

I think it is; I'm not at my dev machine right now

But even if I am able to get the click event to fire, how will I be able to identify the associated checkboxes? They are named ckbx1, ckbx2, and ckbx3 (or so) in the layout file, but there will be (Contacts.Count) of them, so how can I positively identify which ones have been clicked?
My other option is to dynamically create the widgets in the Activity's OnCreate().
My pseudocode for this is the following, and I'm open to suggestions/feedback on whether this makes or is [not] the best way to go about it:
OnCreate() {
  Cursor c = getContacts();
  for (i = 0, i == c.Count, i++) {
    int id = getContactID(i);
    CheckBox ckbx1 = new CheckBox();
    ckbx1.Tag = id;
    ckbx1.OnClick = Checkbox1Click();

    CheckBox ckbx2 = new CheckBox();
    ckbx2.Tag = id;
    ckbx2.OnClick = Checkbox2Click();

    CheckBox ckbx3 = new CheckBox();
    ckbx3.Tag = id;
    ckbx3.OnClick = Checkbox3Click();

    TextView tv = new TextView();
    tv.Text = getContactName(i);
}

Checkbox1Click() {
  int ContactID = (CheckBox)object.Tag;
  switch (ContactID)
  case 1:
    WriteToDB(1, Option1);
  case 2:
    WriteToDB(2, Option1);
  ...
}

This (especially the CheckboxClick event handler) is obviously very rough, but I think you can get the drift of where I'm going with this - saving the "checked" state of the Checkboxes to a SQLite DB so that I know Contact1 wants email (or twitter feed, or whatever the other two checkboxes indicate).
So is my previous method salvageable, or should I go down this new path (or veer off a little from that?)
Answer: Usually i uses View.setTag to identify a view instance. For example,
checkBox.setTag("listItem1");


Xgboost model predicting extreme values for events and non-events | Overfitting

Question: Extreme values are predicted by my trained xgboost classification model in BQML for both events (Y=1) and non-events (Y=0).  For all event observations, the model calculates probability scores that are almost 0.98 and above, while for all non-event data, they are almost 0.02. The box-plots below show the distribution of probability scores for these observations of events and non-events. Furthermore, this comes from the testing dataset. This is overfitting. Any suggestions for how to approach this?
Comment: There is not enough details to offer any appropriate solution, also there is little information on what you have done to resolve your issue. As a generic advice, try to simplify the problem and then slowly make it more complex. For example, if you fed your label as a feature, you would definitely expect classifier to work well. Does it? Next try to predict label from just one feature. This should give you a hint on which features are important and which are less so. Next, if you combine several important features, you would not expect classifier performance to drop etc...
Answer: This is not necessarily overfitting, but it may indicate data leakage i.e you are passing information to the model that is not supposed to be there it may be:

Information that is generated after the event of the target. For example, credit risk would be using information on credit accounts opened after the moment you are evaluating the customer.
The target itself. For example, you add a feature generated only when the target equals 0 or 1. Imagine, for example, using a null feature when the customer is not approved and has a value different from null otherwise.

So it is a problem that may be difficult to address, but you can run a simple validation using permutation importance.
If you see that there is one feature that, when dropped, has a huge impact, it is likely that feature has leakage and thus, the metrics you are seeing are not trustable.
Answer: A high score on the test set does not indicate overfitting.
See Why 100% accuracy on test data is not good? ; you're not quite reaching perfect performance, but you're quite close, and in that seeing it is natural for the model to make confident predictions. You should focus on making sure you haven't leaked future information.


Install Ubuntu touch on x86 tablet

Question: Is there any way to install Ubuntu touch on an x86 tablet? Some images are available for download over there http://cdimage.ubuntu.com/ubuntu-touch/daily-preinstalled/pending but I don't know if I can somehow download and install them on my tablet.
Comment: if you can install ubuntu on it regularly, or other linux systems - I would download the ubuntu desktop next iso and try that
Answer: I am afraid (or hope so?) that all the answers I found so far, searching for the same question, are simply off topic.
Because x86 tablets are NOT ARM devices, those should be regular PCs with some Intel CPU.
The only points to answer, should be how to get GRUB in, and whether certain hardware has its drivers.
The rest should be the same on tiny 7" x86 tablets, as on any standard desktop - with touch screen, which is just a kind of mouse.
So the partial answer is, NOT ubuntu-touch - do not search for images for ARM CPUs, when yours is Intel x86 (and 64-bit).
What is missing is "howto" make that device boot GRUB (perhaps 32-bit EFI?) on certain tablets, and install Ubuntu - "normal" PC Desktop version.
Well, and onscreen keyboard for touch devices, is part of  Ubuntu Desktop, its name is "Onboard". And light desktop environments (xfce4, Xubuntu) may be preferred on tiny devices, to avoid slowdown..
Comment: I don't think this is correct. I'm playing with Ubuntu on a Dell Venue 11 (I5 x86 tablet) and while I'm making headway with "onboard etc" it doesn't seem possible to do Full Disk Encryption without plugging in a keyboard (but I think home directory encryption might work), nor does device rotation work seemlessly, and the GUI needs LOTS of tweeks to make it - sort if - useable.
Answer: I was recently wondering the same thing, so I researched it and found an article that has very easy and simple steps, and lists what you need. It can be found here:
http://www.pcadvisor.co.uk/how-to/linux/3531970/how-install-ubuntu-touch/
Good luck.
*WARNING! UBUNTU TOUCH IS NOT FULLY DEVELOPED YET, AND MAY HARM YOUR DEVICE IF NOT INSTALLED PROPERLY! IT IS RECOMMENDED THAT YOU INSTALL IT ON AN EXTRA OR UNIMPORTANT PHONE/TABLET!
Comment: Those are Android instructions
Comment: @AleksandrDubinsky Although that's probably not the correct answer because I think the Ubuntu touch images are for arm devices, there are some intel based Android devices out there.
Answer: Step 1:
With Ubuntu installed on your PC, ensure you have the universe archive enabled. This is a software repository which is probably commented out – you need to remove the # which precedes it in the file /etc/apt/sources.list
You can find detailed information on how to add repositories here
With Ubuntu universe archive enabled, now you can install the ubuntu-device-flash package – the main tool for installing Ubuntu Touch - as follows.
Step 2:  (you can skip this if you're already running 14.04 as the tools are already included).
You'll need tools in the Phablet Tools PPA in order to install Ubuntu for devices. These are included in 12.04 Precise onwards. On your PC, press Ctrl+Alt+T to start a terminal.
Add the Phablet Tools PPA by typing (at the $ prompt): sudo add-apt-repository ppa:phablet-team/tools
On Ubuntu 12.04, add the Ubuntu SDK Release PPA by typing: sudo add-apt-repository ppa:ubuntu-sdk-team/ppa
Update your system to use the latest packages by typing: sudo apt-get update
Install the ubuntu-device-flash package by typing: sudo apt-get install ubuntu-device-flash
For help with the ubuntu-device-flash tool type: man ubuntu-device-flashYou can type q to exit.
Step 3:
Install phablet-tools package by typing: sudo apt-get install phablet-tools
List its tools by typing: dpkg -L phablet-tools | grep bin
Note that you can show a tool's help by adding –h. For example: phablet-config -h
Step 4:You need to enable Android Developer Mode on your device. To do this, head to Settings and tap About phone (or About tablet) then about. Now tap Build number seven times and you will see a pop-up saying you are now a developer.
You will now have a new menu in Settings called Developer options. Go in here and tick the box next to USB Debugging.  Enabling USB Debugging allows you to send commands to your USB connected device from the terminal.Step 5:
Connect your device via a USB cable to your PC running Ubuntu. You'll be prompted in Android to authorise it. To check the connection is working, type (at the prompt) adb devices
You should see your device listed with a series of numbers and letters. If your device isn't shown, try first typing: adb kill-server
Step 6:
If you haven't already done so, now is the time to back up your Android apps and data. Also, note down your device type and build ID because you will probably want to reinstall Android later (you'll have to download the factory image and use the adb and fastboot tools to install it).Step 7:
To install Ubuntu, you need to unlock your device's bootloader. This process wipes the phone or tablet.
To do this, type at the prompt (as a reminder, hit Ctrl+Alt+T to open a terminal): adb reboot bootloader Now unlock the bootloader by typing: sudo fastboot oem unlock
You'll see a warning on screen. To change from no to yes, use the volume rocker, and to select the option, press the power button.
Now reboot the device by typing: fastboot reboot
You will be taken through the initial setup. Don't worry about entering much information as you're about to remove Android completely by installing Ubuntu.
Step 8:
Power off your device using the power button.
Reboot into the bootloader by using the correct physical button combination for your device For example, the combination for the Nexus 5 is to hold down the volume up, volume down and power buttons simultaneously.
Install Ubuntu by typing: ubuntu-device-flash --channel=devel --bootstrap
The installation should happen automatically with no input from you. It will take a while – the image is initially downloaded to the ~/.cache/ubuntuimages folder on your PC before being transferred to your smartphone or tablet.
To begin with, Ubuntu is a 'recovery' image which you device will boot from. Then, Ubuntu is installed as an OS in its own right. On the next reboot, you should see Ubuntu running.
Step 9:
After installing Ubuntu, you can head to Settings > Updates to get the latest version, and choose whether or not updates are installed automatically.
Comment: Hi MineLover729, you will have to include an attribution (to: By Jim Martin | 15 May 2015) and a source (https://www.techadvisor.co.uk/how-to/linux/how-install-ubuntu-touch-image-3531970/) , but simple complete copies are undesirable.

Install Ubuntu touch on x86 tablet


Using dielectric grease on oven broil element connector

Question: Our upper bake element on our oven wasn't working, so I took it apart last night and found that the spade connector had apparently arced and charred and it was totally disconnected.
I had considered cleaning off the charring and re-using the element since there was a decent bit of spade connector left and it measured fine, but for the price of a new element ($20-$40) I am going to replace the bake element just to be safe.
I will also crimp on a new spade connector, but I talked to someone I trust in electrical matters and they mentioned the possible use of dielectric grease to help ensure that the new connection didn't oxidize.
Now the connection itself gets pushed back into insulation outside of the actual baking area, but:
Is it safe to use dielectric grease on this type of connection?
Do I need to worry about the grease being food safe even if it's not in the oven area?
Comment: try graphite powder or iron filings or AL foil; on AC it's not oxidation, it's a poor fit that causes arcing.
Answer: Make sure to get high tempature spade lugs. Standard tinned copper tend to get loose with heat, the ones I use are rated to 900 f.  As an example I use FR9C-250 terminals from elecdirect (without the name a bunch of gun parts came up).
I have repaired stoves that had some damage but the replacement lug needs full contact with the blade or even high temp connectors will overheat. I am not sure if dielectric grease in this application will do much good but I don't think it would hurt. It may smoke when the element is turned on for the first time or two.
Answer: The Dielectric will all burn off in relatively short order. The smoke and smell, you are not going to want in your kitchen.  Make sure you cut back the lead to good clean wire. Oxidation is not a problem in this situation.  You just want a good clean tight connection.  I strip back the insulation twice the length of what I need then fold conductor in half so I have twice the bulk to stick in the barrel of the connector. + what Ed said.
Comment: This isn't a great picture, but the actual tab connection is behind the screw plate (http://i.ebayimg.com/00/s/NTAwWDUwMA==/z/1X0AAOxyUrZSs9fS/$_3.JPG?set_id=2) and buried in the oven insulation (https://i.ytimg.com/vi/gUv7ajMRmsw/maxresdefault.jpg). I would think that would protect from a majority of the heat so you shouldn't experience burn off? I should probably test that with the back off. Thanks for the answer!


containers and host user space shared when created using virsh

Question: I'm trying to setup a container in redhat. The container should also run redhat version same as that of host. While exploring about these, I came across virsh and docker. Virsh supports host based containers and shares user space with host machine. Here I got confused with user space. Whether it mean filesystem space or some thing else. Can anyone clarify me on this? Also in which scenarios/cases virsh(host based container) can be used so that I can conclude whether its better to use virsh or docker. In my case i need to set up a redhat container in redhat host and run multiple instances of same process in each container. The containers should exchange data across each other without using network interface.
Answer: This should help clarify: http://rhelblog.redhat.com/2015/07/29/architecting-containers-part-1-user-space-vs-kernel-space/
It sounds like you really want to use Docker with -v bind mounts to share data. That is an article for a future day :-)
https://docs.docker.com/userguide/dockervolumes/
Answer: Current Kernels do not support yet the user namespace.
This is a known limitation of current containerization solutions. Unfortunately, usernamespace was implemented in latest kernel releases (staring from kernel 3.8) http://kernelnewbies.org/Linux_3.8 though it is not yet enabled in many mainstream distributions.
This is one of the strongest limitations of containers right now, if you are root (ID 1) in a container, you are root across the machine operating the container.
This is a problem affecting any product based on LXC though there is a strong push to fix this. It is actually a needed thing!
Alternatives is to go for hard Selinux jailing or work with underprivileged users accounts and assigning different users per container.
From Libvirt documentation https://libvirt.org/drvlxc.html:
User and group isolation
If the guest configuration does not list any ID mapping, then the user and group IDs used inside the container will match those used outside the container. In addition, the capabilities associated with a process in the container will infer the same privileges they would for a process in the host. This has obvious implications for security, since a root user inside the container will be able to access any file owned by root that is visible to the container, and perform more or less any privileged kernel operation. In the absence of additional protection from sVirt, this means that the root user inside a container is effectively as powerful as the root user in the host. There is no security isolation of the root user.
The ID mapping facility was introduced to allow for stricter control over the privileges of users inside the container. It allows apps to define rules such as "user ID 0 in the container maps to user ID 1000 in the host". In addition the privileges associated with capabilities are somewhat reduced so that they cannot be used to escape from the container environment. A full description of user namespaces is outside the scope of this document, however LWN has a good write-up on the topic. From the libvirt point of view, the key thing to remember is that defining an ID mapping for users and groups in the container XML configuration causes libvirt to activate the user namespace feature.
Comment: I believe he asking about sharing the user space or not, not to be confused with user namespaces: http://rhelblog.redhat.com/2015/07/07/whats-next-for-containers-user-namespaces/


MySQL Performance Problems

Question: Started having issues with our central production MySQL Database Server today.
We have 1 central production MySQL 5.7.11-log server which is bare metal with 32GB mem and 12 core CPU with 2 SSDs in RAID. This server houses 3 databases which are each used by 1 VM running Apache for Each of our custom Web applications (total of 3 VMs running Apache).
One of the Web servers started to slow down this morning and after a few minutes came to a halt entirely. The other 2 Web apps continue to function and perform normally.
We started digging in Apache, restarted the Apache daemon, no effect, restarted the VM with no effect. I restarted the MySQL daemon and the app starting running fine again. A couple hours later in happened again, I restart mysqld and we're good for another couple of hours.
I've dug through Apache logs, PHP logs, MySQL logs. The only thing that stands out in the mysql error.log is Aborted connection 766409 to db: 'DB' user: 'USER' host: 'HOST' (Got an error reading communication packets) there is nothing in the other logs I've looked through and been monitoring today that looks out of place.
I've been staring at htop, iotop, iftop, and mytop all day and server load on MySQL and the Web VM remains well withing what is normal on any other day. One thing I do notice is in mytop as the slowdown is happening I see a lot of connections piling up from this Web app, almost as many sleeping connections (22) as there were connections waiting or creating (21).

This application has stopped responding a total of 3 times today, a couple hours apart. All three times the other applications which connect to this database server continue to function normally. The first time it happened I didn't get a chance to look at mytop before restarting mysql, but the other 2 times I had mytop running on another monitor and watching it and connections piled up both times.
We're a small company, and do not have a DBA. I'm a developer and have been able to manage and troubleshoot MySQL over the last couple years, but it seems as we grow we're running into things that I just don't have the experience to resolve, I'm talking to the owner of the company about hiring a DBA consultant to help fill the gap in our development team, but in the meantime I have no idea where to look next to continue to troubleshoot this and would really appreciate all the help and advice I can get at this point.
Answer: Based on the information you have provided I would highly scrutinize the oldest queries running when the "slowdown" happens. It's possible the select(green 21) or the update (green 20) are blocking the rest of your queries and causing a pile up.
The thread state seems to be truncated but this can give you more information as to what may be going on.
https://dev.mysql.com/doc/refman/5.7/en/general-thread-states.html
It also could be those very old sleeping connections (1 & 2 red) Even though they are sleeping they could be holding active transactions that are hiding. A 'show engine innodb status' will reveal potential active transactions holding row locks that are causing newer queries to wait.
https://www.percona.com/blog/2006/07/17/show-innodb-status-walk-through
Best of luck to you!

MySQL Performance Problems


Does Snape ever use Legilimency in the books before OOTP?

Question: Does Snape ever clearly use Legilimency in the books before OOTP? I know Harry felt that Snape could read his mind, but do we ever see Snape knowing something that he only could have gotten (or mostly likely had gotten) through Legilimency?
Comment: Occlumency is used to protect your mind. Legilimency is the art of reading another persons mind.
Comment: Can you clarify whether you mean to ask about Legiliemency or Occlumency? You mention Occlumency, and that's what the answer addresses, but your description seems to be of Legilimency.
Comment: Given there is an answer for the Occlumancy version, best fit might be to set this to Occlumancy again, and create a new Legilimency question.
Comment: I meant Legilimency. I'll fix it
Comment: @Jontia Perhaps.
Answer: Maybe
While never expressly stated, Harry describes snape as "Boring into" his own on multiple occasions early on.  In regards to the shenanigans surrounding Hermionie's theft of Polyjuice potion ingrediants in Harry Potter an the Chamber of Secrets and again in Harry Potter and the Prisoner of Azkaban when interrogating Harry about the Marauder's map.  On both occasions Harry isn't "caught out" (I assume because it's against the rules for a Student to have their minds read by a teacher) but Snape seems to know Harry is lying.  Specifically in Harry Potter and the Goblet of Fire when Snape notices Boomslang skin et al being stolen from his stores again he accuses Harry of the theft without any evidence whatsoever.  IMO the only reason he'd do that is if he "knew" those same ingredients were stolen before and Harry had a hand in it.  Both these situations are described similarly to Snapes use of legilimency against Harry in Harry Potter and the Order of the Phoenix after Harry and Draco's bathroom duel.
Note: For those wondering if Legilimency  is something Snape couldn't actually use as evidence, I offer two possibilities: Using legilimency is certainly an invasion of privacy, and quite an extreme one.  OR It may fall under self-incrimination.  Either way it seems very much out-of-bounds for a teacher to do to a student when the student is unwilling.  Especially considering the more serious circumstances (like finding who opened the chamber of secrets) where Legilimency could have been used to identify perpetrators of life-threatening incidents.  The fact that it wasn't leads me to believe that if Snape did use it on Harry in the situations indicated he wouldn't be able to use that knowledge by itself to get Harry into trouble.
Answer: Yes.
In the Goblet of Fire, he has to return to the Death Eaters and carry on the double-agent facade, acting like he was secretly on Riddle's side. Given Voldemort's prowess in Legilimency, he would have had to conceal his thoughts from him.
Lupin also refers to him as "a superb Occlumens". This is praise he could only have earned on account of expertise, and consequently, extensive use.
Comment: I fixed my question. i'm sorry for the misunderstanding.


How to move some software's folder from appdata folder?

Question: I do not want to change the location of appdata.
I want, for example, change the location of firefox folder in appdata to another drive. There
are also other software that I want to move their folders out of appdata.
I use windows 7.
Comment: I see. What does your own research suggest you can do? You can't do what you want for just a few items/directories etc
Answer: It is not possible to move a single folders location unless the application allows this. Firefox as far as I'm aware does allow this though.
Read this:

Modify profiles.ini to point to the new location - Advanced Firefox,
  Thunderbird and SeaMonkey 2 Note: This method does not apply to
  Mozilla Suite/SeaMonkey 1.x, which uses a different system for keeping
  track of profiles. Firefox, Thunderbird, or SeaMonkey 2 should already
  be installed on the computer where you are moving the profile and a
  profile folder and profiles.ini file should already exist. This method
  is recommended for advanced users only since it can be tough to
  troubleshoot. Mozilla applications can be very finicky about the
  contents of the profiles.ini file. They normally do not ignore bad
  entries, regardless of their position in the file. Create a new, empty
  folder in the desired profile location with the name you wish to use
  for the new profile, for example,
  D:\Mozilla\Firefox\Profiles\newprofile Copy the entire contents of the
  profile folder you are moving into the new profile folder you just
  created. If you copied the old profile from a CD, remove the
  write-protection from the copied files. Find the profiles.ini file (it
  will be located in the default profile folder path) and open it in a
  text editor. (Optional) Change the "Name=" line to the name of the new
  profile folder you created, e.g., Name=newprofile Change
  "IsRelative=1" to "IsRelative=0" (non-relative/full path) Change the
  "Path=" line to the actual location of the new profile folder, e.g.,
  Path=D:\Mozilla\Firefox\Profiles\newprofile. If you're using Windows
  non-relative paths use back slashes while relative paths use forward
  slashes so you may need to change the direction of the slashes too. If
  you are moving a profile from its default location, the original
  profile folder can now be removed. If you're using Thunderbird, check
  that you can see the folders for each account. If they're missing, use
  the browse button for the local directory in Tools -> Account Settings
  -> Server Settings and Tools -> Account Settings -> Local Folders to specify the correct account and mail directories. Caution: Incorrect
  editing of the "profiles.ini" file can cause a "already running but is
  not responding" error if the profile cannot be found (bug 278860).

This needs to be application specific, you may also want to look at portable editions of software that are designed to be installed in USB devices, essentially not using any system properties but saving everything in their own files.
http://portableapps.com/apps/internet/firefox_portable
Edit:
You can also use hard links.


Dimensions of a black hole

Question: How big can a black hole become and  how small can a black hole become?(minimum and maximum dimensions of a black hole)
Answer: Primoridial black holes can be found (hypothetically; there is no experimental evidence yet) of any small size above the Planck mass. Stellar black holes, however, cannot have a mass below the TOV limit (1.5 to 3 solar masses)
There does seem to be an upper limit1 of 50 billion solar masses. However, I suspect2 that this takes into consideration formative constraints (i.e. the constraints posed on the formation of such a BH); and does not prohibit such a black hole from existing. After all, the Schwarzschild metric certainly does not impose limits on the size of a black hole.
Note that talking about the limiting dimensions of a black hole is slightly meaningless as the dimensions change in different reference frames. It is far easier to talk about the mass of a black hole; the radius can be calculated in various frames from that information.
1. Natarajan, P. and Treister, E. (2009), Is there an upper limit to black hole masses?. Monthly Notices of the Royal Astronomical Society, 393: 838–845. doi: 10.1111/j.1365-2966.2008.13864.x
2. but cannot confirm yet; I will have to read the paper more thoroughly
Comment: Primordial black holes "can be found"? That's a confusing way to word that statement, since it suggests that they exist. And that there's no evidence for.
Comment: @stan fixed, thanks. Though iirc there's a lot of theoretical evidence showing that our universe should have them.
Answer: theoretically there should be no maximum size/mass of a black hole, or you could say the maximum mass would be if it contained all the mass in the universe;
although the minimum dimension of a black hole would be a Planck length, the minimum mass of a stable black hole is 3 solar masses;
a black hole that has a mass less than 3 solar masses will evaporate, transforming itself into radiation (energy); the smaller it is, the faster it evaporates; if it is small enough, it will instantly turn into a flash of hard radiation;
http://en.wikipedia.org/wiki/Hawking_radiation
if you know the mass of a black hole you can calculate its radius and if you know its radius you can calculate its mass;
note that a curious thing about this equation is that it shows a stellar mass black hole having a high density, whereas a supermassive black hole having a density that decreases as the black hole increases in mass;
http://en.wikipedia.org/wiki/Schwarzschild_radius
so you could transform anything you want, such as your pencil, into a black hole if you wanted to, and could compress it into the required size for it to become a black hole; it is just that it would immediately transform itself (evaporate) completely into a flash of hard radiation, because a pencil is less than the stable black hole mass (3 solar masses);
this is why the CERN experiment could never have created a black hole to swallow the Earth - a subatomic black hole, even one with the mass of the entire Earth, or the Sun, would evaporate before swallowing anything;
there is not enough mass in our solar system to make a stable (3 solar mass) black hole;
Comment: The first part is outright wrong. All (non-extremal) black holes radiate, and there's absolutely nothing qualitatively special about three solar masses in that regard.
Comment: While it's true that 3 solar masses is about the minimum size black hole that we expect to form in the heart of a stellar explosion or from a Neutron Star, there's no reason why a smaller black hole wouldn't be stable.    The problem is in making one.
Answer: To determine size of a black hole first you need to determine its Schwarzschild Radius using this formula Rs= (2MG)/(c^2). To determine its photo-sphere use the formula 3Rs/2 and extends from the surface of its Rs, to determine its accretion disk (PNR for matter) it is 5.5Rs and measured from the surface of its Rs threshold.
Comment: Welcome to Astronomy. This answer doesn't fully answer the question, which was to determine the largest and smallest possible black holes.
Comment: The largest possible BH is not a question of how much matter is available in the Universe, but a question of the processes that result in its creation. As Manishearth answers, there does seem to be a max size, in part because they're Eddington-limited. And although in principle you can a have a BH the size of a H atom, there is no obvious mechanism to create such one, and even if you managed to, it would probably evaporate immediately via Hawking radiation.
Comment: The largest possible in the known universe should be easy to determine.
Comment: The largest possible in the known universe should be easy to determine. All one would need to know is the total mass in the universe. And that wouldn't be determinable for anther 12 Billion years when matter/energy process is spent. However we could estimate. The smallest non-sustaining Scharzschild radius would be as small as a hydrogen atom. The answer to both is likely the Big Bang singularity.

Dimensions of a black hole


How to get artifactory to update the maven-metadata.xml for a virtual repo?

Question: long time reader, first time asker...
I have a standalone network (no internet access).  It has an artifactory server which has virtual libs-snapshot and libs-release repos.  Under libs-snapshot, there are 4 local snapshot repos.  The reason for this is that we get a dump of all the artifactory repos from somewhere else (non-connected), and import it to this network.  But we have to modify a subset of the snapshot artifacts there.  So we created another local snapshot repo, call it mine-snapshot-local (maven 2 repo, set as unique, max artifacts=1?), and added it to the top of the libs-snapshot virtual. In theory, this would allow us to modify the handful of artifacts we needed to, deploy to our own repo, and local developers would pick those up. But we would still have access to the 99% of other artifacts from the periodic dump from the other non-connected system. In addition, we can import the drops from the other network, which are concurrently being modified, on a wholesale basis without touching our standalone network repo (mine-snapshot-local). I guess we're "branching" artifactory repos...
I realize we could probably just deploy straight into one of the imported repos, but the next time we get a dump from the other network, all those custom modified artifacts would go away... so I'd really like to get this method to work if possible.
from my local eclipse, the maven plugin deploys artifacts explicitly, and without error, to the mine-snapshot-local repo.  The issue I'm seeing is that the maven-metadata.xml for the virtual libs-snapshot is not being updated.  The timestamp of that file is updated, and if I browse with a web browser to libs-snapshot/whatever_package, I can see my newly deployed artifacts, with newer timestamps than the existing snapshots. But the maven-metadata.xml file still contains pointers to the "older" snapshot.
maven-metadata.xml is successfully updated in the mine-snapshot-local repo, but it is as if artifactory is not merging all the metadata files together correctly for the virtual repo.  Or, more likely, I have misconfigured something to cause it to ignore our top-layer local repo somehow (but why would the snapshot jar/pom still show up there?).
We are using artifactory 2.6.1 (and do not have the option to upgrade).
I've tried a number of things: setting the snapshot repos to unique, nonunique, deployer, limiting the number of snapshots, etc.  None of it seems to make much of a difference.
The one thing I do see as possibly being an issue is the build number assigned to a snapshot. For example, in the imported repo, the artifact might have a timestamp that is a week old but a build number of 4355.  In my new repo, when i deploy, i have a much newer timestamp, but the build number is 1 (or something much, much smaller than 4355).
Am I barking up the wrong tree by trying to have multiple local snapshot repos like this?  It seems like this should be ok, but maybe not.
Answer: You are using a very (but very) old version of Artifactory and it could be that you are suffering from an issue that was long gone. The normal behavior should be that if you have 4 maven repositories and you updated/deployed new artifacts into one of those repositories, the Virtual repository should aggregate the metadata from all of the listed repositories.
Just to verify, you mentioned that you are deploying from Eclipse, are you referring to P2?  If so just a side note, Artifactory will not calculate metadata for P2 artifacts.
Comment: Ok, now that I've replied I see that this is a 3 years old post so it probably not relevant... :)


-er suffix help

Question: Is there a word for of nouns with the suffix er but have the base of a verb? Ex. Sleeper, singer, swimmer. a type of noun that performs an action. The closest thing I can find is gerund, but I have been told they must end with "ing". I am attempting to perform a translation.
Answer: The general term for such nouns is agent noun:

a noun denoting the performer of an action (as writer, inspector, patron, hanger-on)

Note, however, that agent nouns don't always end in er (as per some of the examples in the definition.)
I know of no term for only er-suffixed agent nouns. I suppose you could use the one that I just wrote.
Answer: Deverbal noun is the usual term for nouns formed from verbs by affixation which denote a person filling the agent role with respect to the verb, such as the ones you cite.
But the term is not specific to just -er nouns. For example, deverbal nouns can also have an -or suffix: "govern ~ governor", "activate ~ activator".
Note that 'gerunds' are not deverbal nouns since they are not formed by affixation of the base form of a verb, but are inflected forms of the verb, e.g. "the killing of the seals", where "killing" is the gerund-participle form of the verb "kill".

-er suffix help


Is endstop / z-probe wire required for BLTouch installation on CR-10S

Question: I am confused about installing BLTouch on CR-10S.
This is my motherboard:

Below is a screenshot for the wiring of the BLTouch sensor:

See the circled sections in yellow.
Notice that the Z- socket is also used  (black and white BLTouch wire) and that's normally where the endstop limit switch sensor is plugged in.
If I unplug the limit switch wire and simply plug the BLTouch wire to this:
1. How can the printer determine when it has reached home?
2. How does it know when to stop when it hits home?
3. I thought BLTouch  is used to do some leveling on the surface... Does BLTouch have a sensor to stop the printer when it hits some?
4. Any way to install BLTouch without removing the Z limit switch sensor?
Sorry for the questions. I am just confused about BLTouch using pins of another sensor that's also required.
Answer: A touch sensor is also a height limiting switch, so you sacrifice the Z- limit switch in favor of the touch sensor (or an inductive sensor). Furthermore, all your concerns are taken care of by the firmware. You configure the firmware so that the nozzle homes Z in the center of the build plate after X and Y are homed first.
It is advised to look up some videos of working touch sensors, then you will get an idea what actually happens. You could start with the inventor of the sensor.
Comment: Ok that really make sense. I also confused Z+- axis with Y-axis because I use Maya which has different ordinate in a way that Y+- is up/down and Z+- is front/back while X+- is right/left. I forget it's different in 3D printing.


Lua API symbol conflicts due to librpmio.so

Question: I'm having a heck of a time getting a program working that uses Lua (version 5.2) if I also have to link against the RPM libraries - specifically librpmio.so. This is part of a large application with several shared libraries that also use Lua.
The underlying problem is that the version of librpmio.so we're using (4.4.X) has a Lua interpreter embedded in it, and it doesn't hide the global symbols contained in the Lua code. The rpmio version of Lua is older (5.0.2) than the Lua we're using (5.2.x), so they're not exactly interchangeable.
So far I haven't been able to get both our own Lua code and the RPM API calls to work. Lua APIs like lua_pushlstring() will bind against whichever of liblua.so or librpmio.so appears first in the chain of loaded modules. If I specify -llua earlier on the linker command line then all of our code works fine, but calls to RPM APIs eventually crash. If -lrpmio is earlier than our code will crash eventually because some Lua calls end up using librpmio's copy of Lua.
I tried versioning the symbols in the liblua.so that we build using a version script like this:
LUA_5.2 {
    global:
            lua_*;
            luaL_*;

    local: *;
};

That wasn't enough however since librpmio.so uses unversioned symbols, and the version script above creates a LUA_5.2 version of the symbols plus a "default" version. The run-time binding seems to favour the unversioned symbol from liblua.so over librpmio.so even though the former is earlier in the chain:
 19075: symbol=lua_pushlstring;  lookup in file=output/Linux64/bin/myapp [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/output/Linux64/lib/lib1.so [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/output/Linux64/lib/lib2.so [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/output/Linux64/lib/lib3.so [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/lib/libwx_base-2.8.so.0 [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/lib/libsqlite.so [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/lib/libssl.so.0.9.8 [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/lib/libcrypto.so.0.9.8 [0]
 19075: symbol=lua_pushlstring;  lookup in file=/lib64/libacl.so.1 [0]
 19075: symbol=lua_pushlstring;  lookup in file=/usr/lib64/librpm-4.4.so [0]
 19075: symbol=lua_pushlstring;  lookup in file=/home/lib/liblua.so [0]
 19075: binding file /usr/lib64/librpmio-4.4.so [0] to /home/lib/liblua.so [0]: normal symbol `lua_pushlstring'

Note the last line - it's resolving a binding for lua_pushlstring within librpmio against my liblua.
I could solve this by setting the -Bsymbolic flag on librpmio.so, but that's a system library we don't control, and who knows what other problems that might cause. I think I might be able to get around the problem if I could eliminate the creation of the default version of each Lua symbol in my liblua.so, but I haven't been able to figure out how to do that from a version script. The GNU version script docs only show how to do that via __asm__ directives.
Does anyone have any ideas other than creating a file containing a bunch of lines like the following and linking it with my build of Lua?
__asm__(".symver lua_pushlstring,lua_pushlstring@LUA_5.2");

Answer: For the sake of those coming across my question in a search, the only way I was able to solve the problem without making a lot of changes to our copy of the Lua source was to dynamically load all of the RPM libraries.
The __asm__ technique for versioning all of the Lua symbols without letting them match an unversioned symbol requires the __asm__ directive to be in the source module where the symbol is defined, which would mean patches to a lot of Lua files.
We only need 12-15 RPM APIs, so the solution I came up with is to load librpmio, librpm, and librpmdb (the latter only exists in RPM <= 4.5) shared libraries dynamically with dlopen(). When calling dlopen() I specify RTLD_NOW|RTLD_LOCAL|RTLD_DEEPBIND for the flags. That causes Lua (and other) symbols within the RPM libraries to be resolved internally.
I have to use dlsym() to get the address of any RPM APIs we use, but at least this prevents librpmio's Lua from clashing with our newer Lua.


In Solidity is it possible to create a token, $TOKEN, where sending $TOKEN from one wallet to another is restricted?

Question: I want to implement this feature in a token for fun. Is there a way to make it so that the only way a wallet can receive tokens is by buying them on a dex, or getting them using a smart contract; not by getting sent tokens from another wallet?
Answer: It is possible to control sender and recipient by overriding transfer and transferFrom and deny the operation by reverting.
A token that prevents user from transferring them would be pretty useless or a scam.


Search and Selection using Visualflows

Question: The user would be presented with a screen into which they insert part of an Account Name.  The flow would look up the Account Name and present users with all accounts containing the search string.  User would select an Account. And proceed to the next step.
As per my understandings, we can assign the searched records to collection variables but we can not let the user display the collection from which user can make further selections.
Is it possible in Visualflows? Any suggestions..
EDIT
After the selection of Accounts are done, the user would be presented with a list of the Brands from the Brand object.  They would select one or more brands and click next much the same as happens when adding Opportunity Products. A loop would ask them if they wanted to add any more brands.  They would click Save and the flow would create Purchase Order records in the background containing the information collected during the flow and assigned to the Account they had selected.
Do I need to maintain 3 different flows working like the following:

From the Custom Button present at child object of Account, invoking a Flow to let the User edit the Account records already populated if any.
If the user wants to re-assign the Account - he may have to search those using visualforce select List.
After the selection of Account, user needs to select multiple brands (is it possible via visual-flows?)

Is this scenario going to use multiple visual-force pages? If so how should I let the user land on multiple pages and maintaining the selected values like brands?
Can't it be possible without using using Visualforce pages?
Answer: You can use onchange attribute of apex:selectlist and use rerender for particular picklist. so it will reflect collection value in selectList.
Comment: I would appreciate if you code share some code snippet for that pls.

Search and Selection using Visualflows