Do hard drives need a GUID partition table (GPT) to boot in UEFI mode?

Question: Is EFI booting something hardware specific? I have a desktop motherboard with a UEFI Bios, but I can only boot from USB drives in "UEFI" mode. Both the DVD drive and the HDD's (a RAID 0 array) boot only on legacy mode. Do the HDDs need to have a GPT partition table in order for them to boot in UEFI mode?
Comment: I think you meant: Your available options in UEFI-only mode are just USB drives.
Not that: You see USB drives just in UEFI-only mode and not in BIOS-mode.
Answer: (U)EFI-based systems, by specification, can only boot from GPT-style disks.  The traditional BIOS can boot from MBR-style disks, and in some cases (depends on the manufacturer), they can also boot from GPT.  However, as per the UEFI specification, the disk should have a GPT partition table.
This MSDN article describes it well:

Systems that support UEFI require that boot partition must reside on a
  GPT disk. Other hard disks can be either MBR or GPT.
Comment: @joaocandre the EFI shell itself is compatible with a typical bootable DVD.  CD/DVDs do not use MBR/GPT style partition schemes, so they are not affected by this change.  The EFI shell will look for the relevant firmware images on the disk, and then proceed to boot using the ones it found.
Comment: As a practical matter, at least some EFIs *can* boot from MBR disks. Certainly some (but not all) of my EFI-based computers can boot from USB flash drives partitioned with MBR. I don't believe I've tested with hard disks, though. Despite its 2000-page length, there's a lot omitted from the EFI spec, and differences in the rules that specific EFIs use to determine boot mode (BIOS/legacy vs. EFI) have slipped into those cracks, which explains inconsistencies in whether specific DVDs or hard disks boot in BIOS/legacy vs. EFI mode.
Comment: Then how do I boot from a DVD in UEFI mode?
Comment: Problem is, when I set boot mode to "UEFI" only in BIOS, I cannot boot from the DVD drive.
Comment: @joaocandre you might want to look at [this Technet article (Installing Windows to an EFI-Based Computer)](http://technet.microsoft.com/en-us/library/dd744321%28WS.10%29.aspx) or [this forum discussion (Force Windows 7 install DVD to do an EFI Boot)](http://www.insanelymac.com/forum/topic/184349-force-windows-7-install-dvd-to-do-an-efi-boot/).
Comment: It's not really about installing Windows, but apparently it depends on the DVD inserted on the drive. The Windows 8 DVD I was trying with does not want to boot in UEFI, while Ubuntu live CD can.
Comment: @joaocandre yes, for some reason the Windows 8 DVD UEFI images are corrupted.  I believe the Windows 7 ones are still okay, as well as the Ubuntu images.  Although as you know by now, details can be found in the aforementioned links.
Comment: @Breakthrough: "for some reason the Windows 8 DVD UEFI images are corrupted" - I remember reading somewhere that it was the DVD created by the Win8 Upgrade Assistant that had this problem, not the retail DVDs or the ones available though MSDN. Is that your experience as well?
Comment: Instead of quoting from the UEFI spec itself (well, I bet you couldn't), you quote from a Microsoft article. What's worse is, even the UEFI variant of Windows Boot Manager itself actually supports being booted from a disk with MBR partition table (so does `bcdboot` supports installing to it that). The partition type code `0xef` has also been reserved for EFI system partition.
Answer: No. The globally unique identifier (GUID) for the EFI system partition in the GUID Partition Table (GPT) scheme is C12A7328-F81F-11D2-BA4B-00A0C93EC93B, while its ID in the master boot record (MBR) partition-table scheme is 0xEF. So it perfectly works as it must from the spec.
"Officially the UEFI 2.x spec requires support for both GPT and MBR partitions. Pages 324 (188.8.131.52), also 72, 113–115, 539, etc"
And also "The UEFI specification requires MBR partition tables to be fully supported. However, some UEFI implementations immediately switch to the BIOS-based CSM booting upon detecting certain types of partition table on the boot disk, effectively preventing UEFI booting to be performed from EFI system partitions contained on MBR-partitioned disks".
https://en.wikipedia.org/wiki/EFI_system_partition
Also see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=821341
Answer:
Is EFI booting something hardware specific?

Yes. Some implementations, especially older ones or those from OEM-locked-down motherboards are more likely to be restricted or buggy.

Do the HDDs need to have a GPT partition table in order for them to boot in UEFI mode?

Technically no, but in your case, "probably, plus you need some other things(notably EFI files and EFI variables)". Here's the long answer (also for anyone else stumbling upon this in the future):
A frequent question that people ask is "Can I UEFI boot from an MBR disk?" The answer is "yes, but it's very tricky." While it's technically possible in the right environment, many things will prevent you from doing so, such as a UEFI environment that adheres very tightly to the spec, or the Windows installer that will insist on installing to the correct type of partition table.
First things first, optical media is not part of this discussion at all. It generally uses a system like ISO9660 or UDF, which lies completely outside of the MBR/GPT realm.
Secondly, removable media tends to be handled a little bit differently than fixed disks. Most UEFI implementations will be much more tolerant of removable ad-hoc UEFI bootable disks than they will be of fixed disks.
That being said, here's how a typical UEFI system will enumerate the bootable devices:

If UEFI booting is enabled:

Look in EFI variables to see if there's any configured boot entries.
Most OSes will create pointers to their boot files within the EFI variable system. These variables are stored in the EFI NVRAM.
Most OSes will also take the extra step of creating an EFI System Partition and storing their boot files there instead of on the main OS volume. This improves flexiblity a little, but also works around a glaring problem with the typical UEFI system: Only FAT32 partitions are natively supported.
Look for any removable drives with an EFI file like "\EFI\BOOT\BOOTX64.EFI"
Remember, most UEFI systems can only read from FAT32, so if your removeable drive is NTFS or something else, it probably won't find the boot files.
Enumerate all optical drives, regardless of whether they have EFI bootcode or not.

If BIOS or CSM booting is enabled:

Enumerate all fixed disks, regardless of whether they have a valid MBR
Enumerate all removable disks, regardless of whether they have a valid MBR
Enumerate optical drives, regardless of whether they have a bootable disc.

There are a few other things not covered by the above, like Option ROMs, PXE boot, etc.
And now some observations on the above process. For starters, optical drives tend to show up all the time, regardless of boot mode. This is usually because neither BIOS nor UEFI systems want to wait for the disc to spin up before continuing with boot. They also tend to show as bootable in both modes simultaneously, so if you have a disc that can boot both ways, you can select one or the other from your BIOS's boot menu.
Because it's a bit hard to programmatically determine whether a drive (fixed or removable) contains valid MBR bootcode, if a system has BIOS or CSM boot available, it tends to just allow booting from any of the disks currently present. However, this is probably the answer to one part of your issue: While most systems should treat a USB stick almost like a fixed disk, perhaps your system is treating it differently. For example, some BIOSes will treat a USB device exactly like a fixed disk, and you may need to adjust the "hard disk boot order" or some such control in the BIOS. Or perhaps your BIOS is locked down or broken, and does not realize that it can be booted in BIOS mode. Some additional pointers: Try pluggin the drive into a USB 2.0 instead of 3.0 port, and enable USB compatiblity options in the BIOS. Some BIOSes have trouble natively working with devices behind third-party USB or ATA controllers, like you find on machines that don't have USB3 integrated into the chipset.
With the advent of EFI, it's now easy for a system to determine what boot devices should be available (by looking at the EFI variables containing boot entries), as well as determine if a specific drive actually contains bootcode (by looking for the presence of a BOOTX64.EFI file). However, this leads to some interesting caveats. While officially an EFI system is supposed to only look for EFI files in GPT disks, most of the time it'll look elsewhere as well. For example, you can copy a Windows 7 or newer installation disc to a FAT32 USB stick, and it'll probably boot just fine in EFI mode. The UEFI is smart enough to check for the presence of the "\EFI\BOOT\BOOTx64.EFI" file in all removable disks, even though no corresponding EFI variable is present in the NVRAM. Most UEFI systems will also boot from an MBR disk just fine, as long as there's EFI variables with the details about where to go and what to do. For example, right now I'm using a Dell laptop that came from the factory with Windows 8.1 booting in UEFI mode with Secure Boot, but the disk was partitioned as MBR.
Some other funny things that can happen: If you install an EFI aware OS like Windows or Ubuntu, it'll create the appropriate EFI variables when installing its bootloader. Then, if you remove or wipe the drive, the system will have the EFI variables, complete with the name of the OS, but cannot boot to them because it cannot find the disk that the variables reference. Also, if you take a fully functioning EFI-bootable disk from one computer to another, it may not boot as seamlessly as an MBR one will. Many UEFI implementations will not allow you to even attempt booting from a fixed disk in UEFI mode if corresponding variables are not present in the NVRAM. This is why your RAID array or other fixed hard drives may not appear in the boot menu as UEFI entries until they have all the proper structures in place, like the EFI variables.
However, given your exact set of issues, I'd chalk most of your problems up to a broken BIOS more than a problem with your setup. Notably, for a USB drive to appear as a UEFI device but not a BIOS device is very strange. Have you turned off Secure Boot and enabled any CSM or BIOS boot options? Also, for your optical drive to show up as a BIOS option but not a UEFI option seems a bit strange, though not unheard of.
Comment: _Officially_ [the UEFI 2.x spec](http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf) requires support for both GPT and MBR partitions. Pages 324 (184.108.40.206), also 72, 113–115, 539, etc.
Comment: This is a good answer. Why the downvote?
I think the OP meant: Available options in UEFI-only mode are just USB drives.
Not that: USB drives are seen just in UEFI-only mode and not in BIOS-mode.
Answer: UEFI does effect how OS's boot. You need to have space allocated for the UEFI on the harddrive. I believe with most Linux operating systems this is either done automatically or you must create a partition to host the UEFI.
Comment: The UEFI itself is a firmware image uploaded to the motherboard itself, and has nothing to do with the actual disk.
Comment: Yet it does need a partition
Answer: Here is what's on MSDN.
Is UEFI required for a GPT disk?
"No. GPT disks are self-identifying. All the information needed to interpret the partitioning scheme of a GPT disk is completely contained in structures in specified locations on the physical media."
Comment: This seems to be the opposite of the question: The question states: Is GPT required for UEFI? And your answer answers the question: Is UEFI required for GPT?


Do we get to be with our wife after we die?

Question: After we die, do we get to be one with our wife that we married here and love her still? Or does that go away?
Comment: Sorry but what "do we get to be" means?
Comment: Welcome to Mi Yodeya. Hopefully, this doesn't happen to you or anyone you know, but **which** wife? There are many people who married multiple times. And, unless you abide by R. Gershom's "ban", polygamy is allowed by the Torah. It was quite common, esp. among Jewish kings, you know.
Comment: are you asking about olam haba or before that?
Answer: If you are asking about a relationship with her in the world of spirits, sometimes called Eden, where we go when we die, there is a famous Agadata in Taanis 25a which states the righteous sit with their wives in the world to come.
How you want to take Agadata is up to you.
From Sefaria:

אמרה ליה דביתהו עד אימת ניזל ונצטער כולי האי אמר לה מאי נעביד בעי רחמי דניתבו לך מידי בעא רחמי יצתה כמין פיסת יד ויהבו ליה חד כרעא דפתורא דדהבא (חזאי) בחלמא עתידי צדיקי דאכלי אפתורא דדהבא דאית ליה תלת כרעי (ואת) אוכלת אפתורא דתרי כרעי
  The Gemara further relates: Rabbi Ḥanina's wife said to him: Until when will we continue to suffer this poverty? He said to her: What can we do? She responded: Pray for mercy that something will be given to you from Heaven. He prayed for mercy and something like the palm of a hand emerged and gave him one leg of a golden table. That night, his wife saw in a dream that in the future, i.e., in the World-to-Come, the righteous will eat at a golden table that has three legs, but she will be eating on a table that has two legs.
  (אמרה ליה) ניחא לך דמיכל אכלי כולי עלמא אפתורא דמשלם ואנן אפתורא דמחסר אמרה ליה ומאי נעביד בעי רחמי דנשקלינהו מינך בעי רחמי ושקלוהו תנא גדול היה נס אחרון יותר מן הראשון דגמירי דמיהב יהבי מישקל לא שקלי
  When she told her husband this story, he said to her: Are you content that everyone will eat at a complete table and we will eat at a defective table? She said to him: But what can we do? Pray for mercy, that the leg of the golden table should be taken from you. He prayed for mercy, and it was taken from him. A tanna taught in a baraita: The last miracle was greater than the first, as it is learned as a tradition that Heaven gives but does not take back.

If you are asking about the situation after the revival of the dead, there is discussion in some sefarim whether the wife of someone who becomes an angel like Eliyahu, or someone brought back to life is still married to him or not.
This discussion is focused on alot in many Kabbalistic works whom I cannot quote or recall the names of, but I've seen quoted in a work called Shaar Reuven by R' Reuven Kamil. This seffer is kind of unobtainium where I live.
Basically there were those who said after Techias Hameisim people are not married or related anymore.
There were those who said they are. Then there later Kabbalists who combined the two approaches. If the body had not completely dissolved yet and it is brought back to life, the relationship continues. If the body had completely dissolved, they are no longer married/related. This seemed to have been a happily accepted medium ground by the seffarim he quoted.
Answer: First Mishna in Kidushin states that there are 2 ways to annul a marriage bond: A Get and Death of the husband.
We also know (from an explicit verse) that one may marry one's wife's sister after one's wife dies - so the wife's death annuls the marriage also.
So in the afterworld (or whatever you want to call it) you'll have to court your spouse and remarry them, if you're both still in love with each other, and are halachically allowed to marry them.
So now we could ask questions like:- Would you be able to choose which of the sisters to marry? They are now both your wife's live sister.- Would a Cohen Gadol be allowed to remarry his wife if he died first? She'd be a widow.
Answer: The gmoro in chezkas habatim says that avrohom was in the bosom of sarah
Comment: That is Avraham. You need to add detail and a source to generalize this.
Comment: In addition to the previous comments, chezkas habatim is a long perek. Adding the daf, in addition to the other improvements mentioned, would greatly enhance this answer.


At what level should I try to tackle Silver challenges?

Question: I'm a level 13 enginner and still get destroyed on silver challenges... at what level should a party of 4 try a Silver challenge? and at what level a gold one?
Comment: Also don't forget to get equipment! That can really make a difference, especially if you know what enemy you are going against (FREX this weekend is all about Reaper).
Comment: I'd recommend saving all your ammo and armor mods for gold runs, silver is easy enough without it.
Answer: With a good party of 4, I've found that anywhere from level 15-20 can handle silver without too much trouble.  I typically do bronze until up to level 12ish before trying out silver.
As for gold, I don't recommend anything other than 4 well prepared level 20s.
Answer: It all depends on your team. I've gotten several good one where we were able to all survive silver while below level 9. If you plan out how to handle diff. maps and enemies and have a diverse team even gold is do-able in the lower teen levels. One of the tricks is not using up equipment on the lower rounds, even if you die on round 3 it wont effect the over all game. Strategy is the best weapon.


Why is food less expensive in India than the United States?

Question: India has 4x the population, less land, and far worse technology and infrastructure than the United States. Shouldn't food cost in the US be less expensive? I've never been to India, but it seems like food costs far less there from what I see on TV (10 cents a meal). Why is this?
Comment: Did you happen to have a look also at the (nominal) wage levels in India compared to US? The real issue is "what money can buy".
Comment: No, the supply of money also plays a part in determining the demand, through its operation on the price level. I can't - in a monetary economy - demand more than I can pay for. Relative to earning power, food is significantly less expensive in the US than in India.
Comment: I understand people get paid less there, but the cost of something shouldn't be determined by how much people get paid. For example, a paper clip doesn't cost $5 just because people can afford it. The cost should be determined by supply and demand, and the reasons I gave make me think the supply should be more and the demand less in the United States compared to India.
Answer: I think your intuition is right that food is cheap there. The Economist Big Mac price index suggests that India has some of the cheapest big macs in the world. More generally, the index indicates that there is a strong relationship between GDP per capita (a proxy for labor costs) and Big Mac prices:

Labor is a significant part of the costs of making food (25-35 percent in America). Transportation is a significant part of the cost of food grown far away (world bank data indicates that even exports fees alone can be substantial). But when food is grown locally and prepared locally, the total costs are significantly determined by local labor costs. In addtion, Indian restaurants probably also serves much smaller portions than in rich countries, particularly the United States. They may also make use of less expensive ingredients generally, more stables and seasonal vegetables and less dairy and meat.
Comment: Big Macs with beef?
Comment: I'm not sure how they deal with quality and compositional issues of the big-mac across countries.


How to know wallet name by wallet Address?

Question: I am fetching the data of  ADA rate in USD through api(https://studio-api.nmkr.io/v2/GetAdaRates) and I want to fetch the some data of related to wallet like its wallet name, wallet image, wallet current balance, ADA rates in USD . So is there any api for this?
Comment: What do you mean by "fetch the same data but related to wallet"? The rate of ADA in USD is the same for every wallet. Maybe you want to get rate in USD but of other `tokens` instead?
Comment: I am getting the ADA rates from nmkr.io which i am using to get current price fluctuations in rates of ADA.
Answer: If you're looking for a simple API to get data from the Cardano Blockchain, you can use Koios or Blockfrost. You can use these APIs to get the wallet balance for example.
Cardano wallets don't have a name or an image/icon, therefore you can't get a these from any API.
Unless you're referring to an Adahandle, in that case you can look for a native asset from the Adahandle policy in the wallet.


Good Designing Software for cheap

Question: So I've seen some very good design software, but almost all of it is very expensive. I'm just wondering if there's a good cheap design software out there.
Comment: Are you seeking technical model creation or artistic model creation or a combination/balance of the two? On what platform will you use the software?
Comment: This question is depending a lot on personal preference. What makes a design software good for your use?
Answer: Try Fusion 360. It's free for educators, students, enthusiasts and start-ups. It's not 100% intuitive, but once you learn the basics, it probably has all the facilities that you will ever need for mechanical design.
Answer: OnShape is free for students and the public and is very similar to Fusion 360.  It works online on almost any device and was built by some of the engineers from Solidworks.  Free accounts can not have any private documents so anyone can see your design.  If you know how to use Solidworks/Inventor you will be able to pickup Fusion 360/OnShape very quickly.
OpenSCAD is also free but works through its own programming language.  It requires a strong math background and some understanding of programming to use as it has no GUI tools.
Comment: OpenSCAD does not require a "strong" math background unless you are going to create some intricate designs. For simple shapes and even a few more-than-simple shapes, it's quite good and easy to learn. I recommend OpenSCAD not as a single tool in the toolbox, but an additional resource.
Comment: And I can create very intricate designs in Inventor with even less of a math background.
Comment: @fred_dot_u - OpenSCAD requires a strong background in dealing with the abstract, which a math background would certainly help with.

Good Designing Software for cheap


How can I do batch analysis of games?

Question: I want to run a batch analysis of games and produce output like Lichess computer analysis. I want to do this offline on my desktop PC. Since Stockfish is free, there must exist some solution. Does anyone have any ideas, please?
Comment: I'd be really curious to know the motives of people downvoting this question.
Comment: I seems obvious to me.  Not being constantly tethered to the cloud, possibly having control over the output files.  Doing data analysis on more that one game, without having to batch lichess API.  There could be a whole swoop of this kind of question for anything online.
Answer: Lichess provides its source code, so it should be easy to use this code, with minor modifications, with any number of scripts.
Most engines already come with a computer analysis, so writing a program to feed in every position from a pgn file is easily done.
The problem with both is programming skills.  I thought that I could do this, but I gave up even before I found the code related to reading pgn files.  There must be a programmer who would do this just for a challenge, but finding him seems impossible today.  On the other hand, Python claims to be easy to program and already has chess code provided, maybe with a little effort, you could accomplish this yourself.
Sory, this is no help, but, although most currently have the spare time, all consider this not prestige enough to bother.
Comment: My first guess would be to look for local server solutions. And finding out what UI does ask server and how it gets its answers.
Answer: The analysis window of Scid vs Pc offers the possibility of analyzing games in batches (same for the older Scid). For this, you need to check the option "Batch annotation" and introduce the number of games to analyze, starting from the present one.
Then, the program will evaluate the position at each move and give you different information depending on how you configured the analysis. Typically it will show you the evaluation for each move and mark blunders. To identify blunders, the program will calculate the change in evaluation score after each move. If the variation is greater than the blunder threshold (that can be defined by the user), it will be marked as a blunder. The program can also mark missed mates, tactical exercises and add variations.
Comment: I have completed the answer with some more information to answer your question. Mainly, the annotation gives you the evaluation, marks blunders and may add variations.
Comment: What does this annotation do? I am looking for something like mass analysis that will point out common themes, positions (error), and perhaps combinations. I assume this means blunders and good ones?
Answer: http://www.open-aurec.com/wbforum/viewtopic.php?t=52576
https://adamsccpages.blogspot.com/p/computer-chess-utility-programs.html#n
https://github.com/fsmosca/EPD-Analyzer
I haven't tested the above programs.
Shredder can include score, but it doesn't suggest the best move and commercial.
Lucaschess can analyze a game, but is a weak program and tends to give incorrect analysis.
Arena has a good strength, but after some time, the program tends to freeze and becomes useless.
Answer: Plenty of programs out there.
You can use something like chessbase which is what I do.
There are free alternatives like SCID.
Another option is to write your own program that passes games to a engine for analysis.Alternatively you could leverage the apis of chess.com and lichess.com.
I play primarily on lichess and have written a program to auto download games and append to a chessbase database. From there I kick off a bulk analysis job. I'm trying to find a way to auto perform analysis on chessbase from a cli but that's overkill easy enough to select the games in mass and kick off from there

How can I do batch analysis of games?


Can a used Mercedes 2014 B200 fob be reprogrammed

Question: I've read differing answers on this. Can a Merc key be re-programmed to suit same model car and can I do it myself? Can anyone help, I'm in Australia. Year is 2014
Comment: see https://mechanics.stackexchange.com/a/3682/10976
Answer: The linked answer in the comments is incorrect. You can in fact unlock them, However it does not make sense to do it in most cases and rarely is it done for newer keys. Only specialists will do Mercedes keys to begin with and usually we will only want to use our own stock that we know the quality of. You will not save money by bringing a key to use.
You can not do it yourself unless you own the proper tools which are specific for the task and fairly expensive.


Where to learn dealing with audio data?

Question: I want to learn how to deal with audio data. But, I did not find any course on signal processing. Can someone suggest me the course or give me a link to that course about signal processing in machine learning. Thanks in advance!!
Comment: There are plenty. Udemy, Udacity, masterclass, the great courses are decent places to start looking.
Comment: This may or may not help out, but if you have an android device, there is a free document app and in that app, hitting ctrl+shift+s activates a free speech to text software (some individual voice learning required) that does a good job, in my experience. I suspect, that it also determines,  if say you are talking words employed in normal terminology found in say science or legal speak, to correctly employ the appropriate terms (possibly via a second pass as you can see it auto change the word to match the context). However, there are times with noisy background, app is bad -obviously confused.
Answer: You could try https://www.coursera.org/learn/advanced-machine-learning-signal-processing#syllabus if you prefer videos or http://web.stanford.edu/class/ee269/slides.html if you prefer lecture slides.
Answer: I'm also a newcomer and a self-learner in this field. I suppose there are two subfields: speech and "others", where "others" can include things like music. I have little experience with the "others" subfield so I will just focus on speech. I think the key thing to note is that audio, like images, can be converted to a series of discrete signals, and hence it falls under the umbrella of signal processing generally.
For example, with 44.1kHz sampling, we have a vector of length 44100 for each second of recording (per channel). For the purpose of analysis, this vector is often turned into a spectrogram representation through discrete Fourier analysis. Typically these spectrograms are based on overlapping "windows", or views of the original sequence, and are calculated every 10ms or 25ms. For speech, we have further transformations to highlight the human voice frequencies, so a special type of spectrogram called the MFCC is usually used.
Many (probably most) speech processing algorithms take this standard transformation as input, so it is possible to go a long way to just focus on these algorithms without worrying too much about the transformation from the raw audio to the MFCC representation.
These days, the best algorithms are done using neural networks, and I find it very helpful to go through the material on Recurrent Neural Networks. I recommend Andrew Ng's coursera course on sequence model. Although its focus is on Language models, I think most of the concepts apply to speech or any audio sequences also.
If you are interested in speech, I think it will also be important to understand the GMM-HMM paradigm, for which I recommend a series of articles by Jonathn Hui on his blog, e.g. this and this.
Answer: The Sound of AI YouTube channel has a series called Deep Learning for Audio in Python, and a newly started series Audio Signal Processing for Machine Learning.
I keep some resources on Machine Hearing, including a list of Stack Overflow answers with code examples. The presentation Audio Classification using Machine Learning  that I did at Europython was also quite well received.

Where to learn dealing with audio data?


How is the cavity of a cyclodextrin chiral?

Question:
I am studying the host-guest chemistry of cyclodextrins with achiral aromatic molecules, and I found out that a useful way of studying them is by induced circular dichroism spectroscopy. This technique is used by taking an achiral molecule and placing it in a chiral environment to induce a CD signal. Apparently, the cavity of a cyclodextrin is chiral, but for the life of me I cannot see HOW it is chiral. I know the glucose molecules the ring is made of are D-glucose, but I still see mirror planes in the structure, and I cannot figure out how the cavity is chiral! Help??
Comment: related https://chemistry.stackexchange.com/questions/153/how-do-you-separate-enantiomers
Comment: You don't look close enough. From pictures it would seem there's center of symmetry no planes, but rotation is blocked - inside of molecule can't become outside so there's no center and cyclodextrin is chiral.
Answer: It is because the constituent glucose molecules are chiral.
In the image you can see that all the $\ce{CH2OH}$ groups in the center are out of the plane (towards you). These groups are on the upper side of the cavity. If they were below the plane, the cyclodextrin would have other interactions with the host molecule.
Comment: So regardless of the mirror planes in the molecule as a whole, it is still chiral, simply because the glucose molecules provide the chiral information individually?
Comment: Not necessarily because there are more chiral centers, but probably the interactions would have much less chiral nature. That cyclodextrin would serve still for non-chiral purposes like solubilizing hydrophobic molecules.
Comment: Yes, as long as there are chiral centers, the whole is chiral (except if it is a *meso* form). If you could invert all the chiral centers of glucose and then make a cyclodextrin of them, you would have the specular form; exactly the same properties except for the optical activity.  This would be, however, very complicated since cyclodextrin is made from starch, and starch comes from biological sources and there the chiralty is as it is.
Comment: There's no mirror planes, there could be only one plane making it meso, but half of glucose units would need to be "backwards".
Comment: @Mithoron I meant it in general. Like in tartaric acid. In the case of glucose I do not think that it is possible to have a *meso* form since both ends of the molecule are not the same ($\ce{CHO}$ and $\ce{CH2OH}$).
Comment: IF cyclodextrin were comprised of alternate D- and L- glucoses, it would be meso even though the both ends of the monomers are different. Cf with nonactin.


Connecting 2 light fixtures with 1 switch between

Question: Redoing an old house. All wiring 12-2. Presently have 1 old light operating to the switch. Have power there. Now, trying to run additional fixture off same existing light switch. Have tried multiple combination but have gotten no results to 2nd light fixture. Power originates in original fixture, and travels to switch.
 Can somebody clear this for me and possibly provide a clear picture? Do I need to pull a single strand from switch to 2nd light, and if so,
Comment: Have you considered pulling the fixture power from the other fixture?
Answer: To move forward, you should really take some time and do some learning about "switch loops".  Do not be experimenting blindly, understand the wiring!
You will not be doing this without either replacing one cable with /3, feeding the second lamp from the first lamp's position, or using smart switches and controllers.
You cannot fake a 12/3 by pulling a single individual wire.  All related wires must travel in the same cable.
Your best bet is probably to convert all wires so they are always-hot and neutral, and then use a smart switch, which talks to two smart controllers associated with the lamp.   There are also smart LED "bulbs" like the Philips HUE which provide a similar functionality; their purpose is to control colors, but they'll also work just fine for on/off.
Answer: Sometimes the power (the hot & neutral feed cable) is in the switch box and sometimes it's in the light fixture box. Either way the best place to connect for an additional light fixture controlled by the same switch is at the original fixture. That way you're sure to have both the switched hot and neutral wires needed for the new light and a better chance than the switch box of having the space for additional wires.
If the existing circuit's wire size is #14, use #14. Don't mix wire sizes. In fact never use #12 wire unless you absolutely have to. #14 wire is probably twice as easy to work with than #12, allowing you to do a much neater and safer job and it's plenty adequate for any well designed residential general lighting circuit.
The increased difficulty of working with #12 wire vs #14 for the DIY'er more often than not results in wiring of less integrity rather than more.  Because now every manner of installing the larger wire becomes sloppier, it defeats any imaginary advantage of using it.


Trip to Estonia Tallinn from Greece

Question: Which is the best way to travel from Greece to Estonia Tallinn?
There isn't any direct flight,the intermediate stops I found was Frankfurt and Moscow (you have to wait one day).
Are there any places you have to visit?
Is it easy to visit neighboring countries and how?
Answer: Indeed Estonia has very few directs flights from anywhere and the situation has gone worse over the last couple of years. But there are a few alternatives which can make everything more fun, if you have time to travel.

Fly to Riga, enjoy this great city for a day or two, take a bus to Tallinn.
The trip takes about 4 hours and costs between 13 and 30€, see schedule.
Fly to Helsinki, dito, take a ferry to Tallinn, to my knowledge there aren't any other two capital cities connected by water by such a close distance.
The trip takes between 2 and 4 hours, depending on the ferry type, prices start from 50€. Just google 'Helsinki Tallinn ferry' to find the different lines, I recommend Silja Line because they're fast and dock in conventient places.
Fly to St. Petersburg or Moscow, dito, take a train to Tallinn.

For finding flights, as Karlson wrote, SkyScanner is your best friend. The chances that somebody will be able to tell you anything SkyScanner doesn't know, are very slim.
Answer: There are multiple options available without the long layover from SkyScanner and Rome2Rio and those with long layovers in Moscow or Munich.
But I am sure that you can find something with a stopovers at other places St. Petersburg, Russia and then just take a train from there.
Comment: If you are a Greek citizen you will need passport + visa to enter Russia.
Comment: There are a few exceptions, but on the whole you normally need a passport to visit other countries!
Comment: @yannishristofakis Yes.  If you have to clear border control you will need a visa and for a 15 hour stay you're likely to have to do that.  Unless you're planning to stay 15+ hours in the terminal.
Comment: I see you recommend Russia,do you know if I need passport in order to travel there;
Comment: @Gagravarr by exceptions you mean?For instance let's say I fly to St. Petersburg  and take the train to move to Tallinn,do I need passport?
Comment: Even for one day?

Trip to Estonia Tallinn from Greece


Unable to access to Magento Connect Manager

Question: When I tried to logged into the Magento Connect Manager with my Magento admin ID and password, I am unable to log in and come out with the message  "Access Denied". As I am the only administrator of the store, how should I grant the access right to myself? Thanks
Answer: Navigate to

System->Permissions->Roles

and click Administrators role.
Check your Role Resources settings just in case, Resource Access dropdown should be already set to All for administrators.
Without changing anything just click "Save Role" button, so that Magento re-saves all permissions.
You should be able to access your new extension now without problems.
Try this LINK it ha a lot of info on this point
Comment: Thanks for your prompt reply. I got the similar solutions when I do my google search. However, I am unable to find the "permission" when I navigate to "system", is there anything else I can do?
Comment: Try creating your own admin programmatically:
http://santoshyadavcse.wordpress.com/2013/02/04/magento-create-admin-user-programmatically/
Comment: Thanks for you help again. I believe I have successfully create a new account through inserting the script into the sql server. However, I got the access denied message when I try to log into the admin panel. Is there any way I can grant access to these username in the sql server?
Comment: I have updated my answer check that link, hopefully that will work
Comment: Hello, here's what I have done but still not successful: I have added the script in a text and name it as test.txt. I uploaded the txt file to the root directory of of magento through ftp. I run this test.txt file in my IE and the file can be loaed successfully. I got the message" Invalid User Name or Password" this time when I log into the admin panel page.
Answer: I had this same problem. There may be corruption in your magento connect config file.
To fix it, delete or rename the file "[install path]/downloader/connect.cfg"
The file will be recreated after you successfully log in again.


Is there any possibility to color the html5 progress tag?

Question: Is there any possibility to color the progress tag in css? I tried it. But only width and height is working. I want to skin the color of progression (inner color which shows the percentage of download). Is it possible?
Comment: If you have the same question and want to change appearance of HTML 5 `` tag, there is a good blog that describe it's how to very well [Here is The link](http://www.useragentman.com/blog/2012/01/03/cross-browser-html5-progress-bars-in-depth/) this post is written a few month after this question. Enjoy!
Comment: This site helped me: http://www.useragentman.com/blog/2012/01/03/cross-browser-html5-progress-bars-in-depth/
Comment: @priya Posted an answer that actually works, please test and accept or at the least comment.
Answer: This is what you are looking for:
progress[value] {color:red} /* IE10 */
progress::-webkit-progress-bar-value {background:red}
progress::-webkit-progress-value {background:red}
progress::-moz-progress-bar {background:red}

It's working just fine on Chrome and Firefox 6.
IE10 also supports the ::-ms-fill pseudo-element.
Comment: @priya if that solves your problem you should click on the checkmark on the left.
Comment: @barraponto what *about* opera?
Comment: just a correction: you can't have them all special progress bar value setups in the same rule, because it breaks in some browsers (opera included). separate them into three different rules with the same body and it's good.
Comment: also webkit needs a special set for progress bar. so add: progress::-webkit-progress-bar { background-color: red }
Answer: Currently no. The design/look-and-feel of the progress bar is currently defined by the browser and CSS cannot style the progress bar.
My current solution to this is to use multiple divs to style and show a progress bar, using CSS sprite images.
Answer: Well I'll see what I can do to help  :/
I have looked at the default style (the css style of it) of the progress tag (using Google Chrome's Inspect element option) and what I found is the following (hope this helps):
1.  -webkit-appearance: progress-bar;
2.  background-attachment: scroll;
3.  background-clip: border-box;
4.  background-color: gray;
5.  background-image: none;
6.  background-origin: padding-box;
7.  border-bottom-color: black;
8.  border-bottom-style: none;
9.  border-bottom-width: 0px;
10. border-left-width: 0px;
11. border-right-width: 0px;
12. border-top-color: black;
13. border-top-style: none;
14. border-top-width: 0px;
15. display: inline-block;
16. font-family: Arial, Helvetica, Verdana, Tahoma, sans-serif;
17. font-size: 16px;
18. height: 16px;
19. line-height: 16px;
20. margin-bottom: 0px;
21. margin-left: 0px;
22. margin-right: 0px;
23. margin-top: 0px;
24. outline-color: black;
25. outline-style: none;
26. outline-width: 0px;
27. padding-bottom: 0px;
28. padding-left: 0px;
29. padding-right: 0px;
30. padding-top: 0px;
31. position: static;
32. text-align: center;
33. vertical-align: -3px;
34. width: 160px;
Styles
________________________________________

element.style {}
Matched CSS Rules
user agent stylesheet

progress {
1.  -webkit-appearance: progress-bar;
2.  display: inline-block;
3.  height: 1em;
4.  width: 10em;
5.  vertical-align: -0.2em;
6.  background-color: gray;
}

Pseudo element
user agent stylesheet

progress::-webkit-progress-bar-value {
1.  -webkit-appearance: progress-bar;
2.  background-color: green;
}

Answer: You can NOT mix Mozilla and WebKit prefixes in the same selector, you must create completely separate rules for both rendering engines...
CSS
progress {background-color: #aaa !important;}

progress::-moz-progress-bar {background-color: #f0f !important;}

progress::-webkit-progress-value {background-color: #f0f !important;}

Tested in Firefox 31 and Chrome 37. Using #f0f because it should be easy to spot unless there are fundamental (and probably psychological) issues with the color scheme.


How to redirect to a specific dynamic url on my page on wordpress

Question: I want the page to be redirected automatically to a specific url.
The url is changing so I guess maybe an anchor function might work.
I am trying to do this on WordPress so a how-to & where-to quick detail will help a lot.
If this is my redirect code
<meta http-equiv="Refresh" content="0; url=Dynamic URL" />
I need the URL content to change automatically to the dynamic link on the page.
The redirection should only happen if the specific dynamic link is found on the page
The website is a blog site on WordPress with multiple categories & the dynamic link can be found in a specific category.
Answer: You should not use html to redirect. Simply add a hook in your functions.php file like this :
add_action( 'init', 'my_redirect' );

function my_redirect() {
     if( $my_condition ) {
         wp_redirect($my_dynamic_url);
         // See https://developer.wordpress.org/reference/functions/wp_redirect/
     }
}


if i unplug and plug back in an xbox one external hardrive will my game downloads/save data be erased from it?

Question: So I might buy an external hardrive so I was wondering if I ever have to unplug and plug back in my external hardrive will my game downloads/save data be erased/formated from it?
Comment: Just for clarification, do you mean unplug the USB connection from the Xbox? Or unplug your hard drive's power supply from the wall socket?
Answer: No.
Hard drives are non-volatile memory. They do not require power to maintain their data.
If you power off the drive while it is currently saving something, that particular file will likely be lost or corrupted.
Comment: thank you for ure answer but i have one more thing to ask if the power goes out and I have the hardrive plugged in will it mess up? (in this situation it wouldn't be saving)
Comment: @captaincj2005 That depends on why the power goes out. If there's a power surge, and your drive isn't connected to a surge protector, then it's *possible* it may be damaged. That's true of any piece of electronics, though, not just hard drives. In general, no, you shouldn't be worried about the power going out.
Comment: @captaincj2005 not sure about the XBone but the PS3 and PS4 when they are turned off improperly (ie. like a sudden cut in power) when they boot up they scan the hard rive for errors and try to correct them. either way this can be helped by getting an Uninterrupted Power Supply (UPS) which keeps things going for a little while longer when power is lost giving you a chance to save and shut down properly


How to back up ps4 data and external drive data to a second external drive

Question: I think my ps4 slim is on its last legs, i want to back up all my data but when i use my WD gaming drive it says the drive can't as its being used as extended storage. When i stop using the drive as extended storage the console says that the extended storage device is not connected. I have a lot of games on this extended storage drive and i want to keep them, i heard you can reformat a drive to work as a backup drive but that it also deletes the data on the drive. I can't transfer all the games to the ps4 system storage as there is no space. Can i buy a new extended  storage device and backup all ps4 system data and the extended storage that has my games on it, or do i have to make sacrifices and just reformat my old one. Ask for clarification if needed.
Comment: I'm not familiar with using external (or any) drives for the PS4, but can you partition your extended storage drive, so you keep your old games, but have another partition to act as backup drive? As long as the partitions are in FAT32/exFAT, that might work..
Answer: If your PS4 is dying, "backup" isn't what you want to do. Backup images are tied to a console, you can't use the backup utility to restore to a different PS4. What you would want to do is copy your save data regularly somewhere safe. If you have PlayStation Plus, then all you need to do is turn on automatic upload of save data to your PS+ cloud save storage. If you don't have PS+, you can copy save data to another USB drive. The PS4 slim does have two USB ports on it (which you could use for backup as well).
Note that you only need to copy the save data somewhere, there's generally no need to copy the game data unless your internet speeds are poor. Digital downloads from the PS Store can always be re-downloaded from your Library.


Make terminal content fit the window size

Question: I have a fluxbox environment that uses Eterm to open a telnet connection to my server.
I set Eterm to have the biggest fint possible, but it's not full-width. Is there a way to set Eterm to make the content fit the window size?
Answer: Not exactly.  A clearer question would help.  Here are the possibilities.  The term screen refers to the computer's display, while window refers to the terminal emulator itself.

Some terminal emulators can stretch their window to match the screen size.  But they draw their characters using a grid which may not evenly divide into the screen size.  If Eterm used TrueType fonts, its developers could have provided for scaling the character-grid to more closely approximate the screen's limits.  But it uses bitmap-fonts, which cannot be adjusted so easily.
In switching to full-screen, some terminal emulators do not necessarily "see" the full size.  You can work around that using resize,  which determines the window's actual size and tells the shell about it.
Comment: Did you mean *window* instead of *screen* in the last sentence of the first paragraph?
Comment: Thanks for the advises and the explaination. I think I know better this issue. I'm going to find a way to use True Type Fonts.


Monotouch and native iOS code

Question: Is it possible to link a C# library compiled using monotouch with an objective-C front end in a single application, or does the app have to be all or nothing?
Comment: I am not sure about monotouch but I think if monotouch compiled it already, the iOS can run the code. I am not sure how you can call the C# library with the API but I think the linking is possible
Answer: It is possible but you aren't going to get any help from the MonoTouch tooling and you can't get away from the fact that you still have to have the Mono runtime to execute your C# code.
In order to provide the Mono runtime to the Objective-C app, the runtime will have to be embedded into the app.  The MonoTouch site has some docs on how to do this here and you can find more technical details about embedding Mono into your application here.
MonoTouch, when compiling your C# code, produces .m and .s files that are used by Objective-C to call that code.  These files will need to be included in the consuming Objective-C project but MonoTouch cleans up those files after they've been used.  In order to keep mtouch, the MonoTouch compiler, from deleting the .m and .s files, use the --keeptemp option when invoking the compiler.  You can find a good sample Makefile here to help you figure out how to call mtouch correctly from the command line.
Finally, you will need the full version of MonoTouch in order to do this.  The trial version will not generate the .s files.
Comment: Thanks for the information.  It's disappointing that the trial version doesn't have the support needed to test this; but the library's large enough that it'd still probably be cheaper than a port.
Comment: As a followup, would the trial version allow compiling the library and running a dummy/proof of concept app to see if it will work?
Comment: Not exactly sure what is different with the proof of concept vs. what you initially described so I can't speak to that. Since you're asking about calling into MT code from ObjC I assume you have the source of the ObjC. You realize you can create bindings for your ObjC code and call into that code from MonoTouch. Trying to call MT from ObjC is like swimming against the current, possible but very tiring and difficult. I'd recommend looking at binding your ObjC code and invoke that from your MT app.  Here is more info on binding http://monotouch.net/Documentation/Binding_New_Objective-C_Types
Comment: I don't have any ObjC code at present.  What I have is a C# windows app.  It's GUI/DAL components would to be replaced, but if possible I'd like to avoid having to spend a month or six porting the calculation library to ObjC.  My interest in calling an MT library from ObjC is trying to minimize the training cost by wrapping the C# code up as much as possible and having a coworker who does iOS apps write the UI.  If I end up writing the entire app 100% MT is more likely since I know C# well, but don't know ObjC at all.

Monotouch and native iOS code


Is there an alternative function which does the same thing as clip raster by masked layer on QGIS?

Question: I am having some technical problems with the clip raster by masked layer and I faintly remember using a different method a long time ago for a similar problem. Anybody familiar with another function?
Answer: Here's a general tip for when you're looking for a tool, when you have some idea what it does but you don't know what it's called.
Open the Processing Toolbox panel, and enter a short keyword into the search bar.
I searched for "clip" and found the following tools. According to the section headers, you can see which tools are for vectors and which ones are for rasters.

The GDAL tool Clip raster by mask layer is the one you already tried (it's also accessible through the Raster menu). Try the SAGA tool Clip raster with polygon.


Linux: Reduce UDP Packets Error

Question: I'm facing UDP packet receive errors (under Linux 'netstat -su' command).
I have 10 x UDP processes running on Machine-A (RHEL 5.2) and each of them send 290-byte packet at 50 times per second to the same address and same UDP port. On the recipient end (Machine-B RHEL5.2), I have a process that listens to this UDP port. Also, at Machine-B, I run 'netstat -su' to check for UDP packet errors.
I read that I need to configure my Machine-B Linux sysctl and I did the following for the above test:
   net.core.rmem_max = 33554432
   net.core.netdev_max_backlog = 2000

Also, I have changed my MTU size for both interfaces in Machine-A and Machine-B to 1380.
With all the above, I still encountered UDP packet receive errors increasing (under netstat)
How come? Anything else I need to configure?
By the way, I also tried net.core.rmem_max = 131071, but still facing packet receive errors :(
Answer: net.core.rmem_max is the maximum value that can be set. However, there is also a default value called net.core.rmem_default - I'd increase this one too.
Also you have to tune your application's buffer settings. Often people try to tune the kernel settings but not forget on application's ones.

Linux: Reduce UDP Packets Error


Human power on treadmill

Question: On an elliptical treadmill a regular person can easily burn 1000 calories in one hour (treadmill reports calories burnt). This translates into:
$$(1\times 10^3\mathrm{cal/hr}\times 4.2\times10^3\mathrm{J/cal})/3.6\times 10^3\mathrm{s/hr} \approx 1.2 \; \mathrm{kW} \approx 1.5 \; \mathrm{hp}$$
On the other hand, Wikipedia says "A trained cyclist can produce about 400 watts of mechanical power for an hour or more..."
Is the problem that the treadmill gives wrong numbers? Or it is true that running using legs and arms - on elliptical machine or cross-country skiing which seems to be similar - a human can produce a lot more mechanical power than cycling? I thought the maximum power is set by the cardiovascular system, so it would be the same, running or cycling.
Comment: There may be a distinction between thermal power (what you've burned) and mechanical power (what can be converted to useful work).
Comment: Yes, perhaps there is some kind of assumption that a calorie of mechanical work produced by a human requires several (3-5) times as many calories of food intake and/or fat burnt. So probably what Wikipedia quotes is the useful output energy (e.g. to power a human-powered aircraft) but what all those treadmills and sports magazines quote is the corresponding energy of food or stored fat. That would explain it. But what is the conversion factor for these calories?
Comment: Also that Wikipedia quote seems a *little* suspect. They seem to claim that cycling is an order of magnitude more work than any other exercise. Is one of the world's most common forms of transportation really so superhuman an endeavor?
Answer: This almost a duplicate of How efficient is the human body?. Humans are about 20% efficient at turning food into mechanical energy, so your cyclist generating 400W is metabolising food at about 2kW or about half a Calorie per second or 1800 Calories per hour.
Answer: The trainers in the gym measure total energy used, based on an estimate of how much oxygen you use for certain levels of workout.
They also notoriously over estimate - if you are at the gym to lose weight you will use the machine that promises 1000cal/hour rather than the one that claims 500. And so the gym will buy the 1000 cal machines.
http://www.ncsf.org/enew/articles/articles-ellipticaltrainersoverestimatecaloricexpenditure.aspx

Human power on treadmill


How can I get the position of a fixture in Farseer Physics 3.5?

Question: I created a body(rectangle). After that, I attached a circle shape to the body.
I need the position(world coodinates) of the circle shape because I want to draw a circle sprite(Texture2D) on that position.
How can I get the world coodinates of the fixture?
Body Rectangle;
Rectangle = BodyFactory.CreateRectangle(world, 1.50f, 0.50f, 1.0f);
Rectangle.BodyType = BodyType.Static;
Rectangle.Position = new Vector2(4.8f, 6.4f);
Rectangle.Rotation = (float)(60 * Math.PI / 180);

CircleShape = new FarseerPhysics.Collision.Shapes.CircleShape(0.5f, 1.0f);
CircleShape.Position = new Vector2(1.0f, 0.0f);
Fixture fixture = Rectangle.CreateFixture(CircleShape, 1.0f);

Answer: You have to get the position of the fixture's body.
Vector2 position = fixture.Body.Position;


Can graphql return aggregate counts?

Question: Graphql is great and I've started using it in my app. I have a page that displays summary information and I need graphql to return aggregate counts? Can this be done?
Answer: You would define a new GraphQL type that is an object that contains a list and a number. The number would be defined by a resolver function.
On your GraphQL server you can define the resolver function and as part of that, you would have to write the code that performs whatever calculations and queries are necessary to get the aggregate counts.
This is similar to how you would write an object serializer for a REST API or a custom REST API endpoint that runs whatever database queries are needed to calculate the aggregate counts.
GraphQL's strength is that it gives the frontend more power in determining what data specifically is returned. Some of what you write in GraphQL will be the same as what you would write for a REST API.
Comment: Good explanation! I think the main takeaway point is that GraphQL doesn't do your calculations and aggregations for you. All of that is supposed to happen in the resolve function of the GraphQL query object, which needs to be told to retrieve the needed pre-aggregated data, does its work on it and then returns the result.
Answer: There's no automatic aggregate function in GraphQL itself.
You can add a field called summary, and in the resolve function calculate the totals.
Answer:
... need graphql to return aggregate counts? Can this be done?

Yes, it can be done.
Does GraphQL does it automatically for you? No, because it does not know / care about where you get your data source.
How? GraphQL does not dictate how you get / mutate the data that the user has queried. It's up to your implementation to get the requested aggregated data. You could get aggregated data directly from your MongoDB and serve it back, or you get all the data you need from your data source and do the aggregation yourself.
Answer: You should define a Type of aggregated data in Graphql and a function you want to implement it. For example, if you want to write the following query:
SELECT age, sum(score) from student group by age;
You should define the data type that you want to return:
 type StudentScoreByAge{
      age: Int
      sumOfScore: Float
    }

and a Graphql function:
 getStudentScoreByAge : [StudentScoreByAge]
    async function(){
        const res = await client.query("SELECT age, sum(score) as sumOfScore
                                        from Student group by age");
        return res.rows;
    }

Answer: If you are using Hasura, in the explorer, you can definitely see an "agregate" table name, thus, your query would look something similar to the following:
query queryTable {
 table_name {
  field1
  field2
}
table_name_aggregate {
aggregate { count }
  }
}

In your results, you will see the total row count for the query
"table_name_aggregate": {
      "aggregate": {
        "count": 9973
      }

Answer: This depends on whether you build the aggregator into your schema and are able to resolve the field.
Can you share what kind of GraphQL Server you're running? As different languages have different implementations, as well as different services (like Hasura, 8base, and Prisma).
Also, when you say "counts", I'm imagining a count of objects in a relation. Such as:
query {
  user(id: "1") {
    name
    summaries {
      count
    }
  }
}

// returns
{
  "data": {
    "user": {
      "name": "Steve",
      "summaries": {
        "count": 10
      }
    }
  }
}

8base provides the count aggregate by default on relational queries.

Can graphql return aggregate counts?


Will there be a capacitance in a wound coil?

Question: A wound coil in general is a series LR circuit. If the coil has N turns, will there be a capacitance in between consecutive turns of the coil? If there is a capacitance, is it parallel to L and R or is it parallel to L? Also what will be the range of this capacitance?
Answer: There's capacitance parallel to each individual winding and there is capacitance between layers of windings. There is also capacitance between isolated coils (as in a transformer). There is also capacitance to the core of the device which may or may not be earthed or somehow connected to ground
There is no simple generic answer but you can reduce each turn to a series R and L all in parallel with C.


What are the differences between extending a web app and adding a host header then adding alternate access mappings in SharePoint 2010

Question: What are the differences between extending a web app and adding a host header then adding alternate access mappings in SharePoint 2010? My understanding is that , if you are using different authentication scheme for different zones , then extending a web app. If you would like to access the same web apps but with different URL for different zones ,using adding a host header then adding alternate access mappings. Please feel free to correct me if I got it complete wrong.
Answer: Extending the application allows you to view over a number of different hosts (using AAM) but more importantly allows you to specify a different authentication provider and security settings.
Comment: Good answer. e.g. if you wanted to extend a Web application for external usage you might choose to use FBA as opposed to Windows authentication.
Answer: See the following answered question for more info on this.
Whats the difference between host headers and alternate access mappings?
SPDoctor has a very good explanation on the difference between the 2 methods for managing IIS and host headers for your SharePoint server.  It is always best to let SharePoint handling IIS by extending the web application instead of manually creating host headers and alternate access mappings.


How long after birth would a Catholic baptism have occurred in the late 19th Century in Mexico?

Question: How long after an infant's birth would the baptism have occurred in the Catholic church in the 1890s in Mexico? I've found a record of a baptism that may be my grandfather's, but it is almost a year after he was born. This seemed odd to me so I thought I would check. Thoughts?
Answer: Typically I have found that Catholics in the 1890s (French, German, American, etc.) had their children baptized within the first 4 or 5 weeks, or whenever mom and baby felt recovered/presentable. Some may have waited a bit longer, to coincide with a coming celebration (holiday/wedding). Earlier generations often had baby baptized on the day of birth or within a week.
There are exceptions, of course. A French family I researched lived in an area where they were the only Catholics. They came to town once every five years, and would have all their newest children, ages 5 and under, baptized together.
Also there are cases where a baby is baptized twice. First by a lay person, and later by a priest. A lay person can baptize a baby if there is imminent danger of death, or if a priest or deacon is absent or impeded from administering the sacrament. I presume the French family above baptized their own children soon after birth.
Often when a lay person performed an emergency baptism, there would be no official record, and a second ceremony was performed later (no rush) with a priest. If a priest performed the emergency baptism, they were less likely to have a second ceremony.
I have also seen babies baptized twice on the same day: first in the father's family's parish, and an hour later at the mother's family's parish.
Answer: I have done quite a bit of Mexican genealogy on my family line. I would say that yes it is strange to have a baptism 1 year after the birth. I would go back and re-read the records and make sure that they are correct.
Comment: Hi user5300, welcome to the site. Would it be possible for you to add some evidence to your answer to back up your claim?
Answer: I am Mexican and we normally baptize our children the first year after they are born or before to celebrate their first birthday along with the baptism. It's very normal, we've done it that way for generationsm speaking from my family. Hope it helps.


Feedback for a new(?) puzzle format

Question: My wife likes solving puzzles and I like creating them. But I'm afraid my latest idea might not be as great as I thought - could you please beta-test it and give feedback on what to improve and how? Or has this idea been used by others I could learn from? The puzzle would be the image below, without any content or clue (at least initially).
Answer: Plotting the brightness of three horizontal slices of the image shows the following:

 Mathematica code:ListLinePlot[#,AspectRatio->1/4]&/@ImageData[img][[125;;375;;125,;;,1]]

It takes a little interpretation, but I think it says something like:

 SHADOWY BLOCKY WORDS

Comments on the puzzle:

 * I pretty much immediately recognized this puzzle as similar to "Merlin and Hermes: Mysterious Lines" by Tryth (thanks to Carmeister in the comments for finding it!). If I wasn't familiar with it then I probably wouldn't have been able to solve it.
 * Being able to plot the brightness made it a lot easier, trying to solve it without the plot would have been more difficult, but probably more interesting as well.
 * Due to those facts, the most difficult part was figuring out the letters from their upper profiles. One thing that made this a lot easier was the unique shape of the letters in this font: for example, you can see the leg of the R that makes it distinct from the B, and the lower end of the S makes it distinct from other curved letters like C and O. Choosing a font where the parts of the letters are more aligned would make this part more difficult and, I think, more interesting. Letter sets that could be made confusable are BDPR (half-round tops) CGOQS (round tops) EFITZ (flat tops) MV (deep vees) XY (shallow vees).
 Two letters that did stump me for a bit were the K, which I thought was an N; and the Y, which I thought was an M for a bit. Then I thought it was an X, which made the letters read "SHADOWXBLOCKXWORDS," which, if I assume X separates words which is something I've seen in cryptography puzzles before, would make the solution "SHADOW BLOCK WORDS," which actually makes sense. Finally I realized that the vee was too high to be an X and could only be Y, which led to the final answer.
Comment: @GarethMcCaughan You're thinking of [this one](https://puzzling.stackexchange.com/questions/6165/merlin-and-hermes-mysterious-lines) I think!
Comment: You got it correct, do you have any feedback to give? I too think I saw something similar but wasn't sure if it was here and recently, or somewhere else, or just in my imagination. Oh, and how did you produce these graphs? I clearly need to clean up a few spots... '-.-
Comment: ^^ Ditto - there is one on this site and I've been looking for it but can't remember any key words from the flavourtext in order to pinpoint it!  It was only about 5 or 6 letters long if I remember correctly...
Comment: There definitely was a similar one before, but I too have failed to find it.
Comment: @Carmeister Yes, that was it, thank you :)
Comment: @zovits Rot13: Lbh pna nyjnlf hc lbhe tnzr naq Sbhevre genafsbez vachg oevtugarffrf svefg... Abj, jbhyqa'g vg or sha? ;)
Comment: @Lodinn I'm still unsure whether the current version is the right difficulty, I'm certainly not looking to dial it up even more :D
Comment: Yup, I confirm that I too was thinking of the one Carmeister found. Well done!

Feedback for a new(?) puzzle format


What is name of this type of complexity?

Question: What is complexity related to number of operations/interactions between objects within a system? as that number increases the programmer capability of understanding and maintaining the system degrade.
Comment: Obligatory:   https://cdn.baekdal.com/_img/2008/intapplications.jpg
Comment: @TulainsCórdova User interaction was explicitly mentioned in the earlier versions of the question.
Comment: As your question now stands, you are just asking about coupling. You are correct that as the amount of coupling goes up, so the ability to understand and maintain the system goes down.
Comment: The concept of complexity is based in the amount of possible interactions between components, so there is no specific name for what you describe. What you describe is simply called "complexity".
Comment: @DavidArno This question is not about user experience, but about interaction between classes/objects etc.
Comment: @RobertHarvey This question is not about user experience, but about interaction between classes/objects etc.
Answer: High coupling may be the closest term. People may argue that having a lot of systems does not necessarily imply high coupling. Hopefully, the systems are well-architected with clearly-defined interfaces and separate concerns. But the OP states that all these systems can interact with every other system. In a streamlined system, every component should not be able to interact with every other component, to address complexity. This is why, for example, networking is laid out in a stack where each layer can only communicate with the layer above and below it.
If there are n components in a system, there are n^2 interactions between components, and 2^n distinct sub-systems. This is a combinatorial explosion in complexity that no developer can manage for even moderate n.
Answer: It's object abstraction, but usually referred to as abstraction.  The principle is that most people can only comprehend 7 +/-2 given objects in short term memory; therefore layers of abstraction through the system should strive to stay within this level.
High Coupling or intracomponent linkage as mentioned by gardenhead is another form of complexity that exists in software systems, but usually the level of intracomponent linkage refers to favoring inheritance over object composition.
But regardless, the four major types of complexity in a software system (abstraction, encapsulation, modularity, hierachy) are correlated.  So usually, a breakdown in modularity (coupling) is a breakdown of general abstraction.  Specifically, anytime you reduce modularity, you almost always simultaneously reduce encapsulation.
Comment: It's actually 7 +/- 2.


XML Parsing through internet in bada

Question: I executed a code to get xml content from timesofindia but its not woking and the code which i used is
<code>doc=xmlReadDoc(NULL,"http://timesofindia.indiatimes.com/rssfeeds/-2128936835.cms",NULL,0);
</code>
I am new to bada.Somebody please help me.
Answer: Please refer to the documentation: http://xmlsoft.org/html/libxml-parser.html#xmlReadDoc
You have to first download the document and then pass it to xmlReadDoc as a null terminated string. The second parameter is like MihaiD said, the base url of your document.
To download the document first, see Osp::Net::Http API documentation.
Answer: I have the feeling you actually have to pass in the document as a string on that first parameter. The second parameter is just a base URL, used probably for converting some relative URLs in the document to absolute URLs.

XML Parsing through internet in bada


What's a good word for 'A short review'?

Question: This would be a topic in a progress report that would outline what the project is about without going into details.
I'm looking for something that means like 'Refresher' but sounds more professional.
Comment: "Overview" could work.
Comment: Summary, is your word.
Answer: Compendium
Conspectus
Synopsis
Comment: +1 for compendium, it pairs well with conclusion (two things commonly found in the same works)
Answer: Are you talking about an abstract? http://en.wikipedia.org/wiki/Abstract_(summary)
Answer: Consider the term precis (or précis)

a summary of the essentials of a text; abstract

[from Collins English Dictionary]
Also

apercu (also aperçu, but some would not consider this English)
synopsis
Comment: Yes. Thank you. 'Abstract' was indeed what I was looking for. But 'précis' sounds even better.
Answer: I think you can use the term  survey:

A gathering of a sample of data or opinions considered to be representative of a whole.

or  summary

A presentation of the substance of a body of material in a condensed form or by reducing it to its main points.
A brief statement that presents the main points in a concise form; "he gave a summary of the conclusions"

Source: http://www.thefreedictionary.com/
Answer: Outline - A general description or plan showing the essential features of something but not the detail.
Look it up in oxford
Answer: I recommend "a brief".  As a noun, it means a short summary, and it's common in legal discussions.


Web-To-Case Checks?

Question: I don't have any code to post, but I have a general SFDC capability question.  Is it possible to place any validations on the Web-To-Case integration so that only a certain number of Cases can be created based upon the value of a p[articular field?  For example, if I have 12 cases coming through the web-to-case integration, but I only want to create cases for the 5 whose Type = Support, can this be done before cases are created?  Would a Before trigger be able to handle tis type of scenario?
Answer: Assuming that all 12 cases are being inserted at the same time,  sure.. But I don't believe that it would be a good idea assuming on that.
If you would be able to get an aggregate off of Cases that have been inserted already it may be reliable, but is there more to this you haven't mentioned?
Comment: The issue I am afraid of is that the standard Web-To-Case action will create a Case for every alert that our system generates.  Conceivably (though not highly likely), this could hit the 5k Case limit per day.  To avoid that, I was hoping to filter the cases created in some way, pre-insertion.
Comment: Interesting problem, It sounds like the standard solution of Web-To-Case may not be the way to go here
Comment: Yes, we are using the Web-To-Case.  I have a Process Builder / Flow solution developed that checks new cases against existing open cases with the same internal identifier.  If found, a new custom object record is created and associated to the existing case and new case is deleted.  If not, the new Case is kept and the custom object record is associated to that.  Problem is we could hit the 5k limit for Cases per day, so was hoping to somehow nip that before creating the Cases.

Web-To-Case Checks?


Integral representation of tempered distributions

Question: After my previous post I got curious about the following very simple question (which I don't seem to find the answer). Given a tempered distribution $K \in \mathcal{S}'(\mathbb{R}^{n_{1}+\cdots+n_{N}})$, does if follow that:
\begin{eqnarray}
K(\varphi_{1}\otimes\cdots\otimes\varphi_{N}) = \int k(x_{1},...,x_{N})\varphi_1(x_{1})\cdots\varphi_{N}(x_{N})dx_{1}\cdots dx_{N}\tag{1}\label{1}
\end{eqnarray}
for some integral kernel $k$ and $\varphi_{j}\in \mathcal{S}(\mathbb{R}^{n_{j}})$? Here
$$
(\varphi_{1}\otimes \cdots \otimes \varphi_{N})(x_{1},...,x_{N}) := \varphi_1(x_{1})\cdots\varphi_{N}(x_{n}).
$$
Answer: Let $\mathcal L$ be a continuous linear mapping from  $\mathscr S(\mathbb R^n)$ into
$\mathscr S'(\mathbb R^n)$. The Laurent Schwartz kernel theorem asserts that there exists $K\in \mathscr S'( \mathbb R^n\times \mathbb R^n)$ such that for all $\phi, \psi\in
\mathscr S(\mathbb R^n)$
$$
\langle\mathcal L\phi,\psi\rangle_{\mathscr S'(\mathbb R^n), \mathscr S(\mathbb R^n)}
=\langle K,\phi\otimes\psi\rangle_{\mathscr S'(\mathbb R^{2n}), \mathscr S(\mathbb R^{2n})}.
$$
If $K$ happens to be locally integrable you get indeed that
$$
\langle K,\phi\otimes\psi\rangle_{\mathscr S'(\mathbb R^{2n}), \mathscr S(\mathbb R^{2n})}
=\iint K(x,y) \phi(y) \psi(x) dx dy,
$$
but most of the time $K$ will be a tempered distribution: take $\mathcal L=Id$, you will get $K=\delta_0(x-y)$, take $\mathcal L=\partial/\partial x_1$, you get
$$
K=\delta'_0(x_1-y_1)\otimes \delta_0(x_2-y_2)\otimes\dots\otimes \delta_0(x_n-y_n).
$$
So somehow your question is tautological: some authors prefer to use the integral sign instead of the brackets of duality, but that notational device does not make all distributions locally integrable, you get two examples above.
One point among others is remarkable in the  Schwartz KT: the kernel $K$ is a tempered distribution and this is a similarity with finite dimensional linear mappings, a sharp contrast for instance with the bounded linear mappings from $L^2(\mathbb R^n)$ into itself, which have also kernels, but in general much more singular than $L^2(x,y)$ (these are compact operators, Hilbert-Schmidt type), think for instance about the Hilbert transform whose kernel is
$$
\text{pv}\frac{1}{x-y}
$$
and is bounded on $L^2(\mathbb R)$.
Comment: This is precisely what concerned me: a lot of authors use the integral representation and this'd confuse me. You explanation is perfect and it was my first guess. Thank you!
Answer: No, and a simple example goes as follows:
$$
\begin{split}
K(\varphi_{1}\otimes\cdots\otimes\varphi_{N})
& =\left(\prod_{i=1}^{N}\prod_{k=1}^{n_i}\frac{\partial}{\partial x_k}\right)\varphi_1(0)\cdot\ldots\cdot\varphi_{N}(0)\\
& \triangleq\left(\prod_{i=1}^{N}\prod_{k=1}^{n_i}\frac{\partial}{\partial x_k}\right)\delta(x_1,\ldots,x_n)\quad x_k\in\Bbb R^{n_k}, k= 1,\ldots, N
\end{split}
$$
where $\delta$ is the customary Dirac distribution in $\mathcal{S}'(\mathbb{R}^{n_{1}+\cdots+n_{N}})$. The distribution $K$ is then obviously a Schwartz distribution but it is not a measure, in a similar way as the example $\text{(NIF)}$ in this answer is not.
The standard kernel theorem ([1] chapter 1, §1.3 pp. 11-20 and §3.5 pp. 73-79) guarantees "only" that there is a distribution which does the job, but does not guarantee that there exists an integral representation, though this can be true for general $n$-linear functionals on a particular function space, or for particular functionals on general function spaces: also, the integral representation may not have the form \eqref{1}. For example, in the case of linear functionals, an integral representation as a contour integral
$$
f(\varphi)=\oint_\gamma v(z)\varphi(z)\mathrm{d}z\quad \varphi\in \mathscr{H\!\!o\!l}(D)
$$
where

$v(z)$ is the Fantappiè indicatrix of the functional, i.e. the (in general meromorphic) function
$$
v(z)=f\left(\frac{1}{\zeta-z}\right)\quad(\zeta\text{ is the "inner" variable})
$$
$\gamma\subset D\subseteq \Bbb C$ is a curve enclosing all singularities of $v$.

holds for every linear analytic functional $f\in\mathscr{O}^\prime\!(\Bbb C)$.
And there are also more general "integral" representations (if you allow for the kernel $K$ to be a Radon Measure) which include large classes of linear functionals and more general generalized functions: for example, see the paper [2].
References
[1] Gel'fand, I. M.; Vilenkin, N. Ya., Generalized functions. Vol. 4: Applications of harmonic analysis, Translated from the Russian by Amiel Feinstein. (English) New York and London: Academic Press. XIV, 384 p. (1964), MR0173945, Zbl 0136.11201.
[2] Kaneko, Akira, "Representation of hyperfunctions by measures and some of its applications", (English) Journal of the Faculty of Science, Section I A 19, 321-352 (1972), MR0336328, Zbl 0247.35007.
Comment: @leomonsaingeon: I agree with you, but $\delta$ it is a Radon measure, so it can be stated that $$ K(\varphi)=\int_{\Bbb R} \varphi \mathrm{d}\mu_{\delta_0}=\varphi(0)$$ at least by (though customary) abuse of notation: I wanted to give an example where the distribution, thought being slowly increasing, in not even a measure.
Comment: An even simpler counterexample: In dimension 1 (with $N=1$ and $n_1=1$) let $K$ be the Dirac mass distribution at the origin $K(\phi):=\phi(0)$. Then obviously $K$ is tempered, and it is a classical exercise to show that it cannot be written as an integral w.r.t. the Lebesgue measure $dx$ on the real line. No need for derivatives or tensor products...
Comment: @DanieleTampieri thank you for the answer! You mentioned the answer to my previous question on the functional derivative. In this case (where $K\in \mathcal{S}'(\mathbb{R}^{d})$ is a derivative of some function $f: \mathcal{S}(\mathbb{R}^{d}) \to \mathbb{C}$, can we garantee the integral representation? This was my first post and it seems we can, but i not sure yet.
Comment: @IamWill surely yes, since $f\in\mathcal{S}(\Bbb R^d)$ implies it is $C^\infty$-smooth and rapidly decreasing, thus \eqref{1} has a precise, standard meaning as a $n$-linear functional. I am adding a few remarks on the topic of integral representations of functionals to my answer, by the way.
Answer: This is a comment since your question has been answered but it will be too long.  Often, a first version of a result can be wrong but it can be tweaked to give a correct formulation.  In your case, this holds, namely, the existence of a kernel $K$ which is $O(|x|^\alpha)$ for some positive $\alpha$ in the classical sense such that your formula is valid
but with each $\phi_i(x_i)$ replaced by $D_i^{r_i}\phi_i(x_i)$ for some index $r_i$. If you are interested, I can provide references.
Comment: +1, indeed this follows from the combo: Kernel Theorem plus the structure theorem about temperate distributions being distributional derivatives of continuous functions.


Why does my computer go "New USB device" every time I plug one into a different port?

Question: Let's say I have a mouse. I plug this mouse into slot 1 out of 4 on a computer. It goes through the new device detected and all of that, which is fine. But if I come back later with the same mouse and plug it into say slot 3, it does the detecting all over again! Why is this?
Comment: And what can we do to fix it?
Answer: According to Raymond Chen:

Why does Windows not recognize my USB device as the same device if I plug it into a different port?
You may have noticed that if you take a USB device and plug it into your computer, Windows recognizes it and configures it. Then if you unplug it and replug it into a different USB port, Windows gets a bout of amnesia and thinks that it's a completely different device instead of using the settings that applied when you plugged it in last time. Why is that?
The USB device people explained that this happens when the device lacks a USB serial number.
Serial numbers are optional on USB devices. If the device has one, then Windows recognizes the device no matter which USB port you plug it into. But if it doesn't have a serial number, then Windows treats each appearance on a different USB port as if it were a new device.
(I remember that one major manufacturer of USB devices didn't quite understand how serial numbers worked. They gave all of their devices serial numbers, that's great, but they all got the same serial number. Exciting things happened if you plugged two of their devices into a computer at the same time.)
But why does Windows treat it as a different device if it lacks a serial number and shows up on a different port? Why can't it just say, "Oh, there you are, over there on another port."
Because that creates random behavior once you plug in two such devices. Depending on the order in which the devices get enumerated by Plug and Play, the two sets of settings would get assigned seemingly randomly at each boot. Today the settings match up one way, but tomorrow when the devices are enumerated in the other order, the settings are swapped. (You get similarly baffling behavior if you plug in the devices in different order.)
In other words: Things suck because (1) things were already in bad shape—this would not have been a problem if the device had a proper serial number—and (2) once you're in this bad state, the alternative sucks more. The USB stack is just trying to make the best of a bad situation without making it any worse.
Comment: One thing I fail to understand is why it needs to reinstall device drivers all over again. Is it gonna maintain separate copies of drivers for the same device on each port now?
Comment: @BrianWhite it goes through the whole download and configuration process. You can watch it by clicking on the notification in the task bar
Comment: I'll take a wild guess that it's just associating existing drivers with the new port designation.
Comment: Oh, I've watched it many times.  It's difficult to tell from that dialog, though, if it's actually fetching new data from the Internet or just using local files (but common dialog text) or something in between.
Comment: @BrianWhite in my case(Windows 7) definitely it fetches new data from Internet, because it completes properly only when my laptop is connected to internet
Comment: Is there anyway to give a USB device a serial number yourself? Or is that something that can only be done on the manufacturing level?
Answer: Windows (as you don't state you OS I assume this is what you are using) associates a device with the port it is plugged into, so it considered "USB DISK A in port X" to be different from "USB DISK A in port Y" and it links up the drivers and registry entries accordingly.
If you use the "show unattached devices" option when viewing Device Manager, you will see the device attached to all the ports it has ever been plugged into but greyed out as it isn't currently in them. When you plug the device into one of these ports Windows will just activate that driver instance, when you plug it into another port it will need to define a new driver instance for that port before activating it (which is the process you see as a user displayed as "adding new device".
This allows you to have to identical devices plugged into different ports working at the same time. There are other ways to achieve this, with little or no practical difference to the end user which technique the OS uses, but that is how Windows chooses to arrange it.
Comment: Close, but not quite. Windows recognizes the same device across different ports, as long as it can track that *exact* device. To do that, the device has to provide a serial number.
Comment: Disks tend to actually have a serial number, its on the media itself and put there by format. Even the really cheap keyfob drive thingies are among the best behaved of all USB devices because of this. Mice, keyboards, joysticks, and other cheap devices tend to be the worst offenders. A real annoyance is a USB to RS-232 serial adapter without a serial number. It will get assigned to a new COM port name each time it is accidentally moved to a new port. Not fun.
Answer: It doesn't do this if the device has a serial number. But why do Windows drivers assign child devices with different instance IDs when they appear on different ports such that when you plug a USB device in on another port, there isn't a registry key for the instance ID, triggering drivers to be reinstalled?
Imagine 2 identical devices were given the same ID on 2 different ports; they'd both use the same registry key, which shouldn't be a problem if the device has identical PID and VID because it's not like they're going to have different drivers, device classes, capabilities. I guess it's possible that they could, and there's no point in relying on that. It's desirable for each device to have its own registry key and DIID (Device Instance ID), and not share them. You may want to change the capabilities value on a device by device basis.
There are settings on group policy to ban certain DIIDs, which bans the device model from being plugged into certain ports. If it had the same DIID everywhere, you would ban the model on all ports.
Also, don't forget ParentIDPrefix. Each USB drive has a ParentIDPrefix that identifies the USBSTOR\ child and hence identifies the volume label in MountedDevices because it is in the data next to the value. If 2 USB drives share the same registry key then it breaks any software that relies on the ParentIDPrefix value. If Windows didn't provide unique instance IDs per port then the 2 USBs would also share the same USBSTOR\ DIID, and partmgr almost certainly uses the name of this key as the disk signature for the volume, and the same disk ID GUID subkey will be used, and this would create an undefined situation for mount manager because it won't see 2 volumes with the same signature but 1 volume asking for a volume letter for a second time but it's actually another volume, this could result in dangerous and undefined behaviour. Windows 7 doesn't support multiple volumes on a USB drive so it uses the DIID instead off a MBR signature and offset.


Could a planet 2 times the mass of earth have floating organisms in its skies

Question: Can a planet 2 times the mass of earth have floating animals in its skys? I watched the netflix documentary series ailen world's and one of the exoplanets atlas was high gravity but was very dense so it had animals that floated in its sky so im wondering could that possibly happen on my high g world
Comment: Gravity isn't the issue. Density is the issue. If the floating object (animal) has a lower density (even if only displaced, like a hot air balloon) than the atmosphere, it'll float no matter the gravity. That's why steel ships float on water.
Comment: Ohhh okay thanks for the advice
Comment: So sky whales can exist on my planet?
Comment: Define "sky whale." The game? The photographed cloud formations or aurora? The anime? You can have anything you want on your fictional world. It will even be realistic if it has a low enough aggregate density or really strong wings.
Comment: A creature that lives in the sky and is pretty big also im going for a more realistic approach but i dont wanna be to limited so i just made the planet 2 earth masses instead of something like 3 or 4 earth masses
Comment: Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
Answer: Fly bladder
Since the issue is density and not weight as someone mentioned, you might want to design an animal that can change it's density at will. Fish do this with their swim bladders, so perhaps think of a fly bladder that the animal can use to change the density of its body.
https://en.wikipedia.org/wiki/Swim_bladder
Alternatively, sharks don't have swim bladders, but there livers contain a lot (like a lot) of fat which has less density than water, keeping them buoyant. So, I'm sure you can think of an analog for a flying species in your world.
In addition, hollow bones, leathery skin between limbs, and feathers like pterodactyls might be useful.
Comment: Hm my main idea was a creature no multiple creatures that actually lived in the skies of my planet like some sorta atmospheric beast if you know what that means
Comment: Why wouldn't this work for a single creature? An animal with a sort of swim/fly bladder to hold air to keep them less dense than their surroundings, hollow bones, wings, and feathers
Comment: Which is what im planning to do for the bird/avian analogs of my planet
Answer: There is also a scenario much overlooked by worldbuilders/speculators. A planet that initially harbored life but has become hotter due to a runaway greenhouse effect. It is speculated that Venus may have been such a planet, and scientists believe that if there are any living organisms on Venus, they are in the upper atmosphere, where temperature is much earth-like.
Speculative life cycles of Venusial life - Source
Life may have had time to adapt until temperature becomes literally too hot at the surface. For instance, most microbial life is speculated to be dependent on updrafts in order to stay away from the hellish surface of Venus. However, if these microbial or single-celled algae want to avoid being drifted into downdrafts they cannot actively swim against the current. My speculation is (and this is just my speculation), those single celled organisms may be under an evolutionary pressure yet have enough time to evolve into a cell colony, say a sphere made up of cells, which may contain flotation gas like hydrogen. Multicellular life may or may not evolve on such a planet. If it does, it is unlikely that early life will be complex enough to fly like birds do. The existing workaround of a flotation bladder may evolve further until some animals are complex enough to fly like birds (because they fly faster). This scenario looks very much like Carl Sagan's speculation of life on a jovian planet like Jupiter: Floaters (with bladders), sinkers (single-celled in the mercy of the currents) and hunters (Flyers). Unlike Venus, Jupiter always had a hellish surface so life may have never evolved there because in the beginning there were the "sinkers" which were carried by downdraft to their death along with their offsprings. Venus is different. It had better days in the past...
Other factors may cause floaters to evolve on earth-like planets as well. In your scenario, a planet more massive than Earth lying in the habitable zone. A more massive planet generates more gases by volcanism, and its higher gravity holds on to more atmosphere. The atmosphere will be denser at the surface. After all, atmospheric pressure is the weight of the atmosphere above you. So a more massive atmosphere and a higher gravity yields a much higher pressure. Above a certain atmospheric density, air resistance becomes significant. In tidally locked planets or slow rotators, one side is exposed to the sun long enough to generate strong winds in a dense atmosphere. Animals will have hard time walking against the wind and many will opt to fly. Many simple organisms may adapt via flotation bladders - possibly even plants, given that soil erosion would be much more significant. The planet would have different geological features compared to Earth. One issue is soil formation and retention.
EDIT I'm not presenting here a floating ecosystem cut off from the surface of the planet. Microorganisms or larger ones - Eventually, primary producers (plants) feeding off minerals and can photosynthesize evolve and become the base of any ecosystem. Depending on the conditions on the planet, it is not necessary that life begins in the air. In the example of Jupiter, there is no "safe" surface. However, the high temperature may allow many elements to evaporate and enrich the atmosphere with elements for life to evolve there. On an Earth like planet, it is likely to evolve on the surface instead. Microorganisms are always present in our atmosphere and Earth is not an exception. However, increase atmospheric density and the wind may carry larger things as well. Wind erosion will bring more nutrients into the air and animals "stranded" in the air may either adapt by flight or by flotation bladder. Plants may choose the latter.
Comment: Well my idea for the animals gaining flight was them actually originally being in water but they developed wings and started to fly in and out of the water and then some of them actually started adapting to the air and land so a group of them evovled to live in the skies
Comment: Also what if there like little mirco organisms that the floaters or bloaters feed on? Like in the sky?
Comment: Im imaging that they eat photosynthetic microorganisms
Comment: @JerryRobinson I edited the answer to pin point the issue you raised.
Answer: As others have said, it isn't only a matter of mass, but also density. Both of the atmosphere and the planet itself. This is due to two things.

The strength of gravity of a planet is not just based upon mass, but also upon radius (and following from that, its density). A planet 2x the mass of Earth could potentially have weaker gravity, if it had a signifigantly lower density. For example, a planet with 2 Earth Masses but a density of 9.975 g/cm3 (basically just all iron core) would have a gravity of 1.859g, but one with a density of 3 g/cm3 (basically just silicate rock) would be 0.84g. If it had equal density to Earth, it would be 1.26g and 1.26 Earth Radii. Thus, density is important to what the gravity of a planet would be. (note, when we talk about planet density, we assume it is homogenous and take an average density, in reality it actually changes a lot and is not uniform, but the lack of uniformity is not important for gravity equations)

The ability of an organism to fly is based upon their ability to be held up by the atmosphere. A denser atmosphere would definitely allow larger flying organisms to exist. This is itself based upon relative density between them, there is a reason birds tend to have hollow bones, reduces their density, and helps them to float in out atmosphere. As others have said, same principle as what allows boats to float on water, even if they weigh several tons.

So, if you want your planet to be able to have large flying organisms, make sure that you give it a thick atmosphere, and make sure that the organisms have a density lower than the atmosphere. Also, preferebly give a large surface area as well, that also helps with aviation.
I do believe that your sky whales could fly if they had large sacks of like, air or open space in them to lower their density relative to a thick atmosphere. Even if it is a higher gravity would.
Comment: Yea that was what i was thinking putting some large sacks of air on them thanks for the great response
Comment: Thanks for the great response
Comment: I was also planning to have some mammal type animals on the surface that didnt fly kinda like a analog between mammals and avians
Comment: Also wouldn't gravity be an issue for these sky whales?