Can the CPU run multiple programs/tasks at the same time? I've been told that the CPU can only run 1 program at a time and the CPU switches between processes very fast; enough for the human eye not to notice. I believe that only applies to single-core, single-thread CPUs, right? From what I've researched, I think that a multi-core CPU can process multiple programs at the same time, e.g., music, video and videogame; and that, a multi-thread CPU can process multiple blocks of code from the same program at the same time. Is this correct, or can't the CPU actually process tasks at the same time?
Can a multi-core processor run multiple processes at the same time? I understand that a multi-core processor can run multiple threads of the same process at the same time using its different cores. Can it also run multiple processes at the same time(each core running a different process)?
What is the difference between the two notions of computational and statistical indistinguishability? Disable the default app key (super+num) functionality on Ubuntu 17.10 and later I like to switch workspaces via Super+Number. But unfortunately the default behavior in Ubuntu for Super+Number is to select applications from the dock.   Is it possible to disable that functionality? I've tried overriding the keyboard shortcuts but it doesn't appear to be working. Do my animals need fences? I have a barn and a coop. Each has several animals in. Because fences keep deteriorating and get in the way, I didn't build any. The animals can roam freely around my farm.  Is there a downside to this? Will the animals eat my crops or escape if I don't enclose them? I got a brand new Windows 7 machine, installed the operating system, created one account and forgot its password. What can I do?  There is no external CD, the operating system is loaded from somewhere inside the machine.  I already tried to remember passwords and tried all candidates with all possible combinations of caps lock, num lock etc. Then what is the probability that out of $n$ men $A_1,A_2,....,A_n$ each aged $x$ years,$A_1$ will die and will be the first to die Let $p$ be the probability that a man aged $x$ years will die in a year time.Then what is the probability that out of $n$ men $A_1,A_2,....,A_n$ each aged $x$ years,$A_1$ will die and will be the first to die?  The probability that a man aged $x$ years will die in a year time$=p$  The probability that a man aged $x$ years will not die in a year time$=1-p$  But from here on,i got stuck.Some hints and suggestions are welcome. A "friends list" on Stack Overflow would be nice I think it would be nice to have a "friends list" on Stack Overflow. This would allow us to be able to follow the questions and answers that are posted by users that we want to watch/monitor.  I suggest it be implemented in the same fashion as DotNetKicks.com; where you can add someone to your "friends list" without them needing to approve you the way that other social networks do it. It should be completely open for us to add anyone to our "friends list" that we like. What plane type will I need to go transatlantic in Pocket Planes? I'm based in North America and have a bunch of major airports on the Eastern Seaboard.  I'm level 14 and just unlocked the Pearjet, but I still don't have a plane with enough range to make it across the Atlantic.  What's the first plane I'll get that will let me make that crossing?  Or more specifically, what's the range from New York (or Boston) to London (or Lisbon) - the smallest range that'll get me across? Diamond moderator privileges vs. 10k rep privileges? As we are in election period, I don't get the difference between getting to 10k reputation point and the diamond. What additional controls do you earn with the diamond ? What are the technical differences between using a DSLR viewfinder and live view? The earlier question  asks for practical advantages of optical viewfinders. But what's the technical difference, and why does a camera behave differently in each mode?  For example, on my Nikon D5100:   Slower auto-focus — I saw this explained in the related issue, but just partially: "The other major drawback of live view is that because it requires the mirror to be locked up, it means that the auto focusing mechanism is unavailable."  option not available. No . The manual says that it's dangerous to shoot direct light, when it's on live-view. There's no range finder available.   Why are all these things different?  Live view also has some advantages, like:   automatic scene selection grid lines on the screen other smaller things, like possibly easier operation on a tripod where the viewfinder might be inconvenient to look through   Some of these things, like the tripod operation, are natural. But are there technical reasons the others can't be done with an optical finder? Are there other advantages enabled by live view for technical reasons? Is there is any way to prove the Faraday's law of induction? I want to know if there is any way to prove the Faraday's law or is it just an experimental observed phenomena?  More specifically, is there any reason why the proportionality constant is 1? How did Faraday discover it? I also heard that we can prove Faraday's law using the principle of least action, but is that true? I've noticed that with the new question asking form, sometimes, attempting to submit a question will post two identical copies of the same question.  I've  (), but at the time, I assumed it was just a temporary fluke. As far as I remember, I just reviewed the question, saw no errors, and submitted it. (That's all the info I have.)  However, I just saw this happen to someone else, so it can't just be a fluke on my end. , and . The author claims there that they did indeed double click the "Review" button, but their question didn't go through since it didn't have a required tag, but when they tried to submit the question with the required tag, they only clicked it once.  Also, now that I think about it, it could not have been just a temporary client-side issue on both our ends. The system is supposed to  if one tries to post more than one question in 30 seconds. Neither of us got a CAPTCHA. This means that the server accepted the double post, and so it's a server issue.  This has the effect of denying users badges that they would have otherwise qualified for, since a single negatively-received, closed, or deleted question . This means that even if the double post is deleted and the original is upvoted, the user won't qualify for that day since they've made a "bad" question on that day. (While they may be able to later reverse this 60 days later by undeleting and re-deleting their question - questions deleted more than 60 days later aren't considered "deleted" for the check - they often won't be able to, since most of the time, users will have downvoted the double post, which also disqualifies one from the badges.)  Can an employee go through server logs to see what happened in both these cases, and add some safeguards to prevent accidental double submissions of questions? This seems to have come up when the new asking form was deployed.  Update: There was another case just now:  was . As both have the exact same time of submission, this is an instance of this bug, since as I said above, this thing is ordinarily prevented by a CAPTCHA. Why does DNS work the way it does? This is a  about DNS (Domain Name Service).   If my understanding of the DNS system is correct, the .com registry holds a table that maps domains (www.example.com) to DNS servers.   What is the advantage? Why not map directly to an IP address? If the only record that needs to change when I am configuring a DNS server to point to a different IP address, is located at the DNS server, why isn't the process instant? If the only reason for the delay are DNS caches, is it possible to bypass them, so I can see what is happening in real time? How to lazy load images in ListView in Android I am using a ListView to display some images and captions associated with those images. I am getting the images from the Internet. Is there a way to lazy load images so while the text displays, the UI is not blocked and images are displayed as they are downloaded?   The total number of images is not fixed. Why does magnetic force vary in proportion to the cube of the distance instead of the square? Magnetic forces vary from gravity and electromagnetic radiation (such as light) in that gravity and radiation diminish by the square of the distance from the source, but magnetism diminishes by the cube of the distance.  Why is this? New breaker and panel: What's the brown goo where they connect? I am using wp_get_attachment_image_src to construct the srcset attribute of an img tag. In that attribute I want to output a comma separated list of image urls along with the image widths.  Using the Media Settings page, I have configured the image sizes to be as follows:   Thumbnail size: 150x150 Medium size: 640x480 Large size: 1024x768 Small size: 278x320   The wp_get_attachment_image_src function returns the correct urls and the correct widths for the image sizes full, medium and small. small is a custom size I added using add_image_size.  If I call wp_get_attachment_image_src( $image_id, 'large' ), the returned array looks like this:  array (     0 =&gt; 'http://localhost/wp-content/uploads/2014/10/image-1024x768.jpg',     1 =&gt; 640,     2 =&gt; 480,     3 =&gt; true, )   Checking the image which can be found at that url turns up the image with the correct dimensions.  Currently i am using the php builtin function  to circumvent this problem, but this function call takes significantly longer than simply accessing the index returned by wp_get_attachment_image_src:  Without getimagesize (mtime before and after execution):   '0.83761000 1415195440' '0.83831600 1415195440'   With getimagesize:   '0.34808000 1415195635'  '0.35323900 1415195635'   What can I do to make wp_get_attachment_image_src return the correct dimensions? Custom thumbnailers don’t work on Ubuntu 18.10 and 18.04 Recently I had a bunch of my own scripts for the thumbnails in Nautilus: , , office documents and so on.  Seems like either I’m doing something wrong (thumbnail generation behavior changed), or custom thumbnailes don’t work in latest GNOME at all, even my previous scripts, which worked smoothly on previous versions of Ubuntu.  I’ve done some research, tried to run a simple script (see below) and it didn’t work out.  My test thumbnailer in /usr/share/thumbnailers/z.thumbnailer:  [Thumbnailer Entry] Exec=/home/maximal/thumb.sh %s %i %u %o MimeType=image/webp;image/x-webp   Where /home/maximal/thumb.sh is:  #!/bin/bash echo $0 &gt;&gt; /home/maximal/thumb.log echo $1 &gt;&gt; /home/maximal/thumb.log echo $2 &gt;&gt; /home/maximal/thumb.log echo $3 &gt;&gt; /home/maximal/thumb.log echo $4 &gt;&gt; /home/maximal/thumb.log   Then, when I remove thumbnail cache rm -rf ~/.cache/thumbnails and restart Nautilus nautilus -q, my log file doesn’t contain anything and ~/.cache/thumbnails/fail/gnome-thumbnail-factory contains all the failed thumbs (looks like corrupted/empty PNGs):    So, apparently, Nautilus even didn’t try to execute my thumbnailer script. When I try to run thumb command itself, it works perfectly. For example convert through cwebp|dwebp package:  convert -thumbnail 256x256 file.webp png:file.webp.png   When I wrap this command to a thumbnailer, it looks like it wasn’t even requested to run by Nautilus.  [Thumbnailer Entry] Exec=convert -thumbnail %sx%s %i png:%o MimeType=image/webp;image/x-webp;   Exactly the same situation occurs with other my thumbnailers: audio waveforms, office documents, photoshop files and so on.  Could anyone help? Crossbow Expert Feat... for Spells? I was thinking about creating a wizard character. Reviewing the spellcasting rules, I saw this:  Most spells that require attack rolls involve ranged attacks. Remember that you have disadvantage on a ranged attack roll if you are within 5 feet of a hostile creature that can see you and that isn't incapacitated (see chapter 9).  There are a lot of occasions that might arise that would make this a problem, or at least a bit of a hindrance. So as a D&amp;D player normally would when they wanted to break a rule without actually cheating, I went to a list of feats and found Crossbow Expert:  Thanks to extensive practice with the crossbow, you gain the following benefits: You ignore the loading quality of crossbows with which you are proficient. Being within 5 feet of a hostile creature doesn't impose disadvantage on your ranged attack rolls. When you use the Attack action and attack with a one handed weapon, you can use a bonus action to attack with a hand crossbow you are holding.  I may be (am) overthinking things, but does this apply to magic attacks, such as cantrips like Eldritch Blast or Fire Bolt? The literal meaning of the feat says that I can, but it could also imply by the title and also the effects of the feat that this only applies to crossbows, or any other ranged weapon, excluding magic. The strongest evidence that it might not affect ability with ranged magic attacks is:  Thanks to extensive practice with the crossbow  With a crossbow, not with magic. Low-RAM Linux Distro Specifically for serving static sites I'm looking for a near-zero-configuration linux distro that is designed specifically for serving static web sites and nothing else on a low-RAM machine (I'm planning on 128MB, but the option of less would be nice).  Any ideas of a linux distro specifically tuned for serving static sites in a small footprint? What is wrong with this fake proof $e^i = 1$? $$e^{i} = e^{i2\pi/2\pi} = (e^{2\pi i})^{1/(2\pi)} = 1^{1/(2\pi )} = 1$$  Obviously, one of my algebraic manipulations is not valid.