So, out of nowhere a 84MB Volume /dev/loop0 popped up. I don't know what it is or why it is there. I did recently install dropbox, Kdenlive, and VLC Media Player. Could one of those programs have caused this? Should I worry? I'm new to Linux. Should I get rid of this Volume, and if so how do I do that?
$ df -kh Filesystem      Size  Used Avail Use% Mounted on udev            7,8G     0  7,8G   0% /dev tmpfs           1,6G   19M  1,6G   2% /run /dev/sda2       622G  227G  364G  39% / tmpfs           7,8G  1,1G  6,7G  14% /dev/shm tmpfs           5,0M  4,0K  5,0M   1% /run/lock tmpfs           7,8G     0  7,8G   0% /sys/fs/cgroup /dev/loop1      143M  143M     0 100% /snap/inkscape/2527 /dev/loop3       79M   79M     0 100% /snap/core/1441 /dev/loop0       79M   79M     0 100% /snap/core/1577 /dev/loop4       79M   79M     0 100% /snap/core/1512 /dev/loop2       62M   62M     0 100% /snap/pencilsheep/5 tmpfs           1,6G   92K  1,6G   1% /run/user/1000   What are these /dev/loop device files? My RAM is always full. Is this related?
$a\equiv\bar a\!\pmod{\!kn}\Rightarrow a\equiv\bar a\!\pmod{\! n};\ $ $(a\bmod kn)\bmod n=a\bmod n.\ $ Congruences persist mod factors of the modulus I noticed relation between modulo operation and number which is power of two  Example I have to calculate $ 3431242341 \mod 2^5 $, which is $ 5 $ but it is equivalent to  $ ( 3431242341 \mod 2^9 ) \mod 2^5 $   I tried many examples and it seems to be true in general, and I am not sure if it is a coincidence or true in general that I can use first modulo operation ( greater number) and the result will be the same. using underscore's “difference” method on arrays of objects In what order should I watch the various Stargate TV Series? I am unfamiliar with the (multiple) Stargate shows and films, other than the movie which I saw a while ago. I want to try watching the series to see if it is something that I like.   What are the non-subjective facts about the series (without spoilers) that I should be aware of when figuring out which series to start with, for example the original airing order of the series, chronological order of the series, frequency of references to a series other than the one that I'm watching, etc. How to create vertical and horizontal dotted lines in a matrix? Search and download audio-only from youtube Is there a way to search and then download from YouTube, with the situation that I only need to download the audio only, not the video. I'm using a \chapterstyle{tandh} because I want my chapters numbered. In order to get a References chapter numbered as well I used the following code:  \renewcommand{\bibsection}{% \chapter{\bibname}}   That worked fine, I got my References chapter numbered!!   But now, in order to get my references in a author-year style I'm using the natbib package. Seems like the package ignores my code and the References chapter is not numbered anymore.  Can someone help me? I'm planning to visit a summer school in the Schengen zone. What kind of visa should I apply for? I will be attending a summer school which will last 10 days.  I want to know: for applying for a Schengen visa, is the purpose of my trip considered as touristic or study? how to change "§" (section symbol) key to write "`" (back quote) I'm using back quote many times but never use the '§' symbol.  I'd like to change the key to always write back quote instead. does anyone know how can I change it programtically? I'm getting this error:  ! Undefined control sequence. l.64 ...p(- \frac{E_j - E_i}{k_B T}) &amp; \quad \text                                                   {:  E_j &gt; E_i}\\ ?  ! Undefined control sequence. l.65     1 &amp; \quad \text                         {:  E_j&lt;E_i}\\ ?    which is from this:  \begin{equation}\label{eq:hop} w_{i,j}=w_0 exp(-2 \gamma R_{i,j})\left\{    \begin{array}{l l}     exp(- \frac{E_j - E_i}{k_B T}) &amp; \quad \text{:  E_j &gt; E_i}\\     1 &amp; \quad \text{:  E_j&lt;E_i}\\   \end{array} \right. \end{equation}   But I don't understand why I get the error. This is my header:  \documentclass[11pt]{iopart} %\newcommand{\gguide}{{\it Preparing graphics for IOP journals}} %Uncomment next line if AMS fonts required \usepackage{iopams} \usepackage{graphicx, wrapfig} \usepackage{fixltx2e} \graphicspath{{images/}} \DeclareGraphicsExtensions{.pdf,.png,.jpg,.gif} \makeatletter \g@addto@macro\@floatboxreset\centering %\def\@cite#1{\textsuperscript{[#1]}} \makeatother   And my class file is the standard IoP one from   Can anyone help me get read of this error? According to , the only restriction on self-deleting an answer is that you can't delete an answer that's been accepted.  But I've also heard of users getting in trouble for deleting (non-accepted) answers, and there's the CC-SA license to consider, so -- quite aside from what is technically possible -- my question is when it's permitted to delete your own answer.  Some cases to consider:   You now believe the answer is incorrect. Your answer is correct, but another answer covers the same territory better. You aren't satisfied with the quality/rigor of your answer, e.g. it's speculative and you didn't back it up (on a site that expects that). Something in the answer embarrasses you and you'd rather just make it go away. Your answer wasn't well-received by the community (whether that's "meh" or "make the rep bleeding stop please"). (I'm sure there are others; this isn't meant to be an exhaustive list.)   Does voting matter, either in absolute terms or in comparison to other answers?  For example, maybe it's ok to delete a lower-voted one but not the top-voted answer, or one with score > N??  There is a badge, Disciplined, for deleting your own post of score 3 or higher.  This tells me that it's sometimes ok to delete upvoted answers.  But I'm not sure how much policy we can infer from badges.  Could we have some clarification please? Delaunay triangulation to generate abstract networks and nodes Is it possible to use Delaunay triangulation to generate an image like the below from a raster or vector of an object (in this case, a human heart)? What software and techniques would be required to make something like this? My intention is to make and use something like this in Inkscape without having to draw all the nodes/lines/effects manually. How to select top 10 records from each category Agreement in "[Singular Noun] Is/Are [Plural Noun]"? My fish's native habitat is rice fields. My fish's native habitat are rice fields.   Which one is correct? I'm pretty sure it's the first, since 'is' modifies 'habitat,' but it still sounds weird... Is there a way to run Python on Android? We are working on an  version and this platform has a nice Python API..  However, there is nothing official about Python on Android, but since  exists, is there a way to let the snake and the robot work together?? How does the Flash breathe while utilizing his super speed? How do the Flashes breathe utilizing their super speed? The air pressure would be extreme. Do they run in a pressurized bubble? Why does shell ignore quoting characters in arguments passed to it through variables? Picture/Video capture programs What software options are there for taking videos and or pictures within Ubuntu (Much like Apple's Photobooth)?  Please limit one software solution per answer and include key features/description of the software timestamp, modification time, and created time of a file Consider a database table holding names, with three rows:  Peter Paul Mary   Is there an easy way to turn this into a single string of Peter, Paul, Mary? Two  have been announced in LoL.  They have an ability that makes them be able to recall together.                                  What are the limits to this ability? Can the 'non-recaller' jump in at the last second and get some kind of instant recall?  Can somebody with the setup to get on PBE test it and tell us what are the limitations of this ability?