How do I easily make a "joke OS"?
How to start a new Linux distro?
What features of Mavericks are beneficial to you? This question serves to share and collect the enhancements that make a large difference to how you use your Mac.   Please post one feature per answer. Please also check to see if your answer has already been posted - duplicate answers will be deleted. To search answers for this question use  (directly from the question page) in addition to your search terms in the search box in the upper right hand corner of this page.  The best answers will not only list a feature, but provide details on how to configure that feature, and provide an image of how to use the feature to be more efficient or effective with Mavericks. When does a flying creature start and end falling? Situation:  Alice the Aarakokra sees Bob the Battlemaster coming. She ascends to 605', just out of the 600' range of Bob's longbow.  Bob (Str 14) performs a running high jump 5' into the air and successfully hits Alice with his longbow, despite firing at disadvantage for long range. He spends one of his maneuver dice to perform the Trip Attack maneuver, and succeeds on the contested roll to knock Alice prone.  Alice is now flying and prone, so she falls. Falling does 1d6 bludgeoning damage per 10' fallen, to a maximum of 20d6.  Questions:   When does Alice start falling? It is on Bob's turn as soon as she's knocked prone, or some time else such as the beginning of her own next turn? When does Alice hit the ground? On Bob's turn as soon as she's knocked prone, or some time else?   These answers determine whether anyone can save Alice from her 20d6 of certain doom.   Is a reaction (e.g. casting Feather Fall) on Bob's turn the only hope? Can Alice's ally Charlie swoop in on his subsequent turn within the same round to catch her? Can Alice spend half her movement on her next turn to "stand from prone" and pull out of her involuntary dive? If Alice had expected to be shot down, could she have spent an action to be Ready to "stand from prone" while moving through Bob's airspace? I'm trying to install the flashybrid but when I enter the apt-get install flashybrid command, I get this error:  root@user-desktop:/home/user# apt-get install flashybrid Reading package lists... Done Building dependency tree Reading state information... Done flashybrid is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0B of additional disk space will be used. debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable Setting up flashybrid (0.15+nmu2) ... debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable dpkg: error processing flashybrid (--configure): subprocess post-installation script returned error exit status 1 Errors were encountered while processing: flashybrid E: Sub-process /usr/bin/dpkg returned an error code (1)   I also tried this one to find what is already using that file:  root@user-desktop:/home/user# lsof | grep /var/cache/debconf/config.dat lsof: WARNING: can't stat() fuse.gvfs-fuse-daemon file system /home/user/.gvfs Output information may be incomplete. dpkg-prec 4672 root 4rW REG 8,6 39658 1697827 /var/cache/debconf/config.dat   But I don't know how to fix this. I installed Ubuntu 14.04 onto my Acer Aspire E15. The PC has a 500 Gigabyte HDD.   During the installation it divided the HDD into separate partitions. However every time I turn on the PC it goes directly into Windows 8.1. It doesn't allow you the opportunity to select which OS you want to use.   Question 1: How do I set the PC so it will allow me to select the OS?  Question 2: And if #1 isn't possible. How to I remove Ubuntu from the PC and recover the partition for Windows Inner join using an array column Having trouble indexing and executing a query in O (log n) time.  The query includes an INNER JOIN, an ORDER BY, and an equality operation. If I understand the laws of databases correctly, a query can be indexed and executed in O (log n) time (or thereabouts) if a non-equality operator is not used on more than one column. In this case, I believe the INNER JOIN does count as an equality operator and the non-equality operator would be the ORDER BY portion of the query. This table has upwards of 10,000,000 rows and needs to handle several reads and writes per second.  Using PostgreSQL. This is what the table looks like. As you can see, the column 'Names' is a list property and it is the column that the INNER JOIN goes against:  Age Names                       Date 34  ['carla', 'john', 'sam']    3/13/2011 26  ['json', 'cindy', 'joel']   3/13/2011 72  ['beth', 'amber', 'susie']  3/13/2011 14  ['john', 'jim', 'debie']    3/13/2011   This is the query that we are trying to do:  SELECT * FROM the_table WHERE Age==26 AND Names=='john' ORDER BY Date   My background is from using App Engine's Big Table, so I've used equality operators here to indicate that 'john' should be one of the names in the Names column. This would be an acceptable query in GAE's big table, it would execute in O (log N) time as all Big Table queries are reqyured to do. I am assuming there is a way to do this in PostgreSQL as well since PostgreSQL accepts list data types as columns.  Is this possible to do in PostgreSQL?  If so, how should the index be set up (we can't figure out how to set up an index that takes into account the three properties)? How can I install Ubuntu on a second hard drive with Windows being on the first? I have recently got an Alienware M17x R4 and since it has two hard drive bays I was thinking of putting my hard drive from my old laptop and installing Ubuntu on it without making any changes to the drive that has Windows on it. Also if possible to add a entry to the Windows boot loader to boot Ubuntu instead of using GRUB. Expected Number of coin flips for 2 consecutive heads for first time. I was working on problems on expectation and found this one as a question from a well-known exam  Assume that you are flipping a fair coin, i.e. probability of heads or tails is equal. Then the expected number of coin flips required to obtain two consecutive heads for the first time is.  (A)4  (B)3  (C)6  (D)10  (E)5  I worked up like Let N be the number of tosses required untill 2 consecutive heads are obtained for the first time.  Let the probability of obtaining heads be p and tails be q and for a coin p=q=1-p=1-q.  For N=2, the probability will be $p^2$  For N=3, the probability will be $p^2.q$  For N=4, the probability will be $q^2.p^2$  For N=5, the probability will be $q^3.p^2$  and so on...  Now, $E[N]=2(p^2)+3(p^2.q)+4(q^2.p^2)+5(q^3.p^2)+......$  and this comes out to be $\frac{3}{2}$ but it matches with none of the options.  Please tell me where I am wrong and what should I do to reach the correct solution? For a given data matrix $A$ (with variables in columns and data points in rows), it seems like $A^TA$ plays an important role in statistics. For example, it is an important part of the analytical solution of ordinary least squares. Or, for PCA, its eigenvectors are the principal components of the data.  I understand how to calculate $A^TA$, but I was wondering if there's an intuitive interpretation of what this matrix represents, which leads to its important role? I am not talking about miracles, religious revelation, or artistic expression, but something more mundane. There is a lot of "empirical" evidence that the Riemann hypothesis is true, the scare quotes indicate that the source of the evidence is "mathematical intuition". In psychology there are mental states that no one sees, touches, hears, smells or tastes, qualia with their perceptual fullness that can not be conceptualized or directly communicated, and abilities/skills "know how" with the same problem. In linguistics Kripke's theory of reference relies on "modal intuitions" to decide the truth of counterfactuals. But an empirical counterfactual is an oxymoron, especially when it is embedded into an entire "possible world".  Freudian psychoanalysis and Husserlian phenomenology are attempts to deal with some of them systematically, but they are traditionally confined to the fringe of science at best. The mainstream approach is empirical second hand, but behaviorism in psychology and linguistics, and nominalism in mathematics, were not very productive.   According to the naturalized epistemology there is no a priori "first philosophy" of science, methodology is subject to the "tribunal of experience" and revision, just as the science itself. Should it apply to non-empirical experience? Sense empiricism has served science well for centuries, and was fully embraced by Quine.  takes him to task for it:     "Cognitive science is an empirical science working to unearth the mechanisms through which natural language constitutes itself. That account has had to recognize the indispensability of mental states, of beliefs, if it is ever to become adequate to the problem... There is still too much "first philosophy" in Quine. We must rescue naturalized epistemology from its own founder".    Note the use of "empirical" together with "mental states".  Questions: Does naturalized epistemology dictate that natural science should relax sense empiricism, and approach non-empirical phenomena partly first hand? If so, how can the scientific method be adapted to introspective/intuitive phenomena that are not readily reproducible, manipulable, measurable, and/or publicly accessible? What would play the selective role of empirical testing? Can there be non-empirical (more likely, not entirely empirical) natural science? I'm trying to wrap my head around how SQL Server decides to grant certain rights based on a users login privileges.  If a user is part of a group "READ ONLY" which has access to DB1, but they are also a part of a group "SysAdmin" which has full db owner rights to the same DB1, which rights are they given when they log in?  On a similar note. What if they are part of a group but also have a standalone account with other middle of the road privileges? Add high-resolution-graphics and / or .svg-icons How does Meta Stack Exchange work? Meta Stack Exchange seems to have different rules and user behavior than the "regular" Stack Exchange sites.  How is it different?    Individual questions answered below:                Related Commenting out large sections To &quot;comment out&quot; a line, I need to insert a % at the beginning of the line (so that the line will not be compiled). Is there a way to comment out a large section without having to manually place % in front of each line? Zoom in/out on click in OpenLayers 3? How to define a bijection between $(0,1)$ and $(0,1]$? How to define a bijection between $(0,1)$ and $(0,1]$?   Or any other open and closed intervals?   If the intervals are both open like $(-1,2)\text{ and }(-5,4)$ I do a cheap trick (don't know if that's how you're supposed to do it): I make a function $f : (-1, 2)\rightarrow (-5, 4)$ of the form $f(x)=mx+b$ by \begin{align*} -5 = f(-1) &amp;= m(-1)+b \\ 4 = f(2) &amp;= m(2) + b \end{align*} Solving for $m$ and $b$ I find $m=3\text{ and }b=-2$ so then $f(x)=3x-2.$  Then I show that $f$ is a bijection by showing that it is injective and surjective. Least-action classical electrodynamics without potentials Is it possible to formulate classical electrodynamics (in the sense of deriving Maxwell's equations) from a least-action principle, without the use of potentials? That is, is there a lagrangian which depends only on the electric and magnetic fields and which will have Maxwell's equations as its Euler-Lagrange equations? If I recall it correctly, this book has two main characters, both male, one of them big and well muscled. During the novel, they found evidence that the current human race descends from ancient Martian astronauts who traveled to Earth in prehistory, causing the extinction of prehistoric Earth humans, (which explains the Missing Link in human evolution).  Later in the novel the big guy travels back in time (no idea of how or why) to Prehistory.  And near the end of the book, the other main character, during an archaeological field research, finds remains of a human being who lived thousand of years ago, a human with large bones, and who holds an item that could not be made in that era (a gold plaque? A metal rod?)  That's all I can remember. I know it is not from the ABC, Asimov, Bradbury or Clarke.  Thanks in advance. What focal length lens do I need for photographing the moon? Correct formula for LED current-limiting resistor? How to make 'python' program command execute Python 3? The python program command executes Python 2. Python 3 can be executed using the python3 command.  How can Python 3 be executed using the python command?