What is the difference between macOS Sierra 10.12.2 Update and macOS Sierra 10.12.2 Combo Update?
What is a combo update and how is it different than the regular update?
How do you create a daemon in Python? reveals x2 code snippets. The first result is to  which has a lot of documentation and explanation, along with some useful discussion underneath.   However, , whilst not containing so much documentation, includes sample code for passing commands such as start, stop and restart. It also creates a PID file which can be handy for checking if the daemon is already running etc.  These samples both explain how to create the daemon. Are there any additional things that need to be considered? Is one sample better than the other, and why? Positrons versus holes as positive charge carriers : [The Dirac sea is a theoretical model of the vacuum as an infinite sea of particles with negative energy. It was first postulated by the British physicist Paul Dirac in 1930 to explain the anomalous negative-energy quantum states predicted by the Dirac equation for relativistic electrons. The positron, the antimatter counterpart of the electron, was originally conceived of as a hole in the Dirac sea, well before its experimental discovery in 1932.]  and:  [Dirac's idea is completely correct in the context of solid state physics, where the valence band in a solid can be regarded as a "sea" of electrons. Holes in this sea indeed occur, and are extremely important for understanding the effects of semiconductors, though they are never referred to as "positrons". Unlike in particle physics, there is an underlying positive charge — the charge of the ionic lattice — that cancels out the electric charge of the sea.]  It always confused me to think of holes as positive charge carriers in semi-conductors as not being real: real electrons move from one lattice-position to another lattice-position, which effectively looks like a positive hole in the lattice that is moving in the other direction, but in reality a real electron moves, the hole is kind of an "illusion".  On the other hand the positrons are always introduced as real hard-core particles.   The quotes from the Wikipedia article make me unsure: how should I look upon these phenomena?   Edit: holes in a Dirac sea give rise to real pos. entities in one case and to unreal pos. entities in another - how can we distinguish, is it a matter of formalism? I saw this in the end of an awesome shell script but I can't understand the login here because I think it's being short-handed for a longer command.  spark ${@:-`cat`}   This apears at the end of . Any ideas?  + Marks for some one who extends it into a full segment of code, even if its slower (Better for explanation) Regression for an outcome (ratio or fraction) between 0 and 1 I am thinking of building a model predicting a ratio $a/b$, where $a \le b$ and $a &gt; 0$ and $b &gt; 0$. So, the ratio would be between $0$ and $1$.  I could use linear regression, although it doesn't naturally limit to 0..1.  I have no reason to believe the relationship is linear, but of course it is often used anyway, as a simple first model.  I could use a logistic regression, although it is normally used to predict the probability of a two-state outcome, not to predict a continuous value from the range 0..1.  Knowing nothing more, would you use linear regression, logistic regression, or hidden option c? System freezes completely with Intel Bay Trail My passport is expiring; can I still travel? How to load and parse SVG documents Location of /etc/fstab in El Capitan I want to activate the . But I can't find the /etc/fstab on my mac. osx 10.11.5 El Capitan How do I get past the "do not enter" traffic sign that stops me from installing "Sierra" instead of "High Sierra"?  I booted into rescue mode and deleted the original "High Sierra" installation, but booting from the USB stick with the "Sierra" installer on it still gives me the "no". Impose strict time-limit for questions on Hot Network Questions list How to find the sum of the sequence $\frac{1}{1+1^2+1^4} +\frac{2}{1+2^2+2^4} +\frac{3}{1+3^2+3^4}+.....$ Problem :   How to find the sum of the sequence $\frac{1}{1+1^2+1^4} +\frac{2}{1+2^2+2^4} +\frac{3}{1+3^2+3^4}+.....$  I am unable to find out how to proceed in this problem.. this is a problem of arithmetic progression... Please suggest how to proceed...Thanks.. Is there any way to ensure that a specific USB key always gets the same drive letter? What is the maximum RAM supported by the desktop and server editions? I have just downloaded "ubuntu-14.04.1-desktop-amd64.iso" and "ubuntu-14.04.1-server-amd64.iso" through "".   Please can someone confirm the maximum RAM that is supported.  According to many sites, Maximum RAM supported by the OS  ubuntu-14.04.1-desktop : " 2^64 bytes " -- Kindly confirm  ubuntu-14.04.1-server : " 2^64 bytes " -- Kindly confirm I want to update Acrobat Reader for Firefox, but the download has the .bin extension. How can I install it? Why there isn't any integer solutions in non-zero integers for $z^3 = 3(x^3 +y^3+2xyz)$? Consider the following Diophantine equation  $$z^3 = 3(x^3 +y^3+2xyz)$$  Is there any elementary proof for the non-solubility in non-zero integers for this  Diophantine equation, where the absolute value of $x, y$ and $z$ are pairwise coprime integers?  I have proved the impossibility of solution of this Diophantine equation in non-zero integers, but that took quite a few pages and I consider this too long. I hope for a much more elementary and shorter proof for this puzzle.  Hint: It should be noted that is also true for the non-availability of the similar form (replacing coefficient 3 by 1) as the following:   $$z^3=x^3+y^3+2xyz,$$ but this case is very simple to prove, where $x, y\;\&amp;\; z$ are nonzero integers. If you are talking on behalf of you and someone else what is the correct usage?  On behalf of my wife and me On behalf of my wife and I On behalf of me and my wife On behalf of myself and my wife On behalf of my wife and myself ...  My understanding is that after that phrase you would carry on talking in first person. Assuming $T_1$ is the force that acts on box $1$ and $T_2$ is the force that acts on box $2$.  Exactly what causes the Tension? Why does $T_1 = T_2$?  The problem is we are told to memorize that $T_1 = T_2$ for mass less ropes, but I do not understand why, especially in an Atwoods machine.  When I think about it, I know it has something to do with the force $m_2g$ which causes the box with mass $m_1$ to rise, and vice versa.  But I cannot apply physics terminology to this, or really understand whats going on. Suppose k is an integer such that $6k + 1$, $12k + 1$, $18k + 1$ are primes. Show that $n = (6k + 1)(12k + 1)(18k + 1)$ is a Carmichael number.  This is a question on a past exam that I find difficulty to answer. Can anyone help? What should the order of DNS servers be for an AD Domain Controller and Why? This is a  about Active Directory DNS Settings. Related:     Assuming an environment with multiple domain controllers (assume that they all run DNS as well):  in what order should the DNS servers be listed in the network adapters for each domain controller? Should 127.0.0.1 be used as the primary DNS server for each domain controller? Does it make any difference, if so what versions are affected and how? I'm subscribed to the Ubuntu Security Notes, so everytime that I receive an e-mail, a new update is avalable.  But in the last update, they wrote something in the end that I coudn't undertand much, so can anyone please tell me what does that means?  ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.   I tried to ask to my friend (who also uses Linux), but he don't know much about kernel.