Several of my servers are running 14.04 with kernel 3.16. The spectre / meltdown patches listed  don't indicate that 3.16 will be patched. Wondering if I should roll these servers back to 3.13? Or am I missing something?
Any questions relating to status updates, or asking if anything is going to be patched for these vulnerabilities should be closed as duplicates of this question.    are in the news right now and sound pretty severe. I don't see any security updates from Ubuntu that cover these vulnerabilities.  What is Ubuntu doing about these vulnerabilities, and what should Ubuntu users be doing?  These are CVE-2017-5753, CVE-2017-5715 and CVE-2017-5754.
I'm reading Algebraic Number Theory by Jurgen Neukirch. I have some problems with some of the exercises in Section 9 of Chapter 1.  They are:  1) If $L / K$ is a Galois extension of algebraic number fields with non-cyclic Galois group, then there are at most finitely many non-split prime ideals of $K$.  2) Let $L / K$ be a finite (not necessarily Galois) extension of algebraic number fields and $N / K$ the normal closure of $L / K$. Show that a prime ideal $p$ of $K$ is totally split in $L$ if and only if it is totally split in $N$.  I have worked on them for a long time but couldn't get any idea of it.   Can you please help? Thank you! Word or phrase for mere coincidence that brings happiness What's in a name: hyperparameters So in a normal distribution, we have two parameters: mean $\mu$ and variance $\sigma^2$. In the book Pattern Recognition and Machine Learning, there suddenly appears a hyperparameter $\lambda$ in the  regularization terms of the error function.  What are hyperparameters? Why are they named as such? And how are they intuitively different from parameters in general? Is ArcSDE no longer needed at ArcGIS 10.1? Better HTTPS support for Stack Exchange sites So it looks like Stack Exchange now supports HTTPS (to some extent). Which is awesome! But there are a few problems, the main one being that some content is delivered over the CDN, which is plain HTTP. This causes browsers to complain about "unsecured content": What is the best way to get a sine wave from a square wave? I am thinking about buying a new lens specifically to take photos of distant targets (birds, bears, etc). I currently own the Canon 70-300 IS USM, which is a nice lens, but I find that if I want to take a photo of anything further away than about 10 meters, the target does not fill a large amount of the frame (meaning I have to significantly crop in post production).  I am currently looking at the Canon prime 400mm, however I would like to determine at what distance an object will fill a reasonable proportion of the frame.  Is there a formula or rule of thumb I can apply that will help me in this situation? I realise the size of the target I am shooting will play a role here, so if we need to make an assumption about the size of the target please let me know. $A$ and $B$ are $n\times n$ matrices and $A+B=AB$. I have an interesting proof that this implies $A$ commutes with $B$, but the proof only works when $||B|| \lt 1$. I'm looking for a way to salvage the proof so that it works for all $B$.  $$A=AB-B$$ $$A=(A-I)B$$ by repeatedly substituting $A$ with $(A-I)B$ on the RHS, $$A= (A-I)B^N - \sum_{i=1} ^{N-1} B^i$$  Since the space of $n\times n$ matrices is Banach (hence complete) under the standard operator norm, the limit $\sum_{i=1}^{\infty}B^i$ is well defined given $||B|| \lt 1$. Hence, taking the limit as $N \rightarrow \infty$, $$A =  -\sum_{i=1}^{\infty}B^i$$  Now the LHS commutes with B, hence so does the RHS.    Is there some trick to extend the method to work with any $B$ where $||B|| \geq 1$? I know that the result is true due to another simple algebraic proof, but I'd like to see if this method can be salvaged. Limit of $\frac{\log(n!)}{n\log(n)}$ as $n\to\infty$. Comparing two java.util.Dates to see if they are in the same day I want to create a function that performs a function passed by parameter on a set of data. How do you pass a function as a parameter in C? How to prove this for positive real numbers? $$a+b+c\leq\frac{a^3}{bc}+\frac{b^3}{ca}+\frac{c^3}{ab}$$  I tried AM-GM, CS inequality but all failed. What is the meaning of "build off of"? What is the meaning of "build off of"? I Googled it, but can't find any definition!  I encountered it in the sentence in a technical book. The sentence is:     For the application we will build, the todos example is the closest   fit, so we'll go ahead and build off of that example.   There is a link related to it I found by Google, But it didn't give the definition! Choosing power supply, how to get the voltage and current ratings? Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device. How to record how much time user has spent on my node? I want to record the time a user has spent on my particular node so I could show a pop up to the user to register once the user has read 3 article. But the user must have spent at least 30 seconds on each node.   There is the  module available, but I wonder if I can merge it with another (custom) module I have created (which records the number of nodes user have visited)? I have a PC with an OEM install of Win 8 updated to 8.1.  It has 3 physical hard drives in it.  The drive where Windows is installed has a LOT of partitions on it already.    Can I install Ubuntu on a different physical hard drive than Windows, and be able to dual-boot?  I am able to boot to a live USB of Ubuntu 14.04, so I think I'm about ready to proceed.  But if I can make my installation easier by using a different physical drive, I'd like to do that. Search window not opening in ArcMap? Elliptic Coordinates - Inverting the transformation The standard way to transform elliptic coordinates $(\mu, \nu)$ $\ to$ Cartesian coordinates $(x,y)$:  $x = a \cosh(\mu) \cos(\nu)$  $y = a \sinh(\mu) \sin(\nu)$  Is there any way to get the transformation $(x,y)$ to $(\mu,\nu)$? Meaning is there a way to find:  $\mu = f(x,y)$  $\nu = g(x,y)$  I'm guessing that it would involve $\sinh^{-1}$'s and $\cosh^{-1}$'s, if it was possible to do this at all. If $AB = I$ then $BA = I$ If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix. Partition around bad drive sectors? I've seen a lot of hard drives with only a few bad (unrecoverable) sectors (as indicated by SMART). Of course the proper thing to do with a bad drive is replace it, as there's a good chance of the drive crashing completely in the near future; I'm aware of that. However, in the interim, or for those who don't want to spend $70 to save data they don't value highly anyway (sigh, non-technical people), or just to get some use out of old hardware instead of throwing it away, I'm wondering if there's a way to identify where the unrecoverable sectors are ("where" meaning numerically, from 0 to the number of sectors on the drive), so I could stick a blank partition in that general area. Yes, this would involve low-level-formatting the drive and reinstalling the OS, of course.  So:  Would partitioning around unrecoverable sectors even be a workable way of reducing the disk of losing data?  If so, is there a way to find the location of these unrecoverable sectors?