Does dd verify data as it is writing?
dd writing on USB flash drive causes massive reads
explicit formula for recurrence relation $a_{n+1}=2a_n+\frac{1}{a_n}$ For $n\in\mathbb N$, $$a_{n+1}=2a_n+\frac{1}{a_n},\quad a_1=1. $$ Can any one give an explicit formula for all $a_n$? If such an explicit general formula doesn't exist, please explain it. I've tried to figure out the $n$-iterated function $f^{(n)}$ where $f(x)=2x+1/x$ or even $f(\tan(t))$. But in either cases, I failed.Since the recurrence isn't linear nor homogeneous,the generating function method doesn't apply here. Can I have 2x2 workspaces in GNOME 3? I have just upgraded to Ubuntu 17.10 and found out there is no option to have 2 by 2 workspaces. I was able to configure 4 "static" workspaces using , but I would like to have them in 2 rows by 2. Any ideas? Why is 'ping' unable to resolve a name when 'nslookup' works fine? On my Windows XP workstation, I can find the machine I want to connect to in DNS with nslookup:  nslookup wolfman Server: dns.company.com Address: 192.168.1.38  Name: wolfman.company.com Address: 192.168.1.178   But, when I try to connect to that machine, I get an error telling me that the machine can't be found (i.e., can't be looked up in DNS):  C:\&gt; ping wolfman Ping request could not find host wolfman. Please check the name and try again.   I am able to connect if I use the IP address directly:  C:\&gt; ping 192.168.1.178  Pinging 192.168.1.178 with 32 bytes of data:  Reply from 192.168.1.178: bytes=32 time=41ms TTL=126 Reply from 192.168.1.178: bytes=32 time=41ms TTL=126 Reply from 192.168.1.178: bytes=32 time=44ms TTL=126 Reply from 192.168.1.178: bytes=32 time=38ms TTL=126   I could work around this by adding an entry to my hosts file, but I would rather find out why this is happening.  The problem is transient, most of the day I can connect to the machine just fine.  How is this possible?  ETA: I left this out for brevity, but it was asked for:  C:\&gt; ping wolfman.company.com Ping request could not find host wolfman.company.com. Please check the name and try again.   ETA: Other applications get the same results.  I only tried ping to simplify.  telnet can't connect, Cygwin apps print a "unknown host wolfman" message.  Update: Using wireshark, I found that my workstation is not attempting a DNS lookup.  It's just reporting the "could not find host" error message. Available space not changing when resizing a partition I want to be able to close an alert box automatically using Javascript after a certain amount of time or on a specific event (i.e. onkeypress).  From my research, it doesn't look like that's possible with the built-in alert() function.  Is there a way to override it and have control over the dialog box that it opens?  Also, I don't want an override that shows a hidden div as the alert.  I need an actual dialog box. Prove that to each $\epsilon >0$, there exists a $\delta >0$ so that the Lebesgue integral... Suppose $f$ is in $L^1$ space of $\mu$, where $\mu$ is the Lebesgue measure. Prove that to each $\epsilon &gt;0$, there exists a $\delta &gt;0$ so that the Lebesgue integral of the absolute value of $f$ is less than $\epsilon$ (over the set $E$) whenever the measure of $E$ is less than $\delta$.  I know that the integral of $f$ is finite. So for arbitrary $f$ we can find the integral of $f$ to be less than some $\epsilon$, but how would I connect that with the measure of $E$ less than $\delta$. Any help would be welcome. TAR 6 GB worth of files into separate 1.9 GB TAR files Suppose that $A$ is an integral domain. If $a,b$ are element of $A$ and $a$ is a unit, then how come the change of variable $X\mapsto aX+b$ extends to a unique automorphism of the polynomial ring $A[X]$, which equals the identity map when restricted to $A$?  Thanks for any ideas or ways to get started. How can I contribute to Ubuntu? I would like to know what kinds of contributions someone can make to Ubuntu. Such as Programmer, User, Proofreader, etc. How to do multiple joins when using groupby in linq Is there a cross-browser onload event when clicking the back button? How are the measurements used by Nielsen evolving to meet new methods of content delivery and viewing? I was interested to find out that in the 1950s, Nielsen used devices in the homes of the families that were surveyed to record their viewing preferences, and only later introduced their system of using a diary to record habits:  ...in 1950...This information was collected on a device that was attached to a television that recorded what was being watched.  In 1953, the company began sending out diaries to a smaller sample of homes (“Nielsen families”) within the survey to have them record what they had watched from   So, presumably as multiple different viewers in the home were considered in the sample, the means through which the ratings were recorded changed. Given that so many people are able to record shows digitally and watch when convenient and that so many view their favorites on outlets such as iTunes, how have the Nielsen ratings systems adapted (or how does the company plan to adapt them) to capture our modern viewing preferences? While a DVR-recorded show still technically makes its original &quot;timeslot&quot; relevant to the equation, will Nielsen consider timeslot-specific data a hindrance to comparisons between those shows viewed on cable and the same show viewed on iTunes? Is it possible to run an x86 binary on an ARM processor? automatically apply special formatting to selected words in text How to convert .bib generated by Mendeley for use with amsrefs I'm using TeX live 2010.  I have a .bib file generated from Mendeley, and  I want to use that with amsrefs, but it's confusing and the amsrefs documentation is somewhat hard to follow: how do I massage the .bib file into something that amsrefs can stomach. (I'm using amsart as the document class). What novel had an isolationist Earth and the rest of humanity in a war of attrition against aliens? How do I configure swappiness? I need a step-by-step, simple and easy way to configure swappiness. I'm trying to make a basic Windows application that builds a string out of user input and then adds it to the clipboard. How do I copy a string to the clipboard using Python? I want to append this text:  &lt;Directory "/var/www/*"&gt;     Order allow,deny     Allow from all     AllowOverride All &lt;/Directory&gt;   to the file /etc/apache2/apache2.conf  I have access via SSH but I don't know how to use VIM. I would like to do this via a command. Is the distribution of an Ito diffusion at time t absolutely continuous wrt Lebesgue measure?