Reading package lists... Error! E: Write error - write (9: Bad file descriptor) E: The package lists or status file could not be parsed or opened. david@david-Inspiron-N5110:~$
The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?
Smart guides aren't smart TL:DR Smart guides aren't accurate - even though the snap, (end up causing more problems in the long run) is there a way to fix it?  Maybe there are some settings that I'm missing (need to be changed)    I use my smart guides all the time (and am overall pleased with them). I do have my issues with it, as explained here:  A lot of times, when I'm trying to make a bunch of triangles like this:    Done by making a triangle, cloning, flipping, rotating etc. Repeat until full  (Perfect) Snapping using Smart Guides    Ends up looking likebetween the triangles (Outline Mode)    Now I personally (with a strong attention to detail) will notice that there is something off after making just 1 or 2 triangles (Even before outline mode... strokes look oh so slightly thicker/off)   And then I check in outline mode... and sure enough:    Notice the line spaces (and this is in outline mode, so if I didn't notice it before, now it's sitting right in front of my nose)  The way I (seemingly) "fixed" the first image was by adding in a thick stroke outline so that masks out the difference, however, in a lot of my cases I don't want to have a stroke at all (and then you really notice the problems). How to get from Heathrow Airport to King's Cross, London? My wife and I will be arriving in London via Heathrow Airport (LHR) and are staying at a hotel near King's Cross station. So, we were wondering what the best (which means fastest but also easiest when carrying two large pieces of luggage and two carry-ons) way to get from LHR to King's Cross?  I gather that, with only one changeover, we can take the Tube. However, in the interest of other passengers, we thought it would be best to take a taxi, or maybe a bus?  Thoughts? How do I remove "permission denied" printout statements from the find program? Code   find / -name netcdf   Output  find: `/root/.dbus': Permission denied find: `/root/.gconf': Permission denied find: `/root/.gconfd': Permission denied find: `/root/.gnome': Permission denied find: `/root/.gnome2': Permission denied find: `/root/.gnome2_private': Permission denied Diplomacy Attacking a Territory as they move How to preserve custom number formatting after closing a workbook? I searched it a while and found some articles regarding Xperia Mini X10 also on XDA but I couldn't understand them easily. So I want help from you geeks who can give me the lighted way with simple steps to root my phone.    I want a step by step guide about to root this model. I'm a not much familiar with this technology so please guide me through some detailed answer. I'm creating a function where I need to pass an object so that it can be modified by the function. What is the difference between:  public void myFunction(ref MyClass someClass)   and  public void myFunction(out MyClass someClass)   Which should I use and why? I've noticed that if I downvote an answer, the record of the downvote is visible to me in my profile.  But when I view my profile from another browser that's not logged into Stack Overflow, I've noticed that I don't see the record of the downvote.  So I was wondering if the downvote record is visible only to me?  If so, is this done to protect downvoters from retaliation? Mid 2012 MBP shuts down claiming no power with charge at 30% or 40% or more If 20 independent Bernoulli trials are carried out each with a different probability of success and therefore failure. What is the probability that exactly n of the 20 trials was successful?  Is there a better way of calculating these probabilities rather than simply summing together the combinations of success and failure probabilities? TL:DR: Is it ever a good idea to train an ML model on all the data available before shipping it to production? Put another way, is it ever ok to train on all data available and not check if the model overfits, or get a final read of the expected performance of the model?    Say I have a family of models parametrized by $\alpha$. I can do a search (e.g. a grid search) on $\alpha$ by, for example, running k-fold cross-validation for each candidate.   The point of using cross-validation for choosing $\alpha$ is that I can check if a learned model $\beta_i$ for that particular $\alpha_i$ had e.g. overfit, by testing it on the "unseen data" in each CV iteration (a validation set). After iterating through all $\alpha_i$'s, I could then choose a model $\beta_{\alpha^*}$ learned for the parameters $\alpha^*$ that seemed to do best on the grid search, e.g. on average across all folds.  Now, say that after model selection I would like to use all the the data that I have available in an attempt to ship the best possible model in production.  For this, I could use the parameters $\alpha^*$ that I chose via grid search with cross-validation, and then, after training the model on the full ($F$) dataset, I would a get a single new learned model $\beta^{F}_{\alpha^*}$   The problem is that, if I use my entire dataset for training,  I can't reliably check if this new learned model $\beta^{F}_{\alpha^*}$ overfits or how it may perform on unseen data. So is this at all good practice? What is a good way to think about this problem? How would one go about proving that the rationals are not the countable intersection of open sets? I guess I've been somewhat ignorant when it comes to the finer details of pcb layout. Lately I've read a couple of books that try their best to lead me on the straight and narrow. Here is a couple of examples of a recent board of mine, and I have highlighted three of the decoupling caps. The MCU is a LQFP100 package and the caps are 100nF in 0402 packages. The vias connect to ground and power plane.     The top cap (C19) is placed according to best practices (as I understand them). The other two are not. I haven't noticed any problems. But then again the board has never been outside the lab.  I guess my question is: How big a deal is this? As long as the tracks are short, does it matter?  The Vref pins (reference voltage for the ADC) also have a 100nF cap across them. Vref+ comes from an onboard TL431 shunt regulator. Vref- goes to ground. Do they require special treatment like shielding or local ground?    EDIT    Thanks for great suggestions! My approach has always been to rely on an unbroken ground plane. A ground plane will have the lowest possible impedance, but this approach may be too simplistic for higher frequency signals. I've made a quick stab at adding local ground and local power under the MCU (The part is an NXP LPC1768 running at 100MHz). The yellow bits are the decoupling caps. I'll look into paralleling caps. The local ground and power are connected to the GND layer and the 3V3 layer where indicated.  The local ground and power are made with polygons (pour). It's going to be a major rerouting job to minimize the length of the "tracks". This technique will limit how many signal tracks can be routed under and across the package.  Is this an acceptable approach? Sitemaps - one per subdomain or one for the base domain? I have more than 5 subdomains on a project, say developer, www, staff and some more, what is the best practice in creating sitemaps?   All subdomains that share a same sitemap at base domain (example.com/sitemap.xml) ? or different sitemaps for different subdomains?(developer.example.com/sitemap.xml and www.example.com/sitemap.xml)   Since the subdomains are several parts of the main application, what are the pros and cons of each, and what should I consider while choosing the one over the other? (one sitemap per subdomain or one for the whole site) I've doing some researches since few days and I haven't really got an answer to my question.  I am in the process of building a huge file server for the company I work for. We bought a server case  with 24 bays and drives. Now I am stuck at the point where I have to choose the RAID card. I saw a RAID card from LSI that offer 6 internals mini-SAS 8087 ports (6x4) and would work perfectly with my build. However, it's not cheap.  I have been reading about the subject and I found something called SAS Expander. They are cheap.  with 6 mini SAS 8087 for 225$ (instead of 1150$ of the other one).  Now my question, how would I link an SAS Expander with a RAID card ? Do I need to a buy a RAID card with only 1 external 8088 port and link it with the other card ? Could someone clarify this for me because I haven't found any good documentation on it.  Thanks you. New top bar quick reference guide / Where has the link to  gone? Since the new top bar has been rolled out - a number of different people, established and new users alike, have asked questions on where a specific link has disappeared to with the new top bar design. Where has the link to &lt;X&gt; gone? Term for being unable to see glaring errors after working for some time on a task? How does Salesforce SSO call just-in-time handler methods I am having a hard time digging up some information on this as I believe it is still relatively new. If you implement SSO with Salesforce you have the ability to enable SAML. I have enabled SAML and have also enabled JIT with an automatically created class to support it.  Out of this newly generated class, there are two global methods that I am assuming are called upon SSO, but I do not know which one is called or how.   global User createUser(Id samlSsoProviderId, Id communityId, Id portalId,     String federationIdentifier, Map&lt;String, String&gt; attributes, String assertion) {     User u = new User();     handleJit(true, u, samlSsoProviderId, communityId, portalId,         federationIdentifier, attributes, assertion);     return u; }  global void updateUser(Id userId, Id samlSsoProviderId, Id communityId, Id portalId,     String federationIdentifier, Map&lt;String, String&gt; attributes, String assertion) {     User u = [SELECT Id, FirstName, ContactId FROM User WHERE Id=:userId];     handleJit(false, u, samlSsoProviderId, communityId, portalId,         federationIdentifier, attributes, assertion); }   Does Salesforce have some backend code that interprets the SAML coming over the SSO and then calls the methods appropriately?   The reason I am asking this is because I would like to cancel a user's SSO if they do not match x fields based off of the values coming across in the SAML in the SSO. If I did not want to update a user or create a user, would I be able to add in my own global class that could be called from the SSO?   Let me know if this is unclear / does not make sense.  Thanks Thousands of .log files in Exchange 2007 Server folder I'm a bit of an Exchange admin noob so I don't know if this is normal, but on our Exchange 2007 server under C:\Program Files\Microsoft\Exchange Server\Mailbox\First Storage Group\ there are 30,000 1MB .log files.  I don't know if those should be there or not, but they keep multiplying like little jackrabbits.  I've so far resisted deleting them as I'm sure something would break, but it's come to the point now where our 80GB disk is completely full up and Exchange has stopped receiving messages.  My best guess is that these are transaction logs and would be useful in rebuilding the database should something go awry, but 30GB of transaction logging seems a bit excessive.  Is there a way to limit it or is that even a good idea?  And of course did I completely miss the point? Captchas not displaying in SO for me When I get a captcha on Stack Overflow, I don't see the image or the input box with Firefox. I originally had the "HTTPS Anywhere" extension installed but still have the same issue when it's disabled (This caused issues previously when Google's SSL certs were expired for an old domain IIRC).  The requests to Google seem to be never-ending; browsing to the URLs that are still loading results in some pages of JavaScript, but no errors as you'd hope.  The screenshot was taken after the page had been open for more than 3 minutes, and I'm not sure why the GETs are still running. The request popup visible in Firebug is for "GET challenge?k=...."  When browsing to the same captcha page in IE, there are no issues.  I'm aware this could be an issue with my Firefox configuration, as opposed to the site, but would appreciate it if someone could verify if it's just me, and suggest a fix.  EDIT   While visiting the Recaptcha site, I can see a Captcha with no problems If I right-click the problem URLs in FF and Open in new tab, the pages load fine. From the fact that FB omits IP Addresses for the problem ones, I assume that it's not even opening a connection (nor perhaps performing a DNS lookup) Other sites that use Recaptcha seem to work fine (I picked 3 at random from Google)