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• GNOME session not starting after filesystem corruption

  - by user3215

  I'm running Ubuntu 9.10 desktop edition. Suddenly today /home became corrupted and I was prompted to run fsck manually. I ran fsck -y /home and rebooted the system. The system booted but I got no GUI interface (GNOME session) but a black screen with a user prompt instead. Any tricks here to start my system normally? Any help is greatly appreciated. EDIT:1 The error were similar to the the following(may be with some mistakes as I had to type it manually): machine1 login: root password: at login Sun Jan 16 15:30:46 IST 2011 on tty1 EXT3-fs error (devie sda1): ext3_lookup :deleted inode referenced aborting journal on device sda1 Remounting filesystem read-only root@machine1:~# startx ktemp: failed to create file via template `/tmp/serverauth.xxxxxxxxxxx: Read-only file /usr/bin/startx: line 157: cannot create temp file for here-document: Read-only file xauth: error in locking authority file /root/.Xauthority /usr/bin/startx: line 173: cannnot create temp file for here-document: Read-only file xauth: error in locking authority file /root/.Xauthority /usr/bin/startx: line 173: cannnot create temp file for here-document: Read-only file X: cannot stat /tmp/.x11-unix (No such file or directory), aborting giving up. xinit: No such file or directory (errno 2): unable to connect to xserver xinit: No such process (errno 3): Server error xauth: error in locking authority file /root/.Xauthority

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• "Opportunity" to take over maintenance of a small internal website. What should I do?

  - by Dan

  I have been offered an "opportunity" to take over maintenance of a small internal website run by my group that provides information about schedules and photos of events the groups done. My manager sent me the link to the site and checked it out. The site looked clean and neat but loaded in ~5 seconds. I thought this was a little long considering the site really didn't contain a lot of content. This prompted me to take a look under the hood at the pages source code. To my horror it'd been totally hacked together using nested tables! I'm new so I really can't say no to this "opportunity" so what should I do with it? Every fiber of my being feels that the only correct thing to do is over hall the site using CSS, Div's, Span's and any other appropriate tags that a sane/good web developer would used to begin with instead of depending on the render incentive magic of tables. But I'd like to ask programmers with more experienced then me, who have been in this situation. What should I do? Is my only realistic option to leave the horror as is and only adjusting the content as requested? I'm really torn between good development and the corporate reality I'm part of. Is there some kind of middle ground where things can be made better even if they're not perfect? Thanks ahead of time.

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• Why do I get disk I/O errors booting the 3.2 kernel on a xen vps server?

  - by Doug

  I have a xen vps, which I just upgraded to the new LTS 12 Precise Pangolin. However, I see this error on booting: [ 12.848076] end_request: I/O error, dev xvda, sector 12841 [ 12.848093] end_request: I/O error, dev xvda, sector 12841 [ 12.848103] Buffer I/O error on device xvda1, logical block 1605 [ 12.848110] lost page write due to I/O error on xvda1 [ 12.848129] Aborting journal on device xvda1. Results in / being mounted read-only. Reboot: [ 3.087257] EXT3-fs (xvda1): warning: ext3_clear_journal_err: Marking fs in need of filesystem check. [ 3.087677] EXT3-fs (xvda1): recovery complete [ 3.088514] EXT3-fs (xvda1): mounted filesystem with ordered data mode Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. fsck from util-linux 2.20.1 PRGMRDISK1 contains a file system with errors, check forced. Checking disk drives for errors. This may take several minutes. Press C to cancel all checks in progress PRGMRDISK1: ***** REBOOT LINUX ***** PRGMRDISK1: 371152/6001184 files (2.8% non-contiguous), 4727949/12000000 blocks mountall: fsck / [308] terminated with status 3 mountall: System must be rebooted: / [ 151.566949] Restarting system. Name ID Mem VCPUs State Time(s) shadowmint 236 2048 1 --p--- 0.0 Reboot - back to 1. This is definitely an issue with the 3.2 kernel, because booting the 3.0.0 or 2.6.38 kernel series make this issue magically disappear. I'm certain this is some kind of weird xen thing, but no idea. Anyone? Anyhow, until this is resolve I strongly recommend against upgrading if you're running a xen server.

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• Terminal/Putty showing control characters (^M) after updating

  - by jaycee48

  I updated my system yesterday afternoon using the recommended updates from Update Manager. After it completed, I shutdown my system and went home for the day. I come in this morning and I am getting control characters displayed when using vi in both the standard terminal emulator, putty, and putty inside of my Windows virtual that I run with VirtualBox. I have made no other system changes and I cannot figure out how this occurred. It's as if every text file I have was created in DOS. I've searched the forums and I haven't found any answers. I am using xterm as my emulator and I checked with 3 of my coworkers and none of them are having this problem so we do not believe it is a server side issue. Especially since I've checked 3 different servers. There's nothing in my .profile other than PATH variables so I'm using the same terminal settings as everyone else. Some files are fine (I can open and read both /etc/environment and my .profile) but most of any kind of server generated log file is trash. Running cat or head on the same file displays the contents without the characters. Any ideas would be appreciated. Thanks.

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• Problem Installing Ubuntu 12.04 - [Errno 5]

  - by Rob Barker

  I'm trying to intall Ubuntu 12.04 to my brand new eBay purchased hard drive. Only got the drive today and already it's causing me problems. The seller is a proper proffesional company with 99.9% positive feedback, so it seems unlikely they would have sold me something rubbish. My old hard drive packed up last Tuesday and so i bought a new one to replace it. Because this was an entirely new drive i decided to install Ubuntu as there was no current operating system. My computer is an eMachines EM250 netbook. There's no disc drive so i am installing from a USB stick. The new operating system loads beautifully, and the desktop appears just as it should. When i click install i am taken to the installer which copies the files to about 35% and then displays this: [Errno 5] Input/output error This is often due to a faulty CD/DVD disk or drive, or a faulty hard disk. It may help to clean the CD/DVD, to burn the CD/DVD at a lower speed, to clean the CD/DVD drive lens (cleaning kits are often available from electronics suppliers), to check whether the hard disk is old and in need of replacement, or to move the system to a cooler environment. The hard drive can be heard constantly crackling. When i booted Ubuntu 12.04 from my old faulty hard drive as a test, i didn't even make it past the purple Ubuntu screen, so it can't be that bad. Any ideas? Message to the moderators. Please do not close this thread. I'm well aware there may be other threads on this, but i don't want it closing as the others do not provide the answer i am looking for. Thank you.

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• Having a Proactive Patch Plan is the way to Go!

  - by user793553

  BUILDING A SUCCESSFUL PATCHING STRATEGY Make Patching Easy! Having a Patching Strategy for your E-Business Suite system is a great way to manage your system downtime, identify the proper resources needed to perform the necessary task and familiarizing yourself with the Patching Tools in EBS. Having a Proactive Patch Plan is the way to Go! Proactive Patching is a preventive measure allowing you to have a complete patching strategy when applying patches periodically. Oracle provides several tools to help you get started to set the foundation for a solid and proactive patching strategy in Note 313.1 - "Patching & Maintenance Advisor: E-Business Suite 11i and R12". It details all the steps and tooling available for the patching strategy along with the benefits. Among other things it covers the following: How to plan ahead for system downtime Patching Tools in E-Business Suite (Autopatch, OUI, OPatch) How to Identify Patches (RUPs, EBS Family Packs, Critical Patch Updates, etc) How to properly test your patching plan and move to Production Make sure you visit the New E-Business Patching Community! We encourage you to access the "E-Business Patching Community" prior to applying an E-Business Suite patch. Doing so will allow you to explore perspectives shared by industry peers, get real-world experiences with the patch, and benefit from known solutions and lessons learned. Additionally, Oracle Support engineers monitor discussion topics to help provide guidance and solutions for your E-Business Suite patching needs. This is a valuable opportunity to "Get Proactive" with the patching and maintenance of your E-Business Suite environment. Start now, and find fast, proactive resolutions before you begin. Related Articles: What's the Best Way to Patch an E-Business Suite Environment? Patch Wizard Utility

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• Event notifications for Reporting Systems

  - by Marc Schluper

  The last couple of months I have been working on an application that allows people to browse a data mart. Nice, but nothing new. In this context I have an idea that I want to publish before anyone else patents it: event notifications. You see, reporting systems are not used as much as we’d like. Typically, users don’t know where to look for reports that might interest them. At best, there are some standard reports that people generate every so often, i.e. based on a time trigger. Or some reporting systems can be configured to send monthly reports around, for convenience. But apart from that, the reporting system is just sitting there, waiting for the rare curious user who makes the effort to dig a bit for treasures to be found. Wouldn’t it be great if there were data triggers? Imagine we could configure the reporting system to let us know when something interesting has happened. It would send us a message containing a link that would take us to the relevant section of the reporting system, showing a report with all the data pertaining to that event, preparing us for proper actions. Here in the North West this would really be great. You see, it rains here most of the time from October to June, so why even check the weather forecast? But sometimes, sometimes it snows. And sometimes the sun shines. So rather than me going to the weather site and seeing over and over again that it will be raining, making me think “why bother?” I’d like to configure the weather site so that it lets me know when the rain stops. Now, hopefully nobody has patented this idea already. Let me know.

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• Parameterized Django models

  - by mgibsonbr

  In principle, a single Django application can be reused in two or more projects, providing functionality relevent to both. That implies that the same database structure (tables and relations) will be re-created identically in different databases, and most times this is not a problem (assuming the projects/databases are unrelated - for instance when someone downloads a complete app to use in their own projects). Sometimes, however, the models must be "tweaked" a little to better fit the problem needs. This can be accomplished by forking the app, but I wondered if there wouldn't be a better option in cases where the app designer can anticipate the most common customizations. For instance, if I have a model that could relate to another as one-to-one or one-to-many, I could specify the unique property as a parameter, that can be specified in the project's settings: class This(models.Model): other = models.ForeignKey(Other, unique=settings.OTHER_TO_THIS) Or if a model can relate to many others, I could create an intermediate table for each of them (thus enforcing referential integrity) instead of using generic fks: for related in settings.MODELS_RELATED_TO_OTHER: model_name = '%s_Other' % related globals()[model_name] = type(model_name, (models.Model,) { me:models.ForeignKey(find_model_class(related)), other:models.ForeignKey(Other), # Some other properties all intersection tables must have }) Etc. Let me stress out that I'm not proposing to change the models at runtime nor anything like that; once the parameters were defined and syncdb called for the first time, those parameters are not to be changed again (unless you're doing a schema migration). Is this a good design? Are there better ways to accomplish the same thing, or maybe drawbacks I coulnd't anticipate? This technique is meant to be used sparingly (only on apps meant to be reused in wildly different contexts, and only when a specific need of customization can be detected while the app model is being designed).

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• Best design for a "Command Executer" class

  - by Justin984

  Sorry for the vague title, I couldn't think of a way to condense the question. I am building an application that will run as a background service and intermittently collect data about the system its running on. A second Android controller application will query the system over tcp/ip for statistics about the system. Currently, the background service has a tcp listener class that reads/writes bytes from a socket. When data is received, it raises an event to notify the service. The service takes the bytes, feeds them into a command parser to figure out what is being requested, and then passes the parsed command to a command executer class. When the service receives a "query statistics" command, it should return statistics over the tcp/ip connection. Currently, all of these classes are fully decoupled from each other. But in order for the command executer to return statistics, it will obviously need access to the socket somehow. For reasons I can't completely articulate, it feels wrong for the command executer to have a direct reference to the socket. I'm looking for strategies and/or design patterns I can use to return data over the socket while keeping the classes decoupled, if this is possible. Hopefully this makes sense, please let me know if I can include any info that would make the question easier to understand.

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• How can I get cross-browser consistent behavior for TR heights within a table with a set height? [migrated]

  - by Dan

  I have an arbitrary number of tables with an arbitrary number of rows in each, and all tables are the same height. My initial approach was to just set the overall height of the table and hope the rows were smart enough to distribute themselves appropriately. That's not the case. I have 4 different behaviors going on with 4 browsers, but I need them to all render at the very least in a similar way. Safari & Chrome (WebKit): All rows are equal height, creating scroll bars as needed and fitting within table height. Firefox: All rows are the height necessary to fit their content, with the remaining rows overflowing out of the table. Additionally, If the content of the rows does not take up all of the height, only the part of the table with content in it takes the background (though it seems, through use of Firebug, that the actual table [and TR] extend to the bottom of the proper table height). IE: All rows are the height necessary to fit their content, with the remaining rows overflowing out of the table. Obviously this only includes one version of each browser and additional variation would likely appear with more being tested. Ideally, a solution where the browser renders TRs with less content smaller than those with larger content, while still using scrolling within the variable height TRs when the overall height of the table is not enough would be optimum. I could potentially see a solution to achieve that with JS, but can it be done with CSS? Or, if not, can the behavior that WebKit displays be made to work across the browsers? Thanks! PS: Example can be found here.

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• Ubuntu 64bit Black Screen on Minecraft

  - by Signify

  I have tried posting on the forums, but I really need help (I'm a server admin and really don't want to have to switch to Windows just to run Minecraft). Anyhow, I originally was running openjdk6 as I was told that 7 was unstable and was getting periodical lag spikes while walking (at least once every 3 seconds the screen would freeze for a tenth of a second). After that, I attempted to install Sun's Java JDK7 (I couldn't get ahold of 6 without signing up for Oracle's newsletters). Upon attempting to run Minecraft, I got a black screen after logging in with this error message: 27 achievements 182 recipes Setting user: Thunder7102, -1618112820878091307 Exception in thread "Minecraft main thread" java.lang.UnsatisfiedLinkError: /home/noiro/.minecraft/bin/natives/liblwjgl.so: /home/noiro/.minecraft/bin/natives/liblwjgl.so: wrong ELF class: ELFCLASS32 (Possible cause: architecture word width mismatch) at java.lang.ClassLoader$NativeLibrary.load(Native Method) at java.lang.ClassLoader.loadLibrary1(ClassLoader.java:1939) at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1864) at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1825) at java.lang.Runtime.load0(Runtime.java:792) at java.lang.System.load(System.java:1059) at org.lwjgl.Sys$1.run(Sys.java:69) at java.security.AccessController.doPrivileged(Native Method) at org.lwjgl.Sys.doLoadLibrary(Sys.java:65) at org.lwjgl.Sys.loadLibrary(Sys.java:81) at org.lwjgl.Sys.<clinit>(Sys.java:98) at org.lwjgl.opengl.Display.<clinit>(Display.java:132) at net.minecraft.client.Minecraft.a(SourceFile:184) at net.minecraft.client.Minecraft.run(SourceFile:657) at java.lang.Thread.run(Thread.java:722) Now, this got me fed up, so I tried to install a Windows 7 virtual machine through virtualbox, I gave it 256mb of graphics memory with 2D and 3D acceleration and 3GB of RAM. I installed Java JDK7 for Windows (which does work from experience on my other Windows 7 partition). Once again, a black screen after login. What the heck is going on guys? My System Specs: Ubuntu 12.04 64bit Fully Updated running Gnome3 Nvidia GTS 450 1.3GB OC'd AMD Athlon II 4x 2.8Ghz 6GB of RAM So, what do you think?

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• How to improve my email communication

  - by SpashHit

  Paraphrase of an email I sent to a colleague I noticed a problem with System A. I have determined that it is not caused by X. I suspect that it is being caused by Y. (since you are in charge of Y) Can you please take a look at it? (The part in parentheses was not included in my email because this colleague knows full well he is in charge of Y... it should be understood that's why I was sending him the email) I run into the colleague half a day later, and say, "did you look at the problem with System A yet?" and he answers, "Oh, yeah, I got your email about System A being broken but I assumed it was probably caused by X, so I was waiting for you to check on that." Obviously my message did not get communicated. This is an all-too-common result of emails I send and is very discouraging... yet, I don't know how I could make my emails any clearer. They are always as brief, clear, and to the point as I can make them. Any suggestions? Maybe there is something inherent about the medium of email that is just not effective for these types of communications?

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• svcbundle for easier SMF manifest creation

  - by Glynn Foster

  One of the new features we've introduced in Oracle Solaris 11.1 is a new utility called svcbundle. This utility allows for the easy creation of Service Management Facility (SMF) manifests and profiles, allowing you to take advantage of the benefits of automatic application restart without requiring you to have full knowledge of the XML file format that is used when integrating with the SMF. Integrating into SMF is one of the easiest and most obvious ways to take advantage of some of the mission critical aspects of the operating system, but many customers were often finding the initial learning curve of creating an XML manifest to be too hard. With the release of Oracle Solaris 11 11/11, SMF had a more integral part to play as more and more system configuration was starting to use the SMF configuration repository for the backend storage. This provides a number of aspects, including the ability to carefully manage customized administrative configuration, site specific configuration, and vendor provided configuration at different layers, helping to preserve them during system update. I've written a new article, Using svcbundle to Create SMF Manifests and Profiles in Oracle Solaris 11, to give you a feel for the help we can provide in converting your applications over to SMF, or doing some site wide configuration using profiles. This is the first pass at creating such a tool, so we'd love to hear feedback of your experiences using it.

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• Enforcing Constraints Upon Data Documents of Various Formats

  - by Christopher Berman

  This seems like the sort of problem that must have been solved elegantly long ago, but I haven't the foggiest how to google it and find it. Suppose you're maintaining a large legacy system, which has a large collection of data (tens of GB) of various formats, including XML and two different internal configuration formats. Suppose further that there are abstract rules governing the values these files may or may not contain. EXAMPLE: File A defines the raw, mathematical data pertaining to the aerodynamics of a car for consumption of the physics component of the system. File B contains certain values from File A in an easily accessible, XML hierarchy for consumption of a different component of the system. There exists, therefore, an abstract rule (or constraint) such that the values from File B must match the values from File A. This is probably the simplest constraint that can be specified, but in practice, the constraints between files can become very complicated indeed. What is the best method for managing these constraints between files of arbitrary formats, short of migrating it over to an RDBMS (which simply isn't feasible for the foreseeable future)? Has this problem been solved already? To be more specific, I would expect the solution to at least produce notifications of violated constraints; the solution need not resolve the constraints. ============================== Sample file structures File A (JeepWrangler2011.emv): MODEL JeepWrangler2011 { EsotericMathValueX 11.1 EsotericMathValueY 22.2 EsotericMathValueZ 33.3 } File B (JeepWrangler2011.xml): <model name="JeepWrangler2011"> <!--These values must correspond File A's EsotericMathValues--> <modelExtent x="11.1" y="22.2" z="33.3"/> [...] </model>

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• Can't run minecraft on ubuntu 12.04 lts [duplicate]

  - by user170011

  This question already has an answer here: How to correctly install and troubleshoot Minecraft (Client) 3 answers I was trying to run minecraft on my laptop with ubuntu 12.04 lts 64 bit. I have a lenovo ideapad p580 with 7.7 Gb and an Intel® Core™ i7-3520M CPU @ 2.90GHz × 4 processor. Under the graphics section of the system overview in ubuntu it says I have none installed. My computer comes with and nvidia geforce graphics card but it isnt recognized. When I start minecraft I get this crash report. ---- Minecraft Crash Report ---- // Shall we play a game? Time: 24/06/13 7:23 PM Description: Failed to start game org.lwjgl.LWJGLException: Could not init GLX at org.lwjgl.opengl.LinuxDisplayPeerInfo.initDefaultPeerInfo(Native Method) at org.lwjgl.opengl.LinuxDisplayPeerInfo.<init>(LinuxDisplayPeerInfo.java:52) at org.lwjgl.opengl.LinuxDisplay.createPeerInfo(LinuxDisplay.java:684) at org.lwjgl.opengl.Display.create(Display.java:854) at org.lwjgl.opengl.Display.create(Display.java:784) at org.lwjgl.opengl.Display.create(Display.java:765) at net.minecraft.client.Minecraft.a(SourceFile:235) at avv.a(SourceFile:56) at net.minecraft.client.Minecraft.run(SourceFile:507) at java.lang.Thread.run(Thread.java:679) A detailed walkthrough of the error, its code path and all known details is as follows: -- System Details -- Details: Minecraft Version: 1.5.2 Operating System: Linux (amd64) version 3.5.0-34-generic Java Version: 1.6.0_27, Sun Microsystems Inc. Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Sun Microsystems Inc. Memory: 406175448 bytes (387 MB) / 514523136 bytes (490 MB) up to 1908932608 bytes (1820 MB) JVM Flags: 2 total; -Xmx2048M -Xms512M AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used Suspicious classes: No suspicious classes found. IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0 LWJGL: 2.4.2 OpenGL: ~~ERROR~~ NullPointerException: null Is Modded: Probably not. Jar signature remains and client brand is untouched. Type: Client (map_client.txt) Texture Pack: Default Profiler Position: N/A (disabled) Vec3 Pool Size: ~~ERROR~~ NullPointerException: null I can run it on different versions of linux such as fedora.

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• Threading models when talking to hardware devices

  - by Fuzz

  When writing an interface to hardware over a communication bus, communications timing can sometimes be critical to the operation of a device. As such, it is common for developers to spin up new threads to handle communications. It can also be a terrible idea to have a whole bunch of threads in your system, an in the case that you have multiple hardware devices you may have many many threads that are out of control of the main application. Certainly it can be common to have two threads per device, one for reading and one for writing. I am trying to determine the pros and cons of the two different models I can think of, and would love the help of the Programmers community. Each device instance gets handles it's own threads (or shares a thread for a communication device). A thread may exist for writing, and one for reading. Requested writes to a device from the API are buffered and worked on by the writer thread. The read thread exists in the case of blocking communications, and uses call backs to pass read data to the application. Timing of communications can be handled by the communications thread. Devices aren't given their own threads. Instead read and write requests are queued/buffered. The application then calls a "DoWork" function on the interface and allows all read and writes to take place and fire their callbacks. Timing is handled by the application, and the driver can request to be called at a given specific frequency. Pros for Item 1 include finer grain control of timing at the communication level at the expense of having control of whats going on at the higher level application level (which for a real time system, can be terrible). Pros for Item 2 include better control over the timing of the entire system for the application, at the expense of allowing each driver to handle it's own business. If anyone has experience with these scenarios, I'd love to hear some ideas on the approaches used.

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• Is file permission secured when it transferred from Ubuntu to Windows?

  - by Gaurav_Java

  I am having 9GB text file which is encrypted . This file contains some confidential data . Which is on my system(Ubuntu) and my external HDD (ntfs) . This file get daily updated and then encrypted . But it has to be shared among 2-3 (Windows) person. I defined permission so that no other person can even read this file(chmod 660). It is too large file, so I can't upload it anywhere and it get updated daily basis. But this file travel on Windows OS and Ubuntu also. Even I am having copy of this on my personal computer. Recently it was deleted by some other user over Windows . I just want to know how can I set permission over that file so that it cannot be deleted from any other operating system. If someone delete this file, then I am having data old for couple of days, which is only on my system. I gone through this question it says there is nothing. And from this question I am not able to understand how can I protect it. Can I do anything for preventing this file from being deleted. Then how can I secure this files from getting deleted any suggestion or software or ideas. Maybe I sound silly or this is stupid question. Please don't close it, thanks for any suggestion or solution.

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• How does datomic handle "corrections"?

  - by blueberryfields

  tl;dr Rich Hickey describes datomic as a system which implicitly deals with timestamps associated with data storage from my experience, data is often imperfectly stored in systems, and on many occasions needs to retroactively be corrected (ie, often the question of "was a True on Tuesday at 12:00pm?" will have an incorrect answer stored in the database) This seems like a spot where the abstractions behind datomic might break - do they? If they don't, how does the system handle such corrections? Rich Hickey, in several of his talks, justifies the creation of datomic, and explains its benefits. His work, if I understand correctly, is motivated by core the insight that humans, when speaking about data and facts, implicitly associate some of the related context into their work(a date-time). By pushing the work required to manage the implicit date-time component of context into the database, he's created a system which is both much easier to understand, and much easier to program. This turns out to be relevant to most database programmers in practice - his work saves everyone a lot of time managing complex, hard to produce/debug/fix, time queries. However, especially in large databases, data is often damaged/incorrect (maybe it was not input correctly, maybe it eroded over time, etc...). While most database updates are insertions of new facts, and should indeed be treated that way, a non-trivial subset of the work required to manage time-queries has to do with retroactive updates. I have yet to see any documentation which explains how such corrections, or retroactive updates, are handled by datomic; from my experience, they are a non-trivial (and incredibly difficult to deal with) subset of time-related data manipulation that database programmers are faced with. Does datomic gracefully handle such updates? If so, how?

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• Ubuntu installation does not recognize drive partinioning

  - by Woltan

  I have a 1TB drive and installed Windows 7 on a 128GB partition. When I now try to install Ubuntu 11.04 it does not recognize the Windows partition but offers the complete 1TB drive to install Ubuntu on instead. It displays: However, in the Ubuntu Disk Utility the Windows partitions are recognized. What do I need to do in order for Ubuntu to recognize the Windows 7 partition and install Ubuntu as a dual boot? Response to comments The following commands were executed and the results are shown below: fdisk -l WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x34a38165 Device Boot Start End Blocks Id System /dev/sda1 * 1 13 102400 7 HPFS/NTFS Partition 1 does not end on cylinder boundary. /dev/sda2 13 16318 130969600 7 HPFS/NTFS Disk /dev/sdb: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x14a714a6 Device Boot Start End Blocks Id System /dev/sdb1 1 60801 488384001 83 Linux parted -l Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0 has been opened read-only. Error: /dev/sr0: unrecognised disk label

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• 11.10 install hangs at different places

  - by TreefrogInc

  I've been trying to install Oneiric for some time now, and I've looked everywhere for a solution to the problems I've been having. So far, I've attempted four times to install it, so now I'm up to a point of panic. So I grabbed the 11.10 x64 iso from the website, and after verifying that the md5 hash is correct, I burned that onto my last remaining clean CD. On my first attempt, everything went perfectly up to the middle of the installation, and the progress bar stopped when it said: "configuring target system." I could do everything else, only the installation seemed to have stopped. After I googled my problem, I went and used the "check disc for errors" option, which said everything was fine. Then I tried the installation again, only this time, I selected "Install Ubuntu Now" instead of the "try before installing". Again, the same problem. My second and third tries didn't even reach the installation phase. It just stopped at the 5 blinking dots and never went any further. I used the same non-rewritable cd for all the attempts, as the error check didn't show any problems and because I'm currently out of usable cds. System: Core i3 CPU @ 3.4 GHz, 500 GB HDD (250g used for Win7, 70g used for preexisting system partitions, 180g unallocated).

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• Which approach is the most maintainable?

  - by 2rs2ts

  When creating a product which will inherently suffer from regression due to OS updates, which of these is the preferable approach when trying to reduce maintenance cost and the likelihood of needing refactoring, when considering the task of interpreting system state and settings for a lay user? Delegate the responsibility of interpreting the results of inspecting the system to the modules which perform these tasks, or, Separate the concerns of interpretation and inspection into two modules? The first obviously creates a blob in which a lot of code would be verbose, redundant, and hard to grok; the second creates a strong coupling in which the interpretation module essentially has to know what it expects from inspection routines and will have to adapt to changes to the OS just as much as the inspection will. I would normally choose the second option for the separation of concerns, foreseeing the possibility that inspection routines could be re-used, but a developer updating the product to deal with a new OS feature or something would have to not only write an inspection routine but also write an interpretation routine and link the two correctly - and it gets worse for a developer who has to change which inspection routines are used to get a certain system setting, or worse yet, has to fix an inspection routine which broke after an OS patch. I wonder, is it better to have to patch one package a lot or two packages, each somewhat less so?

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• correct way to implement auth/acl in mvc

  - by WiseStrawberry

  I am looking into making a correctly laid out MVC auth/acl system. I think I want the authentication of a user (and the session handling) to be seperate from the ACL system. (I don't know why but this seems a good idea from the things I've read) What does mvc have to do with this question you ask? Because I wish for the application to be well integrated with my acl. An example of a controller (CodeIgniter) <?php class forums extends MX_Controller { $allowed = array('users', 'admin'); $need_login = true; function __construct() { //example of checking if logged in. if($this->auth->logged_in() && $this->auth->is_admin()) { echo "you're logged in!"; } } public function add_topic() { if($this->auth->allowed('add_topic') { //some add topic things. } else { echo 'not allowed to add topic'; } } } ?> My thoughts $this->auth would be autoloaded in the system. I would like to check the $allowed array against the user currently (not) logged in and react accordingly. Is this a good way of doing things? I haven't seen much literature on mvc integration and auth. I want to make things as easy as possible.

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• Floating point undesirable in highly critical code?

  - by Kirt Undercoffer

  Question 11 in the Software Quality section of "IEEE Computer Society Real-World Software Engineering Problems", Naveda, Seidman, lists fp computation as undesirable because "the accuracy of the computations cannot be guaranteed". This is in the context of computing acceleration for an emergency braking system for a high speed train. This thinking seems to be invoking possible errors in small differences between measurements of a moving object but small differences at slow speeds aren't a problem (or shouldn't be), small differences between two measurements at high speed are irrelevant - can there be a problem with small roundoff errors during deceleration for an emergency braking system? This problem has been observed with airplane braking systems resulting in hydroplaning but could this actually happen in the context of a high speed train? The concern about fp errors seems to not be well-founded in this context. Any insight? The fp is used for acceleration so perhaps the concern is inching over a speed limit? But fp should be just fine if they use a double in whatever implementation language. The actual problem in the text states: During the inspection of the code for the emergency braking system of a new high speed train (a highly critical, real-time application), the review team identifies several characteristics of the code. Which of these characteristics are generally viewed as undesirable? The code contains three recursive functions (well that one is obvious). The computation of acceleration uses floating point arithmetic. All other computations use integer arithmetic. The code contains one linked list that uses dynamic memory allocation (second obvious problem). All inputs are checked to determine that they are within expected bounds before they are used.

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• First Shard for SQL Azure and SQL Server

  - by Herve Roggero

  That's it!!!!! It's ready to go and be tested, abused and improved! It requires .NET 4.0 and uses some cool technologies, like caching (the new System.Runtime.Caching) and the Task Parallel Library (System.Threading.Tasks). With this library you can: Define a shard of 1, 2 or 100 SQL databases (a mix of SQL Server and SQL Azure) Read from the shard in parallel or sequentially, and cache resultsets Update, Delete a record from the shard Insert records quickly in the shard with a round-robin load Reset the cache You can download the source code and a sample application here: http://enzosqlshard.codeplex.com/  Note about the breadcrumbs: I had to add a connection GUID in order for the library to know which database a record came from. The GUID is currently calculated on the fly in the library using some of the parameters of the connection string. The GUID is also dynamically added to the result set so the client can pass it back to the library. I am curious to get your feedback on this approach. ** Correction from my previous post: this is a library for a Horizontal Partition Shard (HPS): tables are split across databases horizontally. So in essence, the tables need to have the same schema across the databases.

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• Cannot Boot, How to recover

  - by Kendor

  Am running 11.10 64-bit with Gnome-shell. Something happened late Friday whereby my machine never gets to the login screen. I do get to an Ubuntu splash logo, after that I get a text screen that it hangs on. The screen is referring to issues with mounting various network resources, including VMWare and also some references to my NAS that are in fstab. If I hit "esc" I can get to the GRUB menu and into recovery console. If I try to do a file system check, I run into a similar error screen that I see when trying to boot normally. A possible clue here is that during my last good session I made some mods to the /etc/hosts file to reference another system which I'm connecting to with Synergy. I don't believe I have hardware issues as I'm able to boot properly with a Live USB and connect to my network/Internet. A few more tidbits. I have regular Dejadups backups on my NAS. I have a good Clonezilla whole drive image which is 4-6 weeks old.. My home is encrypted. I thought I'd try blowing away my hosts file via live USB, but when I mounted the hard drive everything was read-only and I couldn't figure out how to replace it. P.S. I logged in via CLI and modded the host file to remove the entry I'd made, to no avail. System continue to gets stuck on the following: CIFS VFS: default security mechanism requested. The default security mechanism will be upgraded from ntlm to ntlmv2 in kernel version 3.1s Would love some sober advice on how to attack this.

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