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  • Wireless does not work anymore after software update with Ubuntu 12.10 on a Dell Latitude E6230

    - by Andy
    I just installed Ubuntu 12.10 on my DELL Latitude E6230, on first boot wifi worked properly but when I updated the software it stopped working. I can't figure out the problem... The wireless network controller is a Broadcom Corporation BCM4313 802.11b/g/n Wireless Lan Controller (rev 01) "lshw -class network" gives, for the above controller: *-network UNCLAIMED description: Network controller product: BCM4313 802.11b/g/n Wireless LAN Controller vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 01 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:f7d00000-f7d03fff After reading the answer to another similar question, I edited the file NetworkManager.conf to make "managed=true", but that did not make any difference, it is as if the wireless adapter were not there. In the "Network" setting window, I only see "Wired" and "Network proxy". Wireless has just disappeared: rfkill list all 0: hci0: Bluetooth Soft blocked: no Hard blocked: no and that's it! Nothing about the wireless controller... Any suggestions?

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  • Is it a waste of time to free resources before I exit a process?

    - by Martin
    Let's consider a fictional program that builds a linked list in the heap, and at the end of the program there is a loop that frees all the nodes, and then exits. For this case let's say the linked list is just 500K of memory, and no special space managing is required. Is that a wast of time, because the OS will do that anyway? Will there be a different behavior later? Is that different according to the OS version? I'm mainly interested in UNIX based systems, but any information will be appreciated. I had today my first lesson in OS course and I'm wondering about that now.

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  • Need new developers-laptop, with ubuntu. Multiple ext displays, ssd, dock, NO DVD [closed]

    - by Ole Morten Amundsen
    I'm having a really hard time finding a great alternative for Macbook Pro (I have a MB pro '08). I'd like to return to ubuntu and need a kick-ass laptop. If you help, you've lead me back to linux :) Req: ubuntu friendly lots of memory 8G+ ssd 160GB+ great processor (intel sandy?) connect up to three external displays. this triple display looks cool No optical drive, NO DVD 13-17" dock. In place of the ridiculous optical drive (It's like having a floppy drive IMO): extra battery? 2nd ssd? extra graphics card? your suggestion The laptop should be designed for not having dvd. I can't find many, unless they are tiny 11"... I'm exited to know your answers!

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  • How to "back track"?

    - by esqew
    I find that I start projects and, due to my lack of experience, find that old database structures and huge blocks of code are inefficient and memory-costly. However, by the time I realize a re-design of the entire project is needed, the project has grown to such a size that it is simply too late to go back and modify the project in its current state and requires a completely new project file and the whole shebang. How should I prevent ruts such as this one, where it is too late to go back and modify the current project to fit specifications modified far down the road from the creation of the project? (Apologies in advance for confusing grammar, it's been a long day here... as you can probably tell.)

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  • When attempting to install ubuntu 12.04 from CD, I am stuck on black streen with "loading bootlogo..."

    - by Jessica K
    I downloaded Ubuntu 12.04 to my desktop and burned to a CD using Infra Recorder and instructions on ubuntu website. Restarted PC to boot from CD receive black screen with "Loading bootlogo..." then nothing happens and I have to restart with windows. The CD seems to be correct. Folders include .disk, boot, casper, dists, install, isolinux, pics, pool, preseed, autorun file, md5sum text file, readme.diskdefines file, wubi app. System Information Operating System: Windows Vista™ Home Premium (6.0, Build 6002) Service Pack 2 (6002.vistasp2_gdr.120824-0336) System Manufacturer: TOSHIBA System Model: Satellite L305 BIOS: Default System BIOS Processor: Intel(R) Pentium(R) Dual CPU T2390 @ 1.86GHz (2 CPUs), ~1.9GHz Memory: 3062MB RAM Page File: 1553MB used, 4772MB available Windows Dir: C:\Windows DirectX Version: DirectX 11 DX Setup Parameters: Not found DxDiag Version: 7.00.6002.18107 32bit Unicode Drive: D: Model: PIONEER DVD-RW DVRKD08L ATA Device Driver: c:\windows\system32\drivers\cdrom.sys, 6.00.6002.18005 (English), 4/11/2009 00:39:17, 67072 bytes

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  • Virtual Newsstand Displays Comic Books by Date

    - by Jason Fitzpatrick
    If you’re a comic book aficionado (or just want to take a stroll down memory lane), this virtual newsstand shows you all the comics published for any month and year going all the way back to the 1930s. Courtesy of Mike’s Amazing World of Comics, the virtual newsstand lets you dial in a month, year, sorting style, and shows all publishers or select publishers. The covers are displayed in a grid where you can click through to see a larger version of the cover and read additional information about the comic. It’s a really neat way to check out trends in comic design and artwork over the years. Hit up the link below to take it for the spin. Have a cool comic book resource to share? Sound off in the comments. The Newsstand [via Boing Boing] Why Enabling “Do Not Track” Doesn’t Stop You From Being Tracked HTG Explains: What is the Windows Page File and Should You Disable It? How To Get a Better Wireless Signal and Reduce Wireless Network Interference

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  • How To Properly Scan a Photograph (And Get An Even Better Image)

    - by Eric Z Goodnight
    Somewhere in your home, there’s a box of old analog photographs you probably want digital copies of. Unless you know how to use your scanner correctly, the image quality can turn out poor. Here’s how to get the best results. If your memories are important to you, then it’s worth taking the time to do them right. Today we’re going to look at the largely overlooked tools and methods that’ll give you the best possible quality out of a scan of a less than perfect photo. We’ll see how to make the most of the scanning software and how to use graphics programs to make the image look better than the original photograph. Keep reading! How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

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  • Help slecting dedicated server with good disk I/O & network

    - by JP19
    Hi, I am looking for a cheap dedicated server. (I was earlier happy with VPS, untill I realized that the disk I/O is not at all reliable and depends on what your neighbours are upto at the moment). I was browsing through http://www.lowenddedi.net/the-database I don't understand memory speed and NIC speed columns at all. What will be their affect? Do I need to worry about them? Also, can someone help suggest a provider, with following criteria: 1) Good & reliable Network 2) Price <= $60/month. Thanks JP

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  • No programs or applications show up in dash

    - by sky
    There are no programs on the dash list (seacher on appmenu). Yesterday I logged into my account and I tried to find a particular program, but there weren't any! Additionally, I tried to view installed programs and manually find programs, but nothing was displayed. And today, when I wanted to turn on Ubuntu Software Center, it just don't turn on. I'm using Ubuntu 11.10 (64bit). I installed this as a "fresh" OS a few days ago. Ubuntu is updated and has many Gigabytes of disk memory available.

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  • Habanero

    - by csharp-source.net
    An Enterprise Application Framework for .Net that is ideally suited for developing applications in an agile manner. The framework is used for producing an application from the data layer through to the front-end. Free open source under the LGPL license, it includes ORM, code generation and runtime UI generation to create one application for the desktop & web. Features: * ORM: Map database tables to objects in code * Persist property values to and from the database * Define all mapping in a single XML file * Switch between database vendors with one setting * Support for MySQL, MS Sql Server, MS Access, Oracle, PostgreSQL, SQLite, Firebird * FireStarter GUI class definitions xml manager * Generate user interfaces and map properties to controls * Develop for both desktop (with Windows Forms) and web (with Gizmox' Visual WebGUI) * Generate new projects and code files * Generate UI forms from templates * Reverse engineer class definitions from existing databases * Support variable data sources, including an in-memory database. Ships with Firestarter a free database reverse engineering, Domain Modelling and Code Generator.

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  • Computer Science Fundamentals - Recommended books

    - by contactmatt
    Hey, I'm looking to see if anyone can recommend any books in fundamentals of computer science. I obtained my associates degree as a programmer/analyst a couple years ago and I know a good amount about programming on the .NET framework. I'm even certified on the .NET 4 framework as a web application developer. However, since I was only able to obtain my associates degree, I was deprived at my college on the low-level basics and operations of computers and basic computer science information. I'm really interesting in learning about the low-level operations of a computer and in programming (bytes, bits, memory management, etc.) Can anyone recommend any good computer science books for someone who is decently experienced in programming? Thank You

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  • How to Quickly Resize, Convert & Modify Images from the Linux Terminal

    - by Chris Hoffman
    ImageMagick is a suite of command-line utilities for modifying and working with images. ImageMagick can quickly perform operations on an image from a terminal, perform batch processing of many images, or be integrated into a bash script. ImageMagick can perform a wide variety of operations. This guide will introduce you to ImageMagick’s syntax and basic operations and show you how to combine operations and perform batch processing of many images. The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos

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  • Clock is Ticking for OBI 10g Supported Customers to move to OBI 11g

    - by Mike.Hallett(at)Oracle-BI&EPM
    Now is a perfect time for Partners to approach existing OBI 10g customers, to encourage and help them to upgrade to all the great new features in the current OBI v 11g; including the ability to go Mobile, to be in-memory on Exalytics, and to get tighter integration with Hyperion applications, Strategic Scorecards and Essbase. Oracle Lifetime Support Policy for Oracle BI Suite, version 10gR3, will end ‘normal’ support in July 2013. The final point release of Oracle Business Intelligence EE & Publisher 10gR3 was 10.1.3.4.x, which was generally available from July 2008 and will end “Premier Support” in July 2013.  From this time, customers may purchase “Extended Support” until July 2015, and from then “Sustaining Support”  indefinitely. For more information : Upgrade to Oracle Business Intelligence Enterprise Edition 11g, article on Technet Planning to Upgrade from Oracle BI 10g to BI 11g ?, at docs.oracle.com Oracle Business Intelligence Enterprise Edition 11g Oracle Lifetime Support Policy

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  • Is swing components heavy weight

    - by Pramod PP
    By Adding multiple Panels into a Panel or Dialog, Will it become heavy weight ?. Is there any way to avoid it to make complex views in single panel ? I'm making a java Swing application, there has many controls, I'm placing multiple panel in a single panel and place that panel as the center pane of a dialog. I suspect that the application takes more memory (I don't know it actually takes. Its only a suspect). can anyone please advise on this.

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  • How to debug a server that crashes once in a few days?

    - by Nir
    One of my servers crashes once in a few days. It does low traffic static web serving + low trafic dynamic web serving (PHP, local MYSQL with small data, APC, MEMCACHE) + some background jobs like XML file processing. The only clue I have is that a few hours before the server dies it starts swapping (see screenshot http://awesomescreenshot.com/075xmd24 ) The server has a lot of free memory. Server details: Ubuntu 11.10 oneiric i386 scalarizr (0.7.185) python 2.7.2, chef 0.10.8, mysql 5.1.58, apache 2.2.20, php 5.3.6, memcached 1.4.7 Amazon EC2 (us-west-1) How can I detect the reason for the server crashes ? When it crashes its no longer accessible from the outside world.

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  • jqGrid - dynamically load different drop down values for different rows depending on another column value

    - by Renso
    Goal: As we all know the jqGrid examples in the demo and the Wiki always refer to static values for drop down boxes. This of course is a personal preference but in dynamic design these values should be populated from the database/xml file, etc, ideally JSON formatted. Can you do this in jqGrid, yes, but with some custom coding which we will briefly show below (refer to some of my other blog entries for a more detailed discussion on this topic). What you CANNOT do in jqGrid, referrign here up and to version 3.8.x, is to load different drop down values for different rows in the jqGrid. Well, not without some trickery, which is what this discussion is about. Issue: Of course the issue is that jqGrid has been designed for high performance and thus I have no issue with them loading a  reference to a single drop down values list for every column. This way if you have 500 rows or one, each row only refers to a single list for that particuolar column. Nice! SO how easy would it be to simply traverse the grid once loaded on gridComplete or loadComplete and simply load the select tag's options from scratch, via ajax, from memory variable, hard coded etc? Impossible! Since their is no embedded SELECT tag within each cell containing the drop down values (remeber it only has a reference to that list in memory), all you will see when you inspect the cell prior to clicking on it, or even before and on beforeEditCell, is an empty <TD></TD>. When trying to load that list via a click event on that cell will temporarily load the list but jqGrid's last internal callback event will remove it and replace it with the old one, and you are back to square one. Solution: Yes, after spending a few hours on this found a solution to the problem that does not require any updates to jqGrid source code, thank GOD! Before we get into the coding details, the solution here can of course be customized to suite your specific needs, this one loads the entire drop down list that would be needed across all rows once into global variable. I then parse this object that contains all the properties I need to filter the rows depending on which ones I want the user to see based off of another cell value in that row. This only happens when clicking the cell, so no performance penalty. You may of course to load it via ajax when the user clicks the cell, but I found it more effecient to load the entire list as part of jqGrid's normal editoptions: { multiple: false, value: listingStatus } colModel options which again keeps only a reference to the sinlge list, no duplciation. Lets get into the meat and potatoes of it.         var acctId = $('#Id').val();         var data = $.ajax({ url: $('#ajaxGetAllMaterialsTrackingLookupDataUrl').val(), data: { accountId: acctId }, dataType: 'json', async: false, success: function(data, result) { if (!result) alert('Failure to retrieve the Alert related lookup data.'); } }).responseText;         var lookupData = eval('(' + data + ')');         var listingCategory = lookupData.ListingCategory;         var listingStatus = lookupData.ListingStatus;         var catList = '{';         $(lookupData.ListingCategory).each(function() {             catList += this.Id + ':"' + this.Name + '",';         });         catList += '}';         var lastsel;         var ignoreAlert = true;         $(item)         .jqGrid({             url: listURL,             postData: '',             datatype: "local",             colNames: ['Id', 'Name', 'Commission<br />Rep', 'Business<br />Group', 'Order<br />Date', 'Edit', 'TBD', 'Month', 'Year', 'Week', 'Product', 'Product<br />Type', 'Online/<br />Magazine', 'Materials', 'Special<br />Placement', 'Logo', 'Image', 'Text', 'Contact<br />Info', 'Everthing<br />In', 'Category', 'Status'],             colModel: [                 { name: 'Id', index: 'Id', hidden: true, hidedlg: true },                 { name: 'AccountName', index: 'AccountName', align: "left", resizable: true, search: true, width: 100 },                 { name: 'OnlineName', index: 'OnlineName', align: 'left', sortable: false, width: 80 },                 { name: 'ListingCategoryName', index: 'ListingCategoryName', width: 85, editable: true, hidden: false, edittype: "select", editoptions: { multiple: false, value: eval('(' + catList + ')') }, editrules: { required: false }, formatoptions: { disabled: false} }             ],             jsonReader: {                 root: "List",                 page: "CurrentPage",                 total: "TotalPages",                 records: "TotalRecords",                 userdata: "Errors",                 repeatitems: false,                 id: "0"             },             rowNum: $rows,             rowList: [10, 20, 50, 200, 500, 1000, 2000],             imgpath: jQueryImageRoot,             pager: $(item + 'Pager'),             shrinkToFit: true,             width: 1455,             recordtext: 'Traffic lines',             sortname: 'OrderDate',             viewrecords: true,             sortorder: "asc",             altRows: true,             cellEdit: true,             cellsubmit: "remote",             cellurl: editURL + '?rows=' + $rows + '&page=1',             loadComplete: function() {               },             gridComplete: function() {             },             loadError: function(xhr, st, err) {             },             afterEditCell: function(rowid, cellname, value, iRow, iCol) {                 var select = $(item).find('td.edit-cell select');                 $(item).find('td.edit-cell select option').each(function() {                     var option = $(this);                     var optionId = $(this).val();                     $(lookupData.ListingCategory).each(function() {                         if (this.Id == optionId) {                                                       if (this.OnlineName != $(item).getCell(rowid, 'OnlineName')) {                                 option.remove();                                 return false;                             }                         }                     });                 });             },             search: true,             searchdata: {},             caption: "List of all Traffic lines",             editurl: editURL + '?rows=' + $rows + '&page=1',             hiddengrid: hideGrid   Here is the JSON data returned via the ajax call during the jqGrid function call above (NOTE it must be { async: false}: {"ListingCategory":[{"Id":29,"Name":"Document Imaging & Management","OnlineName":"RF Globalnet"} ,{"Id":1,"Name":"Ancillary Department Hardware","OnlineName":"Healthcare Technology Online"} ,{"Id":2,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":3,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":4,"Name":"Asset Tracking","OnlineName":"Healthcare Technology Online"} ,{"Id":5,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":6,"Name":"Document Imaging & Management","OnlineName":"Healthcare Technology Online"} ,{"Id":7,"Name":"EMR/EHR Software","OnlineName":"Healthcare Technology Online"}]} I only need the Id and Name for the drop down list, but the third column in the JSON object is important, it is the only that I match up with the OnlineName in the jqGrid column, and then in the loop during afterEditCell simply remove the ones I don't want the user to see. That's it!

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  • The practical cost of swapping effects

    - by sebf
    Hello, I use XNA for my projects and on those forums I sometimes see references to the fact that swapping an effect for a mesh has a relatively high cost, which surprises me as I thought to swap an effect was simply a case of copying the replacement shader program to the GPU along with appropriate parameters. I wondered if someone could explain exactly what is costly about this process? And put, if possible, 'relatively' into context? For example say I wanted to use a short shader to help with picking, I would: Change the effect on every object, calculting a unique color to identify it and providing it to the shader. Draw all the objects to a render target in memory. Get the color from the target and use it to look up the selected object. What portion of the total time taken to complete that process would be spent swapping the shaders? My instincts would say that rendering the scene again, no matter how simple the shader, would be an order of magnitude slower than any other part of the process so why all the concern over effects?

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  • Sanity checks vs file sizes

    - by Richard Fabian
    In your game assets do you make room for explicit sanity checks, or do you have some generally expected bounds which you assert? I've been thinking about how we compress data and thought that it's much better to have the former, and less of the latter. If your data can exceed your normal valid ranges, but if it does it's an error, then surely that implies you're not compressing the data well enough? What do you do to find out if your data is compressed as far as it can be, and what do you use to ensure your data isn't corrupted and ensure it's an official release? EDIT I'm not interested in sanity checking the file size, but instead, how you manage your sanity checks and whether you arrange the excess size caused by the opportunity to do sanity checks by using explicit extra data, or through allowing the data enough file space (data member size) to be out of valid range and thus able to be checked merely by looking at the asset in memory after loading.

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  • What You Said: Giving an Old Laptop a New Life

    - by Jason Fitzpatrick
    Earlier this week we asked you to share your tips and tricks for breathing life into an old laptop, now we’re back to share your junk-bin sparing methods. Many of you worked to keep old laptops from getting scrapped by dusting them off and donating them. Mark writes: My acquaintances & friends give me their old computers when they buy a new one. So I disassemble, clean, install an opsys,and get internet working. I also upgrade memory, wireless, etc. from my parts bin. Then I give it to a poor person who needs a computer. Usually a single working mom with kids. I also do the same with old desktops as well. They really appreciate them and It gives me the satisfaction of resurrecting an old computer. Wbrown does the same: How To Delete, Move, or Rename Locked Files in Windows HTG Explains: Why Screen Savers Are No Longer Necessary 6 Ways Windows 8 Is More Secure Than Windows 7

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  • Open Grid Engine or Akka/Something more fault tolerant?

    - by Mike Lyons
    My use case is that I have a pipeline of independent, stand alone programs, that I want to execute in a certain order on specific pieces of data that our output from previous pipeline stages. The pipeline is entirely linear and doesn't do anything in terms of alternate paths through the pipe. I'm currently using SGE to do this and it works OK, however occasionally a job will overstep it's memory bounds, fail, and all jobs that require that output data will fail. The pipe needs to be restarted in that case, and it seems that whatever is providing the fault tolerance in akka might solve that for me?

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  • Hostapd to connect laptop to Android

    - by Kmegamind
    i am trying to set up my laptop as an access point for my Android to use WiFi, so i knew that ubuntu sets the network as Ad-Hoc which is not discoverable by android, So i tried the method explained here -which i found on many other websites- but when i run hostapd.conf this error appears : nl80211: Failed to set interface wlan0 into AP mode nl80211 driver initialization failed. ELOOP: remaining socket: sock=4 eloop_data=0x8e488f8 user_data=0x8e48ea0 handler=0x807c5e0 ELOOP: remaining socket: sock=6 eloop_data=0x8e4aca8 user_data=(nil) handler=0x8086770 this is how my hostapd.conf looks like : interface=wlan0 driver=nl80211 ssid=Any_SSID_name hw_mode=g channel=1 macaddr_acl=0 auth_algs=1 ignore_broadcast_ssid=0 wpa=2 wpa_passphrase=Any_password wpa_key_mgmt=WPA-PSK wpa_pairwise=TKIP rsn_pairwise=CCMP and this is my wireless card info : description: Wireless interface product: BCM43225 802.11b/g/n vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:05:00.0 logical name: wlan0 version: 01 serial: 78:e4:00:73:51:f1 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=brcmsmac driverversion=3.2.0-31-generic-pae firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:f0300000-f0303fff

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  • Periodic clicking sound from PC speaker

    - by John J. Camilleri
    After an update some months ago, my laptop has begun making a low, repeated clicking sound every few seconds. It is not being generated through the regular sound system, as altering the volume and even muting the sound does not make any difference. My regular audio works fine, by the way, so I am guessing this is some sort of PC speaker, since I cannot hear the click when I listen through regular headphones. Strangely, when I open the sound settings dialog the click magically disappears. I don't need to change any settings; if I simply leave the dialog open in the background then the problem disappears. Any ideas what this could be? I am running regular Ubuntu 12.04, and this is the output from lspci -v | grep -A7 -i "audio": 00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02) Subsystem: Acer Incorporated [ALI] Device 0349 Flags: bus master, fast devsel, latency 0, IRQ 44 Memory at 54200000 (64-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: snd_hda_intel Kernel modules: snd-hda-intel

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  • How to completely shutdown Ati card

    - by Celso
    I would like to know how do i prevent my Ati card from turning on when i enter on ubuntu 11.10. My bios only lets-me shutdown intel hd card or leave the both on but i want to know if is possbible to completely shutdown without having to access to the bios.( if is possible to turn of without using Vgaswitcheroo even better!) My system is: Acer 3820tg-- intel core i3 350M, 2.26 Ghz L3, Ati Mobility Radeon HD 5470 up to 2138 MB hyper memory, 13,3" HD LED LCD, 4gb DDR3, SSD corsair 60GB sata 2. EDIT: I now know what is missing on the answers! I edited /etc/rc.local file and added the next lines: Sleep 3 echo ON /sys/kernel/debug/vgaswitcheroo/switch echo IGD /sys/kernel/debug/vgaswitcheroo/switch echo OFF /sys/kernel/debug/vgaswitcheroo/switch And then save the file and restart. It should be possible to use only the intel card now. By the way, i didn't blacklisted the radeon driver because doing it make my ati card wake up. (use it at your own risk. i only tested in my system)

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  • Understanding the 'High Performance' meaning in Extreme Transaction Processing

    - by kyap
    Despite my previous blogs entries on SOA/BPM and Identity Management, the domain where I'm the most passionated is definitely the Extreme Transaction Processing, commonly called XTP.I came across XTP back to 2007 while I was still FMW Product Manager in EMEA. At that time Oracle acquired a company called Tangosol, which owned an unique product called Coherence that we renamed to Oracle Coherence. Beside this innovative renaming of the product, to be honest, I didn't know much about it, except being a "distributed in-memory cache for Extreme Transaction Processing"... not very helpful still.In general when people doesn't fully understand a technology or a concept, they tend to find some shortcuts, either correct or not, to justify their lack-of understanding... and of course I was part of this category of individuals. And the shortcut was "Oracle Coherence Cache helps to improve Performance". Excellent marketing slogan... but not very meaningful still. By chance I was able to get away quickly from that group in July 2007* at Thames Valley Park (UK), after I attended one of the most interesting workshops, in my 10 years career in Oracle, delivered by Brian Oliver. The biggest mistake I made was to assume that performance improvement with Coherence was related to the response time. Which can be considered as legitimus at that time, because after-all caches help to reduce latency on cached data access, hence reduce the response-time. But like all caches, you need to define caching and expiration policies, thinking about the cache-missed strategy, and most of the time you have to re-write partially your application in order to work with the cache. At a result, the expected benefit vanishes... so, not very useful then?The key mistake I made was my perception or obsession on how performance improvement should be driven, but I strongly believe this is still a common problem to most of the developers. In fact we all know the that the performance of a system is generally presented by the Capacity (or Throughput), with the 2 important dimensions Speed (response-time) and Volume (load) :Capacity (TPS) = Volume (T) / Speed (S)To increase the Capacity, we can either reduce the Speed(in terms of response-time), or to increase the Volume. However we tend to only focus on reducing the Speed dimension, perhaps it is more concrete and tangible to measure, and nicer to present to our management because there's a direct impact onto the end-users experience. On the other hand, we assume the Volume can be addressed by the underlying hardware or software stack, so if we need more capacity (scale out), we just add more hardware or software. Unfortunately, the reality proves that IT is never as ideal as we assume...The challenge with Speed improvement approach is that it is generally difficult and costly to make things already fast... faster. And by adding Coherence will not necessarily help either. Even though we manage to do so, the Capacity can not increase forever because... the Speed can be influenced by the Volume. For all system, we always have a performance illustration as follow: In all traditional system, the increase of Volume (Transaction) will also increase the Speed (Response-Time) as some point. The reason is simple: most of the time the Application logics were not designed to scale. As an example, if you have a while-loop in your application, it is natural to conceive that parsing 200 entries will require double execution-time compared to 100 entries. If you need to "Speed-up" the execution, you can only upgrade your hardware (scale-up) with faster CPU and/or network to reduce network latency. It is technically limited and economically inefficient. And this is exactly where XTP and Coherence kick in. The primary objective of XTP is about designing applications which can scale-out for increasing the Volume, by applying coding techniques to keep the execution-time as constant as possible, independently of the number of runtime data being manipulated. It is actually not just about having an application running as fast as possible, but about having a much more predictable system, with constant response-time and linearly scale, so we can easily increase throughput by adding more hardwares in parallel. It is in general combined with the Low Latency Programming model, where we tried to optimize the network usage as much as possible, either from the programmatic angle (less network-hoops to complete a task), and/or from a hardware angle (faster network equipments). In this picture, Oracle Coherence can be considered as software-level XTP enabler, via the Distributed-Cache because it can guarantee: - Constant Data Objects access time, independently from the number of Objects and the Coherence Cluster size - Data Objects Distribution by Affinity for in-memory data grouping - In-place Data Processing for parallel executionTo summarize, Oracle Coherence is indeed useful to improve your application performance, just not in the way we commonly think. It's not about the Speed itself, but about the overall Capacity with Extreme Load while keeping consistant Speed. In the future I will keep adding new blog entries around this topic, with some sample codes experiences sharing that I capture in the last few years. In the meanwhile if you want to know more how Oracle Coherence, I strongly suggest you to start with checking how our worldwide customers are using Oracle Coherence first, then you can start playing with the product through our tutorial.Have Fun !

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  • Ad-Driven Apps Are Sucking Your Android Battery Dry

    - by Jason Fitzpatrick
    Ads in free Android apps might be annoying but you probably never imagined they were radically draining your battery. New research from Purdue University and Microsoft highlight just how much ad-driven apps tank your battery life. What did they find? That poorly designed ad-modules in free ad-driven applications are terrible at conserving energy. In popular applications like Angry Birds and Free Chess 70% of the energy the application consumed was used to drive the ads. They also surveyed other applications and found that ad-driven apps weren’t alone in excessive battery use–the New York Times app, for example, spent 15% of its battery consumption on tracking and background tasks. Hit up the link below to read the full whitepaper for a more in depth look at the methodology and results. Fine Grained Energy Accounting on Smartphones with Eprof (PDF) [via ZDNet] Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos HTG Explains: What Can You Find in an Email Header?

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