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  • The Calmest IT Guy in the World

    - by Markus Weber
    Unplanned outages and downtime still result not only in major productivity losses, but also major financial losses. Along the same lines, if zero planned downtime and zero data loss are key to your IT environment and your business requirements, planning for those becomes very important, all while balancing between performance, high availability, and cost. Oracle Database High Availability technologies will help you achieve these mission-critical goals, and are reflected in Oracle's best practices offerings of the Maximum Availability Architecture, or MAA. We created three neat, short videos showcasing some typical use cases, and highlighting three important components (amongst many more) of MAA: Oracle Real Application Clusters (RAC) Oracle Active Data Guard Oracle Flashback Technologies Make sure to watch those videos here, and learn about challenges, and solutions, around High Availability database environments from a recent Independent Oracle Users Group (IOUG) survey. 

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  • How to prevent wireless network asking password when briefly out of range

    - by Ian Mackinnon
    When I'm connected to a wireless network from quite far away I sometimes briefly lose the connection. Then Network Manager prompts me to re-confirm the password as if it suspected that was the problem that caused the loss of connection (the password is already filled in in the dialog box). Is this normal behaviour? Can I prevent it from happening and have Network Manager automatically reconnect without the password dialog box when the wireless network comes back into range? I'm using 10.04 (32bit, Gnome) on an Acer Aspire one.

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  • DTracing TCP congestion control

    - by user12820842
    In a previous post, I showed how we can use DTrace to probe TCP receive and send window events. TCP receive and send windows are in effect both about flow-controlling how much data can be received - the receive window reflects how much data the local TCP is prepared to receive, while the send window simply reflects the size of the receive window of the peer TCP. Both then represent flow control as imposed by the receiver. However, consider that without the sender imposing flow control, and a slow link to a peer, TCP will simply fill up it's window with sent segments. Dealing with multiple TCP implementations filling their peer TCP's receive windows in this manner, busy intermediate routers may drop some of these segments, leading to timeout and retransmission, which may again lead to drops. This is termed congestion, and TCP has multiple congestion control strategies. We can see that in this example, we need to have some way of adjusting how much data we send depending on how quickly we receive acknowledgement - if we get ACKs quickly, we can safely send more segments, but if acknowledgements come slowly, we should proceed with more caution. More generally, we need to implement flow control on the send side also. Slow Start and Congestion Avoidance From RFC2581, let's examine the relevant variables: "The congestion window (cwnd) is a sender-side limit on the amount of data the sender can transmit into the network before receiving an acknowledgment (ACK). Another state variable, the slow start threshold (ssthresh), is used to determine whether the slow start or congestion avoidance algorithm is used to control data transmission" Slow start is used to probe the network's ability to handle transmission bursts both when a connection is first created and when retransmission timers fire. The latter case is important, as the fact that we have effectively lost TCP data acts as a motivator for re-probing how much data the network can handle from the sending TCP. The congestion window (cwnd) is initialized to a relatively small value, generally a low multiple of the sending maximum segment size. When slow start kicks in, we will only send that number of bytes before waiting for acknowledgement. When acknowledgements are received, the congestion window is increased in size until cwnd reaches the slow start threshold ssthresh value. For most congestion control algorithms the window increases exponentially under slow start, assuming we receive acknowledgements. We send 1 segment, receive an ACK, increase the cwnd by 1 MSS to 2*MSS, send 2 segments, receive 2 ACKs, increase the cwnd by 2*MSS to 4*MSS, send 4 segments etc. When the congestion window exceeds the slow start threshold, congestion avoidance is used instead of slow start. During congestion avoidance, the congestion window is generally updated by one MSS for each round-trip-time as opposed to each ACK, and so cwnd growth is linear instead of exponential (we may receive multiple ACKs within a single RTT). This continues until congestion is detected. If a retransmit timer fires, congestion is assumed and the ssthresh value is reset. It is reset to a fraction of the number of bytes outstanding (unacknowledged) in the network. At the same time the congestion window is reset to a single max segment size. Thus, we initiate slow start until we start receiving acknowledgements again, at which point we can eventually flip over to congestion avoidance when cwnd ssthresh. Congestion control algorithms differ most in how they handle the other indication of congestion - duplicate ACKs. A duplicate ACK is a strong indication that data has been lost, since they often come from a receiver explicitly asking for a retransmission. In some cases, a duplicate ACK may be generated at the receiver as a result of packets arriving out-of-order, so it is sensible to wait for multiple duplicate ACKs before assuming packet loss rather than out-of-order delivery. This is termed fast retransmit (i.e. retransmit without waiting for the retransmission timer to expire). Note that on Oracle Solaris 11, the congestion control method used can be customized. See here for more details. In general, 3 or more duplicate ACKs indicate packet loss and should trigger fast retransmit . It's best not to revert to slow start in this case, as the fact that the receiver knew it was missing data suggests it has received data with a higher sequence number, so we know traffic is still flowing. Falling back to slow start would be excessive therefore, so fast recovery is used instead. Observing slow start and congestion avoidance The following script counts TCP segments sent when under slow start (cwnd ssthresh). #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::connect-request / start[args[1]-cs_cid] == 0/ { start[args[1]-cs_cid] = 1; } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd tcps_cwnd_ssthresh / { @c["Slow start", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } tcp:::send / start[args[1]-cs_cid] == 1 && args[3]-tcps_cwnd args[3]-tcps_cwnd_ssthresh / { @c["Congestion avoidance", args[2]-ip_daddr, args[4]-tcp_dport] = count(); } As we can see the script only works on connections initiated since it is started (using the start[] associative array with the connection ID as index to set whether it's a new connection (start[cid] = 1). From there we simply differentiate send events where cwnd ssthresh (congestion avoidance). Here's the output taken when I accessed a YouTube video (where rport is 80) and from an FTP session where I put a large file onto a remote system. # dtrace -s tcp_slow_start.d ^C ALGORITHM RADDR RPORT #SEG Slow start 10.153.125.222 20 6 Slow start 138.3.237.7 80 14 Slow start 10.153.125.222 21 18 Congestion avoidance 10.153.125.222 20 1164 We see that in the case of the YouTube video, slow start was exclusively used. Most of the segments we sent in that case were likely ACKs. Compare this case - where 14 segments were sent using slow start - to the FTP case, where only 6 segments were sent before we switched to congestion avoidance for 1164 segments. In the case of the FTP session, the FTP data on port 20 was predominantly sent with congestion avoidance in operation, while the FTP session relied exclusively on slow start. For the default congestion control algorithm - "newreno" - on Solaris 11, slow start will increase the cwnd by 1 MSS for every acknowledgement received, and by 1 MSS for each RTT in congestion avoidance mode. Different pluggable congestion control algorithms operate slightly differently. For example "highspeed" will update the slow start cwnd by the number of bytes ACKed rather than the MSS. And to finish, here's a neat oneliner to visually display the distribution of congestion window values for all TCP connections to a given remote port using a quantization. In this example, only port 80 is in use and we see the majority of cwnd values for that port are in the 4096-8191 range. # dtrace -n 'tcp:::send { @q[args[4]-tcp_dport] = quantize(args[3]-tcps_cwnd); }' dtrace: description 'tcp:::send ' matched 10 probes ^C 80 value ------------- Distribution ------------- count -1 | 0 0 |@@@@@@ 5 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 0 512 | 0 1024 | 0 2048 |@@@@@@@@@ 8 4096 |@@@@@@@@@@@@@@@@@@@@@@@@@@ 23 8192 | 0

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  • C++ : Lack of Standardization at the Binary Level

    - by Nawaz
    Why ISO/ANSI didn't standardize C++ at the binary level? There are many portability issues with C++, which is only because of lack of it's standardization at the binary level. Don Box writes, (quoting from his book Essential COM, chapter COM As A Better C++) C++ and Portability Once the decision is made to distribute a C++ class as a DLL, one is faced with one of the fundamental weaknesses of C++, that is, lack of standardization at the binary level. Although the ISO/ANSI C++ Draft Working Paper attempts to codify which programs will compile and what the semantic effects of running them will be, it makes no attempt to standardize the binary runtime model of C++. The first time this problem will become evident is when a client tries to link against the FastString DLL's import library from a C++ developement environment other than the one used to build the FastString DLL. Are there more benefits Or loss of this lack of binary standardization?

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  • Computer Networks UNISA - Chap 14 &ndash; Insuring Integrity &amp; Availability

    - by MarkPearl
    After reading this section you should be able to Identify the characteristics of a network that keep data safe from loss or damage Protect an enterprise-wide network from viruses Explain network and system level fault tolerance techniques Discuss issues related to network backup and recovery strategies Describe the components of a useful disaster recovery plan and the options for disaster contingencies What are integrity and availability? Integrity – the soundness of a networks programs, data, services, devices, and connections Availability – How consistently and reliably a file or system can be accessed by authorized personnel A number of phenomena can compromise both integrity and availability including… security breaches natural disasters malicious intruders power flaws human error users etc Although you cannot predict every type of vulnerability, you can take measures to guard against the most damaging events. The following are some guidelines… Allow only network administrators to create or modify NOS and application system users. Monitor the network for unauthorized access or changes Record authorized system changes in a change management system’ Install redundant components Perform regular health checks on the network Check system performance, error logs, and the system log book regularly Keep backups Implement and enforce security and disaster recovery policies These are just some of the basics… Malware Malware refers to any program or piece of code designed to intrude upon or harm a system or its resources. Types of Malware… Boot sector viruses Macro viruses File infector viruses Worms Trojan Horse Network Viruses Bots Malware characteristics Some common characteristics of Malware include… Encryption Stealth Polymorphism Time dependence Malware Protection There are various tools available to protect you from malware called anti-malware software. These monitor your system for indications that a program is performing potential malware operations. A number of techniques are used to detect malware including… Signature Scanning Integrity Checking Monitoring unexpected file changes or virus like behaviours It is important to decide where anti-malware tools will be installed and find a balance between performance and protection. There are several general purpose malware policies that can be implemented to protect your network including… Every compute in an organization should be equipped with malware detection and cleaning software that regularly runs Users should not be allowed to alter or disable the anti-malware software Users should know what to do in case the anti-malware program detects a malware virus Users should be prohibited from installing any unauthorized software on their systems System wide alerts should be issued to network users notifying them if a serious malware virus has been detected. Fault Tolerance Besides guarding against malware, another key factor in maintaining the availability and integrity of data is fault tolerance. Fault tolerance is the ability for a system to continue performing despite an unexpected hardware or software malfunction. Fault tolerance can be realized in varying degrees, the optimal level of fault tolerance for a system depends on how critical its services and files are to productivity. Generally the more fault tolerant the system, the more expensive it is. The following describe some of the areas that need to be considered for fault tolerance. Environment (Temperature and humidity) Power Topology and Connectivity Servers Storage Power Typical power flaws include Surges – a brief increase in voltage due to lightening strikes, solar flares or some idiot at City Power Noise – Fluctuation in voltage levels caused by other devices on the network or electromagnetic interference Brownout – A sag in voltage for just a moment Blackout – A complete power loss The are various alternate power sources to consider including UPS’s and Generators. UPS’s are found in two categories… Standby UPS – provides continuous power when mains goes down (brief period of switching over) Online UPS – is online all the time and the device receives power from the UPS all the time (the UPS is charged continuously) Servers There are various techniques for fault tolerance with servers. Server mirroring is an option where one device or component duplicates the activities of another. It is generally an expensive process. Clustering is a fault tolerance technique that links multiple servers together to appear as a single server. They share processing and storage responsibilities and if one unit in the cluster goes down, another unit can be brought in to replace it. Storage There are various techniques available including the following… RAID Arrays NAS (Storage (Network Attached Storage) SANs (Storage Area Networks) Data Backup A backup is a copy of data or program files created for archiving or safekeeping. Many different options for backups exist with various media including… These vary in cost and speed. Optical Media Tape Backup External Disk Drives Network Backups Backup Strategy After selecting the appropriate tool for performing your servers backup, devise a backup strategy to guide you through performing reliable backups that provide maximum data protection. Questions that should be answered include… What data must be backed up At what time of day or night will the backups occur How will you verify the accuracy of the backups Where and for how long will backup media be stored Who will take responsibility for ensuring that backups occurred How long will you save backups Where will backup and recovery documentation be stored Different backup methods provide varying levels of certainty and corresponding labour cost. There are also different ways to determine which files should be backed up including… Full backup – all data on all servers is copied to storage media Incremental backup – Only data that has changed since the last full or incremental backup is copied to a storage medium Differential backup – Only data that has changed since the last backup is coped to a storage medium Disaster Recovery Disaster recovery is the process of restoring your critical functionality and data after an enterprise wide outage has occurred. A disaster recovery plan is for extreme scenarios (i.e. fire, line fault, etc). A cold site is a place were the computers, devices, and connectivity necessary to rebuild a network exist but they are not appropriately configured. A warm site is a place where the computers, devices, and connectivity necessary to rebuild a network exists with some appropriately configured devices. A hot site is a place where the computers, devices, and connectivity necessary to rebuild a network exists and all are appropriately configured.

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  • ubuntu software center only opens for a few seconds, then crashes?

    - by Sarah Mae
    so i've been googling this question all day, and i've tried everything. i've tried uninstalling and reinstalling USC multiple times, i've tried basically all of the terminal commands that these forums/ask boards have recommended, to no avail. i'm at a loss. i'm using ubuntu 12.04 :O edit// i should probably be more specific about my problem! ahah. everytime i try to open USC, the frame and everything will show up & it'll load for about 5 seconds, then it'll turn gray & i'll have to force quit it :I

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  • Dual Screen with 12.04 ATI randr extension is not present

    - by Trevor Pearson
    Here's my problem I have two screens. One is a 22"led monitor and the other is 42 inch led tv. In windows 7 I run xbmc on the second monitor. I'm trying to mimic the same function in setting xbmc to display on the tv only. So I installed the latest x64 linux drivers from ATI. I configured (using the catalyst control panel) using single display (multi desktop) I then got a white screen with black x so I enable xinerama. with xinerama enable I got the displays to work correctly, however I received an error when I tried to enter display settings to change the launcher location. the error message was " "randr extension not present =" So I tried to install libxandr2 using terimal but here's what I get trev@Lrig:~$ sudo get-apt install libxander2 [sudo] password for trev: sudo: get-apt: command not found I'm at a loss now because I can't find a solution for the xandr error message. I'f my specs are important amd athx2 6400+ ghz 8 gigs ram radeon hd6950

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  • I need recommendations on free, open source, PHP-based business intelligence widget frameworks [on hold]

    - by Volomike
    I'm a PHP developer on Linux, and my manager wants a business intelligence dashboard. He wants to see in real-time our profit/loss stuff in fancy charts, based on our software sales. I could code it all from scratch and use Google Charts API or some other charts API to help me. However, I wanted to know if there was a free, open source, PHP-based business intelligence package out there, or some sort of widget framework that I could start with. That way, I can build the BI widgets inside that framework and not have to do everything from scratch. I apologize ahead of time if this is the wrong stackexchange where to place this query. I don't know where to place this query, and do want to follow the rules.

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  • Do you use your personal laptop for work?

    - by davekaro
    We're trying to get our company to let us use our own personal laptop for client work. We've agreed that any code/data will be encrypted using something like TrueCrypt, in case the laptop is stolen or lost. However, the company is still skeptical and not sure they want to allow us to use our personal machines for development. They would rather buy us laptops... but we want to use MacBook Pros and they don't want to pay for them. Even if they did buy us laptops, we would stil have the issue of needing to encrypt the code/data in case of theft/loss. Do you use your own laptop for work? What are the arguments for/against this?

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  • The Apple iPad &ndash; I&rsquo;m gonna get it!

    - by Sahil Malik
    Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). Well, heck, here comes another non-techie blogpost. You know I’m a geek, so I love gadgets! I found it RATHER interesting to see all the negative news on the blogosphere about the iPad. The main bitch points are - No Multi tasking No Flash Just a bigger iPhone. So here’s the deal! My view is, the above 3 are EXACTLY what I had personally hoped for in the Apple iPad. Before the release, I had gone on the record saying - “If the Apple Tablet is able to run full fledged iTunes (so I can get rid of iTunes on my desktop, I don’t like iTunes on Windows), can browse the net, can read PDFs, and will be under $1000, I’ll buy it”. Well, so, the released iPad wasn’t exactly like my dream tablet. The biggest downer IMO was it’s inability to run full iTunes. But, really, in retrospect, I like the newly released iPad. And here is why. No Multi tasking and No Flash, means much better battery life. Frankly, I rarely multi task on my laptop/desktop .. yeah I know my OS does .. but ME – I don’t multi task, and I don’t think you do either!! As I type this blogpost, I have a few windows running behind the scenes, but they are simply waiting for me to get back to them. The only thing truly running and I am making use of, other than this blogost, is media player playing some music – which the iPad can do. Also, I am logged into IM/Email – which again, iPad can do via notifications. It does the limited multitasking I need, without chewing down on batteries. Smart thinking, precisely the reason I love the iPhone. I don’t want a bulky battery consuming machine. Lack of flash? Okay sure, I can’t see Hulu on my iPad. That’s some loss. I can see youtube. Also, per Adobe I can’t see some porn sites, which I don’t want to see on my iPad. But, Flash is heavy. Especially flash video. My dream is to see silverlight run on the iPhone and iPad. No flash = not such a big loss. Speaking of battery life – 10 hours is plenty. I haven’t been away from electricity for that long usually, so I’m okay with charging it up when it runs low. It’s really not such a big deal honestly. Finally, eBook functionality – wow! I went on the record saying, eBook readers are not for me, but seriously, the iPad is perfect for my eBook needs at least. And as far it being just a bigger iPhone? I’ve always wanted a bigger iPhone, precisely for the eBook reading experience. I love my iPhone, I love the apps on it. The only thing that sucks about the iPhone is battery life, but other than that, it is the best gadget I have ever bought! And something that runs on mobile chips, is that thin, and those newly written apps .. mail, calendar .. I am very very excited to get my iPad, which will be the 64gig 3G version. The biggest plus in an iPad ……… no contract on data. I am *hoping*, this means that I can buy a SIM card in Europe, and use the iPad here. That would be killer awesome! But hey, if I had to pick downers in the iPad, they would be - - I wish they had a 128G Version. Now that we have a good video viewing machine, I know I’d chew up space quickly.- Sync over WIFI, seriously Apple.  Both for iPhone and iPad.- 3 month wait!!- Existing iPhone users should get a discount on the iPad data plan. Comment on the article ....

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  • Black Hat Hackers vs Programmers?

    - by Matt Ridge
    This came up with another question I had here, I have decided on a programming verification system that requires a hardware verification system, a software key, and a name/password system. Now people are saying that hackers will bypass any new security, which may be true, but I have a few questions. There has to be a balance between programmers programming and hackers stealing software, otherwise programs wouldn’t be made, and we wouldn’t be where we are today. What is that balance? 5%, 10%, 20%, 50%? What is too much security for the end user? What is too little security so the hacker can just push through without issue? If your software becomes popular, what should you expect or accept as acceptable loss? Why should we accept black hat hackers as a way of life?

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  • I see files in filezilla, but the internet denies their existance

    - by Zach L.
    I am doing some updates to a 10-year old site, and I am baffled. Everything worked great locally, so I uploaded a bunch of stuff to the server using filezilla. Within filezilla I can see all of the files, but for some reason I get a 404 when trying to view them. It seems as though (at least for the folder Im currently checking) this is happening for items which are "farther down the list" alphabetically. I tried to re-upload a file individually but it didn't change anything. Is this an indication that I hit some sort of limit with the hosting company? And if so why can I still view the files from filezilla? Please offer guidance. I am at a loss.

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  • Best Dedicated Hosting with RAID 1 and managed backup

    - by Animesh
    Hi All, I run a (CentOS-powered) website currently, and we are currently planning on moving to a dedicated server. One of the essentials for us is preventing data loss with the least amount of bother. Therefore, I feel that the following features are important for us RAID 1 Managed backups by the hosting company, with at least a 7 day retention In my search for providers, I found some which provide RAID 1, but none apart from GoDaddy which provide Managed backups. 1&1 provides "FTP backup bandwidth", but I have to provide the backup location myself. Am I missing something? Are there other reputable hosting providers which can provide managed backups as part of their dedicated hosting plans? Some pointers will be much appreciated. Thanks, -A

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  • Resizing my linux partition

    - by de1337ed
    So, I was getting rid of my openSUSE to install lubuntu. In the process, I didn't manage my hard drive partitions well enough and as a result, I lost my windows 7 partition. I got over the loss, and formatted my entire hard drive by install lubuntu over all the space. (I tried first installing windows 7, but I kept getting some weird errors during the partitioning process). I was wondering now if I could resize my lubuntu partition so I can install windows 7 again. Here is a gparted screenshot: Can anyone help me out? I have all my Linux disks and my windows disks. Thank you.

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  • Installing 64bit Java 7 - Cannot Execute Binary File

    - by warpstack
    So I downloaded the latest version of Java from Oracle so I could get a 64bit JVM on Ubuntu Server 10.10. After extracting the file and updating the alternatives I went to check my installation by running java -version and I get this error: -bash: /usr/bin/java: cannot execute binary file I'm at a loss for what to do here. My alternatives menu looks like this: Selection Path Priority Status ------------------------------------------------------------ 0 /usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 auto mode 1 /usr/lib/jvm/java-6-openjdk/jre/bin/java 1061 manual mode 2 /usr/lib/jvm/java-7-openjdk-i386/jre/bin/java 1051 manual mode * 3 /usr/lib/jvm/jdk1.7.0/bin/java 3 manual mode After restarting the system I seem to be getting a totally new error when checking the java version. usr/bin/java: 1: Syntax error: end of file unexpected (expecting ")")

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  • Drawing of a huge model - How to regain performance?

    - by marc wellman
    I have a huge model I want to draw in my XNA application but because of its size I am experiencing a tremendous loss of performance. The model has about ~50 000 000 edges and has a size on disk of 205 MB in DirectX Format. Please don't ask whether this model has to be that big - yes it has! Is there a way to transfer the model directly to my GPU in order to let the GPU do the drawing like when transferring a VertexBuffer like this: graphicsDevice.Vertices[1].SetSource(_instanceBuffers[i], 0, _sizeofMatrix); because when I try to fill a vertexBuffer with all the vertices I am getting a OutOfMemoryException.

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  • Skip the first RenderTarget when writing to MRT with Opaque blending

    - by cubrman
    I am writing to three rendertargets and whant to know how to tell a GPU not to write to the first RT. When you write a shader you can simply output less data than you have RTs (like output a single float4 when writing to three RTs) and only the first RTs will be affected, but you cannot specify to output this data anywhere else but to COLOR0, then 1, etc. Is there a way to write to several RTs but skip the first target? If I output zeroes, the data in the target will become zeroes, but I need it to remain untuched in the first target and only change in the specified ones. The reason I need this is to prevent data loss when calling SetRendertarget() with DiscardContents RTs. I write to all the RTs at one point and I need to write to only the specified ones afterwards. It must be the first texture as I have a depth buffer linked to it (XNA 4.0). Thanks.

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  • Google Goals process not working through similarly named pages

    - by David
    Well, I'm at a loss. I've ensured that my tracking script is in etc etc, and I've set up my goal and funnel path, but only the first step is ever being shown on the funnel. Goal URL: /checkout/checkoutComplete/ Type: Head Match ... but should this be /checkout/checkoutComplete/(.*) and set to regex rather because there are parameters after the main part of the URL (I thought that's what head match was for) Step 1: /checkout/ <-- required Step 2: /checkout/confirm/ both the above are valid and correct URLs for my domain. But for some reason, the funnel visualization shows entries into the first step, then an exits count that matches the entry count, including /checkout/confirm - but it doesn't go on to the next step! Perhaps I'm doing something obviously wrong...but I can't quite see it? Also, semi-related questions. Making a change to the funnel, does it only affect new incoming data? And how often does it update? Thanks in advance for your help.

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  • Bouncing ball slowing down over time

    - by user46610
    I use the unreal engine 4 to bounce a ball off of walls in a 2D space, but over time the ball gets slower and slower. Movement happens in the tick function of the ball FVector location = GetActorLocation(); location.X += this->Velocity.X * DeltaSeconds; location.Y += this->Velocity.Y * DeltaSeconds; SetActorLocation(location, true); When a wall gets hit I get a Hit Event with the normal of the collision. This is how I calculate the new velocity of the ball: FVector2D V = this->Velocity; FVector2D N = FVector2D(HitNormal.X, HitNormal.Y); FVector2D newVelocity = -2 * (V.X * N.X + V.Y * N.Y) * N + V; this->Velocity = newVelocity; Over time, the more the ball bounced around, the velocity gets smaller and smaller. How do I prevent speed loss when bouncing off walls like that? It's supposed to be a perfect bounce without friction or anything.

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  • Finding it Hard to Deliver Right Customer Experience: Think BPM!

    - by Ajay Khanna
    Our relationship with our customers is not a just a single interaction and we should not treat it like one. A customer’s relationship with a vendor is like a journey which starts way before customer makes a purchase and lasts long after that. The journey may start with customer researching a product that may lead to the eventual purchase and may continue with support or service needs for the product. A typical customer journey can be represented as shown below: As you may notice, customers tend to use multiple channels to interact with a company throughout their journey.  They also expect that they should get consistent experience, no matter what interaction channel they may choose. Customers do not like to repeat the information they have already provided and expect companies to remember their preferences, and offer them relevant products and services. If the company fails to meet this expectation, customers not only will abandon the purchase and go to the competitor but may also influence others’ purchase decision. Gone are the days when word of mouth was the only medium, and the customer could influence “Six” others. This is the age of social media and customer’s good or bad experience, especially bad get highly amplified and may influence hundreds of others. Challenges that face B2C companies today include: Delivering consistent experience: The reason that delivering consistent experience is challenging is due to fragmented data, disjointed systems and siloed multichannel interactions. Customers tend to get different service quality if they use web vs. phone vs. store. They get different responses from different service agents or get inconsistent answers if they call sales vs. service group in the company. Such inconsistent experiences result in lower customer satisfaction or NPS (net promoter score) numbers. Increasing Revenue: To stay competitive companies frequently introduce new products and services. Delay in launching such offerings has a significant impact on revenue realization. In addition to new product revenue, there are multiple opportunities to up-sell and cross-sell that impact bottom line. If companies are not able to identify such opportunities, bring a product to market quickly, or not offer the right product to the right customer at the right time, significant loss of revenue may occur. Ensuring Compliance: Companies must be compliant to ever changing regulations, these could be about Know Your Customer (KYC), Export/Import regulations, or taxation policies. In addition to government agencies, companies also need to comply with the SLA that they have committed to their customers. Lapse in meeting any of these requirements may lead to serious fines, penalties and loss in business. Companies have to make sure that they are in compliance will all such regulations and SLA commitments, at any given time. With the advent of social networks and mobile technology, companies not only need to focus on process efficiency but also on customer engagement. Improving engagement means delivering the customer experience as the customer is expecting and interacting with the customer at right time using right channel. Customers expect to be able to contact you via any channel of their choice (web, email, chat, mobile, social media), purchase via any viable channel (web, phone, store, mobile). Customers expect companies to understand their particular needs and remember their preferences on repeated visits. To deliver such an integrated, consistent, and contextual experience, power of BPM in must. Your company may be organized in departments like Marketing, Sales, Service. You may hold prospect data in SFA, order information in ERP, customer issues in CRM. However, the experience delivered to the customer must not be constrained by your system legacy. BPM helps in designing the right experience for the right customer and integrates all the underlining channels, systems, applications to make sure right information will be delivered to the right knowledge worker or to the customer every single time.     Orchestrating information across all systems (MDM, CRM, ERP), departments (commerce, merchandising, marketing service) and channels (Email, phone, web, social)  is the key, and that’s what BPM delivers. In addition to orchestrating systems and channels for consistency, BPM also provides an ability for analysis and decision management. By using data from historical transactions, social media and from other systems, users can determine the customer preferences, customer value, and churn propensity. This information, in the context, is then used while making a decision at a process step. Working with real-time decision management system can also suggest right up-sell or cross-sell offers, discounts or next-best-action steps for a particular customer. Timely action on customer issues or request is also a key tenet of a good customer experience. BPM’s complex event processing capabilities help companies to take proactive actions before issues get escalated. BPM system can be designed to listen to a certain event patters then deduce from those customer situations (credit card stolen, baggage lost, change of address) and do a triage before situation goes out of control. If such a situation arises you can send alerts to right people or immediately invoke corrective actions. Last but not least one of BPM’s key values is to drive continuous improvement. Learning about customers past experiences, interactions and social conversations, provide valuable insight. Such insight can be used to improve products, customer facing processes, and customer experience. You may take these insights as an input to design better more efficient and customer friendly sales, contact center or self-service processes. If customer experience is important for your business, make sure you have incorporated BPM as a part of your strategy to design, orchestrate and improve your customer facing processes.

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  • Ubuntu Server 12.04 Screen Resolution "Out of Range"

    - by Alastair Mackie
    I'm fairly new to ubuntu and have just installed Ubuntu Server 12.04 on a spare machine to experiment and play with! The installation went without problem, however whenever the OS boots the monitor displays a an error message saying the resolution is "out of range" and i can't see to do anything - i can wait as long as i like, but nothing appears. Ubuntu is the only OS installed so bypasses GRUB on boot, although the GRUB screen is also out of range if forced on startup. I can access a shell from the recover mode and i can get at a terminal through a LiveCD of the Desktop version but have had little luck with either. I've been trying to figure this out for days and i'm at a total loss. Any thoughts?

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  • Bug once in a while,but high priority

    - by Shirish11
    I am working on a CNC (computer numerical control) project which cuts shapes into metal with help of laser. Now my problem is once in a while (1-2 times in 20 odd days) the cutting goes wrong or not according to what is set. But this causes loss so the client is not very happy about it. I tried to find out the the cause of it by Including log files Debugging Repeating the same environment. But it wont repeat. A pause and continue operation will again make it to run smoothly with the bug reappearing. How do I tackle this issue? Should I state it as a Hardware Problem?

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  • Unable to install 12.10 on asus r500v

    - by bmdr38
    I have been unable to get beyond the grub boot screen of the live dvd/usb. The Try Ubuntu without installing, Install Ubuntu, etc menu shows, and I have tried adding/replacing nomodeset and no splash with neither helping. Even "Check disc for defects" does not display anything when selected. I am at a complete loss as to how to fix this one. I have had many successful installs in the past, but this is definitely a first for me. Just as FYI, Gfx card: Geforce GT 635M I realize this particular card has Optimus on it, however even the alternative boot/command line install fails to load. Any help would be appreciated. I realize there have been multiple threads on this, but none of the methods within them have solved this yet. Thanks

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  • How to Find Your Lost Android Phone, Even if You Never Set Up a Tracking App

    - by Chris Hoffman
    Android doesn’t come with a “find my Android” feature, so there’s no official way to track your phone if you lose it. You should prepare your phone for loss by setting up such a tracking app — but what if you didn’t? Your first instinct may be to download Lookout’s Plan B, which has been the go-to app for this purpose. However, Plan B only runs on Android 2.3 Gingerbread and lower, so modern Android phones will require a new solution. If you are still running 2.3 or lower, you should definitely check it out, but everybody else can keep reading.    

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  • SEO disasters moving domain for a high traffic website?

    - by chrism2671
    We're looking at moving our website from http://www.wikijob.co.uk to http://www.wikijob.com/uk as we spread our wings internationally. Our .co.uk website has a PR6 and received around 1/2 million visitors a month, 40% international. The wikijob.com domain, while registered for a while, has not been used nor promoted. I am concerned that moving domain could really haemorrhage our traffic and result in a loss of goodwill from Google, even if we use a 301, but equally, if we could transfer that pagerank to the .com domain, that would give us a massive head start around the world. Should we do it, or should we start over with .com and leave .co.uk as is?

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