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  • Google I/O 2010 - Making smart & scalable Wave robots

    Google I/O 2010 - Making smart & scalable Wave robots Google I/O 2010 - Making smart & scalable Wave robots Wave 201 David Byttow, Marcel Prasetya A smart robot must be able to store persistent data. Wave robots can store data in wave structures, like wavelets, datadocs, and annotations, instead of traditional datastores. A scalable robot must perform operations with minimal bandwidth. Wave robots can optimize by selecting the appropriate amount of context, the optimal events, and narrow filters for events. In this talk, we'll share best practices on data storage and scaling. For all I/O 2010 sessions, please go to code.google.com From: GoogleDevelopers Views: 9 0 ratings Time: 58:25 More in Science & Technology

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  • Hello NHibernate! Quickstart with NHibernate (Part 1)

    - by BobPalmer
    When I first learned NHibernate, I could best describe the experience as less of a learning curve and more like a learning cliff.  A large part of that was the availability of tutorials.  In this first of a series of articles, I will be taking a crack at providing people new to NHibernate the information they need to quickly ramp up with NHibernate. For the first article, I've decided to address the gap of just giving folks enough code to get started.  No UI, no fluff - just enough to connect to a database and do some basic CRUD operations.  In future articles, I will discuss a repository pattern for NHibernate, parent-child relationships, and other more advanced topics. You can find the entire article via this Google Docs link: http://docs.google.com/Doc?docid=0AUP-rKyyUMKhZGczejdxeHZfOGMydHNqdGc0&hl=en Enjoy! -Bob

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  • It's Time to Chart Your Course with Oracle HCM Applications - Featuring Row Henson

    - by jay.richey
    Total human capital costs average nearly 70% of operating expenses. There's never been more pressure on HR professionals to deliver mission-critical programs to retain rising stars, develop core performers, and cut costs from workforce operations. Join Row Henson, Oracle HCM Fellow, and Scott Ewart, Senior Director of Product Marketing, to find out: What real-world strategies HR practitioners and experts are prioritizing today to optimize their investment in people Why nearly two-thirds of PeopleSoft and E-Business Suite HCM customers have chosen to upgrade to the latest releases and where Oracle's strategic product roadmaps are headed How Fusion HCM will introduce a new standard for work and innovation - not only for the HR professional, but for every single employee and manager in your business Date: January 20th, 2011 at 9:00 PST / 12:00 EST Register now!

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  • Mount to /dev/sdb1 without password

    - by Jarmo
    I am unable to mount a USB drive (or SD card) to my system without root access. When I plug in a USB drive, it is visible in the left column of Nautilus, but when I click on it to open it, I receive the error message Unable to mount 2.1 GB Filesystem Error mounting: mount exited with exit code 1: helper failed with: mount: only root can mount /dev/sdb1 on /media/sdb1 I am able to mount the drive using sudo mount -w /dev/sdb1, but this causes problems for operations such as creating startup discs, which requires unmounting and remounting the drive. I suspect this problem may be caused by the fact that when I upgraded from 11.10 to 12.04, I had an SD card plugged in. This caused the system to stall during later startups, as it could not find this drive. I remedied this by editing a line of /etc/fstab to read /dev/sdb1 /media/sdb1 vfat noauto 0 0 However, I am dual booting Ubuntu with Windows XP, and I have no problem mounting the C: drive of the Windows system without root access, so I feel that this is a problem related to the mount point rather than mounting in general.

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  • Why should I adopt MVC?

    - by Andrew
    I decided to get my hands wet and got the YII framework for PHP. I created my first application, then created new controller, model and view. Connected to database, got my record passed from controller to the view and printed the hello world. I am confused now. If I have to do the same thing for each page, this seems like a nightmare to me. In each controller I have to do a lot of same operations - declare variables, and pass them to views. I also need to create models for each page and this is all confusing to me. In my idea the main goal of development is to avoid duplication, but what I see here is lots and lots of duplicated code. Please advise and clarify. Maybe you could suggest a good reading about MVC and coding patterns and best practices in MVC. Because so far, it takes much more time to create a small site using MVC than using my own programming schema.

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  • Getting started with Team Foundation Server

    - by joe
    At work, we recently started using Team Foundation Server to manage our source code, i have no idea how to use this system. I do not know even know how to check source code in and out. Does anyone know of a step-by-step tutorial on how to work with TFS? Just for basic operations e.g. get latest version, upload your changes, etc. I am accessing it from Visual Studio 2010. I also have access to the TFS web interface.

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  • What Can You Do When You Need More Than Just CRM?

    - by charles.knapp
    Sometimes a company needs more than just CRM to grow profitably. What if you also need ERP for streamlining the rest of your operations? Unlike CRM-only companies, Oracle can help you - today. For example, Myriad Genetics was an early pioneer and is currently a global life sciences leader in the exciting field of molecular diagnostic products. To keep pace with company growth, Myriad needed to integrate disparate systems and automate paper-based processes. Furthermore, Myriad needed to increase sales pipeline visibility to maximize customer service. Myriad selected Oracle CRM On Demand and E-Business Suite ERP applications. As a result, Myriad standardized sales processes, ensured greater visibility into the pipeline, and improved customer service. Read more here about Myriad and their business results.

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  • GLOBALFOUNDRIES Accelerates Innovation while Protecting IP with AutoVue for Agile

    - by Celine Beck
    GLOBALFOUNDRIES is a full-service semiconductor foundry with a global footprint. Launched in March 2009, the company quickly grew to be the second-largest foundry in the world, providing a unique combination of advanced technology and manufacturing to more than 160 customers. With operations in Singapore, Germany, and the United States, GLOBALFOUNDRIES is the only foundry that offers the flexibility of having secure manufacturing centers that span three continents.We sat down with Kishan Shah, Manager of PLM Practice at GLOBALFOUNDRIES so that he can explain how Oracle AutoVue integrated with Oracle Agile PLM supports the company’s mission of “turning sand into gold” ; enabling collaborative design-for-manufacturing and fostering innovation, all while protecting critical intellectual property.You can watch the video interview by clicking here. A customer success story is also available on Oracle’s website. 

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  • Method chaining vs encapsulation

    - by Oak
    There is the classic OOP problem of method chaining vs "single-access-point" methods: main.getA().getB().getC().transmogrify(x, y) vs main.getA().transmogrifyMyC(x, y) The first seems to have the advantage that each class is only responsible for a smaller set of operations, and makes everything a lot more modular - adding a method to C doesn't require any effort in A, B or C to expose it. The downside, of course, is weaker encapsulation, which the second code solves. Now A has control of every method that passes through it, and can delegate it to its fields if it wants to. I realize there's no single solution and it of course depends on context, but I would really like to hear some input about other important differences between the two styles, and under what circumstances should I prefer either of them - because right now, when I try to design some code, I feel like I'm just not using the arguments to decide one way or the other.

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  • Extending the Value of Your Oracle Financials Applications Investment with Document Capture, Imaging and Workflow

    Learn how Oracles end-to-end document imaging system extends the value and increases the automation of your Oracle Financials applications by using intelligent capture and imaging technologies to streamline high volume operations like accounts payable. Oracle Imaging and Process Management 11g (Oracle I/PM 11g) offers an integrated system that digitizes paper invoices, intelligently extracts header information and line item details, initiates automated workflows, and enables in-context access to imaged invoices directly from Oracle Applications, including Oracle E-Business Suite Financials and PeopleSoft Enterprise Financial Management. Come hear more about these certfied, standards-based application integrations as well as how document imaging can help your organization achieve quick, measurable ROI, by increasing efficiencies across financial departments, and reducing costs related to paper storage and handling.

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  • ORM Release History : Q1 2010 SP 1 (v2010.01.0527)

    Enhancements Full support for Visual Studio 2010 - the visual designer is now working in Visual Studio 2010 Ria Provider beta - supports all basic operations (query, insert, update, delete) New Enhancer - The enhancer has been replaced by a new implementation based on mono cecil. This fixes all known enhancer bugs and speeds up the enhancing process as well. Data Services Wizard integration - The Data Services Wizard is now integrated into the OpenAccess product. You can start it by using the...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • UPK Pre-Built Content Update

    - by Karen Rihs
    UPK pre-built content development efforts are always underway and growing. Over the last few months, the following new and upgraded modules became available:  NEW CONTENT RELEASES E-Business Suite 12.1 Field Service Manufacturing Operations Center Process Manufacturing:  System Administration Strategic Network Optimization U.S. Federal Financials Oracle Communications 11.1 Oracle Communications UPK for Pricing Design Center, Voice and Data Offerings Oracle Mobile Workforce 2.1.0 Administrative Setup User Tasks Primavera Primavera Portfolio Management 9.0 UPK CONTENT UPGRADES JDE E1 9.1 HCM Fundamentals for EnterpriseOne Manufacturing - Product Data Management Manufacturing Management Discrete Shop Floor Management Procurement and Subcontract Management JDE World A9.3 Accounts Payable Address Book  Common Foundation General Ledger For a list of modules currently available for each product line, visit the UPK Resource Library on Oracle.com. For more information on how your organization can take advantage of UPK pre-built content, see our previous blog,  The Value of UPK Pre-Built Content. - Karen Rihs, UPK Outbound Product Management

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  • Do you have an address column somewhere in your database?

    - by shay.shmeltzer
    Do you have an address column somewhere in your database? If the answer is yes - then the Web seminar I'm going to run together with the guys from Navteq on May 26th, might be of interest to you. You see, we all have geographical related information in our database, but many of us don't actually use this to do any geographical type of operations/representation with it. Well once you attend the "Add Maps to Your Java Applications - the Easy Way" seminar this might change. In the seminar we'll give you a quick overview of the Spatial related capabilities of the Oracle DB, Middleware and tools. And a demo showing you how easy it is to actually get data to show up on a map in your application and to interact with it. So register today, and mark your calendar.

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  • Oracle NoSQL Database Exceeds 1 Million Mixed YCSB Ops/Sec

    - by Charles Lamb
    We ran a set of YCSB performance tests on Oracle NoSQL Database using SSD cards and Intel Xeon E5-2690 CPUs with the goal of achieving 1M mixed ops/sec on a 95% read / 5% update workload. We used the standard YCSB parameters: 13 byte keys and 1KB data size (1,102 bytes after serialization). The maximum database size was 2 billion records, or approximately 2 TB of data. We sized the shards to ensure that this was not an "in-memory" test (i.e. the data portion of the B-Trees did not fit into memory). All updates were durable and used the "simple majority" replica ack policy, effectively 'committing to the network'. All read operations used the Consistency.NONE_REQUIRED parameter allowing reads to be performed on any replica. In the past we have achieved 100K ops/sec using SSD cards on a single shard cluster (replication factor 3) so for this test we used 10 shards on 15 Storage Nodes with each SN carrying 2 Rep Nodes and each RN assigned to its own SSD card. After correcting a scaling problem in YCSB, we blew past the 1M ops/sec mark with 8 shards and proceeded to hit 1.2M ops/sec with 10 shards.  Hardware Configuration We used 15 servers, each configured with two 335 GB SSD cards. We did not have homogeneous CPUs across all 15 servers available to us so 12 of the 15 were Xeon E5-2690, 2.9 GHz, 2 sockets, 32 threads, 193 GB RAM, and the other 3 were Xeon E5-2680, 2.7 GHz, 2 sockets, 32 threads, 193 GB RAM.  There might have been some upside in having all 15 machines configured with the faster CPU, but since CPU was not the limiting factor we don't believe the improvement would be significant. The client machines were Xeon X5670, 2.93 GHz, 2 sockets, 24 threads, 96 GB RAM. Although the clients had 96 GB of RAM, neither the NoSQL Database or YCSB clients require anywhere near that amount of memory and the test could have just easily been run with much less. Networking was all 10GigE. YCSB Scaling Problem We made three modifications to the YCSB benchmark. The first was to allow the test to accommodate more than 2 billion records (effectively int's vs long's). To keep the key size constant, we changed the code to use base 32 for the user ids. The second change involved to the way we run the YCSB client in order to make the test itself horizontally scalable.The basic problem has to do with the way the YCSB test creates its Zipfian distribution of keys which is intended to model "real" loads by generating clusters of key collisions. Unfortunately, the percentage of collisions on the most contentious keys remains the same even as the number of keys in the database increases. As we scale up the load, the number of collisions on those keys increases as well, eventually exceeding the capacity of the single server used for a given key.This is not a workload that is realistic or amenable to horizontal scaling. YCSB does provide alternate key distribution algorithms so this is not a shortcoming of YCSB in general. We decided that a better model would be for the key collisions to be limited to a given YCSB client process. That way, as additional YCSB client processes (i.e. additional load) are added, they each maintain the same number of collisions they encounter themselves, but do not increase the number of collisions on a single key in the entire store. We added client processes proportionally to the number of records in the database (and therefore the number of shards). This change to the use of YCSB better models a use case where new groups of users are likely to access either just their own entries, or entries within their own subgroups, rather than all users showing the same interest in a single global collection of keys. If an application finds every user having the same likelihood of wanting to modify a single global key, that application has no real hope of getting horizontal scaling. Finally, we used read/modify/write (also known as "Compare And Set") style updates during the mixed phase. This uses versioned operations to make sure that no updates are lost. This mode of operation provides better application behavior than the way we have typically run YCSB in the past, and is only practical at scale because we eliminated the shared key collision hotspots.It is also a more realistic testing scenario. To reiterate, all updates used a simple majority replica ack policy making them durable. Scalability Results In the table below, the "KVS Size" column is the number of records with the number of shards and the replication factor. Hence, the first row indicates 400m total records in the NoSQL Database (KV Store), 2 shards, and a replication factor of 3. The "Clients" column indicates the number of YCSB client processes. "Threads" is the number of threads per process with the total number of threads. Hence, 90 threads per YCSB process for a total of 360 threads. The client processes were distributed across 10 client machines. Shards KVS Size Clients Mixed (records) Threads OverallThroughput(ops/sec) Read Latencyav/95%/99%(ms) Write Latencyav/95%/99%(ms) 2 400m(2x3) 4 90(360) 302,152 0.76/1/3 3.08/8/35 4 800m(4x3) 8 90(720) 558,569 0.79/1/4 3.82/16/45 8 1600m(8x3) 16 90(1440) 1,028,868 0.85/2/5 4.29/21/51 10 2000m(10x3) 20 90(1800) 1,244,550 0.88/2/6 4.47/23/53

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  • What Counts For a DBA: Fitness

    - by Louis Davidson
    If you know me, you can probably guess that physical exercise is not really my thing. There was a time in my past when it a larger part of my life, but even then never in the same sort of passionate way as a number of our SQL friends.  For me, I find that mental exercise satisfies what I believe to be the same inner need that drives people to run farther than I like to drive on most Saturday mornings, and it is certainly just as addictive. Mental fitness shares many common traits with physical fitness, especially the need to attain it through repetitive training. I only wish that mental training burned off a bacon cheeseburger in the same manner as does jogging around a dewy park on Saturday morning. In physical training, there are at least two goals, the first of which is to be physically able to do a task. The second is to train the brain to perform the task without thinking too hard about it. No matter how long it has been since you last rode a bike, you will be almost certainly be able to hop on and start riding without thinking about the process of pedaling or balancing. If you’ve never ridden a bike, you could be a physics professor /Olympic athlete and still crash the first few times you try, even though you are as strong as an ox and your knowledge of the physics of bicycle riding makes the concept child’s play. For programming tasks, the process is very similar. As a DBA, you will come to know intuitively how to backup, optimize, and secure database systems. As a data programmer, you will work to instinctively use the clauses of Transact-SQL DML so that, when you need to group data three ways (and not four), you will know to use the GROUP BY clause with GROUPING SETS without resorting to a search engine.  You have the skill. Making it naturally then requires repetition and experience is the primary requirement, not just simply learning about a topic. The hardest part of being really good at something is this difference between knowledge and skill. I have recently taken several informative training classes with Kimball University on data warehousing and ETL. Now I have a lot more knowledge about designing data warehouses than before. I have also done a good bit of data warehouse designing of late and have started to improve to some level of proficiency with the theory. Yet, for all of this head knowledge, it is still a struggle to take what I have learned and apply it to the designs I am working on.  Data warehousing is still a task that is not yet deeply ingrained in my brain muscle memory. On the other hand, relational database design is something that no matter how much or how little I may get to do it, I am comfortable doing it. I have done it as a profession now for well over a decade, I teach classes on it, and I also have done (and continue to do) a lot of mental training beyond the work day. Sometimes the training is just basic education, some reading blogs and attending sessions at PASS events.  My best training comes from spending time working on other people’s design issues in forums (though not nearly as much as I would like to lately). Working through other people’s problems is a great way to exercise your brain on problems with which you’re not immediately familiar. The final bit of exercise I find useful for cultivating mental fitness for a data professional is also probably the nerdiest thing that I will ever suggest you do.  Akin to running in place, the idea is to work through designs in your head. I have designed more than one database system that would revolutionize grocery store operations, sales at my local Target store, the ordering process at Amazon, and ways to improve Disney World operations to get me through a line faster (some of which they are starting to implement without any of my help.) Never are the designs truly fleshed out, but enough to work through structures and processes.  On “paper”, I have designed database systems to catalog things as trivial as my Lego creations, rental car companies and my audio and video collections. Once I get the database designed mentally, sometimes I will create the database, add some data (often using Red-Gate’s Data Generator), and write a few queries to see if a concept was realistic, but I will rarely fully flesh out the database since I have no desire to do any user interface programming anymore.  The mental training allows me to keep in practice for when the time comes to do the work I love the most for real…even if I have been spending most of my work time lately building data warehouses.  If you are really strong of mind and body, perhaps you can mix a mental run with a physical run; though don’t run off of a cliff while contemplating how you might design a database to catalog the trees on a mountain…that would be contradictory to the purpose of both types of exercise.

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  • How do you test an ICF based connector using Connector Facade Standalone?

    - by Shashidhar Malyala
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The following code helps in writing a standalone java program to test an ICF based connector. The sample code in this example takes into account an ICF based flatfile connector. It is possible to test various operations like create, update, delete, search etc... It is also possible to set values to the connector configuration parameters, add/remove attributes and their values. public class FlatFile { private static final java.lang.String BUNDLE_NAME = "<PACKAGE_NAME>"; //Ex: org.info.icf.flatfile private static final java.lang.String BUNDLE_VERSION = "1.0.0"; private static final java.lang.String CONNECTOR_NAME = "org.info.icf.flatfile.FlatFileConnector"; // Name of connector class i.e. the class implemting the connector SPI operations public ConnectorFacade getFacade() throws IOException { ConnectorInfoManagerFactory fact = ConnectorInfoManagerFactory .getInstance(); File bundleDirectory = new File("<BUNDLE_LOCATION>"); //Ex: /usr/oracle/connector_bundles/ URL url = IOUtil.makeURL(bundleDirectory, "org.info.icf.flatfile-1.0.0.jar"); ConnectorInfoManager manager = fact.getLocalManager(url); ConnectorKey key = new ConnectorKey(BUNDLE_NAME, BUNDLE_VERSION, CONNECTOR_NAME); ConnectorInfo info = manager.findConnectorInfo(key); // From the ConnectorInfo object, create the default APIConfiguration. APIConfiguration apiConfig = info.createDefaultAPIConfiguration(); // From the default APIConfiguration, retrieve the // ConfigurationProperties. ConfigurationProperties properties = apiConfig .getConfigurationProperties(); // Print out what the properties are (not necessary) List propertyNames = properties.getPropertyNames(); for (String propName : propertyNames) { ConfigurationProperty prop = properties.getProperty(propName); System.out.println("Property Name: " + prop.getName() + "\tProperty Type: " + prop.getType()); } properties .setPropertyValue("fileLocation", "/usr/oracle/accounts.csv"); // Set all of the ConfigurationProperties needed by the connector. // properties.setPropertyValue("host", FOOBAR_HOST); // properties.setPropertyValue("adminName", FOOBAR_ADMIN); // properties.setPropertyValue("adminPassword", FOOBAR_PASSWORD); // properties.setPropertyValue("useSSL", false); // Use the ConnectorFacadeFactory's newInstance() method to get a new // connector. ConnectorFacade connFacade = ConnectorFacadeFactory.getInstance() .newInstance(apiConfig); // Make sure we have set up the Configuration properly connFacade.validate(); return connFacade; } public static void main(String[] args) throws IOException { FlatFile file = new FlatFile(); ConnectorFacade cfac = file.getFacade(); Set attrSet = new HashSet(); attrSet.add(AttributeBuilder.build(Name.NAME, "Test01")); attrSet.add(AttributeBuilder.build("FIRST_NAME", "Test_First")); attrSet.add(AttributeBuilder.build("LAST_NAME", "Test_Last")); //Create Uid uid = cfac.create(ObjectClass.ACCOUNT, attrSet, null); //Delete Uid uidP = new Uid("Test01"); cfac.delete(ObjectClass.ACCOUNT, uidP, null); } }

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  • Navigant Consulting Implements Oracle's PeopleSoft Enterprise 9.1 to Integrate Financial and HR Information

    - by jay.richey
    Integration to Help Global Consultancy Increase Business Productivity and Streamline Operations Redwood Shores, Calif. - Dec. 15, 2010 "Our business is based on the seamless execution and expertise of our highly-trained consultants and we're always seeking ways to improve processes so they can focus on providing excellent client service," said Changappa Kodendera, CIO, Navigant Consulting. "Our phased implementation of Oracle's PeopleSoft Enterprise 9.1 will provide us with a solid technology foundation that we can rely on to support our global consulting business, with a scalable platform that facilitates further improvement." Read the press release Watch their video

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  • Oracle Process Accelerators Release 11.1.1.7.0 Now Available

    - by Cesare Rotundo
    The new Oracle Process Accelerators (PA) Release (11.1.1.7.0) delivers key functionality in many dimensions: new PAs across industries, new functionality in preexisting PAs, and an improved installation process. All PAs in Release 11.1.1.7.0 run on the latest Oracle BPM Suite and SOA Suite, 11.1.1.7. New PAs include: Financial Reports Approval (FRA): end-to-end solution for efficient and controlled Financial Report review and approval process, enabling financial analysts and decision makers to collaborate around Excel. Electronic Forms Management (EFM): supports the process to design and expose eForms with the ability to quickly design eForms and associate approval processes to them, and to then enable users to select, fill, and submit eForms for approval Mobile Data Offloading (MDO): enables telecommunications providers to reduce congestion on cellular networks and lower cost of operations by using Oracle Event Processing (OEP) and BAM to switch devices from cellular networks to Wi-Fi. By adopting the latest PA release , customers will also be able to better identify and kick-start smart extension of their processes where business steps are supported by Apps: PA 11.1.1.7.0 includes out-of-the-box business process extension scenarios with Oracle Apps such as Siebel (FSLO) and PeopleSoft (EOB).

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  • CPU Usage in Very Large Coherence Clusters

    - by jpurdy
    When sizing Coherence installations, one of the complicating factors is that these installations (by their very nature) tend to be application-specific, with some being large, memory-intensive caches, with others acting as I/O-intensive transaction-processing platforms, and still others performing CPU-intensive calculations across the data grid. Regardless of the primary resource requirements, Coherence sizing calculations are inherently empirical, in that there are so many permutations that a simple spreadsheet approach to sizing is rarely optimal (though it can provide a good starting estimate). So we typically recommend measuring actual resource usage (primarily CPU cycles, network bandwidth and memory) at a given load, and then extrapolating from those measurements. Of course there may be multiple types of load, and these may have varying degrees of correlation -- for example, an increased request rate may drive up the number of objects "pinned" in memory at any point, but the increase may be less than linear if those objects are naturally shared by concurrent requests. But for most reasonably-designed applications, a linear resource model will be reasonably accurate for most levels of scale. However, at extreme scale, sizing becomes a bit more complicated as certain cluster management operations -- while very infrequent -- become increasingly critical. This is because certain operations do not naturally tend to scale out. In a small cluster, sizing is primarily driven by the request rate, required cache size, or other application-driven metrics. In larger clusters (e.g. those with hundreds of cluster members), certain infrastructure tasks become intensive, in particular those related to members joining and leaving the cluster, such as introducing new cluster members to the rest of the cluster, or publishing the location of partitions during rebalancing. These tasks have a strong tendency to require all updates to be routed via a single member for the sake of cluster stability and data integrity. Fortunately that member is dynamically assigned in Coherence, so it is not a single point of failure, but it may still become a single point of bottleneck (until the cluster finishes its reconfiguration, at which point this member will have a similar load to the rest of the members). The most common cause of scaling issues in large clusters is disabling multicast (by configuring well-known addresses, aka WKA). This obviously impacts network usage, but it also has a large impact on CPU usage, primarily since the senior member must directly communicate certain messages with every other cluster member, and this communication requires significant CPU time. In particular, the need to notify the rest of the cluster about membership changes and corresponding partition reassignments adds stress to the senior member. Given that portions of the network stack may tend to be single-threaded (both in Coherence and the underlying OS), this may be even more problematic on servers with poor single-threaded performance. As a result of this, some extremely large clusters may be configured with a smaller number of partitions than ideal. This results in the size of each partition being increased. When a cache server fails, the other servers will use their fractional backups to recover the state of that server (and take over responsibility for their backed-up portion of that state). The finest granularity of this recovery is a single partition, and the single service thread can not accept new requests during this recovery. Ordinarily, recovery is practically instantaneous (it is roughly equivalent to the time required to iterate over a set of backup backing map entries and move them to the primary backing map in the same JVM). But certain factors can increase this duration drastically (to several seconds): large partitions, sufficiently slow single-threaded CPU performance, many or expensive indexes to rebuild, etc. The solution of course is to mitigate each of those factors but in many cases this may be challenging. Larger clusters also lead to the temptation to place more load on the available hardware resources, spreading CPU resources thin. As an example, while we've long been aware of how garbage collection can cause significant pauses, it usually isn't viewed as a major consumer of CPU (in terms of overall system throughput). Typically, the use of a concurrent collector allows greater responsiveness by minimizing pause times, at the cost of reducing system throughput. However, at a recent engagement, we were forced to turn off the concurrent collector and use a traditional parallel "stop the world" collector to reduce CPU usage to an acceptable level. In summary, there are some less obvious factors that may result in excessive CPU consumption in a larger cluster, so it is even more critical to test at full scale, even though allocating sufficient hardware may often be much more difficult for these large clusters.

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  • Enzo Backup for SQL Azure Beta Released!

    - by ScottKlein
    Blue Syntax is happy to announce the release of their SQL Azure database backup product! Enzo Backup for SQL Azure offers unparalleled backup and restored functionlity and flexibility of a SQL Azure database. You can download the beta release here: http://www.bluesyntax.net/backup.aspx With Enzo Backup for SQL Azure, you can: Create a backup blob, or a backup file from a SQL Azure database Restore a SQL Azure database from a backup blob, or a backup file Perform limited backup and restore of SQL Server databases (see details) Run backups entirely in the cloud using a remote agent Backup a single schema of a database Restore specific tables only Copy backup devices from on-premise to the cloud Use a command-line utility to perform backup operations Perform transactionally consistent backups for SQL Azure Please download it and provide us your feed back!

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  • What is the increase in developer productivity while using Hibernate?

    - by Tarun Kohli
    I was curious to find out the percentage increase in developer's productivity by using Hibernate. We use both Hibernate and NHibernate extensively and find them to be extremely elegant frameworks but haven't undertaken any study to find out the time savings by using them. IMHO, one could get a good 30 to 40% jump in developer productivity as one doesn't have to write the basic CRUD operations and bother about caching. But, are there are any formal case studies which prove that point? I would really appreciate if someone could direct me to a published white paper about some statistics about the productivity gains.

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  • Test driven development - convince me!

    - by Casebash
    I know some people are massive proponents of test driven development. I have used unit tests in the past, but only to test operations that can be tested easily or which I believe will quite possibly be correct. Complete or near complete code coverage sounds like it would take a lot of time. What projects do you use test-driven development for? Do you only use it for projects above a certain size? Should I be using it or not? Convince me!

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  • How can I resize an external USB NTFS partition?

    - by chris
    I have a new USB drive which came with a single NTFS partition. How can I shrink that so that I can create an ext4 partition? gparted does not seem to have the "Resize" option highlighted. Update: After following the directions below, after unmounting I am still not able to resize the partition. There is a warning though: "Unable to find mount point. Unable to read the contents of this file system! Because of this, some operations may be unavailable. The following list of software packages is required for ntfs file system support: ntfsprogs". However, with the partition mounted, I can read & write to the file system on the drive just fine, and ntfsprogs is installed and current. What's next?

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  • How to correctly create a virtual file system?

    - by Paul
    A task in my homework assignment asks me to create a virtual file system, mount it, and perform some operations on it. I am supposed to create a file of 10 MB whose bits are all set to 0, format it as ext3 and mount it. This is how I've done that: dd if=/dev/zero of=~/filesyst bs=10485760 count=1 sudo mkfs.ext3 ~/filesyst sudo mount –o loop ~/filesyst /media/fuse Even though I've used /dev/sero, the file i still full of gibberish characters (mostly at-signs). The permissions on /media/fuse are drw-rw-rw- (which are alright), but the permissions on the files inside it are something like this: d????????? ? ? ? ? ? lost+found -????????? ? ? ? ? ? secret_bin Where have I gone wrong?

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  • About to graduate from good school without any progamming skills

    - by newprint
    Not sure if it is good place to ask this question, but found this section to be suitable. I am about to graduate from a good school (in the US) with Computer Science degree, having good grades and high GPA. I have no freaking clue how to write a good program, how to properly test it... nada, zero. We were never been taught how to write software. Ye, sure the Comp. Architecture class is important, and I can tell you a lot about how MIPS processor works, and I can tell you about Binary Trees and Red-Black Trees and running time of operations in Big Oh, but it has nothing to do with programming in "real" life. For god sake, none of my classmates know how to use STLs or write templated code! To be honest, I found that many of my classes to be waste of time. What should I do ? How to step into real life and learn how to program ?

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