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• How to Achieve Real-Time Data Protection and Availabilty....For Real

  - by JoeMeeks

  There is a class of business and mission critical applications where downtime or data loss have substantial negative impact on revenue, customer service, reputation, cost, etc. Because the Oracle Database is used extensively to provide reliable performance and availability for this class of application, it also provides an integrated set of capabilities for real-time data protection and availability. Active Data Guard, depicted in the figure below, is the cornerstone for accomplishing these objectives because it provides the absolute best real-time data protection and availability for the Oracle Database. This is a bold statement, but it is supported by the facts. It isn’t so much that alternative solutions are bad, it’s just that their architectures prevent them from achieving the same levels of data protection, availability, simplicity, and asset utilization provided by Active Data Guard. Let’s explore further. Backups are the most popular method used to protect data and are an essential best practice for every database. Not surprisingly, Oracle Recovery Manager (RMAN) is one of the most commonly used features of the Oracle Database. But comparing Active Data Guard to backups is like comparing apples to motorcycles. Active Data Guard uses a hot (open read-only), synchronized copy of the production database to provide real-time data protection and HA. In contrast, a restore from backup takes time and often has many moving parts - people, processes, software and systems – that can create a level of uncertainty during an outage that critical applications can’t afford. This is why backups play a secondary role for your most critical databases by complementing real-time solutions that can provide both data protection and availability. Before Data Guard, enterprises used storage remote-mirroring for real-time data protection and availability. Remote-mirroring is a sophisticated storage technology promoted as a generic infrastructure solution that makes a simple promise – whatever is written to a primary volume will also be written to the mirrored volume at a remote site. Keeping this promise is also what causes data loss and downtime when the data written to primary volumes is corrupt – the same corruption is faithfully mirrored to the remote volume making both copies unusable. This happens because remote-mirroring is a generic process. It has no  intrinsic knowledge of Oracle data structures to enable advanced protection, nor can it perform independent Oracle validation BEFORE changes are applied to the remote copy. There is also nothing to prevent human error (e.g. a storage admin accidentally deleting critical files) from also impacting the remote mirrored copy. Remote-mirroring tricks users by creating a false impression that there are two separate copies of the Oracle Database. In truth; while remote-mirroring maintains two copies of the data on different volumes, both are part of a single closely coupled system. Not only will remote-mirroring propagate corruptions and administrative errors, but the changes applied to the mirrored volume are a result of the same Oracle code path that applied the change to the source volume. There is no isolation, either from a storage mirroring perspective or from an Oracle software perspective.  Bottom line, storage remote-mirroring lacks both the smarts and isolation level necessary to provide true data protection. Active Data Guard offers much more than storage remote-mirroring when your objective is protecting your enterprise from downtime and data loss. Like remote-mirroring, an Active Data Guard replica is an exact block for block copy of the primary. Unlike remote-mirroring, an Active Data Guard replica is NOT a tightly coupled copy of the source volumes - it is a completely independent Oracle Database. Active Data Guard’s inherent knowledge of Oracle data block and redo structures enables a separate Oracle Database using a different Oracle code path than the primary to use the full complement of Oracle data validation methods before changes are applied to the synchronized copy. These include: physical check sum, logical intra-block checking, lost write validation, and automatic block repair. The figure below illustrates the stark difference between the knowledge that remote-mirroring can discern from an Oracle data block and what Active Data Guard can discern. An Active Data Guard standby also provides a range of additional services enabled by the fact that it is a running Oracle Database - not just a mirrored copy of data files. An Active Data Guard standby database can be open read-only while it is synchronizing with the primary. This enables read-only workloads to be offloaded from the primary system and run on the active standby - boosting performance by utilizing all assets. An Active Data Guard standby can also be used to implement many types of system and database maintenance in rolling fashion. Maintenance and upgrades are first implemented on the standby while production runs unaffected at the primary. After the primary and standby are synchronized and all changes have been validated, the production workload is quickly switched to the standby. The only downtime is the time required for user connections to transfer from one system to the next. These capabilities further expand the expectations of availability offered by a data protection solution beyond what is possible to do using storage remote-mirroring. So don’t be fooled by appearances.  Storage remote-mirroring and Active Data Guard replication may look similar on the surface - but the devil is in the details. Only Active Data Guard has the smarts, the isolation, and the simplicity, to provide the best data protection and availability for the Oracle Database. Stay tuned for future blog posts that dive into the many differences between storage remote-mirroring and Active Data Guard along the dimensions of data protection, data availability, cost, asset utilization and return on investment. For additional information on Active Data Guard, see: Active Data Guard Technical White Paper Active Data Guard vs Storage Remote-Mirroring Active Data Guard Home Page on the Oracle Technology Network

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• Xml failing to deserialise

  - by Carnotaurus

  I call a method to get my pages [see GetPages(String xmlFullFilePath)]. The FromXElement method is supposed to deserialise the LitePropertyData elements to strongly type LitePropertyData objects. Instead it fails on the following line: return (T)xmlSerializer.Deserialize(memoryStream); and gives the following error: <LitePropertyData xmlns=''> was not expected. What am I doing wrong? I have included the methods that I call and the xml data: public static T FromXElement<T>(this XElement xElement) { using (var memoryStream = new MemoryStream(Encoding.ASCII.GetBytes(xElement.ToString()))) { var xmlSerializer = new XmlSerializer(typeof(T)); return (T)xmlSerializer.Deserialize(memoryStream); } } public static List<LitePageData> GetPages(String xmlFullFilePath) { XDocument document = XDocument.Load(xmlFullFilePath); List<LitePageData> results = (from record in document.Descendants("row") select new LitePageData { Guid = IsValid(record, "Guid") ? record.Element("Guid").Value : null, ParentID = IsValid(record, "ParentID") ? Convert.ToInt32(record.Element("ParentID").Value) : (Int32?)null, Created = Convert.ToDateTime(record.Element("Created").Value), Changed = Convert.ToDateTime(record.Element("Changed").Value), Name = record.Element("Name").Value, ID = Convert.ToInt32(record.Element("ID").Value), LitePageTypeID = IsValid(record, "ParentID") ? Convert.ToInt32(record.Element("ParentID").Value) : (Int32?)null, Html = record.Element("Html").Value, FriendlyName = record.Element("FriendlyName").Value, Properties = record.Element("Properties") != null ? record.Element("Properties").Element("LitePropertyData").FromXElement<List<LitePropertyData>>() : new List<LitePropertyData>() }).ToList(); return results; } Here is the xml: <?xml version="1.0" encoding="utf-8"?> <root> <rows> <row> <ID>1</ID> <ImageUrl></ImageUrl> <Html>Home page</Html> <Created>01-01-2012</Created> <Changed>01-01-2012</Changed> <Name>Home page</Name> <FriendlyName>home-page</FriendlyName> </row> <row xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Guid>edeaf468-f490-4271-bf4d-be145bc6a1fd</Guid> <ID>8</ID> <Name>Unused</Name> <ParentID>1</ParentID> <Created>2006-03-25T10:57:17</Created> <Changed>2012-07-17T12:24:30.0984747+01:00</Changed> <ChangedBy /> <LitePageTypeID xsi:nil="true" /> <Html> What is the purpose of this option? This option checks the current document for accessibility issues. It uses Bobby to provide details of whether the current web page conforms to W3C's WCAG criteria for web content accessibility. Issues with Bobby and Cynthia Bobby and Cynthia are free services that supposedly allow a user to expose web page accessibility barriers. It is something of a guide but perhaps a blunt instrument. I tested a few of the webpages that I have designed. Sure enough, my pages fall short and for good reason. I am not about to claim that Bobby and Cynthia are useless. Although it is useful and commendable tool, it project appears to be overly ambitious. Nevertheless, let me explain my issues with Bobby and Cynthia: First, certain W3C standards for designing web documents are often too strict and unworkable. For instance, in some versions W3C standards for HTML, certain tags should not include a particular attribute, whereas in others they are requisite if the document is to be ???well-formed???. The standard that a designer chooses is determined usually by the requirements specification document. This specifies which browsers and versions of those browsers that the web page is expected to correctly display. Forcing a hypertext document to conform strictly to a specific W3C standard for HTML is often no simple task. In the worst case, it cannot conform without losing some aesthetics or accessibility functionality. Second, the case of HTML documents is not an isolated case. Standards for XML, XSL, JavaScript, VBScript, are analogous. Therefore, you might imagine the problems when you begin to combine these languages and formats in an HTML document. Third, there is always more than one way to skin a cat. For example, Bobby and Cynthia may flag those IMG tags that do not contain a TITLE attribute. There might be good reason that a web developer chooses not to include the title attribute. The title attribute has a limited numbers of characters and does not support carriage returns. This is a major defect in the design of this tag. In fact, before the TITLE attribute was supported, there was the ALT attribute. Most browsers support both, yet they both perform a similar function. However, both attributes share the same deficiencies. In practice, there are instances where neither attribute would be used. Instead, for example, the developer would write some JavaScript or VBScript to circumvent these deficiencies. The concern is that Bobby and Cynthia would not notice this because it does not ???understand??? what the JavaScript does. </Html> <FriendlyName>unused</FriendlyName> <IsDeleted>false</IsDeleted> <Properties> <LitePropertyData> <Description>Image for the page</Description> <DisplayEditUI>true</DisplayEditUI> <OwnerTab>1</OwnerTab> <DisplayName>Image Url</DisplayName> <FieldOrder>1</FieldOrder> <IsRequired>false</IsRequired> <Name>ImageUrl</Name> <IsModified>false</IsModified> <ParentPageID>3</ParentPageID> <Type>String</Type> <Value xsi:type="xsd:string">smarter.jpg</Value> </LitePropertyData> <LitePropertyData> <Description>WebItemApplicationEnum</Description> <DisplayEditUI>true</DisplayEditUI> <OwnerTab>1</OwnerTab> <DisplayName>WebItemApplicationEnum</DisplayName> <FieldOrder>1</FieldOrder> <IsRequired>false</IsRequired> <Name>WebItemApplicationEnum</Name> <IsModified>false</IsModified> <ParentPageID>3</ParentPageID> <Type>Number</Type> <Value xsi:type="xsd:string">1</Value> </LitePropertyData> </Properties> <Seo> <Author>Phil Carney</Author> <Classification /> <Copyright>Carnotaurus</Copyright> <Description> What is the purpose of this option? This option checks the current document for accessibility issues. It uses Bobby to provide details of whether the current web page conforms to W3C's WCAG criteria for web content accessibility. Issues with Bobby and Cynthia Bobby and Cynthia are free services that supposedly allow a user to expose web page accessibility barriers. It is something of a guide but perhaps a blunt instrument. I tested a few of the webpages that I have designed. Sure enough, my pages fall short and for good reason. I am not about to claim that Bobby and Cynthia are useless. Although it is useful and commendable tool, it project appears to be overly ambitious. Nevertheless, let me explain my issues with Bobby and Cynthia: First, certain W3C standards for designing web documents are often too strict and unworkable. For instance, in some versions W3C standards for HTML, certain tags should not include a particular attribute, whereas in others they are requisite if the document is to be ???well-formed???. The standard that a designer chooses is determined usually by the requirements specification document. This specifies which browsers and versions of those browsers that the web page is expected to correctly display. Forcing a hypertext document to conform strictly to a specific W3C standard for HTML is often no simple task. In the worst case, it cannot conform without losing some aesthetics or accessibility functionality. Second, the case of HTML documents is not an isolated case. Standards for XML, XSL, JavaScript, VBScript, are analogous. Therefore, you might imagine the problems when you begin to combine these languages and formats in an HTML document. Third, there is always more than one way to skin a cat. For example, Bobby and Cynthia may flag those IMG tags that do not contain a TITLE attribute. There might be good reason that a web developer chooses not to include the title attribute. The title attribute has a limited numbers of characters and does not support carriage returns. This is a major defect in the design of this tag. In fact, before the TITLE attribute was supported, there was the ALT attribute. Most browsers support both, yet they both perform a similar function. However, both attributes share the same deficiencies. In practice, there are instances where neither attribute would be used. Instead, for example, the developer would write some JavaScript or VBScript to circumvent these deficiencies. The concern is that Bobby and Cynthia would not notice this because it does not ???understand??? what the JavaScript does. </Description> <Keywords>unused</Keywords> <Title>unused</Title> </Seo> </row> </rows> </root> EDIT Here are my entities: public class LitePropertyData { public virtual string Description { get; set; } public virtual bool DisplayEditUI { get; set; } public int OwnerTab { get; set; } public virtual string DisplayName { get; set; } public int FieldOrder { get; set; } public bool IsRequired { get; set; } public string Name { get; set; } public virtual bool IsModified { get; set; } public virtual int ParentPageID { get; set; } public LiteDataType Type { get; set; } public object Value { get; set; } } [Serializable] public class LitePageData { public String Guid { get; set; } public Int32 ID { get; set; } public String Name { get; set; } public Int32? ParentID { get; set; } public DateTime Created { get; set; } public String CreatedBy { get; set; } public DateTime Changed { get; set; } public String ChangedBy { get; set; } public Int32? LitePageTypeID { get; set; } public String Html { get; set; } public String FriendlyName { get; set; } public Boolean IsDeleted { get; set; } public List<LitePropertyData> Properties { get; set; } public LiteSeoPageData Seo { get; set; } /// <summary> /// Saves the specified XML full file path. /// </summary> /// <param name="xmlFullFilePath">The XML full file path.</param> public void Save(String xmlFullFilePath) { XDocument doc = XDocument.Load(xmlFullFilePath); XElement demoNode = this.ToXElement<LitePageData>(); demoNode.Name = "row"; doc.Descendants("rows").Single().Add(demoNode); doc.Save(xmlFullFilePath); } }

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• BPM 11g - Dynamic Task Assignment with Multi-level Organization Units

  - by Mark Foster

  I've seen several requirements to have a more granular level of task assignment in BPM 11g based on some value in the data passed to the process. Parametric Roles is normally the first port of call to try to satisfy this requirement, but in this blog we will show how a lot of use-cases can be satisfied by the easier to implement and flexible Organization Unit. The Use-Case Task assignment is to an approval group containing several users. At runtime, a location value in the input data determines which of the particular users the task is ultimately assigned to. In this case we use the Demo Community referenced in the SOA Admin Guide, and specifically the "LoanAnalyticGroup" which contains three users; "szweig", "mmitch" & "fkafka". In our scenario we would like to assign a task to "szweig" if the input data specifies that the location is "JapanCentral", to "fkafka" if the location is "JapanNorth" and to "mmitch" if "JapanSouth", and to all of them if the location is "Japan" i.e....   The Process Simple one human task process.... In the output data association of the "Start" activity we need to set the value of the "Organization Unit" predefined variable based on the input data (note that the  predefined variables can only be set on output data associations)....  ...and in the output data association of the human activity we will reset the "Organization Unit" to empty, always good practice to ensure that the Organization Unit will not be used for any subsequent human activities for which we do not require it.... Set Up the Organization Unit  Log in to the BPM Workspace with an administrator user (weblogic/welcome1 in our case) and choose the "Administration" option. Within "Roles" assign the "ProcessOwner" swim-lane for our process to "LoanAnalyticGroup".... Within "Organization Units" we can model our organization.... "Root Organization Unit" as "Japan" and "Child Organization Unit" as "Central", "South" & "North" as shown. As described previously, add user "szweig" to "Central", "mmitch" to "South" and "fkafka" to "North"....   Test the Process Invalid Data  First let us test with invalid data in the input to see what the consequences are, here we use "X" as input.... ...and looking at the instance we can see it has errored.... Organization Unit Root Level Assignment  Now let us see what happens if we have "Japan" in the input data.... ...looking in the "flow trace" we can see that the task has been assigned....  ... but who has the task been assigned to ? Let us look in the BPM Workspace for user "szweig"....  ...and for "mmitch"....  ... and for "fkafka"....  ...so we can see that with an Organization Unit at "Root" level we have successfully assigned the task to all users. Organization Unit Child Level Assignment  Now let us test with "Japan/North" in the input data.... ...and looking in "fkafka" workspace we see the task has been assigned, remember, he was associated with "JapanNorth"....   ... but what about the workspace of "szweig"....  ...no tasks assigned, neither has "mmitch", just as we expected. Summary  We have seen in this blog how to easily implement multi-level dynamic task routing using Organization Units, a common use-case and a simpler solution than Parametric Roles. 

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• What Keeps You from Changing Your Public IP Address and Wreaking Havoc on the Internet?

  - by Jason Fitzpatrick

  What exactly is preventing you (or anyone else) from changing their IP address and causing all sorts of headaches for ISPs and other Internet users? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Whitemage is curious about what’s preventing him from wantonly changing his IP address and causing trouble: An interesting question was asked of me and I did not know what to answer. So I’ll ask here. Let’s say I subscribed to an ISP and I’m using cable internet access. The ISP gives me a public IP address of 60.61.62.63. What keeps me from changing this IP address to, let’s say, 60.61.62.75, and messing with another consumer’s internet access? For the sake of this argument, let’s say that this other IP address is also owned by the same ISP. Also, let’s assume that it’s possible for me to go into the cable modem settings and manually change the IP address. Under a business contract where you are allocated static addresses, you are also assigned a default gateway, a network address and a broadcast address. So that’s 3 addresses the ISP “loses” to you. That seems very wasteful for dynamically assigned IP addresses, which the majority of customers are. Could they simply be using static arps? ACLs? Other simple mechanisms? Two things to investigate here, why can’t we just go around changing our addresses, and is the assignment process as wasteful as it seems? The Answer SuperUser contributor Moses offers some insight: Cable modems aren’t like your home router (ie. they don’t have a web interface with simple point-and-click buttons that any kid can “hack” into). Cable modems are “looked up” and located by their MAC address by the ISP, and are typically accessed by technicians using proprietary software that only they have access to, that only runs on their servers, and therefore can’t really be stolen. Cable modems also authenticate and cross-check settings with the ISPs servers. The server has to tell the modem whether it’s settings (and location on the cable network) are valid, and simply sets it to what the ISP has it set it for (bandwidth, DHCP allocations, etc). For instance, when you tell your ISP “I would like a static IP, please.”, they allocate one to the modem through their servers, and the modem allows you to use that IP. Same with bandwidth changes, for instance. To do what you are suggesting, you would likely have to break into the servers at the ISP and change what it has set up for your modem. Could they simply be using static arps? ACLs? Other simple mechanisms? Every ISP is different, both in practice and how close they are with the larger network that is providing service to them. Depending on those factors, they could be using a combination of ACL and static ARP. It also depends on the technology in the cable network itself. The ISP I worked for used some form of ACL, but that knowledge was a little beyond my paygrade. I only got to work with the technician’s interface and do routine maintenance and service changes. What keeps me from changing this IP address to, let’s say, 60.61.62.75 and mess with another consumer’s internet access? Given the above, what keeps you from changing your IP to one that your ISP hasn’t specifically given to you is a server that is instructing your modem what it can and can’t do. Even if you somehow broke into the modem, if 60.61.62.75 is already allocated to another customer, then the server will simply tell your modem that it can’t have it. David Schwartz offers some additional insight with a link to a white paper for the really curious: Most modern ISPs (last 13 years or so) will not accept traffic from a customer connection with a source IP address they would not route to that customer were it the destination IP address. This is called “reverse path forwarding”. See BCP 38. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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• Thought Oracle Usability Advisory Board Was Stuffy? Wrong. Justification for Attending OUAB: ROI

  - by ultan o'broin

  Looking for reasons tell your boss why your organization needs to join the Oracle Usability Advisory Board or why you need approval to attend one of its meetings (see the requirements)? Try phrases such as "Continued Return on Investment (ROI)", "Increased Productivity" or "Happy Workers". With OUAB your participation is about realizing and sustaining ROI across the entire applications life-cycle from input to designs to implementation choices and integration, usage and performance and on measuring and improving the onboarding and support experience. If you think this is a boring meeting of middle-aged people sitting around moaning about customizing desktop forms and why the BlackBerry is here to stay, think again! How about this for a rich agenda, all designed to engage the audience in a thought-provoking and feedback-illiciting day of swirling interactions, contextual usage, global delivery, mobility, consumerizationm, gamification and tailoring your implementation to reflect real users doing real work in real environments.  Foldable, rollable ereader devices provide a newspaper-like UK for electronic news. Or a way to wrap silicon chips, perhaps. Explored at the OUAB Europe Meeting (photograph from Terrace Restaurant in TVP. Nom.) At the 7 December 2012 OUAB Europe meeting in Oracle Thames Valley Park, UK, Oracle partners and customers stepped up to the mic and PPT decks with a range of facts and examples to astound any UX conference C-level sceptic. Over the course of the day we covered much ground, but it was all related in a contextual, flexibile, simplication, engagement way aout delivering results for business: that means solving problems. This means being about the user and their tasks and how to make design and technology transforms work into a productive activity that users and bean counters will be excited by. The sessions really gelled for me: 1. Mobile design patterns and the powerful propositions for customers and partners offered by using the design guidance with Oracle ADF Mobile. Customers' and partners' developers existing ADF developers are now productive, efficient ADF Mobile developers applying proven UX guidance using ADF Mobile components and other Oracle Fusion Middleware in the development toolkit. You can find the Mobile UX Design Patterns and Guidance on Building Mobile Apps on OTN. 2. Oracle Voice and Apps. How this medium offers so much potentual in the enterprise and offers a window in Fusion Apps cloud webservices, Oracle RightNow NLP and Nuance technology. Exciting stuff, demoed live on a mobile phone. Stay tuned for more features and modalities and how you can tailor your own apps experience.  3. Oracle RightNow Natural Language Processing (NLP) Virtual Assistant technology (Ella): how contextual intervention and learning from users sessions delivers a great personalized UX for users interacting with Ella, a fifth generation VA to solve problems and seek knowledge. 4. BYOD Keynote: A balanced keynote address contrasting Fujitsu's explaining of the conceprt, challenges, and trends and setting the expectation that BYOD must be embraced in a flexible way,  with the resolute, crafted high security enterprise requirements that nuancing the BYOD concept and proposals with the realities of their world of water tight information and device sharing policies. Fascinating stuff, as well providing anecdotes to make us thing about out own DYOD Deployments. One size does not fit all. 5. Icon Cultural Surveys Results and Insights Arising: Ever wondered about the cultural appropriateness of icons used in software UIs and how these icons assessed for global use? Or considered that social media "Like" icons might be  unacceptable hand gestures in culture or enterprise? Or do the old world icons like Save floppy disk icons still find acceptable? Well the survey results told you. Challenges must be tested, over time, and context of use is critical now, including external factors such as the internet and social media adoption. Indeed the fears about global rejection of the face and hand icons was not borne out, and some of the more anachronistic icons (checkbooks, microphones, real-to-real tape decks, 3.5" floppies for "save") have become accepted metaphors for current actions. More importantly the findings brought into focus the reason for OUAB - engage with and illicit feedback though working groups before we build anything. 6. EReaders and Oracle iBook: What is the uptake and trends of ereaders? And how about a demo of an iBook with enterprise apps content?  Well received by the audience, the session included a live running poll of ereader usage. 7. Gamification Design Jam: Fun, hands on event for teams of Oracle staff, partners and customers, actually building gamified flows, a practice that can be applied right away by customers and partners.  8. UX Direct: A new offering of usability best practices, coming to an external website for you in 2013. FInd a real user, observe their tasks, design and approve, build and measure. Simple stuff to improve apps implications no end. 9. FUSE (an internal term only, basically Fusion Simplified Experience): demo of the new Face of Fusion Applications: inherently mobile, simple to use, social, personalizable and FAST, three great demos from the HCM, CRM and ICT world on how these UX designs can be used in different ways. So, a powerful breadth and depth of UX solutions and opporunities for customers and partners to engage with and explore how they can make their users happy and benefit their business reaping continued ROI from those apps investments. Find out more about the OUAB and how to get involved here ... 

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• Best Method For Evaluating Existing Software or New Software

  How many of us have been faced with having to decide on an off-the-self or a custom built component, application, or solution to integrate in to an existing system or to be the core foundation of a new system? What is the best method for evaluating existing software or new software still in the design phase? One of the industry preferred methodologies to use is the Active Reviews for Intermediate Designs (ARID) evaluation process.  ARID is a hybrid mixture of the Active Design Review (ADR) methodology and the Architectural Tradeoff Analysis Method (ATAM). So what is ARID? ARD’s main goal is to ensure quality, detailed designs in software. One way in which it does this is by empowering reviewers by assigning generic open ended survey questions. This approach attempts to remove the possibility for allowing the standard answers such as “Yes” or “No”. The ADR process ignores the “Yes”/”No” questions due to the fact that they can be leading based on how the question is asked. Additionally these questions tend to receive less thought in comparison to more open ended questions. Common Active Design Review Questions What possible exceptions can occur in this component, application, or solution? How should exceptions be handled in this component, application, or solution? Where should exceptions be handled in this component, application, or solution? How should the component, application, or solution flow based on the design? What is the maximum execution time for every component, application, or solution? What environments can this component, application, or solution? What data dependencies does this component, application, or solution have? What kind of data does this component, application, or solution require? Ok, now I know what ARID is, how can I apply? Let’s imagine that your organization is going to purchase an off-the-shelf (OTS) solution for its customer-relationship management software. What process would we use to ensure that the correct purchase is made? If we use ARID, then we will have a series of 9 steps broken up by 2 phases in order to ensure that the correct OTS solution is purchases. Phase 1 Identify the Reviewers Prepare the Design Briefing Prepare the Seed Scenarios Prepare the Materials When identifying reviewers for a design it is preferred that they be pulled from a candidate pool comprised of developers that are going to implement the design. The believe is that developers actually implementing the design will have more a vested interest in ensuring that the design is correct prior to the start of code. Design debriefing consist of a summary of the design, examples of the design solving real world examples put in to use and should be no longer than two hours typically. The primary goal of this briefing is to adequately summarize the design so that the review members could actually implement the design. In the example of purchasing an OTS product I would attempt to review my briefing prior to its distribution with the review facilitator to ensure that nothing was excluded that should have not been. This practice will also allow me to test the length of the briefing to ensure that can be delivered in an appropriate about of time. Seed Scenarios are designed to illustrate conceptualized scenarios when applied with a set of sample data. These scenarios can then be used by the reviewers in the actual evaluation of the software, All materials needed for the evaluation should be prepared ahead of time so that they can be reviewed prior to and during the meeting. Materials Included: Presentation Seed Scenarios Review Agenda Phase 2 Present ARID Present Design Brainstorm and prioritize scenarios Apply scenarios Summarize Prior to the start of any ARID review meeting the Facilitator should define the remaining steps of ARID so that all the participants know exactly what they are doing prior to the start of the review process. Once the ARID rules have been laid out, then the lead designer presents an overview of the design which typically takes about two hours. During this time no questions about the design or rational are allowed to be asked by the review panel as a standard, but they are written down for use latter in the process. After the presentation the list of compiled questions is then summarized and sent back to the lead designer as areas that need to be addressed further. In the example of purchasing an OTS product issues could arise regarding security, the implementation needed or even if this is this the correct product to solve the needed solution. After the Design presentation a brainstorming and prioritize scenarios process begins by reducing the seed scenarios down to just the highest priority scenarios.  These will then be used to test the design for suitability. Once the selected scenarios have been defined the reviewers apply the examples provided in the presentation to the scenarios. The intended output of this process is to provide code or pseudo code that makes use of the examples provided while solving the selected seed scenarios. As a standard rule, the designers of the systems are not allowed to help the review board unless they all become stuck. When this occurs it is documented and along with the reason why the designer needed to help the review panel back on track. Once all of the scenarios have been completed the review facilitator reviews with the group issues that arise during the process. Then the reviewers will be polled as to efficacy of the review experience. References: Clements, Paul., Kazman, Rick., Klien, Mark. (2002). Evaluating Software Architectures: Methods and Case Studies Indianapolis, IN: Addison-Wesley

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• Easy Made Easier

  - by dragonfly

      How easy is it to deploy a 2 node, fully redundant Oracle RAC cluster? Not very. Unless you use an Oracle Database Appliance. The focus of this member of Oracle's Engineered Systems family is to simplify the configuration, management and maintenance throughout the life of the system, while offering pay-as-you-grow scaling. Getting a 2-node RAC cluster up and running in under 2 hours has been made possible by the Oracle Database Appliance. Don't take my word for it, just check out these blog posts from partners and end users. The Oracle Database Appliance Experience - Zip Zoom Zoom http://www.fuadarshad.com/2012/02/oracle-database-appliance-experience.html Off-the-shelf Oracle database servers http://normanweaver.wordpress.com/2011/10/10/off-the-shelf-oracle-database-servers/ Oracle Database Appliance – Deployment Steps http://marcel.vandewaters.nl/oracle/database-appliance/oracle-database-appliance-deployment-steps     See how easy it is to deploy an Oracle Database Appliance for high availability with RAC? Now for the meat of this post, which is the first in a series of posts describing tips for making the deployment of an ODA even easier. The key to the easy deployment of an Oracle Database Appliance is the Appliance Manager software, which does the actual software deployment and configuration, based on best practices. But in order for it to do that, it needs some basic information first, including system name, IP addresses, etc. That's where the Appliance Manager GUI comes in to play, taking a wizard approach to specifying the information needed.     Using the Appliance Manager GUI is pretty straight forward, stepping through several screens of information to enter data in typical wizard style. Like most configuration tasks, it helps to gather the required information before hand. But before you rush out to a committee meeting on what to use for host names, and rely on whatever IP addresses might be hanging around, make sure you are familiar with some of the auto-fill defaults for the Appliance Manager. I'll step through the key screens below to highlight the results of the auto-fill capability of the Appliance Manager GUI.     Depending on which of the 2 Configuration Types (Config Type screen) you choose, you will get a slightly different set of screens. The Typical configuration assumes certain default configuration choices and has the fewest screens, where as the Custom configuration gives you the most flexibility in what you configure from the start. In the examples below, I have used the Custom config type.     One of the first items you are asked for is the System Name (System Info screen). This is used to identify the system, but also as the base for the default hostnames on following screens. In this screen shot, the System Name is "oda".     When you get to the next screen (Generic Network screen), you enter your domain name, DNS IP address(es), and NTP IP address(es). Next up is the Public Network screen, seen below, where you will see the host name fields are automatically filled in with default host names based on the System Name, in this case "oda". The System Name is also the basis for default host names for the extra ethernet ports available for configuration as part of a Custom configuration, as seen in the 2nd screen shot below (Other Network). There is no requirement to use these host names, as you can easily edit any of the host names. This does make filling in the configuration details easier and less prone to "fat fingers" if you are OK with these host names. Here is a full list of the automatically filled in host names. 1 2 1-vip 2-vip -scan 1-ilom 2-ilom 1-net1 2-net1 1-net2 2-net2 1-net3 2-net3     Another auto-fill feature of the Appliance Manager GUI follows a common practice of deploying IP Addresses for a RAC cluster in sequential order. In the screen shot below, I entered the first IP address (Node1-IP), then hit Tab to move to the next field. As a result, the next 5 IP address fields were automatically filled in with the next 5 IP addresses sequentially from the first one I entered. As with the host names, these are not required, and can be changed to whatever your IP address values are. One note of caution though, if the first IP Address field (Node1-IP) is filled out and you click in that field and back out, the following 5 IP addresses will be set to the sequential default. If you don't use the sequential IP addresses, pay attention to where you click that mouse. :-)     In the screen shot below, by entering the netmask value in the Netmask field, in this case 255.255.255.0, the gateway value was auto-filled into the Gateway field, based on the IP addresses and netmask previously entered. As always, you can change this value.     My last 2 screen shots illustrate that the same sequential IP address autofill and netmask to gateway autofill works when entering the IP configuration details for the Integrated Lights Out Manager (ILOM) for both nodes. The time these auto-fill capabilities save in entering data is nice, but from my perspective not as important as the opportunity to avoid data entry errors. In my next post in this series, I will touch on the benefit of using the network validation capability of the Appliance Manager GUI prior to deploying an Oracle Database Appliance.

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• 5 Android Keyboard Replacements to Help You Type Faster

  - by Chris Hoffman

  Android allows developers to replace its keyboard with their own keyboard apps. This has led to experimentation and great new features, like the gesture-typing feature that’s made its way into Android’s official keyboard after proving itself in third-party keyboards. This sort of customization isn’t possible on Apple’s iOS or even Microsoft’s modern Windows environments. Installing a third-party keyboard is easy — install it from Google Play, launch it like another app, and it will explain how to enable it. Google Keyboard Google Keyboard is Android’s official keyboard, as seen on Google’s Nexus devices. However, there’s a good chance your Android smartphone or tablet comes with a keyboard designed by its manufacturer instead. You can install the Google Keyboard from Google Play, even if your device doesn’t come with it. This keyboard offers a wide variety of features, including a built-in gesture-typing feature, as popularized by Swype. It also offers prediction, including full next-word prediction based on your previous word, and includes voice recognition that works offline on modern versions of Android. Google’s keyboard may not offer the most accurate swiping feature or the best autocorrection, but it’s a great keyboard that feels like it belongs in Android. SwiftKey SwiftKey costs $4, although you can try it free for one month. In spite of its price, many people who rarely buy apps have been sold on SwiftKey. It offers amazing auto-correction and word-prediction features. Just mash away on your touch-screen keyboard, typing as fast as possible, and SwiftKey will notice your mistakes and type what you actually meant to type. SwiftKey also now has built-in support for gesture-typing via SwiftKey Flow, so you get a lot of flexibility. At $4, SwiftKey may seem a bit pricey, but give the month-long trial a try. A great keyboard makes all the typing you do everywhere on your phone better. SwiftKey is an amazing keyboard if you tap-to-type rather than swipe-to-type. Swype While other keyboards have copied Swype’s swipe-to-type feature, none have completely matched its accuracy. Swype has been designing a gesture-typing keyboard for longer than anyone else and its gesture feature still seems more accurate than its competitors’ gesture support. If you use gesture-typing all the time, you’ll probably want to use Swype. Swype can now be installed directly from Google Play without the old, tedious process of registering a beta account and sideloading the Swype app. Swype offers a month-long free trial and the full version is available for $1 afterwards. Minuum Minuum is a crowdfunded keyboard that is currently still in beta and only supports English. We include it here because it’s so interesting — it’s a great example of the kind of creativity and experimentation that happens when you allow developers to experiment with their own forms of keyboard. Minuum uses a tiny, minimum keyboard that frees up your screen space, so your touch-screen keyboard doesn’t hog your device’s screen. Rather than displaying a full keyboard on your screen, Minuum displays a single row of letters.  Each letter is small and may be difficult to hit, but that doesn’t matter — Minuum’s smart autocorrection algorithms interpret what you intended to type rather than typing the exact letters you press. Just swipe to the right to type a space and accept Minuum’s suggestion. At $4 for a beta version with no trial, Minuum may seem a bit pricy. But it’s a great example of the flexibility Android allows. If there’s a problem with this keyboard, it’s that it’s a bit late — in an age of 5″ smartphones with 1080p screens, full-size keyboards no longer feel as cramped. MessagEase MessagEase is another example of a new take on text input. Thankfully, this keyboard is available for free. MessagEase presents all letters in a nine-button grid. To type a common letter, you’d tap the button. To type an uncommon letter, you’d tap the button, hold down, and swipe in the appropriate direction. This gives you large buttons that can work well as touch targets, especially when typing with one hand. Like any other unique twist on a traditional keyboard, you’d have to give it a few minutes to get used to where the letters are and the new way it works. After giving it some practice, you may find this is a faster way to type on a touch-screen — especially with one hand, as the targets are so large. Google Play is full of replacement keyboards for Android phones and tablets. Keyboards are just another type of app that you can swap in. Leave a comment if you’ve found another great keyboard that you prefer using. Image Credit: Cheon Fong Liew on Flickr     

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• Career guidance/advice for Junior-level Software Engineer [closed]

  - by John Do

  I have quite a few questions on my mind, so please bare with me. Please don't feel obligated to answer all of them, any as you choose will do. I'd appreciate if you could share some insight on any of these. Before I begin, some context: I currently have almost two years of professional experience as a Software Engineer, mainly developing software in Java. At this point, I feel that I have reached the peak in my career growth at the current company I am at and therefore I am looking for a new job, ideally again, as a Software Engineer. I have been interviewing for the past few months casually but have not had luck with companies I have a passion for. So, in no particular order - 1) In general, what are your thoughts on having graduate degrees in CS / Software Engineering. How much does it influence a salary increase, and do you think it's beneficial when working on real-world problems? I get the sense that a graduate degree in the field is trivial unless you really have a passion for research. 2) In general, in professional practice, how often had you have to write your own data structures and "complex" algorithms from scratch? In my own work, I have found myself relying mainly on third-party frameworks and the Java standard library to implement solutions as per business requirements. What are your thoughts on this? 3) In terms of resume, I feel the most ambivalent here. I want to be able to "blemish" my resume to a certain extent so that it stands out from others', but at the same time I do not want to over-exagerate my abilities. How do you strike a balance here? For example: I say that I am proficient in Java with data structures and algorithms. This is obviously a subjective and relative statement. I've taken the classes in my undergrad, and I've applied it in my work experience. What I feel as "prociency" can be seen as junior-level to others. How do you know what to say? Most of the time, recruiters (with no technical background) will be looking for keywords that stand out. This leads me to my next question (4). 4) Just from interviewing for the past few months (and getting plenty of rejections), I've come to realize that I may not be as proficient in data structures and algorithms as I thought I was. Do you think it's a good idea to remove the "proficient in java/data structure and algorithms"? I feel that being too hoenst on the resume will impede me from scoring opportunities to even have an interview with top-notch companies. What are your thoughts? 5) What is the absolute "must-have" knowledge going into a technical interview? I've been practicing several algorithmic and data sturcture problems now, and I feel that my abilities to solve arbitrary problems efficiently has not gotten significantly better. Do you think these abilities are something innate - it's either you have in you, or you don't? How can you teach yourself to learn, if you will? 6) How easy is it to go from industry/function to the next? I work mainly with backend technologies and I'm now interested in working with the frontend, i.e javascript,jquery,php or even mobile development. In your own experience, how did you not get pidgeon holed in your career? I feel that the choices you make now ultimately decide your future. As cliche as it sounds, I think it may be true. Here's what I mean: you've worked mainly as a backend engineer, people are interested in you doing the same thing since you've already accumulated experience in that function. How do get experience in a new function if people won't accept you because you don't already have it? It's a catch 22, you see... Are side projects the only real way to help you move from one function to another that you're truly interested in? For example: I could start writing my own mobile applications, even though I've worked mainly on the backend. Thanks so much for the long read. As a relatively new engineer to the real world, I am very humble and would like those who are experienced to shed some light. Thank you so much.

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• Session Report - Modern Software Development Anti-Patterns

  - by Janice J. Heiss

  In this standing-room-only session, building upon his 2011 JavaOne Rock Star “Diabolical Developer” session, Martijn Verburg, this time along with Ben Evans, identified and explored common “anti-patterns” – ways of doing things that keep developers from doing their best work. They emphasized the importance of social interaction and team communication, along with identifying certain psychological pitfalls that lead developers astray. Their emphasis was less on technical coding errors and more how to function well and to keep one’s focus on what really matters. They are the authors of the highly regarded The Well-Grounded Java Developer and are both movers and shakers in the London JUG community and on the Java Community Process. The large room was packed as they gave a fast-moving, witty presentation with lots of laughs and personal anecdotes. Below are a few of the anti-patterns they discussed.Anti-Pattern One: Conference-Driven DeliveryThe theme here is the belief that “Real pros hack code and write their slides minutes before their talks.” Their response to this anti-pattern is an expression popular in the military – PPPPPP, which stands for, “Proper preparation prevents piss-poor performance.”“Communication is very important – probably more important than the code you write,” claimed Verburg. “The more you speak in front of large groups of people the easier it gets, but it’s always important to do dry runs, to present to smaller groups. And important to be members of user groups where you can give presentations. It’s a great place to practice speaking skills; to gain new skills; get new contacts, to network.”They encouraged attendees to record themselves and listen to themselves giving a presentation. They advised them to start with a spouse or friends if need be. Learning to communicate to a group, they argued, is essential to being a successful developer. The emphasis here is that software development is a team activity and good, clear, accessible communication is essential to the functioning of software teams. Anti-Pattern Two: Mortgage-Driven Development The main theme here was that, in a period of worldwide recession and economic stagnation, people are concerned about keeping their jobs. So there is a tendency for developers to treat knowledge as power and not share what they know about their systems with their colleagues, so when it comes time to fix a problem in production, they will be the only one who knows how to fix it – and will have made themselves an indispensable cog in a machine so you cannot be fired. So developers avoid documentation at all costs, or if documentation is required, put it on a USB chip and lock it in a lock box. As in the first anti-pattern, the idea here is that communicating well with your colleagues is essential and documentation is a key part of this. Social interactions are essential. Both Verburg and Evans insisted that increasingly, year by year, successful software development is more about communication than the technical aspects of the craft. Developers who understand this are the ones who will have the most success. Anti-Pattern Three: Distracted by Shiny – Always Use the Latest Technology to Stay AheadThe temptation here is to pick out some obscure framework, try a bit of Scala, HTML5, and Clojure, and always use the latest technology and upgrade to the latest point release of everything. Don’t worry if something works poorly because you are ahead of the curve. Verburg and Evans insisted that there need to be sound reasons for everything a developer does. Developers should not bring in something simply because for some reason they just feel like it or because it’s new. They recommended a site run by a developer named Matt Raible with excellent comparison spread sheets regarding Web frameworks and other apps. They praised it as a useful tool to help developers in their decision-making processes. They pointed out that good developers sometimes make bad choices out of boredom, to add shiny things to their CV, out of frustration with existing processes, or just from a lack of understanding. They pointed out that some code may stay in a business system for 15 or 20 years, but not all code is created equal and some may change after 3 or 6 months. Developers need to know where the code they are contributing fits in. What is its likely lifespan? Anti-Pattern Four: Design-Driven Design The anti-pattern: If you want to impress your colleagues and bosses, use design patents left, right, and center – MVC, Session Facades, SOA, etc. Or the UML modeling suite from IBM, back in the day… Generate super fast code. And the more jargon you can talk when in the vicinity of the manager the better.Verburg shared a true story about a time when he was interviewing a guy for a job and asked him what his previous work was. The interviewee said that he essentially took patterns and uses an approved book of Enterprise Architecture Patterns and applied them. Verburg was dumbstruck that someone could have a job in which they took patterns from a book and applied them. He pointed out that the idea that design is a separate activity is simply wrong. He repeated a saying that he uses, “You should pay your junior developers for the lines of code they write and the things they add; you should pay your senior developers for what they take away.”He explained that by encouraging people to take things away, the code base gets simpler and reflects the actual business use cases developers are trying to solve, as opposed to the framework that is being imposed. He told another true story about a project to decommission a very long system. 98% of the code was decommissioned and people got a nice bonus. But the 2% remained on the mainframe so the 98% reduction in code resulted in zero reduction in costs, because the entire mainframe was needed to run the 2% that was left. There is an incentive to get rid of source code and subsystems when they are no longer needed. The session continued with several more anti-patterns that were equally insightful.

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• Code refactoring with Visual Studio 2010 Part-4

  - by Jalpesh P. Vadgama

  I have been writing few post with code refactoring features in Visual Studio 2010. This post also will be part of series and this post will be last of the series. In this post I am going explain two features 1) Encapsulate Field and 2) Extract Interface. Let’s explore both features in details. Encapsulate Field: This is a nice code refactoring feature provides by Visual Studio 2010. With help of this feature we can create properties from the existing private field of the class. Let’s take a simple example of Customer Class. In that I there are two private field called firstName and lastName. Below is the code for the class. public class Customer { private string firstName; private string lastName; public string Address { get; set; } public string City { get; set; } } Now lets encapsulate first field firstName with Encapsulate feature. So first select that field and goto refactor menu in Visual Studio 2010 and click on Encapsulate Field. Once you click that a dialog box will appear like following. Now once you click OK a preview dialog box will open as we have selected preview reference changes. I think its a good options to check that option to preview code that is being changed by IDE itself. Dialog will look like following. Once you click apply it create a new property called FirstName. Same way I have done for the lastName and now my customer class code look like following. public class Customer { private string firstName; public string FirstName { get { return firstName; } set { firstName = value; } } private string lastName; public string LastName { get { return lastName; } set { lastName = value; } } public string Address { get; set; } public string City { get; set; } } So you can see that its very easy to create properties with existing fields and you don’t have to change anything there in code it will change all the stuff itself. Extract Interface: When you are writing software prototype and You don’t know the future implementation of that then its a good practice to use interface there. I am going to explain here that How we can extract interface from the existing code without writing a single line of code with the help of code refactoring feature of Visual Studio 2010. For that I have create a Simple Repository class called CustomerRepository with three methods like following. public class CustomerRespository { public void Add() { // Some code to add customer } public void Update() { //some code to update customer } public void Delete() { //some code delete customer } } In above class there are three method Add,Update and Delete where we are going to implement some code for each one. Now I want to create a interface which I can use for my other entities in project. So let’s create a interface from the above class with the help of Visual Studio 2010. So first select class and goto refactor menu and click Extract Interface. It will open up dialog box like following. Here I have selected all the method for interface and Once I click OK then it will create a new file called ICustomerRespository where it has created a interface. Just like following. Here is a code for that interface. using System; namespace CodeRefractoring { interface ICustomerRespository { void Add(); void Delete(); void Update(); } } Now let's see the code for the our class. It will also changed like following to implement the interface. public class CustomerRespository : ICustomerRespository { public void Add() { // Some code to add customer } public void Update() { //some code to update customer } public void Delete() { //some code delete customer } } Isn't that great we have created a interface and implemented it without writing a single line of code. Hope you liked it. Stay tuned for more.. Till that Happy Programming.

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• Keep a programming language backwards compatible vs. fixing its flaws

  - by Radu Murzea

  First, some context (stuff that most of you know anyway): Every popular programming language has a clear evolution, most of the time marked by its version: you have Java 5, 6, 7 etc., PHP 5.1, 5.2, 5.3 etc. Releasing a new version makes new APIs available, fixes bugs, adds new features, new frameworks etc. So all in all: it's good. But what about the language's (or platform's) problems? If and when there's something wrong in a language, developers either avoid it (if they can) or they learn to live with it. Now, the developers of those languages get a lot of feedback from the programmers that use them. So it kind of makes sense that, as time (and version numbers) goes by, the problems in those languages will slowly but surely go away. Well, not really. Why? Backwards compatibility, that's why. But why is this so? Read below for a more concrete situation. The best way I can explain my question is to use PHP as an example: PHP is loved thousands of people and hated by just as many thousands. All languages have flaws, but apparently PHP is special. Check out this blog post. It has a very long list of so called flaws in PHP. Now, I'm not a PHP developer (not yet), but I read through all of it and I'm sure that a big chunk of that list are indeed real issues. (Not all of it, since it's potentially subjective). Now, if I was one of the guys who actively develops PHP, I would surely want to fix those problems, one by one. However, if I do that, then code that relies on a particular behaviour of the language will break if it runs on the new version. Summing it up in 2 words: backwards compatibility. What I don't understand is: why should I keep PHP backwards compatible? If I release PHP version 8 with all those problems fixed, can't I just put a big warning on it saying: "Don't run old code on this version !"? There is a thing called deprecation. We had it for years and it works. In the context of PHP: look at how these days people actively discourage the use of the mysql_* functions (and instead recommend mysqli_* and PDO). Deprecation works. We can use it. We should use it. If it works for functions, why shouldn't it work for entire languages? Let's say I (the developer of PHP) do this: Launch a new version of PHP (let's say 8) with all of those flaws fixed New projects will start using that version, since it's much better, clearer, more secure etc. However, in order not to abandon older versions of PHP, I keep releasing updates to it, fixing security issues, bugs etc. This makes sense for reasons that I'm not listing here. It's common practice: look for example at how Oracle kept updating version 5.1.x of MySQL, even though it mostly focused on version 5.5.x. After about 3 or 4 years, I stop updating old versions of PHP and leave them to die. This is fine, since in those 3 or 4 years, most projects will have switched to PHP 8 anyway. My question is: Do all these steps make sense? Would it be so hard to do? If it can be done, then why isn't it done? Yes, the downside is that you break backwards compatibility. But isn't that a price worth paying ? As an upside, in 3 or 4 years you'll have a language that has 90 % of its problems fixed.... a language much more pleasant to work with. Its name will ensure its popularity. EDIT: OK, so I didn't expressed myself correctly when I said that in 3 or 4 years people will move to the hypothetical PHP 8. What I meant was: in 3 or 4 years, people will use PHP 8 if they start a new project.

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• My error with upgrading 4.0 to 4.2- What NOT to do...

  - by Steve Tunstall

  Last week, I was helping a client upgrade from the 2011.1.4.0 code to the newest 2011.1.4.2 code. We downloaded the 4.2 update from MOS, upload and unpacked it on both controllers, and upgraded one of the controllers in the cluster with no issues at all. As this was a brand-new system with no networking or pools made on it yet, there were not any resources to fail back and forth between the controllers. Each controller had it's own, private, management interface (igb0 and igb1) and that's it. So we took controller 1 as the passive controller and upgraded it first. The first controller came back up with no issues and was now on the 4.2 code. Great. We then did a takeover on controller 1, making it the active head (although there were no resources for it to take), and then proceeded to upgrade controller 2. Upon upgrading the second controller, we ran the health check with no issues. We then ran the update and it ran and rebooted normally. However, something strange then happened. It took longer than normal to come back up, and when it did, we got the "cluster controllers on different code" error message that one gets when the two controllers of a cluster are running different code. But we just upgraded the second controller to 4.2, so they should have been the same, right??? Going into the Maintenance-->System screen of controller 2, we saw something very strange. The "current version" was still on 4.0, and the 4.2 code was there but was in the "previous" state with the rollback icon, as if it was the OLDER code and not the newer code. I have never seen this happen before. I would have thought it was a bad 4.2 code file, but it worked just fine with controller 1, so I don't think that was it. Other than the fact the code did not update, there was nothing else going on with this system. It had no yellow lights, no errors in the Problems section, and no errors in any of the logs. It was just out of the box a few hours ago, and didn't even have a storage pool yet. So.... We deleted the 4.2 code, uploaded it from scratch, ran the health check, and ran the upgrade again. once again, it seemed to go great, rebooted, and came back up to the same issue, where it came to 4.0 instead of 4.2. See the picture below.... HERE IS WHERE I MADE A BIG MISTAKE.... I SHOULD have instantly called support and opened a Sev 2 ticket. They could have done a shared shell and gotten the correct Fishwork engineer to look at the files and the code and determine what file was messed up and fixed it. The system was up and working just fine, it was just on an older code version, not really a huge problem at all. Instead, I went ahead and clicked the "Rollback" icon, thinking that the system would rollback to the 4.2 code.   Ouch... What happened was that the system said, "Fine, I will delete the 4.0 code and boot to your 4.2 code"... Which was stupid on my part because something was wrong with the 4.2 code file here and the 4.0 was just fine.  So now the system could not boot at all, and the 4.0 code was completely missing from the system, and even a high-level Fishworks engineer could not help us. I had messed it up good. We could only get to the ILOM, and I had to re-image the system from scratch using a hard-to-get-and-use FishStick USB drive. These are tightly controlled and difficult to get, almost always handcuffed to an engineer who will drive out to re-image a system. This took another day of my client's time.  So.... If you see a "previous version" of your system code which is actually a version higher than the current version... DO NOT ROLL IT BACK.... It did not upgrade for a very good reason. In my case, after the system was re-imaged to a code level just 3 back, we once again tried the same 4.2 code update and it worked perfectly the first time and is now great and stable.  Lesson learned.  By the way, our buddy Ryan Matthews wanted to point out the best practice and supported way of performing an upgrade of an active/active ZFSSA, where both controllers are doing some of the work. These steps would not have helpped me for the above issue, but it's important to follow the correct proceedure when doing an upgrade. 1) Upload software to both controllers and wait for it to unpack 2) On controller "A" navigate to configuration/cluster and click "takeover" 3) Wait for controller "B" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 4) Wait for controller "B" to apply the update and finish rebooting 5) Login to controller "B", navigate to configuration/cluster and click "takeover" 6) Wait for controller "A" to finish restarting, then login to it, navigate to maintenance/system, and roll forward to the new software. 7) Wait for controller "A" to apply the update and finish rebooting 8) Login to controller "B", navigate to configuration/cluster and click "failback"

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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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• Business Case for investing time developing Stubs and BizUnit Tests

  - by charlie.mott

  I was recently in a position where I had to justify why effort should be spent developing Stubbed Integration Tests for BizTalk solutions. These tests are usually developed using the BizUnit framework. I assumed that most seasoned BizTalk developers would consider this best practice. Even though Microsoft suggest use of BizUnit on MSDN, I've not found a single site listing the justifications for investing time writing stubs and BizUnit tests. Stubs Stubs should be developed to isolate your development team from external dependencies. This is described by Michael Stephenson here. Failing to do this can result in the following problems: In contract-first scenarios, the external system interface will have been defined.  But the interface may not have been setup or even developed yet for the BizTalk developers to work with. By the time you open the target location to see the data BizTalk has sent, it may have been swept away. If you are relying on the UI of the target system to see the data BizTalk has sent, what do you do if it fails to arrive? It may take time for the data to be processed or it may be scheduled to be processed later. Learning how to use the source\target systems and investigations into where things go wrong in these systems will slow down the BizTalk development effort. By the time the data is visible in a UI it may have undergone further transformations. In larger development teams working together, do you all use the same source and target instances. How do you know which data was created by whose tests? How do you know which event log error message are whose?  Another developer may have “cleaned up” your data. It is harder to write BizUnit tests that clean up the data\logs after each test run. What if your B2B partners' source or target system cannot support the sort of testing you want to do. They may not even have a development or test instance that you can work with. Their single test instance may be used by the SIT\UAT teams. There may be licencing costs of setting up an instances of the external system. The stubs I like to use are generic stubs that can accept\return any message type.  Usually I need to create one per protocol. They should be driven by BizUnit steps to: validates the data received; and select a response messages (or error response). Once built, they can be re-used for many integration tests and from project to project. I’m not saying that developers should never test against a real instance.  Every so often, you still need to connect to real developer or test instances of the source and target endpoints\services. The interface developers may ask you to send them some data to see if everything still works.  Or you might want some messages sent to BizTalk to get confidence that everything still works beyond BizTalk. Tests Automated “Stubbed Integration Tests” are usually built using the BizUnit framework. These facilitate testing of the entire integration process from source stub to target stub. It will ensure that all of the BizTalk components are configured together correctly to meet all the requirements. More fine grained unit testing of individual BizTalk components is still encouraged.  But BizUnit provides much the easiest way to test some components types (e.g. Orchestrations). Using BizUnit with the Behaviour Driven Development approach described by Mike Stephenson delivers the following benefits: source: http://biztalkbddsample.codeplex.com – Video 1. Requirements can be easily defined using Given/When/Then Requirements are close to the code so easier to manage as features and scenarios Requirements are defined in domain language The feature files can be used as part of the documentation The documentation is accurate to the build of code and can be published with a release The scenarios are effective to document the scenarios and are not over excessive The scenarios are maintained with the code There’s an abstraction between the intention and implementation of tests making them easier to understand The requirements drive the testing These same tests can also be used to drive load testing as described here. If you don't do this ... If you don't follow the above “Stubbed Integration Tests” approach, the developer will need to manually trigger the tests. This has the following risks: Developers are unlikely to check all the scenarios each time and all the expected conditions each time. After the developer leaves, these manual test steps may be lost. What test scenarios are there?  What test messages did they use for each scenario? There is no mechanism to prove adequate test coverage. A test team may attempt to automate integration test scenarios in a test environment through the triggering of tests from a source system UI. If this is a replacement for BizUnit tests, then this carries the following risks: It moves the tests downstream, so problems will be found later in the process. Testers may not check all the expected conditions within the BizTalk infrastructure such as: event logs, suspended messages, etc. These automated tests may also get in the way of manual tests run on these environments.

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• Rules for Naming

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Naming Documents (or is it “Document, Naming”?) Tis but thy name that is my enemy; Thou art thyself, though not a Montague. What's Montague? It is nor hand, nor foot, Nor arm, nor face, nor any other part Belonging to a man. O, be some other name! What's in a name? That which we call a rose By any other name would smell as sweet; So Romeo would, were he not Romeo call'd, Retain that dear perfection which he owes Without that title. Romeo, doff thy name And for that name which is no part of thee Take all myself.  Shakespeare – Romeo and Juliet Act II, Scene 2 We normally only use the bold portion of the famous Shakespearean quote above, but it is really out of context. As the play unfolds, we learn that a name is all too powerful. Indeed it is because of their names that the doomed lovers die. There might be life and death in a name (BTW, when I wrote this monogram, I was in Hatfield, PA. Remember the Hatfields and the McCoys?) This is a bit extreme, but in the field of Knowledge Management (KM) names are of the utmost importance as well. When I write an article about managing SharePoint sites, how should I name it? “Managing a site” or “Site, managing”? Nine times out of ten I’d opt for the latter. Almost everything we do is “Managing” so to make life easier for a person looking for meaningful content, we title our articles starting with the differentiator rather than the common factor. As a rule of thumb, we start the name with the noun rather than the verb. It is not what we do that is the primary key; it is what we do it to. So, answer this – is it a “rule of thumb” or a “thumb rule?” This is tough. A lot of what we do when naming is a judgment call. Both thumb and rule are nouns, albeit concrete and abstract (more about this later), but to most people “thumb rule” is meaningless while “rule of thumb” is an idiom. The difference between knowledge and information is that knowledge is meaningful information placed in context. Thus I elect the “rule of thumb”. It is the more meaningful title. Abstract and Concrete are relative terms. Many nouns (and verbs) that are abstract to a commoner, are concrete to a practitioner of one profession or another and may even have different concrete meanings in different professional jargons. Think about “running”. To an executive it means running a business, to a marathoner its meaning is much more literal. Generally speaking, we store and disseminate knowledge within a practice more than we do it in general. Even dictionaries encyclopedias define terms as they apply to different audiences. The rule of thumb is to put the more concrete first, but within the audience’s jargon. Even the title of this monogram is a question. Do I name it “Naming Documents” or “Documents, Naming”? Well, my own rule of thumb (“Here he goes again!?”) states that the latter is better because it starts with a noun, but this is a document about naming more than it about documents. The rules of naming also apply to graphs and charts, excel spreadsheets, and so on. Thus, I vote for the former.  A better title could have been “Naming Objects” only the word “Object” is a bit too abstract. How about just “Naming” or “Naming, rules of”? You get the drift. One of the ways to resolve all of this is to store the documents in Knowledge-Bases, which may become the subjects of a future punditry. Knowledge bases use keywords to describe their content.  Use a Metadata store for the keywords to at least attempt some common grounds. Here is another general rule (rule of thumb?!!) – put at least the one keyword in the title. Use subtitles. Here is an example: Migrating documents – Screening, cleaning, and organizing our knowledge. The main keyword is “documents”, next is “migrating”, other keywords also appear in the subtitle. They are “screening”, “cleaning”, and “organizing”. Any questions? Send me an amply named document by email: [email protected]

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• ADF Business Components

  - by Arda Eralp

  ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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• CS, SE, HCI, Information Science, Please recommendation for further education of the former performing art manager seeking career in IT industries? [on hold]

  - by Baek Seungjoo

  IT specialists there J Thank you very much for your collective efforts here, and I got huge help reading your professional comments and advices on each questions I have searched so far! This time, I would like to ask for your practical advices or recommendation on what I am struggling on at this moment. I am currently seeking higher education for my career transition from performing art manager and director to “IT software and/or service development and management specialist”. However, as this field is quite new to me, and there are lots of different work positions, I have no idea which grad major I better pursue in order to get qualification. Of course I know this question could sounds wired as it is kind of personal choice. But my lack of understanding on how IT software companies work in general, your practical and experience-based advice will be great help to me, who spent more than two months of self-research on net. OK. Before my question, here is my plan and history, which are quite different from those currently in IT industry I think… 1) Target Firstly, get career transition into IT service or products companies and get experiences. Eventually, pursue IT entrepreneurship in combination with my arts and cultural production and business expertise. 2) Background Career: performing arts director and manager in theatre-based scale opera and musical Art education in youth BA in literature and Chinese studies (Art & Humanities) MA in Cultural & Creative Industries (Art & Humanities) – dissertation with focus on digital prosumption and the lived experience of the prosumer. (a qualitative research on the agents in the digital world) 2) Personally Huge interest in IT hardware and software, and their trend. Skills to build up, repair, tune PCs -of course this is no more than personal hobby, but shows my interests in this field. 4) Problem Encounter a question “So, what do you think you can contribute practically in this position”. This question turn me down everytime I go through job interviews, and I decided more education in the relevant area. Here are my questions. 1) In terms of work positions in IT software companies, I wonder if I can put the comparison of what “Artists” is to “Arts Manager or Director” is what “Developer” is to “Product Manager”. (Of course, this stereotypical division of Artist-Art Manager is out of sense because the domain overlaps to some extent, and is blurring at least in my field, and they are in different contexts, but just speaking easily.) Normally, artist comes with special arts educations, and they live in their own world of artistic inspiration and creation, and they feel alive in practice and on stages. Meanwhile, from the point of staging and managing productions, the role of art manager is critical as well. Our role cares how the production appeals to the audience in effective way, how to make profit and future sustainable management through that, how to set up future strategy in consideration of the external conditions such as political and social circumstances, audience trend and level, other production trends from on-going and historical perspectives, how and what the production make voice to the society from political, economic, humanitarian stances. So, we need keen eyes on economic, political, and societal environment, have to understand human-being and their desires, must know how to make presentation and attract investors, must have sense in managing and fighting over the limited financial resource, how to extend networking and so on. It is common that the two agents create productions in collaboration (normally not in that ideal way but in conflict and fight though J ). So, we need to know each other’s expertise to some extent, for better production. What are the work positions in IT software industries equivalent to the role of “art manager” in performing arts? From my view, considering developers come with special education in the world of computer science, software engineering, or others (self-education sometimes), and they express themselves with the arts of coding, computer languages on the black screen, and make sort of their artistic production online to the audience, I guess there might be someone who collaborate with developers in creating, managing, and launching IT services or products. 2) Which education among CS, SE, HCI, Information Science, is needed for those seeking such work position? Especially for person like me. (At this moment, Information Science has the highest possibility to get in, since I lack Calculus and Math in undergrad educaiton. But please let me know irrespective of this concern, I think there are ways to back it up if CS or SE education needed in my case) 3) Which field between Information Science and HCI can be more practical background regarding job hungting? And which of them have more demands in job market? AS I checked, HCI is more close to CS than IS in its focus of study area. Thank you very much for your patience reading such a long inquiry, and I appreciate to your efforts in advance. Have a nice day in this beautiful summer.

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• World Backup Day

  - by red(at)work

  Here at Red Gate Towers, the SQL Backup development team have been hunkered down in their shed for the last few months, with the toolbox, blowtorch and chamois leather out, upgrading SQL Backup. When we started, autumn leaves were falling. Now we're about to finish, spring flowers are budding. If not quite a gleaming new machine, at the very least a familiar, reliable engine with some shiny new bits on it will trundle magnificently out of the workshop. One of the interesting things I've noticed about working on software development teams is that the team is together for so long 'implementing' stuff - designing, coding, testing, fixing bugs and so on - that you occasionally forget why you're doing what you're doing. Doubt creeps in. It feels like a long time since we launched this project in a fanfare of optimism and enthusiasm, and all that clarity of purpose and mission "yee-haw" has dissipated with the daily pressures of development. Every now and again, we look up from our bunker and notice all those thousands of users out there, with their different configurations and working practices and each with their own set of problems and requirements, and we ask ourselves "does anyone care about what we're doing?" Has the world moved on while we've been busy? Could we have been doing something more useful with the time and talent of all these excellent people we've assembled? In truth, you can research and test and validate all you like, but you never really know if you've done the right thing (or at least, something valuable for some users) until you release. All projects suffer this insecurity. If they don't, maybe you're not worrying enough about what you're building. The two enemies of software development are certainty and complacency. Oh, and of course, rival teams with Nerf guns. The goal of SQL Backup 7 is to make it so easy to schedule regular restores of your backups that you have no excuse not to. Why schedule a restore? Because your data is not as good as your last backup. It's only as good as your last successful restore. If you're not checking your backups by restoring them and running an integrity check on the database, you're only doing half the job. It seems that most DBAs know that this is best practice, but it can be tricky and time-consuming to set up, so it's one of those tasks that can get forgotten in the midst all the other demands on their time. Sometimes, they're just too busy firefighting. But if it was simple to do? That was our inspiration for SQL Backup 7. So it was heartening to read Brent Ozar's blog post the other day about World Backup Day. To be honest, I'd never heard of World Backup Day (Talk Like a Pirate Day, yes, but not this one); however, its emphasis on not just backing up your data but checking the validity of those backups was exactly the same message we had in mind when building SQL Backup 7. It's printed on a piece of A3 above our planning board - "Make backup verification so easy to do that no DBA has an excuse for not doing it" It's the missing piece that completes the puzzle. Simple idea, great concept, useful feature, but, as it turned out, far from straightforward to implement. The problem is the future. As Marty McFly discovered over the course of three movies, the future is uncertain and hard to predict - so when you are scheduling a restore to take place an hour, day, week or month after the backup, there are all kinds of questions that you wouldn't normally have to consider. Where will this backup live? Will it even exist at the time? Will it be split into multiple files? What will the file names be? Will it be encrypted? What files should it be restored to? SQL Backup needs to know what to expect at the time the restore job is actually run. Of course, a DBA will know the answer to all these questions, but to deliver the whole point of version 7, we wanted to make it easy for them to input that information into SQL Backup. We think we've done that. When you create your scheduled backup job, there is now an option to create a "reminder" to follow it up with a scheduled restore to verify the resulting backups. Actually, it's much more than a reminder, as it stores all the relevant data so you can click it and pre-populate the wizard with all the right settings to set up your verification restores. Simple. But, what do you think? We'd love you to try it. Post by Brian Harris

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• Proxied calls not working as expected

  - by AndyH

  I have been modifying an application to have a cleaner client/server split to allow for load splitting and resource sharing etc. Everything is written to an interface so it was easy to add a remoting layer to the interface using a proxy. Everything worked fine. The next phase was to add a caching layer to the interface and again this worked fine and speed was improved but not as much as I would have expected. On inspection it became very clear what was going on. I feel sure that this behavior has been seen many times before and there is probably a design pattern to solve the problem but it eludes me and I'm not even sure how to describe it. It is easiest explained with an example. Let's imagine the interface is interface IMyCode { List<IThing> getLots( List<String> ); IThing getOne( String id ); } The getLots() method calls getOne() and fills up the list before returning. The interface is implemented at the client which is proxied to a remoting client which then calls the remoting server which in turn calls the implementation at the server. At the client and the server layers there is also a cache. So we have :- Client interface | Client cache | Remote client | Remote server | Server cache | Server interface If we call getOne("A") at the client interface, the call is passed to the client cache which faults. This then calls the remote client which passes the call to the remote server. This then calls the server cache which also faults and so the call is eventually passed to the server interface which actually gets the IThing. In turn the server cache is filled and finally the client cache also. If getOne("A") is again called at the client interface the client cache has the data and it gets returned immediately. If a second client called getOne("B") it would fill the server cache with "B" as well as it's own client cache. Then, when the first client calls getOne("B") the client cache faults but the server cache has the data. This is all as one would expect and works well. Now lets call getLots( [ "C", "D" ] ). This works as you would expect by calling getOne() twice but there is a subtlety here. The call to getLots() cannot directly make use of the cache. Therefore the sequence is to call the client interface which in turn calls the remote client, then the remote server and eventually the server interface. This then calls getOne() to fill the list before returning. The problem is that the getOne() calls are being satisfied at the server when ideally they should be satisfied at the client. If you imagine that the client/server link is really slow then it becomes clear why the client call is more efficient than the server call once the client cache has the data. This example is contrived to illustrate the point. The more general problem is that you cannot just keep adding proxied layers to an interface and expect it to work as you would imagine. As soon as the call goes 'through' the proxy any subsequent calls are on the proxied side rather than 'self' side. Have I failed to learn or not learned something correctly? All this is implemented in Java and I haven't used EJBs. It seems that the example may be confusing. The problem is nothing to do with cache efficiencies. It is more to do with an illusion created by the use of proxies or AOP techniques in general. When you have an object whose class implements an interface there is an assumption that a call on that object might make further calls on that same object. For example, public String getInternalString() { return InetAddress.getLocalHost().toString(); } public String getString() { return getInternalString(); } If you get an object and call getString() the result depends where the code is running. If you add a remoting proxy to the class then the result could be different for calls to getString() and getInternalString() on the same object. This is because the initial call gets 'deproxied' before the actual method is called. I find this not only confusing but I wonder how I can control this behavior especially as the use of the proxy may be by a third party. The concept is fine but the practice is certainly not what I expected. Have I missed the point somewhere?

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• Synergy - easy share of keyboard and mouse between multiple computers

  Did you ever have the urge to share one set of keyboard and mouse between multiple machines? If so, please read on... Using multiple machines Honestly, as a software craftsman it is my daily business to run multiple machines - either physical or virtual - to be able to solve my customers' requirements. Recent hardware equipment allows this very easily. For laptops it's a no-brainer to attach a second or even a third screen in order to extend your native display. This works quite handy and in my case I used to attached two additional screens - one via HD15 connector, the other via HDMI. But... as it's a laptop and therefore a mobile unit there are slight restrictions. Detaching and re-attaching all cables when changing locations is one of them but hardware limitations, too. After all, it's a laptop and not a workstation. I guess, that anyone working in IT (or ICT) has more than one machine at their workplace or their home office and at least I find it quite annoying to have multiple sets of keyboard and mouse conquering my remaining space on my desk. Despite the ugly looks of all those cables and whatsoever 'chaos of distraction' I prefer a more clean solution and working environment. This allows me to actually focus on my work and tasks to do rather than to worry about choosing the right combination of keyboard/mouse. My current workplace is a patch work of various pieces of hardware (approx. 2-3 years): DIY desktop on Ubuntu 12.04 64-bit, Core2 Duo (E7400, 2.8GHz), 4GB RAM, 2x 250GB HDD, nVidia GPU 512MB Dell Inspiron 1525 on Windows 8 64-bit, 4GB RAM, 200GB HDD HP Compaq 6720s on Windows Vista 32-bit, Core2 Duo (T5670, 1.8GHz), 2GB RAM, 160GB HDD Mac mini on Mac OS X 10.7, Core i5 (2.3 GHz), 2GB RAM, 500GB HDD I know... Not the latest and greatest but a decent combination to work with. New system(s) is/are already on the shopping list but I live in the 'wrong' country to buy computer hardware. So, the next trip abroad will provide me with some new stuff. Using multiple operating systems The list of hardware above already names different operating systems, and actually I have only one preference: Linux. But still my job as a software craftsman for Visual FoxPro and .NET development requires other OSes, too. Not a big deal, it's just like this. Additionally to those physical machines, there are a bunch of virtual machines around. Most of them running either Windows XP or Windows 7. Since years I have the practice that each development for one customer is isolated into its own virtual machine and environment. This keeps it clean and version-safe. But as you can easily imagine with that setup there are a couple of constraints referring to keyboard and mouse. Usually, those systems require their own pieces of hardware attached. As stated, I don't like clutter on my desk's surface, so a cross-platform solution has to come in here. In the past, I tried it with various applications, hardware or network protocols like X11, RDP, NX, TeamViewer, RAdmin, KVM switch, etc. but the problem in this case is that they either allow you to remotely connect to the other system or exclusively 'bind' your peripherals to the active system. Not optimal after all. Synergy to the rescue Quote from their website: "Synergy lets you easily share your mouse and keyboard between multiple computers on your desk, and it's Free and Open Source. Just move your mouse off the edge of one computer's screen on to another. You can even share all of your clipboards. All you need is a network connection. Synergy is cross-platform (works on Windows, Mac OS X and Linux)." Yep, that's it! All I need for my setup here... Actually, I couldn't believe it myself that I didn't stumble over synergy earlier but 'Get over it' and there we go. And despite the fact that it is Open Source, no, it's also for free. Donations for the developers are very welcome and recently they introduced Synergy Premium. A possibility to buy so-called premium votes that can be used to put more weight / importance on specific issues or bugs that you would like the developers to look into. Installation and configuration Simply download the installation packages for your systems of choice, run the installer and enter some minor information about your network setup. I chose my desktop machine for the role of the Synergy server and configured my screen setup as follows: The screen setup allows you currently to build or connect up to 15 machines. The number of screens can be higher as those machine might have multiple screens physically attached. Synergy takes this into the overall calculations and simply works as expected. I tried it for fun with a second monitor each connected to both laptops to have a total number of 6 active screens. No flaws after all - stunning! All the other machines are configured as clients like so: Side note: The screenshot was taken on Windows 8 and pasted via clipboard into Gimp running on Ubuntu. Resume Synergy is now definitely in my box of tools for my daily work, and amongst the first pieces of software I install after the operating system. It just simplifies my life and cleans my desk. Never again without Synergy!Now, only waiting for an Android version to integrate my Galaxy Tab 10.1, too. ;-) Please, check out that superb product and enjoy sharing one keyboard, one mouse and one clipboard between your various machines and operating systems.

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• Pirates, Treasure Chests and Architectural Mapping

  Pirate 1: Why do pirates create treasure maps? Pirate 2: I do not know.Pirate 1: So they can find their gold. Yes, that was a bad joke, but it does illustrate a point. Pirates are known for drawing treasure maps to their most prized possession. These documents detail the decisions pirates made in order to hide and find their chests of gold. The map allows them to trace the steps they took originally to hide their treasure so that they may return. As software engineers, programmers, and architects we need to treat software implementations much like our treasure chest. Why is software like a treasure chest? It cost money, time,  and resources to develop (Usually) It can make or save money, time, and resources (Hopefully) If we operate under the assumption that software is like a treasure chest then wouldn’t make sense to document the steps, rationale, concerns, and decisions about how it was designed? Pirates are notorious for documenting where they hide their treasure.  Shouldn’t we as creators of software do the same? By documenting our design decisions and rationale behind them will help others be able to understand and maintain implemented systems. This can only be done if the design decisions are correctly mapped to its corresponding implementation. This allows for architectural decisions to be traced from the conceptual model, architectural design and finally to the implementation. Mapping gives software professional a method to trace the reason why specific areas of code were developed verses other options. Just like the pirates we need to able to trace our steps from the start of a project to its implementation,  so that we will understand why specific choices were chosen. The traceability of a software implementation that actually maps back to its originating design decisions is invaluable for ensuring that architectural drifting and erosion does not take place. The drifting and erosion is prevented by allowing others to understand the rational of why an implementation was created in a specific manor or methodology The process of mapping distinct design concerns/decisions to the location of its implemented is called traceability. In this context traceability is defined as method for connecting distinctive software artifacts. This process allows architectural design models and decisions to be directly connected with its physical implementation. The process of mapping architectural design concerns to a software implementation can be very complex. However, most design decision can be placed in  a few generalized categories. Commonly Mapped Design Decisions Design Rationale Components and Connectors Interfaces Behaviors/Properties Design rational is one of the hardest categories to map directly to an implementation. Typically this rational is mapped or document in code via comments. These comments consist of general design decisions and reasoning because they do not directly refer to a specific part of an application. They typically focus more on the higher level concerns. Components and connectors can directly be mapped to architectural concerns. Typically concerns subdivide an application in to distinct functional areas. These functional areas then can map directly back to their originating concerns.Interfaces can be mapped back to design concerns in one of two ways. Interfaces that pertain to specific function definitions can be directly mapped back to its originating concern(s). However, more complicated interfaces require additional analysis to ensure that the proper mappings are created. Depending on the complexity some Behaviors\Properties can be translated directly into a generic implementation structure that is ready for business logic. In addition, some behaviors can be translated directly in to an actual implementation depending on the complexity and architectural tools used. Mapping design concerns to an implementation is a lot of work to maintain, but is doable. In order to ensure that concerns are mapped correctly and that an implementation correctly reflects its design concerns then one of two standard approaches are usually used. All Changes Come From ArchitectureBy forcing all application changes to come through the architectural model prior to implementation then the existing mappings will be used to locate where in the implementation changes need to occur. Allow Changes From Implementation Or Architecture By allowing changes to come from the implementation and/or the architecture then the other area must be kept in sync. This methodology is more complex compared to the previous approach.  One reason to justify the added complexity for an application is due to the fact that this approach tends to detect and prevent architectural drift and erosion. Additionally, this approach is usually maintained via software because of the complexity. Reference:Taylor, R. N., Medvidovic, N., & Dashofy, E. M. (2009). Software architecture: Foundations, theory, and practice Hoboken, NJ: John Wiley & Sons  

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• Tip #19 Module Private Visibility in OSGi

  - by ByronNevins

  I hate public and protected methods and classes.  It requires so much work to change them in a huge project like GlassFish.  Not to mention that you may well have to support those APIs forever.  They are highly overused in GlassFish.  In fact I'd bet that > 95% of classes are marked as public for no good reason.  It's just (bad) habit is my guess. private and default visibility (I call it package-private) is easier to maintain.  It is much much easier to change such classes and methods around.  If you have ANY public method or public class in GlassFish you'll need to grep through a tremendous amount of source code to find all callers.  But even that won't be theoretically reliable.  What if a caller is using reflection to access public methods?  You may never find such usages. If you have package private methods, it's easy.  Simply grep through all the code in that one package.  As long as that package compiles ok you're all set.  There can' be any compile errors anywhere else.  It's a waste of time to even look around or build the "outside" world.  So you may be thinking: "Aha!  I'll just make my module have one giant package with all the java files.  Then I can use the default visibility and maintenance will be much easier.  But there's a problem.  You are wasting a very nice feature of java -- organizing code into separate packages.  It also makes the code much more encapsulated.  Unfortunately to share code between the packages you have no choice but to declare public visibility. What happens in practice is that a module ends up having tons of public classes and methods that are used exclusively inside the module.  Which finally brings me to the point of this blog:  If Only There Was A Module-Private Visibility Available Well, surprise!  There is such a mechanism.  If your project is running under OSGi that is.  Like GlassFish does!  With this mechanism you can easily add another level of visibility by telling OSGi exactly which public you want to be exposed outside of the module.  You get the best of both worlds: Better encapsulation of your code so that maintenance is easier and productivity is increased. Usage of public visibility inside the module so that you can encapsulate intra-module better with packages. How I do this in GlassFish: Carefully plan out at least one package that will contain "true" publics.  This is the package that will be exported by OSGi.  I recommend just one package. Here is how to tell OSGi to use it in GlassFish -- edit osgi.bundle like so:-exportcontents:     org.glassfish.mymodule.truepublics;  version=${project.osgi.version} Now all publics declared in any other packages will be visible module-wide but not outside the module. There is one caveat: Accessing "module-private" items outside of the module is controlled at run-time, not compile-time.  The compiler has no clue that a public in a dependent module isn't really public.  it will happily compile it.  At runtime you will definitely see fireworks.  The good news is that you don't have to wait for the code path that tries to use the "module-private" items to fire.  OSGi will complain loudly when that module gets loaded.  OSGi will refuse to load it.  You will see an error like this: remote failure: Error while loading FOO: Exception while adding the new configuration : Error occurred during deployment: Exception while loading the app : org.osgi.framework.BundleException: Unresolved constraint in bundle com.oracle.glassfish.miscreant.code [115]: Unable to resolve 115.0: missing requirement [115.0] osgi.wiring.package; (osgi.wiring.package=org.glassfish.mymodule.unexported). Please see server.log for more details. That is if you accidentally change code in module B to use a public that is really a "module-private" in module A, then you will see the error immediately when you try to test whatever you were changing in module B.

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• Coherence Data Guarantees for Data Reads - Basic Terminology

  - by jpurdy

  When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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• Navigation in a #WP7 application with MVVM Light

  - by Laurent Bugnion

  In MVVM applications, it can be a bit of a challenge to send instructions to the view (for example a page) from a viewmodel. Thankfully, we have good tools at our disposal to help with that. In his excellent series “MVVM Light Toolkit soup to nuts”, Jesse Liberty proposes one approach using the MVVM Light messaging infrastructure. While this works fine, I would like to show here another approach using what I call a “view service”, i.e. an abstracted service that is invoked from the viewmodel, and implemented on the view. Multiple kinds of view services In fact, I use view services quite often, and even started standardizing them for the Windows Phone 7 applications I work on. If there is interest, I will be happy to show other such view services, for example Animation services, responsible to start/stop animations on the view. Dialog service, in charge of displaying messages to the user and gathering feedback. Navigation service, in charge of navigating to a given page directly from the viewmodel. In this article, I will concentrate on the navigation service. The INavigationService interface In most WP7 apps, the navigation service is used in quite a straightforward way. We want to: Navigate to a given URI. Go back. Be notified when a navigation is taking place, and be able to cancel. The INavigationService interface is quite simple indeed: public interface INavigationService { event NavigatingCancelEventHandler Navigating; void NavigateTo(Uri pageUri); void GoBack(); } Obviously, this interface can be extended if necessary, but in most of the apps I worked on, I found that this covers my needs. The NavigationService class It is possible to nicely pack the navigation service into its own class. To do this, we need to remember that all the PhoneApplicationPage instances use the same instance of the navigation service, exposed through their NavigationService property. In fact, in a WP7 application, it is the main frame (RootFrame, of type PhoneApplicationFrame) that is responsible for this task. So, our implementation of the NavigationService class can leverage this. First the class will grab the PhoneApplicationFrame and store a reference to it. Also, it registers a handler for the Navigating event, and forwards the event to the listening viewmodels (if any). Then, the NavigateTo and the GoBack methods are implemented. They are quite simple, because they are in fact just a gateway to the PhoneApplicationFrame. The whole class is as follows: public class NavigationService : INavigationService { private PhoneApplicationFrame _mainFrame; public event NavigatingCancelEventHandler Navigating; public void NavigateTo(Uri pageUri) { if (EnsureMainFrame()) { _mainFrame.Navigate(pageUri); } } public void GoBack() { if (EnsureMainFrame() && _mainFrame.CanGoBack) { _mainFrame.GoBack(); } } private bool EnsureMainFrame() { if (_mainFrame != null) { return true; } _mainFrame = Application.Current.RootVisual as PhoneApplicationFrame; if (_mainFrame != null) { // Could be null if the app runs inside a design tool _mainFrame.Navigating += (s, e) => { if (Navigating != null) { Navigating(s, e); } }; return true; } return false; } } Exposing URIs I find that it is a good practice to expose each page’s URI as a constant. In MVVM Light applications, a good place to do that is the ViewModelLocator, which already acts like a central point of setup for the views and their viewmodels. Note that in some cases, it is necessary to expose the URL as a string, for instance when a query string needs to be passed to the view. So for example we could have: public static readonly Uri MainPageUri = new Uri("/MainPage.xaml", UriKind.Relative); public const string AnotherPageUrl = "/AnotherPage.xaml?param1={0}&param2={1}"; Creating and using the NavigationService Normally, we only need one instance of the NavigationService class. In cases where you use an IOC container, it is easy to simply register a singleton instance. For example, I am using a modified version of a super simple IOC container, and so I can register the navigation service as follows: SimpleIoc.Register<INavigationService, NavigationService>(); Then, it can be resolved where needed with: SimpleIoc.Resolve<INavigationService>(); Or (more frequently), I simply declare a parameter on the viewmodel constructor of type INavigationService and let the IOC container do its magic and inject the instance of the NavigationService when the viewmodel is created. On supported platforms (for example Silverlight 4), it is also possible to use MEF. Or, of course, we can simply instantiate the NavigationService in the ViewModelLocator, and pass this instance as a parameter of the viewmodels’ constructor, injected as a property, etc… Once the instance has been passed to the viewmodel, it can be used, for example with: NavigationService.NavigateTo(ViewModelLocator.ComparisonPageUri); Testing Thanks to the INavigationService interface, navigation can be mocked and tested when the viewmodel is put under unit test. Simply implement and inject a mock class, and assert that the methods are called as they should by the viewmodel. Conclusion As usual, there are multiple ways to code a solution answering your needs. I find that view services are a really neat way to delegate view-specific responsibilities such as animation, dialogs and of course navigation to other classes through an abstracted interface. In some cases, such as the NavigationService class exposed here, it is even possible to standardize the implementation and pack it in a class library for reuse. I hope that this sample is useful! Happy coding. Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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