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• networking tunnel adapter connections?

  - by Karthik Balaguru

  I understand that Tunnel Adapter LAN is for encapsulating IPv6 packets with an IPv4 header so that they can be sent across an IPv4 network. Few queries popped up in my mind based on this :- If i do 'ipconfig', Apart from ethernet adapter LAN details, I get a series of statments as below - Tunnel adapter Local Area Connection* 6 Tunnel adapter Local Area Connection* 7 Tunnel adapter Local Area Connection* 12 Tunnel adapter Local Area Connection* 13 Tunnel adapter Local Area Connection* 14 Tunnel adapter Local Area Connection* 15 Tunnel adapter Local Area Connection* 16 Except for the *16, all the other Tunnel Adapter Local Area Connections show Media Disconnected. Why is the numbering for the Tunnel adapter LAN not sequential? It is like 6, 7, 12, 13, 14, 15, 16. A strange numbering scheme! I tried to figure it out by thinking of some arithmetic series. But, it does not seem to fit in. There is a huge gap between 7 and 12. Any ideas? What is the need for so many Tunnel Adapter LAN connections? Can you tell me a scenario that requires all of those ? I did ipconfig /all to get more information. From the listing, I understand that: 16, 15, 14, 12 are Microsoft 6to4 Adapters 13, 6 are isatap Adapters 7 is Teredo Tunneling Pseudo-interface I understand that the above are for automatic tunneling so that the tunnel endpoints are determined automatically by the routing infrastructure. 6to4 is recommended by RFC3056 for automatic tunneling that uses protocol 41 for encapsulation. It is typically used when an end-user wants to connect to the IPv6 Internet using their existing IPv4 connection. Teredo is an automatic tunneling technique that uses UDP encapsulation across multiple NATs. That is, It is to grant IPv6 connectivity to nodes that are located behind IPv6-unaware NAT devices ISATAP treats the IPv4 network as a virtual IPv6 local link, with mappings from each IPv4 address to a link-local IPv6 address. That is to transmit IPv6 packets between dual-stack nodes on top of an IPv4 network. That is, to put in simple words, ISATAP is an intra-site mechanism, while the 6to4 and Teredo are for inter-site tunnelling mechanisms. It seems that Teredo should alone enabled by default in Vista, But my system does not show it to be enabled by default. Interestingly, it shows a 6to4 tunnel adapter (Tunnel adapter LAN connection 16) to be enabled by default? Any specific reasons for it? If i do ipconfig /all, why is only one Teredo present while four 6to4 are present ? I searched the internet for answers to the above queries, but I am unable to find clear answers.

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• Converting an EC2 AMI to vmdk image

  - by Reed G. Law

  I've come quite close to getting Amazon Linux to boot inside VirtualBox, thanks to this answer and these websites. A quick overview of the steps I've taken: Launch EC2 instance with Amazon Linux 2011.09 64-bit AMI dd the contents of the EBS volume over ssh to a local image file. Mount the image file as a loopback device and then to a local mount point. Create a new empty disk image file, partition with an offset for a bootloader, and create an ext4 filesystem. Mount the new image's partition and copy everything from the EC2 image. Install grub (using Ubuntu's grub-legacy-ec2 package, not grub2). Convert the image file to vmdk using qemu-img. Create a new VirtualBox VM with the vmdk. Now the VM boots, grub loads, and the kernel is found. But it fails when it tries to mount the root device: dracut Warning: No root device "block:/dev/xvda1" found dracut Warning: Boot has failed. To debug this issue add "rdshell" to the kernel command line. dracut Warning: Signal caught! dracut Warning: Boot has failed. To debug this issue add "rdshell" to the kernel command line. Kernel panic - not syncing: Attempted to kill init! Pid: 1, comm: init Not tainted 2.6.35.14-107.1.39.amzn1.x86_64 #1 I have tried changing /boot/grub/menu.lst to find the root device by label and UUID, but nothing works. I'm guessing the xen kernel is not compatible with VirtualBox. The reasoning behind all this effort is to make a Vagrant box that is as close to possible as the production enviroment, so deploys can be tested locally. I know it's cheap to do test runs on EC2, but poor connectivity often ruins the experience. Plus it would be really nice to have a virtual machine with the production environment so that co-workers don't have to install everything under the sun just to get up and running with app development. If I were to try running a different kernel, what kernel could I get to be as close as possible to Amazon Linux 2011.09?

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• IIS/ASP.NET performance incident - Perfmon Current Annonymous Users going through roof but Requests/sec low

  - by Laurence

  Setup: ASP.NET 4.0 website on IIS 6.0 on Win 2003 64 bit, 8xCPUs, 16GB memory, separate SQL 2005 DB server. Had a serious slowdown today with any otherwise fairly well performing ASP.NET site. For a period of a couple of hours all page requests were taking a very long time to be served - e.g. 30-60s compared to usual 2s. The w3wp.exe's CPU and memory usage on the webserver was not much higher than normal. The application pool was not in the middle of recycling (and it hadn't recycled for several hours). Bottlenecks in the database were ruled out - no blocks occurring and query results were being returned quickly. I couldn't make any sense of it and set up the following Perfmon counters: Current Anonymous Users (for site in question) Get requests/sec (ditto) Requests/sec for the ASP.NET application running the site Get requests/sec was averaging 100-150. Requests/sec for ASP.NET was averaging 5-10. However Current Anonymous Users was around 200. And then as I was watching, the Current Anonymous Users began to climb steeply going up to about 500 within a few minutes. All this time Get requests/sec & Requests/sec for ASP.NET was if anything going down. I did a whole load of things (in a panic!) to try to get the site working, like shutting it down, recycling the app pool, and adding another worker process to the pool. I also extended the expiration time for content (in IIS under HTTP Headers) in an attempt to lower the number of requests for static files (there are a lot of images on the site). The site is now back to normal, and the counters are fairly steady and reading (added Current Connections counter): Current Anonymous Users : average 30 Get requests/sec : average 100 Requests/sec for ASP.NET : 5 Current Connections : average 300 I have also observed an inverse relationship between Get requests/sec & Current Anonymous Users. Usually both are fairly steady but there will be short periods when Get requests/sec will go down dramatically and Current Anonymous Users will go up in a perfect mirror image. Then they will flip back to their usual levels. So, my questions are: Thinking of the original performance issue - if w3wp.exe CPU, memory usage were normal and there was no DB bottleneck, what could explain page requests taking 20 times longer to be served than usual? What other counters should I be looking at if this happens again? What explains the inverse relationship between Get requests/sec & Current Anonymous Users? What could explain Current Anonymous Users going from 200 to 500 within a few minutes? Many thanks for any insight into this.

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• Hell: NTFS "Restore previous versions"...

  - by ttsiodras

  The hell I have experienced these last 24h: Windows 7 installation hosed after bluetooth driver install. Attempting to recover using restore points via "Repair" on the bootable Win7 installation CD. Attempting to go back one day in the restore points. No joy. Attempting to go back two days in the restore points. No joy. Attempting to go back one week in the restore points. Stil no joy. Windows won't boot. Apparently something is REALLY hosed. And then it hits me - PANIC - the restore points somehow reverted DATA files to their older versions! Word, Powerpoint, SPSS, etc document versions are all one week old now. Using the "freshest" restore point. Failed to restore yesterday's restore point!!! I am stuck at old versions of the data!!! Booting KNOPPIX, mounting NTFS partition as read-only under KNOPPIX. Checking. Nope, the data files are still the one week old versions. Booting Win7 CD, Recovery console - Cmd prompt - navigating - yep, data files are still one week old. Removing the drive, mounting it under other Win7 installation. Still old data. Running NTFS undelete on the drive (read-only scan), searching for file created yesterday. Not found. Despair. At this point, idea: I will install a brand new Windows installation, keeping the old one in Windows.old (default behaviour of Windows installs). I boot the new install, I go to my C:\Data\ folder, I choose "Restore previous versions", click on yesterday's date, and click open... YES! It works! I can see the latest versions of my files (e.g. from yesterday). Thank God. And then, I try to view the files under the "yesterday snapshot-version" of c:\Users\MyAccount\Desktop ... And I get "Permission Denied" as soon as I try to open "Users\MyAccount". I make sure I am an administrator. No joy. Apparently, the new Windows installation does not have access to read the "NTFS snapshots" or "Volume Shadow Snapshots" of my old Windows account! Cross-installation permissions? I need to somehow tell the new Windows install that I am the same "old" user... So that I will be able to access the "Users\MyAccount" folder of the snapshot of my old user account. Help?

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• Ubuntu 12.04 crash analysis - strange binary data on all open files at the moment of crash

  - by lanbo

  A couple of hours ago we got a system crash on Ubuntu 12.04. We checked all the log files and there is nothing suspicious to blame to. Last stuff that was logged was some dovecot activity. There are no kernel panic messages. Nothing. It is a new server (new hardware) we are testing before production. And because it is new hard, I'm suspicious the problem may be due to some faulty hardware. We already run memtester with no problem detected. I'll be happy to hear from other hardware testing tools (the machine has SSD). Anyway, the thing I wanted to ask you is a different one. The strange thing is on every open file at the moment of the crash we found the next sequence of symbols was written into them: "@^@^@^@^@^@^@...". For example, on the syslog log file we got: Apr 16 15:53:56 odyssey dovecot: pop3-login: Aborted login (auth failed, 1 attempts): user=<info>, method=PLAIN, rip=46.29.255.73, lip=5.9.58.177 ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^ [these continues for about 1000 chars...] ^@^@^@^@Apr 16 15:55:12 odyssey kernel: imklog 5.8.6, log source = /proc/kmsg started. We got all these symbols in all open files. These include: syslog, mail.log, kern.log, ... But also on some logs that are output by php scripts run in CRONs from user accounts (not root). So, any idea why all open files got these characters written during the crash? This is pretty bad since the crash corrupted many files (we don't even know which other ones may be affected). We are suspicious that all open files (in write mode maybe) at the moment of the crash got all these symbols inserted. Why is that? BTW [in case it helps], the system automatically rebooted after the crash but Apache did not start. There were not traces in /var/apache2/*log why apache did not start. After running a "service apache2 start" it started with no problems. Also, we rebooted the machine manually and Apache also started on reboot. But it did not start after the crash and no errors were reported. Thanks guys!

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• If Nvidia Shield can stream a game via wifi, why can I not do the same via ethernet to any other PC?

  - by Enigma

  I think it absurd that a wireless game streaming solution is the *first to hit the market when a 1000mbps+ Ethernet connection would accomplish the same feat with roughly 6x the available bandwidth. I can only assume that there must be some reason behind this or a limitation preventing this, but what? 150mbps wifi is in no way superior to a 1000mbps LAN connection aside from well wireless mobility. Not only that but I have a secondary laptop and desktop which should by hardware comparison completely outperform anything the Tegra in the Nvidia Shield can do. Is this all just a marketing scheme to force people to buy the shield for the streaming benefit? Chief among these is that NVIDIA’s Shield handheld game console will be getting a microconsole-like mode, dubbed “Shield Console Mode”, that will allow the handheld to be converted into a more traditional TV-connected console. In console mode Shield can be controlled with a Bluetooth controller, and in accordance with the higher resolution of TVs will accept 1080p game streaming from a suitably equipped PC, versus 720p in handheld mode. With that said 1080p streaming will require additional bandwidth, and while 720p can be done over WiFi NVIDIA will be requiring a hardline GigE connection for 1080p streaming (note that Shield doesn’t have Ethernet, so this is presumably being done over USB). Streaming aside, in console mode Shield will also support its traditional local gaming/application functionality. - http://www.anandtech.com/show/7435/nvidia-consolidates-game-streaming-tech-under-gamestream-brand-announces-shield-console-mode ^ This is not acceptable for me for a number of reasons not to mention the ridiculousness of having a little screen+controller unit sitting there while using a secondary controller and screen instead. That kind of redundant absurdity exemplifies how wrong of a solution that is. They need a second product for this solution without the screen or controller for it to make sense... at which point your just buying a little computer that does what most other larger computers do better. All that is required, by my understanding, is the ability to decode H.264 video compression and transmit control/feedback so by any logical comparison, one (Nvidia especially) should have no difficulty in creating an application for PC's (win32/64 environment) that does the exact same thing their android app does. I have 2 video cards capable of streaming (encoding) H.264 so by right they must be capable of decoding it I would think. I haven't found anything stating plans to allow non-shield owners to do this. Can a third party create this software or does it hinge on some limitation that only Nvidia can overcome? (*) - perhaps this isn't the first but afaik it is the first complete package.

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• Framework 4 Features: Summary of Security enhancements

  - by Anthony Shorten

  In the last log entry I mentioned one of the new security features in Oracle Utilities Application Framework 4.0.1. Security is one of the major "tent poles" (to borrow a phrase from Steve Jobs) in this release of the framework. There are a number of security related enhancements requested by customers and as a result of internal reviews that we have introduced. Here is a summary of some of the security enchancements we have added in this release: Security Cache Changes - Security authorization information is automatically cached on the server for performance reasons (security is checked for every single call the product makes for all modes of access). Prior to this release the cache auto-refreshed every 30 minutes (or so). This has beem made more nimble by supporting a cache refresh every minute (or so). This means authorization changes are reflected quicker than before. Business Level security - Business Services are configurable services that are based upon Application Services. Typically, the business service inherited its security profile from its parent service. Whilst this is sufficient for most needs, it is now required to further specify security on the Business Service definition itself. This will allow granular security and allow the same application service to be exposed as different Business Services with their own security. This is particularly useful when you base a Business Service on a query zone. User Propogation - As with other client server applications, the database connections are pooled and shared as needed. This means that a common database user is used to access the database from the pool to allow sharing. Unfortunently, this means that tracability at the database level is that much harder. In Oracle Utilities Application Framework V4 the end userid is now propogated to the database using the CLIENT_IDENTIFIER as part of the Oracle JDBC connection API. This not only means that the common database userid is still used but the end user is indentifiable for the duration of the database call. This can be used for monitoring or to hook into Oracle's database security products. This enhancement is only available to Oracle Database customers. Enhanced Security Definitions - Security Administrators use the product browser front end to control access rights of defined users. While this is sufficient for most sites, a new security portal has been introduced to speed up the maintenance of security information. Oracle Identity Manager Integration - With the popularity of Oracle's Identity Management Suite, the Framework now provides an integration adapter and Identity Manager Generic Transport Connector (GTC) to allow users and group membership to be provisioned to any Oracle Utilities Application Framework based product from Oracle's Identity Manager. This is also available for Oracle Utilties Application Framework V2.2 customers. Refer to My Oracle Support KBid 970785.1 - Oracle Identity Manager Integration Overview. Audit On Inquiry - Typically the configurable audit facility in the Oracle Utilities Application Framework is used to audit changes to records. In Oracle Utilities Application Framework the Business Services and Service Scripts could be configured to audit inquiries as well. Now it is possible to attach auditing capabilities to zones on the product (including base package ones). Time Zone Support - In some of the Oracle Utilities Application Framework based products, the timezone of the end user is a factor in the processing. The user object has been extended to allow the recording of time zone information for use in product functionality. JAAS Suport - Internally the Oracle Utilities Application Framework uses a number of techniques to validate and transmit security information across the architecture. These various methods have been reconciled into using Java Authentication and Authorization Services for standardized security. This is strictly an internal change with no direct on how security operates externally. JMX Based Cache Management - In the last bullet point, I mentioned extra security applied to cache management from the browser. Alternatively a JMX based interface is now provided to allow IT operations to control the cache without the browser interface. This JMX capability can be initiated from a JSR120 compliant JMX console or JMX browser. I will be writing another more detailed blog entry on the JMX enhancements as it is quite a change and an exciting direction for the product line. Data Patch Permissions - The database installer provided with the product required lower levels of security for some operations. At some sites they wanted the ability for non-DBA's to execute the utilities in a controlled fashion. The framework now allows feature configuration to allow delegation for patch execution. User Enable Support - At some sites, the use of temporary staff such as contractors is commonplace. In this scenario, temporary security setups were required and used. A potential issue has arisen when the contractor left the company. Typically the IT group would remove the contractor from the security repository to prevent login using that contractors userid but the userid could NOT be removed from the authorization model becuase of audit requirements (if any user in the product updates financials or key data their userid is recorded for audit purposes). It is now possible to effectively diable the user from the security model to prevent any use of the useridwhilst retaining audit information. These are a subset of the security changes in Oracle Utilities Application Framework. More details about the security capabilities of the product is contained in My Oracle Support KB Id 773473.1 - Oracle Utilities Application Framework Security Overview.

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• Mobile HCM: It’s not the future, it is right now

  - by Natalia Rachelson

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A guest post by Steve Boese, Director Product Strategy, Oracle I’ll bet you reached for your iPhone or Android or BlackBerry and took a quick look at email or Facebook or last night’s text messages before you even got out of bed this morning. Come on, admit it, it’s ok, you are among friends here. See, feel better now? But seriously, the incredible growth and near-ubiquity of increasingly powerful, capable, and for many of us, essential in our daily lives mobile devices has profoundly changed the way we communicate, consume information, socialize, and more and more, conduct business and get our work done. And if you doubt that profound change has happened, just think for a moment about the last time you misplaced your iPhone.  The shivers, the cold sweats, the panic... We have all been there. And indeed your personal experiences with mobile technology echoes throughout the world - here are a few data points to consider: Market research firm IDC estimates 1.8 billion mobile phones will be shipped in 2012. A recent Pew study reports 46% of Americans own a smartphone of some kind. And finally in the USA, ownership of tablets like the iPad has doubled from 10% to 19% in the last year. So truly for the Human Resources leader, the question is no longer, ‘Should HR explore ways to exploit mobile devices and their always-on nature to better support and empower the modern workforce?’, but rather ‘How can HR best take advantage of smartphone and tablet capability to provide information, enable transactions, and enhance decision making?’. Because even though moving HCM applications to mobile devices seems inherently logical given today’s fast-moving and mobile workforces, and its promise to deliver incredible value to the organization, HR leaders also have to consider many factors before devising their Mobile HCM strategy and embarking on mobile HR technology projects. Here are just some of the important considerations for HR leaders as you build your strategies and evaluate mobile HCM solutions: Does your organization provide mobile devices to the workforce today, and if so, will the current set of deployed devices have the necessary capability and ecosystems to support your mobile HCM initiatives? Will you allow workers to use or bring their own mobile devices, (commonly abbreviated as ‘BYOD’), and if so are your IT and Security organizations in agreement and capable of supporting that strategy? Do you know which workers need access to mobile HCM applications? Often mobile HCM capability flows down in an organization, with executives and other ‘road-warrior’ types having the most immediate needs, followed by field sales staff, project managers, and even potential job candidates. But just as an organization will have to spend time understanding ‘who’ should have access to mobile HCM technology, the ‘what’ of the way the solutions should be deployed to these groups will also vary. What works and makes sense for the executive, (company-wide dashboards and analytics on an iPad), might not be as relevant for a retail store manager, (employee schedules, location-level sales and inventory data, transaction approvals, etc.). With Oracle Fusion HCM, we are taking an approach to mobile HR that encompasses not just the mobile solution needs for the various types of worker, but also incorporates the fundamental attributes of great mobile applications - the ability to support end-to-end transactions, apps that respond with lightning-fast speed, with functions that are embedded in a worker’s daily activities, and features that can be mashed-up easily with other business areas like Finance and CRM. Finally, and perhaps most importantly for the Oracle Fusion HCM team, delivering mobile experiences that truly enhance, enable, and empower the mobile workforce, and deliver on the design mantras of the best-in-class consumer applications, continues to shape and drive design decisions. Mobile is no longer the future, it is right now, and the cutting-edge HR leader of today will need to consider how mobile fits her HCM technology strategy from here on out. You can learn more about our ideas and plans for Oracle Fusion HCM mobile solutions at https://fusiontap.oracle.com/.

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• Messaging Systems – Handshaking, Reconciliation and Tracking for Data Transparency

  - by Ahsan Alam

  As many corporations build business partnerships with other organizations, the need to share information becomes necessary. Large amount of data sharing using snail mail, email and/or fax are quickly becoming a thing of the past. More and more organizations are relying heavily on Ftp and/or Web Service to exchange data. Corporations apply wide range of technologies and techniques based on available resources and data transfer needs. Sometimes, it involves simple home-grown applications. Other times, large investments are made on products like BizTalk, TIBCO etc. Complexity of information management also varies significantly from one organizations to another. Some may deal with handful of simple steps to process and manage shared data; whereas others may rely on fairly complex processes with heavy interaction with internal and external systems in order to serve the business needs. It is not surprising that many of these systems end up becoming black boxes over a period of time. Consequently, people and business start to rely more and more on developers and support personnel just to extract simple information adding to the loss of productivity. One of the most important factor in any business is transparency to data irrespective of technology preferences and the complexity of business processes. Not knowing the state of data could become very costly to the business. Being involved in messaging systems for some time now, I have heard the same type of questions over and over again. Did we transmit messages successfully? Did we get responses back? What is the expected turn-around-time? Did the system experience any errors? When one company transmits data to one or more company, it may invoke a set of processes that could complete in matter of seconds, or it could days. As data travels from one organizations to another, the uncertainty grows, and the longer it takes to track uncertain state of the data the costlier it gets for the business, So, in every business scenario, it's extremely important to be aware of the state of the data.   Architects of messaging systems can take several steps to aid with data transparency. Some forms of data handshaking and reconciliation mechanism as well as extensive data tracking can be incorporated into the system to provide clear visibility to the data. What do I mean by handshaking and reconciliation? Some might consider these to be a single concept; however, I like to consider them in two unique categories. Handshaking serves as message receipts or acknowledgment. When one transmits messages to another, the receiver must acknowledge each message by sending immediate responses for each transaction. Whenever we use Web Services, handshaking is often achieved utilizing request/reply pattern. Similarly, if Ftp is used, a receiver can acknowledge by dropping messages for the sender as soon as the files are picked up. These forms of handshaking or acknowledgment informs the message sender and receiver that a successful transaction has occurred. I have mentioned earlier that it could take anywhere from a few seconds to a number of days before shared data is completely processed. In addition, whenever a batched transaction is used, processing time for each data element inside the batch could also vary significantly. So, in order to successfully manage data processing, reconciliation becomes extremely important; otherwise it may result into data loss or in some cases hefty penalty. Reconciliation can be done in many ways. Partner organizations can share and compare ad hoc reports to achieve reconciliation. On the other hand, partners can agree on some type of systematic reconciliation messages. Systems within responsible parties can trigger messages to partners as soon as the data process completes.   Next step in the data transparency is extensive data tracking. Some products such as BizTalk and TIBCO provide built-in functionality for data tracking; however, built-in functionality may not always be adequate. Sometimes additional tracking system (or databases) needs to be built in order monitor all types of data flow including, message transactions, handshaking, reconciliation, system errors and many more. If these types of data are captured, then these can be presented to business users in any forms or fashion. When business users are empowered with such information, then the reliance on developers and support teams decreases dramatically.   In today's collaborative world of information sharing, data transparency is key to the success of every business. The state of business data will constantly change. However, when people have easier access to various states of data, it allows them to make better and quicker decisions. Therefore, I feel that data handshaking, reconciliation and tracking is very important aspect of messaging systems.

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• Do You Develop Your PL/SQL Directly in the Database?

  - by thatjeffsmith

  I know this sounds like a REALLY weird question for many of you. Let me make one thing clear right away though, I am NOT talking about creating and replacing PLSQL objects directly into a production environment. Do we really need to talk about developers in production again? No, what I am talking about is a developer doing their work from start to finish in a development database. These are generally available to a development team for building the next and greatest version of your databases and database applications. And of course you are using a third party source control system, right? Last week I was in Tampa, FL presenting at the monthly Suncoast Oracle User’s Group meeting. Had a wonderful time, great questions and back-and-forth. My favorite heckler was there, @oraclenered, AKA Chet Justice.  I was in the middle of talking about how it’s better to do your PLSQL work in the Procedure Editor when Chet pipes up - Don’t do it that way, that’s wrong Just press play to edit the PLSQL directly in the database Or something along those lines. I didn’t get what the heck he was talking about. I had been showing how the Procedure Editor gives you much better feedback and support when working with PLSQL. After a few back-and-forths I got to what Chet’s main objection was, and again I’m going to paraphrase: You should develop offline in your SQL worksheet. Don’t do anything in the database until it’s done. I didn’t understand. Were developers expected to be able to internalize and mentally model the PL/SQL engine, see where their errors were, etc in these offline scripts? No, please give Chet more credit than that. What is the ideal Oracle Development Environment? If I were back in the ‘real world’ of database development, I would do all of my development outside of the ‘dev’ instance. My development process looks a little something like this: Do I have a program that already does something like this – copy and paste Has some smart person already written something like this – copy and paste Start typing in the white-screen-of-panic and bungle along until I get something that half-works Tweek, debug, test until I have fooled my subconscious into thinking that it’s ‘good’ As you might understand, I don’t want my co-workers to see the evolution of my code. It would seriously freak them out and I probably wouldn’t have a job anymore (don’t remind me that I already worked myself out of development.) So here’s what I like to do: Run a Local Instance of Oracle on my Machine and Develop My Code Privately I take a copy of development – that’s what source control is for afterall – and run it where no one else can see it. I now get to be my own DBA. If I need a trace – no problem. If I want to run an ASH report, no worries. If I need to create a directory or run some DataPump jobs, that’s all on me. Now when I get my code ‘up to snuff,’ then I will check it into source control and compile it into the official development instance. So my teammates suddenly go from seeing no program, to a mostly complete program. Is this right? If not, it doesn’t seem wrong to me. And after talking to Chet in the car on the way to the local cigar bar, it seems that he’s of the same opinion. So what’s so wrong with coding directly into a development instance? I think ‘wrong’ is a bit strong here. But there are a few pitfalls that you might want to look out for. A few come to mind – and I’m sure Chet could add many more as my memory fails me at the moment. But here goes: Development instance isn’t properly backed up – would hate to lose that work Development is wiped once a week and copied over from Prod – don’t laugh Someone clobbers your code You accidentally on purpose clobber someone else’s code The more developers you have in a single fish pond, the greater chance something ‘bad’ will happen This Isn’t One of Those Posts Where I Tell You What You Should Be Doing I realize many shops won’t be open to allowing developers to stage their own local copies of Oracle. But I would at least be aware that many of your developers are probably doing this anyway – with or without your tacit approval. SQL Developer can do local file tracking, but you should be using Source Control too! I will say that I think it’s imperative that you control your source code outside the database, even if your development team is comprised of a single developer. Store your source code in a file, and control that file in something like Subversion. You would be shocked at the number of teams that do not use a source control system. I know I continue to be shocked no matter how many times I meet another team running by the seat-of-their-pants. I’d love to hear how your development process works. And of course I want to know how SQL Developer and the rest of our tools can better support your processes. And one last thing, if you want a fun and interactive presentation experience, be sure to have Chet in the room

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• Slow boot on Ubuntu 12.04

  - by Hailwood

  My Ubuntu is booting really slow (Windows is booting faster...). I am using Ubuntu a Dell Inspiron 1545 Pentium(R) Dual-Core CPU T4300 @ 2.10GHz, 4GB Ram, 500GB HDD running Ubuntu 12.04 with gnome-shell 3.4.1. After running dmesg the culprit seems to be this section, in particular the last three lines: [26.557659] ADDRCONF(NETDEV_UP): eth0: link is not ready [26.565414] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.355355] Console: switching to colour frame buffer device 170x48 [27.362346] fb0: radeondrmfb frame buffer device [27.362347] drm: registered panic notifier [27.362357] [drm] Initialized radeon 2.12.0 20080528 for 0000:01:00.0 on minor 0 [27.617435] init: udev-fallback-graphics main process (1049) terminated with status 1 [30.064481] init: plymouth-stop pre-start process (1500) terminated with status 1 [51.708241] CE: hpet increased min_delta_ns to 20113 nsec [59.448029] eth2: no IPv6 routers present But I have no idea how to start debugging this. sudo lshw -C video $ sudo lshw -C video *-display description: VGA compatible controller product: RV710 [Mobility Radeon HD 4300 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 32 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=fglrx_pci latency=0 resources: irq:48 memory:e0000000-efffffff ioport:de00(size=256) memory:f6df0000-f6dfffff memory:f6d00000-f6d1ffff After loading the propriety driver my new dmesg log is below (starting from the first major time gap): [2.983741] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null) [25.094327] ADDRCONF(NETDEV_UP): eth0: link is not ready [25.119737] udevd[520]: starting version 175 [25.167086] lp: driver loaded but no devices found [25.215341] fglrx: module license 'Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY' taints kernel. [25.215345] Disabling lock debugging due to kernel taint [25.231924] wmi: Mapper loaded [25.318414] lib80211: common routines for IEEE802.11 drivers [25.318418] lib80211_crypt: registered algorithm 'NULL' [25.331631] [fglrx] Maximum main memory to use for locked dma buffers: 3789 MBytes. [25.332095] [fglrx] vendor: 1002 device: 9552 count: 1 [25.334206] [fglrx] ioport: bar 1, base 0xde00, size: 0x100 [25.334229] pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [25.334235] pci 0000:01:00.0: setting latency timer to 64 [25.337109] [fglrx] Kernel PAT support is enabled [25.337140] [fglrx] module loaded - fglrx 8.96.4 [Mar 12 2012] with 1 minors [25.342803] Adding 4189180k swap on /dev/sda7. Priority:-1 extents:1 across:4189180k [25.364031] type=1400 audit(1338241723.027:2): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=606 comm="apparmor_parser" [25.364491] type=1400 audit(1338241723.031:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=606 comm="apparmor_parser" [25.364760] type=1400 audit(1338241723.031:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=606 comm="apparmor_parser" [25.394328] wl 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [25.394343] wl 0000:0c:00.0: setting latency timer to 64 [25.415531] acpi device:36: registered as cooling_device2 [25.416688] input: Video Bus as /devices/LNXSYSTM:00/device:00/PNP0A03:00/device:34/LNXVIDEO:00/input/input6 [25.416795] ACPI: Video Device [VID] (multi-head: yes rom: no post: no) [25.416865] [Firmware Bug]: Duplicate ACPI video bus devices for the same VGA controller, please try module parameter "video.allow_duplicates=1"if the current driver doesn't work. [25.425133] lib80211_crypt: registered algorithm 'TKIP' [25.448058] snd_hda_intel 0000:00:1b.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 [25.448321] snd_hda_intel 0000:00:1b.0: irq 47 for MSI/MSI-X [25.448353] snd_hda_intel 0000:00:1b.0: setting latency timer to 64 [25.738867] eth1: Broadcom BCM4315 802.11 Hybrid Wireless Controller 5.100.82.38 [25.761213] input: HDA Intel Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input7 [25.761406] input: HDA Intel Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input8 [25.783432] dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2) [25.908318] EXT4-fs (sda6): re-mounted. Opts: errors=remount-ro [25.928155] input: Dell WMI hotkeys as /devices/virtual/input/input9 [25.960561] udevd[543]: renamed network interface eth1 to eth2 [26.285688] init: failsafe main process (835) killed by TERM signal [26.396426] input: PS/2 Mouse as /devices/platform/i8042/serio2/input/input10 [26.423108] input: AlpsPS/2 ALPS GlidePoint as /devices/platform/i8042/serio2/input/input11 [26.511297] Bluetooth: Core ver 2.16 [26.511383] NET: Registered protocol family 31 [26.511385] Bluetooth: HCI device and connection manager initialized [26.511388] Bluetooth: HCI socket layer initialized [26.511391] Bluetooth: L2CAP socket layer initialized [26.512079] Bluetooth: SCO socket layer initialized [26.530164] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [26.530168] Bluetooth: BNEP filters: protocol multicast [26.553893] type=1400 audit(1338241724.219:5): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=928 comm="apparmor_parser" [26.554860] Bluetooth: RFCOMM TTY layer initialized [26.554866] Bluetooth: RFCOMM socket layer initialized [26.554868] Bluetooth: RFCOMM ver 1.11 [26.557910] type=1400 audit(1338241724.223:6): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper" pid=927 comm="apparmor_parser" [26.559166] type=1400 audit(1338241724.223:7): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=928 comm="apparmor_parser" [26.559574] type=1400 audit(1338241724.223:8): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=928 comm="apparmor_parser" [26.575519] type=1400 audit(1338241724.239:9): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/mission-control-5" pid=931 comm="apparmor_parser" [26.581100] type=1400 audit(1338241724.247:10): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/telepathy-*" pid=931 comm="apparmor_parser" [26.582794] type=1400 audit(1338241724.247:11): apparmor="STATUS" operation="profile_load" name="/usr/bin/evince" pid=929 comm="apparmor_parser" [26.605672] ppdev: user-space parallel port driver [27.592475] sky2 0000:09:00.0: eth0: enabling interface [27.604329] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.606962] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.852509] vesafb: mode is 1024x768x32, linelength=4096, pages=0 [27.852513] vesafb: scrolling: redraw [27.852515] vesafb: Truecolor: size=0:8:8:8, shift=0:16:8:0 [27.852523] mtrr: type mismatch for e0000000,400000 old: write-back new: write-combining [27.852527] mtrr: type mismatch for e0000000,200000 old: write-back new: write-combining [27.852531] mtrr: type mismatch for e0000000,100000 old: write-back new: write-combining [27.852534] mtrr: type mismatch for e0000000,80000 old: write-back new: write-combining [27.852538] mtrr: type mismatch for e0000000,40000 old: write-back new: write-combining [27.852541] mtrr: type mismatch for e0000000,20000 old: write-back new: write-combining [27.852544] mtrr: type mismatch for e0000000,10000 old: write-back new: write-combining [27.852548] mtrr: type mismatch for e0000000,8000 old: write-back new: write-combining [27.852551] mtrr: type mismatch for e0000000,4000 old: write-back new: write-combining [27.852554] mtrr: type mismatch for e0000000,2000 old: write-back new: write-combining [27.852558] mtrr: type mismatch for e0000000,1000 old: write-back new: write-combining [27.853154] vesafb: framebuffer at 0xe0000000, mapped to 0xffffc90005580000, using 3072k, total 3072k [27.853405] Console: switching to colour frame buffer device 128x48 [27.853426] fb0: VESA VGA frame buffer device [28.539800] fglrx_pci 0000:01:00.0: irq 48 for MSI/MSI-X [28.540552] [fglrx] Firegl kernel thread PID: 1168 [28.540679] [fglrx] Firegl kernel thread PID: 1169 [28.540789] [fglrx] Firegl kernel thread PID: 1170 [28.540932] [fglrx] IRQ 48 Enabled [29.845620] [fglrx] Gart USWC size:1236 M. [29.845624] [fglrx] Gart cacheable size:489 M. [29.845629] [fglrx] Reserved FB block: Shared offset:0, size:1000000 [29.845632] [fglrx] Reserved FB block: Unshared offset:fc21000, size:3df000 [29.845635] [fglrx] Reserved FB block: Unshared offset:1fffb000, size:5000 [59.700023] eth2: no IPv6 routers present

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• Integration with Multiple Versions of BizTalk HL7 Accelerator Schemas

  - by Paul Petrov

  Microsoft BizTalk Accelerator for HL7 comes with multiple versions of the HL7 implementation. One of the typical integration tasks is to receive one format and transmit another. For example, system A works HL7 v2.4 messages, system B with v2.3, and system C with v2.2. The system A is exchanging messages with B and C. The logical solution is to create schemas in separate namespaces for each system and assign maps on send ports. Schematic diagram of the messaging solution is shown below:   Nothing is complex about that conceptually. On the implementation level things can get nasty though because of the elaborate nature of HL7 schemas and sheer amount of message types involved. If trying to implement maps directly in BizTalk Map Editor one would quickly get buried by thousands of links between subfields of HL7 segments. Since task is repetitive because HL7 segments are reused between message types it's natural to take advantage of such modular structure and reduce amount of work through reuse. Here's where it makes sense to switch from visual map editor to old plain XSLT. The implementation is done in three steps. First, create XSL templates to map from segments of one version to another. This can be done using BizTalk Map Editor subsequently copying and modifying generated XSL code to create one xsl:template per segment. Group all segments for format mapping in one XSL file (we call it SegmentTemplates.xsl). Here's how template for the PID segment (Patient Identification) would look like this: <xsl:template name="PID"> <PID_PatientIdentification> <xsl:if test="PID_PatientIdentification/PID_1_SetIdPatientId"> <PID_1_SetIdPid> <xsl:value-of select="PID_PatientIdentification/PID_1_SetIdPatientId/text()" /> </PID_1_SetIdPid> </xsl:if> <xsl:for-each select="PID_PatientIdentification/PID_2_PatientIdExternalId"> <PID_2_PatientId> <xsl:if test="CX_0_Id"> <CX_0_Id> <xsl:value-of select="CX_0_Id/text()" /> </CX_0_Id> </xsl:if> <xsl:if test="CX_1_CheckDigit"> <CX_1_CheckDigitSt> <xsl:value-of select="CX_1_CheckDigit/text()" /> </CX_1_CheckDigitSt> </xsl:if> <xsl:if test="CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed"> <CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed> <xsl:value-of select="CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed/text()" /> </CX_2_CodeIdentifyingTheCheckDigitSchemeEmployed> . . . // skipped for brevity This is the most tedious and time consuming part. Templates can be created for only those segments that are used in message interchange. Once this is done the rest goes much easier. The next step is to create message type specific XSL that references (imports) segment templates XSL file. Inside this file simple call segment templates in appropriate places. For example, beginning of the mapping XSL for ADT_A01 message would look like this:   <xsl:import href="SegmentTemplates_23_to_24.xslt" />  <xsl:output omit-xml-declaration="yes" method="xml" version="1.0" />   <xsl:template match="/">    <xsl:apply-templates select="s0:ADT_A01_23_GLO_DEF" />  </xsl:template>   <xsl:template match="s0:ADT_A01_23_GLO_DEF">    <ns0:ADT_A01_24_GLO_DEF>      <xsl:call-template name="EVN" />      <xsl:call-template name="PID" />      <xsl:for-each select="PD1_PatientDemographic">        <xsl:call-template name="PD1" />      </xsl:for-each>      <xsl:call-template name="PV1" />      <xsl:for-each select="PV2_PatientVisitAdditionalInformation">        <xsl:call-template name="PV2" />      </xsl:for-each> This code simply calls segment template directly for required singular elements and in for-each loop for optional/repeating elements. And lastly, create BizTalk map (btm) that references message type specific XSL. It is essentially empty map with Custom XSL Path set to appropriate XSL: In the end, you will end up with one segment templates file that is referenced by many message type specific XSL files which in turn used by BizTalk maps. Once all segment maps are created they are widely reusable and all the rest work is very simple and clean.

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• Downloading stuff from Oracle: an example

  - by user12587121

  Introduction Oracle has a lot of software on offer.  Components of the stack can evolve at different rates and different versions of the components may be in use at any given time.  All this means that even the process of downloading the bits you need can be somewhat daunting.  Here, by way of example, and hopefully to convince you that there is method in the downloading madness,  we describe how to go about downloading the bits for Oracle Identity Manager  (OIM) 11.1.1.5.Firstly, a couple of preliminary points: Folks with Oracle products already installed and looking for bug fixes, patch bundles or patch sets would go directly to the Oracle support website. This Oracle document is a comprehensive description of the Oracle FMW download process and the licensing that applies to downloaded software.   Downloading Oracle Identity Manager 11.1.1.5     To be sure we download the right versions, first locate the Certification Matrix for OIM 11.1.1.5: first go to the Fusion Certification Page then go to the “System Requirements and Supported Platforms for Oracle Identity and Access Management 11gR1” link. Let’s assume you have a 64 bit Linux Machine and an Oracle database already.  Then our  goal is to end up with a list of files like the following: jdk-6u29-linux-x64.bin                    (Java JDK)V26017-01.zip                             (the Repository Creation Utility to create the DB schemas)wls1035_generic.jar                       (the Weblogic Application Server)ofm_iam_generic_11.1.1.5.0_disk1_1of1.zip (the Identity Managament bits)ofm_soa_generic_11.1.1.5.0_disk1_1of2.zip (the SOA bits)ofm_soa_generic_11.1.1.5.0_disk1_2of2.zip jdevstudio11115install.exe                (optional: JDeveloper IDE)soa-jdev-extension.zip                    (optional: SOA extensions for JDeveloper) Downloading the bits 1.    Download the Java JDK, 64 bit version 1.6.0_24+.2.    Download the RCU: here you will see that the RCU is mentioned on the Identity Management home page but no link is provided.  Do not panic.  Due to the amount and turnover of software available only the latest versions are available for download from the main Oracle site.  Over time software gets moved on to the Oracle edelivery site and it is here that we find the RCU version we require: a.    Go to edelivery: https://edelivery.oracle.com b.    Choose Pack ‘ Oracle Fusion Middleware’ and ‘Linux x86-64’ c.    Click on ‘Oracle Fusion Middleware 11g Media Pack for Linux x86-64’ d.    Download: ‘Oracle Fusion Middleware Repository Creation Utility 11g (11.1.1.5.0) for Linux x86’ (V26017.zip) 3.    Download the Weblogic Application Server: WLS 10.3.54.    Download the Oracle Identity Manager bits: one point to clarify here is that currently  the Identity Management bits come in two trains, essentially one for the Directory Services piece and the other for the Access Management and Identity Management parts.  We need to be careful not to confuse the two, in particular to be clear which of the trains is being referred to by  the documentation: a.   So, with this in mind, go to ‘ Oracle Identity and Access Management (11.1.1.5.0)’ and download Disk1. 5.    Download the SOA bits: a.    Go to the edelivery area as for the RCU and download: i.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 1 of 2) ii.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 2 of 2) 6.    You will want to download some development tooling (for plugins or BPEL workflow development): a.    Download Jdeveloper 11.1.1.5 (11.1.1.6 may work but best to stick to the versions that correspond to the WLS version we are using) b.    Go to the site for  SOA tools and download the SOA Composite Editor 11.1.1.5 That’s it, you may proceed to the installation. 

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• Threads are facing deadlock in socket program [migrated]

  - by ankur.trapasiya

  I am developing one program in which a user can download a number of files. Now first I am sending the list of files to the user. So from the list user selects one file at a time and provides path where to store that file. In turn it also gives the server the path of file where does it exist. I am following this approach because I want to give stream like experience without file size limitation. Here is my code.. 1) This is server which gets started each time I start my application public class FileServer extends Thread { private ServerSocket socket = null; public FileServer() { try { socket = new ServerSocket(Utils.tcp_port); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } @Override public void run() { try { System.out.println("request received"); new FileThread(socket.accept()).start(); } catch (IOException ex) { ex.printStackTrace(); } } } 2) This thread runs for each client separately and sends the requested file to the user 8kb data at a time. public class FileThread extends Thread { private Socket socket; private String filePath; public String getFilePath() { return filePath; } public void setFilePath(String filePath) { this.filePath = filePath; } public FileThread(Socket socket) { this.socket = socket; System.out.println("server thread" + this.socket.isConnected()); //this.filePath = filePath; } @Override public void run() { // TODO Auto-generated method stub try { ObjectInputStream ois=new ObjectInputStream(socket.getInputStream()); try { //************NOTE filePath=(String) ois.readObject(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } File f = new File(this.filePath); byte[] buf = new byte[8192]; InputStream is = new FileInputStream(f); BufferedInputStream bis = new BufferedInputStream(is); ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); int c = 0; while ((c = bis.read(buf, 0, buf.length)) > 0) { oos.write(buf, 0, c); oos.flush(); // buf=new byte[8192]; } oos.close(); //socket.shutdownOutput(); // client.shutdownOutput(); System.out.println("stop"); // client.shutdownOutput(); ois.close(); // Thread.sleep(500); is.close(); bis.close(); socket.close(); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE: here filePath represents the path of the file where it exists on the server. The client who is connecting to the server provides this path. I am managing this through sockets and I am successfully receiving this path. 3) FileReceiverThread is responsible for receiving the data from the server and constructing file from this buffer data. public class FileReceiveThread extends Thread { private String fileStorePath; private String sourceFile; private Socket socket = null; public FileReceiveThread(String ip, int port, String fileStorePath, String sourceFile) { this.fileStorePath = fileStorePath; this.sourceFile = sourceFile; try { socket = new Socket(ip, port); System.out.println("receive file thread " + socket.isConnected()); } catch (IOException ex) { ex.printStackTrace(); } } @Override public void run() { try { ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); oos.writeObject(sourceFile); oos.flush(); // oos.close(); File f = new File(fileStorePath); OutputStream os = new FileOutputStream(f); BufferedOutputStream bos = new BufferedOutputStream(os); byte[] buf = new byte[8192]; int c = 0; //************ NOTE ObjectInputStream ois = new ObjectInputStream( socket.getInputStream()); while ((c = ois.read(buf, 0, buf.length)) > 0) { // ois.read(buf); bos.write(buf, 0, c); bos.flush(); // buf = new byte[8192]; } ois.close(); oos.close(); // os.close(); bos.close(); socket.close(); //Thread.sleep(500); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE : Now the problem that I am facing is at the first time when the file is requested the outcome of the program is same as my expectation. I am able to transmit any size of file at first time. Now when the second file is requested (e.g. I have sent file a,b,c,d to the user and user has received file a successfully and now he is requesting file b) the program faces deadlock at this situation. It is waiting for socket's input stream. I put breakpoint and tried to debug it but it is not going in FileThread's run method second time. I could not find out the mistake here. Basically I am making a LAN Messenger which works on LAN. I am using SWT as UI framework.

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• Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

  - by MarkPearl

  After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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• On Reflector Pricing

  - by Nick Harrison

  I have heard a lot of outrage over Red Gate's decision to charge for Reflector. In the interest of full disclosure, I am a fan of Red Gate. I have worked with them on several usability tests. They also sponsor Simple Talk where I publish articles. They are a good company. I am also a BIG fan of Reflector. I have used it since Lutz originally released it. I have written my own add-ins. I have written code to host reflector and use its object model in my own code. Reflector is a beautiful tool. The care that Lutz took to incorporate extensibility is amazing. I have never had difficulty convincing my fellow developers that it is a wonderful tool. Almost always, once anyone sees it in action, it becomes their favorite tool. This wide spread adoption and usability has made it an icon and pivotal pillar in the DotNet community. Even folks with the attitude that if it did not come out of Redmond then it must not be any good, still love it. It is ironic to hear everyone clamoring for it to be released as open source. Reflector was never open source, it was free, but you never were able to peruse the source code and contribute your own changes. You could not even use Reflector to view the source code. From the very beginning, it was never anyone's intention for just anyone to examine the source code and make their own contributions aside from the add-in model. Lutz chose to hand over the reins to Red Gate because he believed that they would be able to build on his original vision and keep the product viable and effective. He did not choose to make it open source, hoping that the community would be up to the challenge. The simplicity and elegance may well have been lost with the "design by committee" nature of open source. Despite being a wonderful and beloved tool, Reflector cannot be an easy tool to maintain. Maybe because it is so wonderful and beloved, it is even more difficult to maintain. At any rate, we have high expectations. Reflector must continue to be able to reasonably disassemble every language construct that the framework and core languages dream up. We want it to be fast, and we also want it to continue to be simple to use. No small order. Red Gate tried to keep the core product free. Sadly there was not enough interest in the Pro version to subsidize the rest of the expenses. $35 is a reasonable cost, more than reasonable. I have read the blog posts and forum posts complaining about the time associated with getting the expense approved. I have heard people complain about the cost being unreasonable if you are a developer from certain countries. Let's do the math. How much of a productivity boost is Reflector? How many hours do you think it saves you in a typical project? The next question is a little easier if you are a contractor or a consultant, but what is your hourly rate? If you are not a contractor, you can probably figure out an hourly rate. How long does it take to get a return on your investment? The value added proposition is not a difficult one to make. I have read people clamoring that Red Gate sucks and is evil. They complain about broken promises and conflicts of interest. Relax! Red Gate is not evil. The world is not coming to an end. The sun will come up tomorrow. I am sure that Red Gate will come up with options for volume licensing or site licensing for companies that want to get a licensed copy for their entire team. Don't panic, and I am sure that many great improvements are on the horizon. Switching the UI to WPF and including a tabbed interface opens up lots of possibilities.

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• Building Enterprise Smartphone App &ndash; Part 2: Platforms and Features

  - by Tim Murphy

  This is part 2 in a series of posts based on a talk I gave recently at the Chicago Information Technology Architects Group.  Feel free to leave feedback. In the previous post I discussed what reasons a company might have for creating a smartphone application.  In this installment I will cover some of history and state of the different platforms as well as features that can be leveraged for building enterprise smartphone applications. Platforms Before you start choosing a platform to develop your solutions on it is good to understand how we got here and what features you can leverage. History To my memory we owe all of this to a product called the Apple Newton that came out in 1987. It was the first PDA and back then I was much more of an Apple fan.  I was very impressed with this device even though it never really went anywhere.  The Palm Pilot by US Robotics was the next major advancement in PDA. It had a simple short hand window that allowed for quick stylus entry.. Later, Windows CE came out and started the broadening of the PDA market. After that it was the Palm and CE operating systems that started showing up on cell phones and for some time these were the two dominant operating systems that were distributed with devices from multiple hardware vendors. Current The iPhone was the first smartphone to take away the stylus and give us a multi-touch interface.  It was a revolution in usability and really changed the attractiveness of smartphones for the general public.  This brought us to the beginning of the current state of the market with the concept of an online store that makes it easy for customers to get new features and functionality on demand. With Android, Google made this more than a one horse race.  Not only did they come to compete, their low cost actually made them the leading OS.  Of course what made Android so attractive also is its major fault.  It is so open that it has been a target for malware which leaves consumers exposed.  Fortunately for Google though, most consumers aren’t aware of the threat that they are under. Although Microsoft had put out one of the first smart phone operating systems with CE it had to play catch up and finally came out with the Windows Phone.  They have gone for a market approach between those of iOS and Android.  They support multiple hardware vendors like Google, but they kept a certification process for applications that is similar to Apple.  They also created a user interface that was different enough to give it a clear separation from the other two platforms. The result of all this is hundreds of millions of smartphones being sold monthly across all three platforms giving us a wide range of choices and challenges when it comes to developing solutions. Features So what are the features that make these devices flexible enough be considered for use in the enterprise? The biggest advantage of today's devices is network connectivity.  The ability to access information from multiple sources at a moment’s notice is critical for businesses.  Add to that the ability to communicate over a variety of text, voice and video modes and we have a powerful starting point. Every smartphone has a cameras and they are not just useful for posting to Instagram. We are seeing more applications such as Bing vision that allow us to scan just about any printed code or text to find information.  These capabilities have been made available to developers in the form of standard libraries for reading barcodes of just about an flavor and optical character recognition (OCR) interpretation. Bluetooth give us the ability to communicate with multiple devices. Whether these are headsets, keyboard or printers the wireless communication capabilities are just starting to evolve.  The more these wireless communication protocols grow, the more opportunities we will see to transfer data between users and a variety of devices. Local storage of information that can be called up even when the device cannot reach the network is the other big capability.  This give users the ability to work offline as well and transmit information when connections are restored. These are the tools that we have to work with to build applications that can be leveraged to gain a competitive advantage for companies that implement them. Coming Up In the third installment I will cover key concerns that you face when building enterprise smartphone apps. del.icio.us Tags: smartphones,enterprise smartphone Apps,architecture,iOS,Android,Windows Phone

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• Exiting a reboot loop

  - by user12617035

  If you're in a situation where the system is panic'ing during boot, you can use # boot net -s to regain control of your system. In my case, I'd added some diagnostic code to a (PCI) driver (that is used to boot the root filesystem). There was a bug in the driver, and each time during boot, the bug occurred, and so caused the system to panic: ... 000000000180b950 genunix:vfs_mountroot+60 (800, 200, 0, 185d400, 1883000, 18aec00) %l0-3: 0000000000001770 0000000000000640 0000000001814000 00000000000008fc %l4-7: 0000000001833c00 00000000018b1000 0000000000000600 0000000000000200 000000000180ba10 genunix:main+98 (18141a0, 1013800, 18362c0, 18ab800, 180e000, 1814000) %l0-3: 0000000070002000 0000000000000001 000000000180c000 000000000180e000 %l4-7: 0000000000000001 0000000001074800 0000000000000060 0000000000000000 skipping system dump - no dump device configured rebooting... If you're logged in via the console, you can send a BREAK sequence in order to gain control of the firmware's (OBP's) prompt. Enter Ctrl-Shift-[ in order to get the TELNET prompt. Once telnet has control, enter this: telnet> send brk You'll be presented with OBP's prompt: ok You then enter the following in order to boot into single-user mode via the network: ok boot net -s Note that booting from the network under Solaris will implicitly cause the system to be INSTALLED with whatever software had last been configured to be installed. However, we are using boot net -s as a "handle" with which to get at the Solaris prompt. Once at that prompt, we can perform actions as root that will let us back out our buggy driver (ok... MY buggy driver :-)) ...and replace it with the original, non-buggy driver. Entering the boot command caused the following output, as well as left us at the Solaris prompt (in single-user-mode): Sun Blade 1500, No Keyboard Copyright 1998-2004 Sun Microsystems, Inc. All rights reserved. OpenBoot 4.16.4, 1024 MB memory installed, Serial #53463393. Ethernet address 0:3:ba:2f:c9:61, Host ID: 832fc961. Rebooting with command: boot net -s Boot device: /pci@1f,700000/network@2 File and args: -s 1000 Mbps FDX Link up Timeout waiting for ARP/RARP packet Timeout waiting for ARP/RARP packet 4000 1000 Mbps FDX Link up Requesting Internet address for 0:3:ba:2f:c9:61 SunOS Release 5.10 Version Generic_118833-17 64-bit Copyright 1983-2005 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Booting to milestone "milestone/single-user:default". Configuring devices. Using RPC Bootparams for network configuration information. Attempting to configure interface bge0... Configured interface bge0 Requesting System Maintenance Mode SINGLE USER MODE # Our goal is to now move to the directory containing the buggy driver and replace it with the original driver (that we had saved away before ever loading our buggy driver! :-) However, since we booted from the network, the root filesystem ("/") is NOT mounted on one of our local disks. It is mounted on an NFS filesystem exported by our install server. To verify this, enter the following command: # mount | head -1 / on my-server:/export/install/media/s10u2/solarisdvd.s10s_u2dvd/latest/Solaris_10/Tools/Boot remote/read/write/setuid/devices/dev=4ac0001 on Wed Dec 31 16:00:00 1969 As a result, we have to create a temporary mount point and then mount the local disk onto that mount point: # mkdir /tmp/mnt # mount /dev/dsk/c0t0d0s0 /tmp/mnt Note that your system will not necessarily have had its root filesystem on "c0t0d0s0". This is something that you should also have recorded before you ever loaded your.. er... "my" buggy driver! :-) One can find the local disk mounted under the root filesystem by entering: # df -k / Filesystem kbytes used avail capacity Mounted on /dev/dsk/c0t0d0s0 76703839 4035535 71901266 6% / To continue with our example, we can now move to the directory of buggy-driver in order to replace it with the original driver. Note that /tmp/mnt is prefixed to the path of where we'd "normally" find the driver: # cd /tmp/mnt/platform/sun4u/kernel/drv/sparcv9 # ls -l pci\* -rw-r--r-- 1 root root 288504 Dec 6 15:38 pcisch -rw-r--r-- 1 root root 288504 Dec 6 15:38 pcisch.aar -rwxr-xr-x 1 root sys 211616 Jun 8 2006 pcisch.orig # cp -p pcisch.orig pcisch We can now synchronize any in-memory filesystem data structures with those on disk... and then reboot. The system will then boot correctly... as expected: # sync;sync # reboot syncing file systems... done Sun Blade 1500, No Keyboard Copyright 1998-2004 Sun Microsystems, Inc. All rights reserved. OpenBoot 4.16.4, 1024 MB memory installed, Serial #xxxxxxxx. Ethernet address 0:3:ba:2f:c9:61, Host ID: yyyyyyyy. Rebooting with command: boot Boot device: /pci@1e,600000/ide@d/disk@0,0:a File and args: SunOS Release 5.10 Version Generic_118833-17 64-bit Copyright 1983-2005 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Hostname: my-host NIS domain name is my-campus.Central.Sun.COM my-host console login: ...so that's how it's done! Of course, the easier way is to never write a buggy-driver... but.. then.. we all "have an eraser on the end of each of our pencils"... don't we ? :-) "...thank you... and good night..."

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• MSDTC - Communication with the underlying transaction manager has failed (Firewall open, MSDTC netwo

  - by SocialAddict

  I'm having problems with my ASP.NET web forms system. It worked on our test server but now we are putting it live one of the servers is within a DMZ and the SQL server is outside of that (on our network still though - although a different subnet) I have open up the firewall completely between these two boxes to see if that was the issue and it still gives the error message "Communication with the underlying transaction manager has failed" whenever we try and use the "TransactionScope". We can access the data for retrieval it's just transactions that break it. We have also used msdtc ping to test the connection and with the amendments on the firewall that pings successfully, but the same error occurs! How do i resolve this error? Any help would be great as we have a system to go live today. Panic :) Edit: I have created a more straightforward test page with a transaction as below and this works fine. Could a nested transaction cause this kind of error and if so why would this only cause an issue when using a live box in a dmz with a firewall? AuditRepository auditRepository = new AuditRepository(); try { using (TransactionScope scope = new TransactionScope()) { auditRepository.Add(DateTime.Now, 1, "TEST-TRANSACTIONS#1", 1); auditRepository.Save(); auditRepository.Add(DateTime.Now, 1, "TEST-TRANSACTIONS#2", 1); auditRepository.Save(); scope.Complete(); } } catch (Exception ex) { Response.Write("Test Error For Transaction: " + ex.Message + "<br />" + ex.StackTrace); } This is the ErrorStack we are getting when the problem occurs: at System.Transactions.TransactionInterop.GetOletxTransactionFromTransmitterPropigationToken(Byte[] propagationToken) at System.Transactions.TransactionStatePSPEOperation.PSPEPromote(InternalTransaction tx) at System.Transactions.TransactionStateDelegatedBase.EnterState(InternalTransaction tx) at System.Transactions.EnlistableStates.Promote(InternalTransaction tx) at System.Transactions.Transaction.Promote() at System.Transactions.TransactionInterop.ConvertToOletxTransaction(Transaction transaction) at System.Transactions.TransactionInterop.GetExportCookie(Transaction transaction, Byte[] whereabouts) at System.Data.SqlClient.SqlInternalConnection.GetTransactionCookie(Transaction transaction, Byte[] whereAbouts) at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx) at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx) at System.Data.SqlClient.SqlInternalConnectionTds.Activate(Transaction transaction) at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction) at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) at System.Data.SqlClient.SqlConnection.Open() at System.Data.Linq.SqlClient.SqlConnectionManager.UseConnection(IConnectionUser user) at System.Data.Linq.SqlClient.SqlProvider.get_IsSqlCe() at System.Data.Linq.SqlClient.SqlProvider.InitializeProviderMode() at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.ChangeDirector.StandardChangeDirector.DynamicInsert(TrackedObject item) at System.Data.Linq.ChangeDirector.StandardChangeDirector.Insert(TrackedObject item) at System.Data.Linq.ChangeProcessor.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges() at RegBook.classes.DbBase.Save() at RegBook.usercontrols.BookingProcess.confirmBookingButton_Click(Object sender, EventArgs e)

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• Linux - serial port read returning EAGAIN...

  - by Andre

  Hello all! I am having some trouble reading some data from a serial port I opened the following way. I've used this instance of code plenty of times and all worked fine, but now, for some reason that I cant figure out, I am completely unable to read anything from the serial port. I am able to write and all is correctly received on the other end, but the replies (which are correctly sent) are never received (No, the cables are all ok ;) ) The code I used to open the serial port is the following: fd = open("/dev/ttyUSB0", O_RDWR | O_NONBLOCK | O_NOCTTY); if (fd == -1) { Aviso("Unable to open port"); return (fd); } else { //Get the current options for the port... bzero(&options, sizeof(options)); /* clear struct for new port settings */ tcgetattr(fd, &options); /*-- Set baud rate -------------------------------------------------------*/ if (cfsetispeed(&options, SerialBaudInterp(BaudRate))==-1) perror("On cfsetispeed:"); if (cfsetospeed(&options, SerialBaudInterp(BaudRate))==-1) perror("On cfsetospeed:"); //Enable the receiver and set local mode... options.c_cflag |= (CLOCAL | CREAD); options.c_cflag &= ~PARENB; /* Parity disabled */ options.c_cflag &= ~CSTOPB; options.c_cflag &= ~CSIZE; /* Mask the character size bits */ options.c_cflag |= SerialDataBitsInterp(8); /* CS8 - Selects 8 data bits */ options.c_cflag &= ~CRTSCTS; // disable hardware flow control options.c_iflag &= ~(IXON | IXOFF | IXANY); // disable XON XOFF (for transmit and receive) options.c_cflag |= CRTSCTS; /* enable hardware flow control */ options.c_cc[VMIN] = 0; //min carachters to be read options.c_cc[VTIME] = 0; //Time to wait for data (tenths of seconds) //Set the new options for the port... tcflush(fd, TCIFLUSH); if (tcsetattr(fd, TCSANOW, &options)==-1) { perror("On tcsetattr:"); } PortOpen[ComPort] = fd; } return PortOpen[ComPort]; After the port is initializeed I write some stuff to it through simple write command... int nc = write(hCom, txchar, n); where hCom is the file descriptor (and it's ok), and (as I said) this works. But... when I do a read afterwards, I get a "Resource Temporarily Unavailable" error from errno. I tested select to see when the file descriptor had something t read... but it always times out! I read data like this: ret = read(hCom, rxchar, n); and I always get an EAGAIN and I have no idea why. All help would be appreciated. Cheers

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• Synchronization requirements for FileStream.(Begin/End)(Read/Write)

  - by Doug McClean

  Is the following pattern of multi-threaded calls acceptable to a .Net FileStream? Several threads calling a method like this: ulong offset = whatever; // different for each thread byte[] buffer = new byte[8192]; object state = someState; // unique for each call, hence also for each thread lock(theFile) { theFile.Seek(whatever, SeekOrigin.Begin); IAsyncResult result = theFile.BeginRead(buffer, 0, 8192, AcceptResults, state); } if(result.CompletedSynchronously) { // is it required for us to call AcceptResults ourselves in this case? // or did BeginRead already call it for us, on this thread or another? } Where AcceptResults is: void AcceptResults(IAsyncResult result) { lock(theFile) { int bytesRead = theFile.EndRead(result); // if we guarantee that the offset of the original call was at least 8192 bytes from // the end of the file, and thus all 8192 bytes exist, can the FileStream read still // actually read fewer bytes than that? // either: if(bytesRead != 8192) { Panic("Page read borked"); } // or: // issue a new call to begin read, moving the offsets into the FileStream and // the buffer, and decreasing the requested size of the read to whatever remains of the buffer } } I'm confused because the documentation seems unclear to me. For example, the FileStream class says: Any public static members of this type are thread safe. Any instance members are not guaranteed to be thread safe. But the documentation for BeginRead seems to contemplate having multiple read requests in flight: Multiple simultaneous asynchronous requests render the request completion order uncertain. Are multiple reads permitted to be in flight or not? Writes? Is this the appropriate way to secure the location of the Position of the stream between the call to Seek and the call to BeginRead? Or does that lock need to be held all the way to EndRead, hence only one read or write in flight at a time? I understand that the callback will occur on a different thread, and my handling of state, buffer handle that in a way that would permit multiple in flight reads. Further, does anyone know where in the documentation to find the answers to these questions? Or an article written by someone in the know? I've been searching and can't find anything. Relevant documentation: FileStream class Seek method BeginRead method EndRead IAsyncResult interface

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• Uploading a file using post() method of QNetworkAccessManager

  - by user304361

  I'm having some trouble with a Qt application; specifically with the QNetworkAccessManager class. I'm attempting to perform a simple HTTP upload of a binary file using the post() method of the QNetworkAccessManager. The documentation states that I can give a pointer to a QIODevice to post(), and that the class will transmit the data found in the QIODevice. This suggests to me that I ought to be able to give post() a pointer to a QFile. For example: QFile compressedFile("temp"); compressedFile.open(QIODevice::ReadOnly); netManager.post(QNetworkRequest(QUrl("http://mywebsite.com/upload") ), &compressedFile); What seems to happen on the Windows system where I'm developing this is that my Qt application pushes the data from the QFile, but then doesn't complete the request; it seems to be sitting there waiting for more data to show up from the file. The post request isn't "closed" until I manually kill the application, at which point the whole file shows up at my server end. From some debugging and research, I think this is happening because the read() operation of QFile doesn't return -1 when you reach the end of the file. I think that QNetworkAccessManager is trying to read from the QIODevice until it gets a -1 from read(), at which point it assumes there is no more data and closes the request. If it keeps getting a return code of zero from read(), QNetworkAccessManager assumes that there might be more data coming, and so it keeps waiting for that hypothetical data. I've confirmed with some test code that the read() operation of QFile just returns zero after you've read to the end of the file. This seems to be incompatible with the way that the post() method of QNetworkAccessManager expects a QIODevice to behave. My questions are: Is this some sort of limitation with the way that QFile works under Windows? Is there some other way I should be using either QFile or QNetworkAccessManager to push a file via post()? Is this not going to work at all, and will I have to find some other way to upload my file? Any suggestions or hints would be appreciated. Thanks, Don

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• Accurately display upload progress in Silverilght upload

  - by Matt

  I'm trying to debug a file upload / download issue I'm having. I've got a Silverlight file uploader, and to transmit the files I make use of the HttpWebRequest class. So I create a connection to my file upload handler on the server and begin transmitting. While a file uploads I keep track of total bytes written to the RequestStream so I can figure out a percentage. Now working at home I've got a rather slow connection, and I think Silverlight, or the browser, is lying to me. It seems that my upload progress logic is inaccurate. When I do multiple file uploads (24 images of 3-6mb big in my testing), the logic reports the files finish uploading but I believe that it only reflects the progress of written bytes to the RequestStream, not the actual amount of bytes uploaded. What is the most accurate way to measure upload progress. Here's the logic I'm using. public void Upload() { if( _TargetFile != null ) { Status = FileUploadStatus.Uploading; Abort = false; long diff = _TargetFile.Length - BytesUploaded; UriBuilder ub = new UriBuilder( App.siteUrl + "upload.ashx" ); bool complete = diff <= ChunkSize; ub.Query = string.Format( "{3}name={0}&StartByte={1}&Complete={2}", fileName, BytesUploaded, complete, string.IsNullOrEmpty( ub.Query ) ? "" : ub.Query.Remove( 0, 1 ) + "&" ); HttpWebRequest webrequest = ( HttpWebRequest ) WebRequest.Create( ub.Uri ); webrequest.Method = "POST"; webrequest.BeginGetRequestStream( WriteCallback, webrequest ); } } private void WriteCallback( IAsyncResult asynchronousResult ) { HttpWebRequest webrequest = ( HttpWebRequest ) asynchronousResult.AsyncState; // End the operation. Stream requestStream = webrequest.EndGetRequestStream( asynchronousResult ); byte[] buffer = new Byte[ 4096 ]; int bytesRead = 0; int tempTotal = 0; Stream fileStream = _TargetFile.OpenRead(); fileStream.Position = BytesUploaded; while( ( bytesRead = fileStream.Read( buffer, 0, buffer.Length ) ) != 0 && tempTotal + bytesRead < ChunkSize && !Abort ) { requestStream.Write( buffer, 0, bytesRead ); requestStream.Flush(); BytesUploaded += bytesRead; tempTotal += bytesRead; int percent = ( int ) ( ( BytesUploaded / ( double ) _TargetFile.Length ) * 100 ); UploadPercent = percent; if( UploadProgressChanged != null ) { UploadProgressChangedEventArgs args = new UploadProgressChangedEventArgs( percent, bytesRead, BytesUploaded, _TargetFile.Length, _TargetFile.Name ); SmartDispatcher.BeginInvoke( () => UploadProgressChanged( this, args ) ); } } //} // only close the stream if it came from the file, don't close resizestream so we don't have to resize it over again. fileStream.Close(); requestStream.Close(); webrequest.BeginGetResponse( ReadCallback, webrequest ); }

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• client side application not working as intended while using AsyncSocket

  - by Miraaj

  Hi All, I am using AsyncSocket class in a simple client-server application. As a first step I want that - as soon as connection is established between client and server, client transmit a welcome message - "connected to xyz server" to server and server displays it in textview. //The code in ClientController class is: -(void)awakeFromNib{ NSError *error = nil; if (![connectSocket connectToHost:@"192.168.0.32" onPort:25242 error:&error]) { NSLog(@"Error starting client: %@", error); return; } NSLog(@"xyz chat client started on port %hu",[connectSocket localPort]); } - (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{ [sock writeData:[@"connected to xyz server" dataUsingEncoding:NSUTF8StringEncoding] withTimeout:30.0 tag:0]; } - (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{ // some relevant code goes here } - (void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag{ NSLog(@"within didWriteDataWithTag:"); // getting this message, means it should have written something to remote socket but // delegate- onSocket:didReadData:withTag: at server side is not getting invoked } // The code in ServerController class is: - (IBAction)startStop:(id)sender{ NSLog(@"startStopAction"); if(!isRunning) { NSError *error = nil; if(![listenSocket acceptOnPort:INPUT_PORT error:&error]) { NSLog(@"Error starting server: %@", error); return; } NSLog(@"Echo server started on port %hu",[listenSocket localPort]); isRunning = YES; [sender setTitle:@"Stop"]; } else { // Stop accepting connections [listenSocket disconnect]; // Stop any client connections int i; for(i = 0; i < [connectedSockets count]; i++) { // Call disconnect on the socket, // which will invoke the onSocketDidDisconnect: method, // which will remove the socket from the list. [[connectedSockets objectAtIndex:i] disconnect]; } NSLog(@"Stopped Echo server"); isRunning = false; [sender setTitle:@"Start"]; } } - (void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket{ [connectedSockets addObject:newSocket]; } - (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port{ NSLog(@"Accepted client %@:%hu", host, port); // it is getting displayed [sock readDataToData:[AsyncSocket CRLFData] withTimeout:READ_TIMEOUT tag:0]; } - (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{ NSString *msgReceived = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease]; NSLog(@"msgReceived in didReadData- %@",msgReceived); // it is not getting displayed [outputView insertText:msgReceived]; [sock readDataToData:[AsyncSocket CRLFData] withTimeout:READ_TIMEOUT tag:0]; } Can anyone suggest me where I may be wrong?? Thanks in advance...... Miraaj

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• Instagram API and Zend/Loader.php

  - by Jaemin Kim

  I want to use Instagram API and I found this code. <html> <head></head> <body> <h1>Popular on Instagram</h1> <?php // load Zend classes require_once 'Zend/Loader.php'; Zend_Loader::loadClass('Zend_Http_Client'); // define consumer key and secret // available from Instagram API console $CLIENT_ID = 'YOUR-CLIENT-ID'; $CLIENT_SECRET = 'YOUR-CLIENT-SECRET'; try { // initialize client $client = new Zend_Http_Client('https://api.instagram.com/v1/media/popular'); $client->setParameterGet('client_id', $CLIENT_ID); // get popular images // transmit request and decode response $response = $client->request(); $result = json_decode($response->getBody()); // display images $data = $result->data; if (count($data) > 0) { echo '<ul>'; foreach ($data as $item) { echo '<li style="display: inline-block; padding: 25px"><a href="' . $item->link . '"><img src="' . $item->images->thumbnail->url . '" /></a> <br/>'; echo 'By: <em>' . $item->user->username . '</em> <br/>'; echo 'Date: ' . date ('d M Y h:i:s', $item->created_time) . '<br/>'; echo $item->comments->count . ' comment(s). ' . $item->likes->count . ' likes. </li>'; } echo '</ul>'; } } catch (Exception $e) { echo 'ERROR: ' . $e->getMessage() . print_r($client); exit; } ?> </body> </html> In here, I found Zender/Load.php, and I've never heard about that. Is it okay to go http://www.zend.com/en/products/guard/downloads here, and download Zend for linux?? And for another question, is this code available to use Instagram API?? For last, could you let me know that is there any simple code to use Instagram API? Thank you.

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