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• NLP with greatly contrained input and abilities

  - by Mike F

  Hat in hand here. I'm a seasoned developer and I would be grateful for a bit of help. I don't have time to read or digest long intricate discussions on theoretical concepts around NLP (or go get my PHD). That said, I have read a few and it's a damn interesting field. The problem is I need real world solutions, for real world products, in real world time frames. The problem I'm having is right now I'm not sure what the right questions are to ask to get started implementing. I believe this is mostly related to vocabulary. I'll read somewhere, a blog post, a forum post, a whitepaper, and it says, I'm doing flooping with the blargy blarg method, and I go google flooping and blargy blarg, and I get references to more obscurity. It seemingly never ends. So, my question is multiphased. First, more generally, how do I become passingly educated on this quickly? Just in time educated. I only need to know what I need to know to take the next step. I've spent 20 years writing code. Explain quick. I'll get it. (I mean provide a reference to something that explains quickly of course). I'm happy to read the right book, but I don't want to read a book where I read the chapter introduction that explains what floopy floop is and then skip over the rest of the chapter with examples of floopy flooping (because now I get what it is). I also don't want to read a book that goes into too much detail with theoretical underpinnings or history. For example, the Jurafsky book seems like way more than I need: http://www.amazon.com/gp/product/0131873210. But I will read it if this is the right book to read. (It's also dang expensive!) I need the root node of the expedited learning tree here, if you will. Point me in the right direction and I'll be quite grateful. I'm expecting quite a lot of firehose drinking - I just need the right firehose. Second, what I need to do is take a single sentence, with a very reduced vocabulary, and get a grammar tree (sorry if this is the wrong terminology) that I can do something with. I know I could easily write this command line input style in c in a more conventional manner, but I need it to be way better than that. But I don't need a chatterbot either. What I'm doing needs to live in a constrained environment. I can't use Python (unfortunately). I can't ship with gigabytes of corpuses. I need any libraries I use to be in c/c++. If I have to write this myself, I will. Hopefully, it will be achievable considering the reduced problem set. Maybe, probably, that's just naive. If so, let me know. :-) Thanks in advance - Mike

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• Why does C# thread die?

  - by JackN

  This is my 1st C# project so I may be doing something obviously improper in the code below. I am using .NET, WinForms (I think), and this is a desktop application until I get the bugs out. UpdateGui() uses Invoke((MethodInvoker)delegate to update various GUI controls based on received serial data and sends a GetStatus() command out the serial port 4 times a second. Thread Read() reads the response from serial port whenever it arrives which should be near immediate. SerialPortFixer is a SerialPort IOException Workaround in C# I found at http://zachsaw.blogspot.com/2010/07/serialport-ioexception-workaround-in-c.html. After one or both threads die I'll see something like The thread 0x1288 has exited with code 0 (0x0). in the debug code output. Why do UpdateGui() and/or Read() eventually die? public partial class UpdateStatus : Form { private readonly byte[] Command = new byte[32]; private readonly byte[] Status = new byte[32]; readonly Thread readThread; private static readonly Mutex commandMutex = new Mutex(); private static readonly Mutex statusMutex = new Mutex(); ... public UpdateStatus() { InitializeComponent(); SerialPortFixer.Execute("COM2"); if (serialPort1.IsOpen) { serialPort1.Close(); } try { serialPort1.Open(); } catch (Exception e) { labelWarning.Text = LOST_COMMUNICATIONS + e; labelStatus.Text = LOST_COMMUNICATIONS + e; labelWarning.Visible = true; } readThread = new Thread(Read); readThread.Start(); new Timer(UpdateGui, null, 0, 250); } static void ProcessStatus(byte[] status) { Status.State = (State) status[4]; Status.Speed = status[6]; // MSB Status.Speed *= 256; Status.Speed += status[5]; var Speed = Status.Speed/GEAR_RATIO; Status.Speed = (int) Speed; ... } public void Read() { while (serialPort1 != null) { try { serialPort1.Read(Status, 0, 1); if (Status[0] != StartCharacter[0]) continue; serialPort1.Read(Status, 1, 1); if (Status[1] != StartCharacter[1]) continue; serialPort1.Read(Status, 2, 1); if (Status[2] != (int)Command.GetStatus) continue; serialPort1.Read(Status, 3, 1); ... statusMutex.WaitOne(); ProcessStatus(Status); Status.update = true; statusMutex.ReleaseMutex(); } catch (Exception e) { Console.WriteLine(@"ERROR! Read() " + e); } } } public void GetStatus() { const int parameterLength = 0; // For GetStatus statusMutex.WaitOne(); Status.update = false; statusMutex.ReleaseMutex(); commandMutex.WaitOne(); if (!SendCommand(Command.GetStatus, parameterLength)) { Console.WriteLine(@"ERROR! SendCommand(GetStatus)"); } commandMutex.ReleaseMutex(); } private void UpdateGui(object x) { try { Invoke((MethodInvoker)delegate { Text = DateTime.Now.ToLongTimeString(); statusMutex.WaitOne(); if (Status.update) { if (Status.Speed > progressBarSpeed.Maximum) { Status.Speed = progressBarSpeed.Maximum; } progressBarSpeed.Value = Status.Speed; labelSpeed.Text = Status.Speed + RPM; ... } else { labelWarning.Text = LOST_COMMUNICATIONS; labelStatus.Text = LOST_COMMUNICATIONS; labelWarning.Visible = true; } statusMutex.ReleaseMutex(); GetStatus(); }); } catch (Exception e) { Console.WriteLine(@"ERROR! UpdateGui() " + e); } } }

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• OpenGL texture misaligned on quad

  - by user308226

  I've been having trouble with this for a while now, and I haven't gotten any solutions that work yet. Here is the problem, and the specifics: I am loading a 256x256 uncompressed TGA into a simple OpenGL program that draws a quad on the screen, but when it shows up, it is shifted about two pixels to the left, with the cropped part appearing on the right side. It has been baffling me for the longest time, people have suggested clamping and such, but somehow I think my problem is probably something really simple, but I just can't figure out what it is! Here is a screenshot comparing the TGA (left) and how it appears running in the program (right) for clarity. Also take note that there's a tiny black pixel on the upper right corner, I'm hoping that's related to the same problem. Here's the code for the loader, I'm convinced that my problem lies in the way that I'm loading the texture. Thanks in advance to anyone who can fix my problem. bool TGA::LoadUncompressedTGA(char *filename,ifstream &texturestream) { cout << "G position status:" << texturestream.tellg() << endl; texturestream.read((char*)header, sizeof(header)); //read 6 bytes into the file to get the tga header width = (GLuint)header[1] * 256 + (GLuint)header[0]; //read and calculate width and save height = (GLuint)header[3] * 256 + (GLuint)header[2]; //read and calculate height and save bpp = (GLuint)header[4]; //read bpp and save cout << bpp << endl; if((width <= 0) || (height <= 0) || ((bpp != 24) && (bpp !=32))) //check to make sure the height, width, and bpp are valid { return false; } if(bpp == 24) { type = GL_RGB; } else { type = GL_RGBA; } imagesize = ((bpp/8) * width * height); //determine size in bytes of the image cout << imagesize << endl; imagedata = new GLubyte[imagesize]; //allocate memory for our imagedata variable texturestream.read((char*)imagedata,imagesize); //read according the the size of the image and save into imagedata for(GLuint cswap = 0; cswap < (GLuint)imagesize; cswap += (bpp/8)) //loop through and reverse the tga's BGR format to RGB { imagedata[cswap] ^= imagedata[cswap+2] ^= //1st Byte XOR 3rd Byte XOR 1st Byte XOR 3rd Byte imagedata[cswap] ^= imagedata[cswap+2]; } texturestream.close(); //close ifstream because we're done with it cout << "image loaded" << endl; glGenTextures(1, &texID); // Generate OpenGL texture IDs glBindTexture(GL_TEXTURE_2D, texID); glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glTexImage2D(GL_TEXTURE_2D, 0, type, width, height, 0, type, GL_UNSIGNED_BYTE, imagedata); delete imagedata; return true; } //Public loading function for TGA images. Opens TGA file and determines //its type, if any, then loads it and calls the appropriate function. //Returns: TRUE on success, FALSE on failure bool TGA::loadTGA(char *filename) { cout << width << endl; ifstream texturestream; texturestream.open(filename,ios::binary); texturestream.read((char*)header,sizeof(header)); //read 6 bytes into the file, its the header. //if it matches the uncompressed header's first 6 bytes, load it as uncompressed LoadUncompressedTGA(filename,texturestream); return true; }

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• Adjust parameters of serial port reading

  - by clinisbut

  Hello. I'm facing a particular issue that regards serial communication under win32. I'm communicating with a device can only accept frames when it is not already communicating. So I must find a valid frame and then inmediatelly send my request. I developed a class named Serial that handles basic operations on serial port (open, close, read, write) and then a Thread calls inside a loop read and write functions. Thread loop //Device is an object of class Serial while( device->isOpen() && !terminate ) { unsigned int readed = 0; unsigned long error = ERROR_SUCCESS; unsigned char* data = device->read( &readed, &error ); if( error==ERROR_SUCCESS ) { //If data received, deliver to upper level if( readed>0 ) { QByteArray output( (const char*)data, (signed int)readed ); emit dataArrived( output, readed ); } } else { //unrelated stuff } //Here I manage the writting issue //Only when nothing is received, and Upper layer wants to send a frame //(Upper layer only will mark as something to send when it detects a valid frame) if( readed==0 ) { out_lock.lock(); //If something to send... if( something_to_send > 0 ) { if( device->write( output_buffer, output_size, &error ) ) { //things... } } } } The Thread basically keeps reading, and when nothing is received, sees if somebody has signaled to send a frame (this means that a valid frame is just received). When this happens, it writes the frame through serial port. Here comes my problem. Inside the Serial::read() function: I use the overlapped way of reading: ::ClearCommError( handle, &dwErrors, &stat); if( stat.cbInQue ) { //If there's something to read, read it, please note the bytes to read parameter, here 1. bool ok = ::ReadFile( handle, buffer_in, 1, &bytes_read, &ov_reader ); if( !ok ) { DWORD _error = ::GetLastError(); if( _error == ERROR_IO_PENDING ) { DWORD result = ::WaitForMultipleObjects( 2, waiters, FALSE,INFINITE ); switch( result ) { //Eventshutdown case WAIT_OBJECT_0: /*code omitted*/break; case WAIT_OBJECT_0+1: ok = ::GetOverlappedResult( handle, &ov_reader, &bytes_read, true ); //check ok value omitted break; } } } } if( bytes_read>0 ) { *size = bytes_read; } Here starts my problem. When device sends me small frames (around 30 bytes) everything works fine, but when larger frames are sent, the code is not able to find any free time between frames causing the thread to never be able send any frame because readed is never 0. If I increase the number of bytes to read inside the read() function, lose the ability to detect when the device "listens": bool ok = ::ReadFile(handle, buffer_in, 50, &bytes_read, &ov_reader ); This happens because my app can receive the end of a frame together with the start of the next one. This behaviour is very common. In the other hand, if I change the INFINITE argument by a valid timeout in the WaitForMultipleObjects function, I lose data. So my question basically is... what I'm doing wrong? Why when reading 1 byte each time I don't find any free time to send my own frames? Thank you

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• SQLAuthority News – 1600 Blog Post Articles – A Milestone

  - by pinaldave

  It was really a very interesting moment for me when I was writing my 1600th milestone blog post. Now it`s a lot more exciting because this time it`s my 1600th blog post. Every time I write a milestone blog post such as this, I have the same excitement as when I was writing my very first blog post. Today I want to write about a few statistics of the blog. Statistics I am frequently asked about my blog stats, so I have already published my blog stats which are measured by WordPress.com. Currently, I have more than 22 Million+ Views on this blog from various sources. There are more than 6200+ feed subscribers in Google Reader only; I think I don`t have to count all other subscribers. My LinkedIn has 1250+ connection, while my Twitter has 2150+. Because I feel that I`m well connected with the Community, I am very thankful to you, my readers. Today I also want to say Thank You to those experts who have helped me to improve. I have maintained a list of all the articles I have written. If you go to my first articles, you will notice that they were a little different from the articles I am writing today. The reason for this is simple: I have two kinds of people helping me write all the better: readers and experts. To my Readers You read the articles and gave me feedback about what was right or wrong, what you liked or disliked. Quite often, you were helpful in writing guest posts, and I also recognize how you were a bit brutal in criticizing some articles, making me re-write them. Because of you, I was able to write better blog posts. To Experts You read the articles and helped me improve. I get inspiration from you and learned a lot from you. Just like everybody, I am a guy who is trying to learn. There are times when I had vague understanding of some subjects, and you did not hesitate to help me. Number of Posts Many ask me if the number of posts is important to me. My answer is YES. Actually, it`s just not about the number of my posts; it is about my blog, my routine, my learning experience and my journey. During the last four years, I have decided that I would be learning one thing a day. This blog has helped me accomplish this goal because in here I have been able to keep my notes and bookmarks. Whatever I learn or experience, I blog and share it with the Community. For me, the blog post number is more than just a number: it`s a summary of my experiences and memories. Once again, thanks for reading and supporting my blog! Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, Pinal Dave, PostADay, SQL, SQL Authority, SQL Milestone, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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• SQL SERVER – Auto Complete and Format T-SQL Code – Devart SQL Complete

  - by pinaldave

  Some people call it laziness, some will call it efficiency, some think it is the right thing to do. At any rate, tools are meant to make a job easier, and I like to use various tools. If we consider the history of the world, if we all wanted to keep traditional practices, we would have never invented the wheel.  But as time progressed, people wanted convenience and efficiency, which then led to laziness. Wanting a more efficient way to do something is not inherently lazy.  That’s how I see any efficiency tools. A few days ago I found Devart SQL Complete.  It took less than a minute to install, and after installation it just worked without needing any tweaking.  Once I started using it I was impressed with how fast it formats SQL code – you can write down any terms or even copy and paste.  You can start typing right away, and it will complete keywords, object names, and fragmentations. It completes statement expressions.  How many times do we write insert, update, delete?  Take this example: to alter a stored procedure name, we don’t remember the code written in it, you have to write it over again, or go back to SQL Server Studio Manager to create and alter which is very difficult.  With SQL Complete , you can write “alter stored procedure,” and it will finish it for you, and you can modify as needed. I love to write code, and I love well-written code.  When I am working with clients, and I find people whose code have not been written properly, I feel a little uncomfortable.  It is difficult to deal with code that is in the wrong case, with no line breaks, no white spaces, improper indents, and no text wrapping.  The worst thing to encounter is code that goes all the way to the right side, and you have to scroll a million times because there are no breaks or indents.  SQL Complete will take care of this for you – if a developer is too lazy for proper formatting, then Devart’s SQL formatter tool will make them better, not lazier. SQL Management Studio gives information about your code when you hover your mouse over it, however SQL Complete goes further in it, going into the work table, and the current rate idea, too. It gives you more information about the parameters; and last but not least, it will just take you to the help file of code navigation.  It will open object explorer in a document viewer.  You can start going through the various properties of your code – a very important thing to do. Here are are interesting Intellisense examples: 1) We are often very lazy to expand *however, when we are using SQL Complete we can just mouse over the * and it will give us all the the column names and we can select the appropriate columns. 2) We can put the cursor after * and it will give us option to expand it to all the column names by pressing the Tab key. 3) Here is one more Intellisense feature I really liked it. I always alias my tables and I always select the alias with special logic. When I was using SQL Complete I selected just a tablename (without schema name) and…(just like below image) … and it autocompleted the schema and alias name (the way I needed it). I believe using SQL Complete we can work faster.  It supports all versions of SQL Server, and works SQL formatting.  Many businesses perform code review and have code standards, so why not use an efficiency tool on everyone’s computer and make sure the code is written correctly from the first time?  If you’re interested in this tool, there are free editions available.  If you like it, you can buy it.  I bought it because it works.  I love it, and I want to hear all your opinions on it, too. You can get the product for FREE.  Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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• The dislikes of TDD

  - by andrewstopford

  I enjoy debates about TDD and Brian Harrys blog post is no exception. Brian sounds out what he likes and dislikes about TDD and it's the dislikes I'll focus on. The idea of having unit tests that cover virtually every line of code that I’ve written that I have to refactor every time I refactor my code makes me shudder.  Doing this way makes me take nearly twice as long as it would otherwise take and I don’t feel like I get sufficient benefits from it. Refactoring your tests to match your refactored code sounds like the tests are suffering. Too many hard dependencies with no SOLID concerns are a sure fire reason you would do this. Maybe at the start of a TDD cycle you would need to do this as your design evolves and you remove these dependencies but this should quickly be resolved as you refactor. If you find your self still doing it then stop and look back at your design. Don’t get me wrong, I’m a big fan of unit tests.  I just prefer to write them after the code has stopped shaking a bit.  In fact most of my early testing is “manual”.  Either I write a small UI on top of my service that allows me to plug in values and try it or write some quick API tests that I throw away as soon as I have validated them. The problem with this is that a UI can make assumptions on your code that then just unit test around and very quickly the design becomes bad and you technical debt sweeps in. If you want to blackbox test your code with a UI then do so after your TDD cycles not before. This is probably by biggest issue with a literal TDD interpretation.  TDD says you never write a line of code without a failing test to show you need it.  I find it leads developers down a dangerous path.  Without any help from a methodology, I have met way too many developers in my life that “back into a solution”.  By this, I mean they write something, it mostly works and they discover a new requirement so they tack it on, and another and another and when they are done, they’ve got a monstrosity of special cases each designed to handle one specific scenario.  There’s way more code than there should be and it’s way too complicated to understand. I believe in finding general solutions to problems from which all the special cases naturally derive rather than building a solution of special cases.  In my mind, to do this, you have to start by conceptualizing and coding the framework of the general algorithm.  For me, that’s a relatively monolithic exercise. TDD is an development pratice not a methodology, the danger is that the solution becomes a mass of different things that violate DRY. TDD won't solve these problems, only good communication and practices like pairing will help. Above all else an assumption that TDD replaces a methodology is a mistake, combine it with what ever works for your team\business but only good communication will help. A good naming scheme\structure for folders, files and tests can help you and your team isolate what tests are for what.

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• What’s the use of code reuse?

  - by Tony Davis

  All great developers write reusable code, don’t they? Well, maybe, but as with all statements regarding what “great” developers do or don’t do, it’s probably an over-simplification. A novice programmer, in particular, will encounter in the literature a general assumption of the importance of code reusability. They spend time worrying about DRY (don’t repeat yourself), moving logic into specific “helper” modules that they can then reuse, agonizing about the minutiae of the class structure, inheritance and interface design that will promote easy reuse. Unfortunately, writing code specifically for reuse often leads to complicated object hierarchies and inheritance models that are anything but reusable. If, instead, one strives to write simple code units that are highly maintainable and perform a single function, in a concise, isolated fashion then the potential for reuse simply “drops out” as a natural by-product. Programmers, of course, care about these principles, about encapsulation and clean interfaces that don’t expose inner workings and allow easy pluggability. This is great when it helps with the maintenance and development of code but how often, in practice, do we actually reuse our code? Most DBAs and database developers are familiar with the practical reasons for the limited opportunities to reuse database code and its potential downsides. However, surely elsewhere in our code base, reuse happens often. After all, we can all name examples, such as date/time handling modules, which if we write with enough care we can plug in to many places. I spoke to a developer just yesterday who looked me in the eye and told me that in 30+ years as a developer (a successful one, I’d add), he’d never once reused his own code. As I sat blinking in disbelief, he explained that, of course, he always thought he would reuse it. He’d often agonized over its design, certain that he was creating code of great significance that he and other generations would reuse, with grateful tears misting their eyes. In fact, it never happened. He had in his head, most of the algorithms he needed and would simply write the code from scratch each time, refining the algorithms and tailoring the code to meet the specific requirements. It was, he said, simply quicker to do that than dig out the old code, check it, correct the mistakes, and adapt it. Is this a common experience, or just a strange anomaly? Viewed in a certain light, building code with a focus on reusability seems to hark to a past age where people built cars and music systems with the idea that someone else could and would replace and reuse the parts. Technology advances so rapidly that the next time you need the “same” code, it’s likely a new technique, or a whole new language, has emerged in the meantime, better equipped to tackle the task. Maybe we should be less fearful of the idea that we could write code well suited to the system requirements, but with little regard for reuse potential, and then rewrite a better version from scratch the next time.

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• Detecting Process Shutdown/Startup Events through ActivationAgents

  - by Ramkumar Menon

  @10g - This post is motivated by one of my close friends and colleague - who wanted to proactively know when a BPEL process shuts down/re-activates. This typically happens when you have a BPEL Process that has an inbound polling adapter, when the adapter loses connectivity to the source system. Or whatever causes it. One valuable suggestion came in from one of my colleagues - he suggested I write my own ActivationAgent to do the job. Well, it really worked. Here is a sample ActivationAgent that you can use. There are few methods you need to override from BaseActivationAgent, and you are on your way to receiving notifications/what not, whenever the shutdown/startup events occur. In the example below, I am retrieving the emailAddress property [that is specified in your bpel.xml activationAgent section] and use that to send out an email notification on the activation agent initialization. You could choose to do different things. But bottomline is that you can use the below-mentioned API to access the very same properties that you specify in the bpel.xml. package com.adapter.custom.activation; import com.collaxa.cube.activation.BaseActivationAgent; import com.collaxa.cube.engine.ICubeContext; import com.oracle.bpel.client.BPELProcessId; import java.util.Date; import java.util.Properties; public class LifecycleManagerActivationAgent extends BaseActivationAgent { public BPELProcessId getBPELProcessId() { return super.getBPELProcessId(); } private void handleInit() throws Exception { //Write initialization code here System.err.println("Entered initialization code...."); //e.g. String emailAddress = getActivationAgentDescriptor().getPropertyValue(emailAddress); //send an email sendEmail(emailAddress); } private void handleLoad() throws Exception { //Write load code here System.err.println("Entered load code...."); } private void handleUnload() throws Exception { //Write unload code here System.err.println("Entered unload code...."); } private void handleUninit() throws Exception { //Write uninitialization code here System.err.println("Entered uninitialization code...."); } public void init(ICubeContext icubecontext) throws Exception { super.init(icubecontext); System.err.println("Initializing LifecycleManager Activation Agent ....."); handleInit(); } public void unload(ICubeContext icubecontext) throws Exception { super.unload(icubecontext); System.err.println("Unloading LifecycleManager Activation Agent ....."); handleUnload(); } public void uninit(ICubeContext icubecontext) throws Exception{ super.uninit(icubecontext); System.err.println("Uninitializing LifecycleManager Activation Agent ....."); handleUninit(); } public String getName() { return "Lifecyclemanageractivationagent"; } public void onStateChanged(int i, ICubeContext iCubeContext) { } public void onLifeCycleChanged(int i, ICubeContext iCubeContext) { } public void onUndeployed(ICubeContext iCubeContext) { } public void onServerShutdown() { } } Once you compile this code, generate a jar file and ensure you add it to the server startup classpath. The library is ready for use after the server restarts. To use this activationAgent, add an additional activationAgent entry in the bpel.xml for the BPEL Process that you wish to monitor. After you deploy the process, the ActivationAgent object will be called back whenever the events mentioned in the overridden methods are raised. [init(), load(), unload(), uninit()]. Subsequently, your custom code is executed. Sample bpel.xml illustrating activationAgent definition and property definition. <?xml version="1.0" encoding="UTF-8"? <BPELSuitcase timestamp="1291943469921" revision="1.0" <BPELProcess wsdlPort="{http://xmlns.oracle.com/BPELTest}BPELTestPort" src="BPELTest.bpel" wsdlService="{http://xmlns.oracle.com/BPELTest}BPELTest" id="BPELTest" <partnerLinkBindings <partnerLinkBinding name="client" <property name="wsdlLocation"BPELTest.wsdl</property </partnerLinkBinding <partnerLinkBinding name="test" <property name="wsdlLocation"test.wsdl</property </partnerLinkBinding </partnerLinkBindings <activationAgents <activationAgent className="oracle.tip.adapter.fw.agent.jca.JCAActivationAgent" partnerLink="test" <property name="portType"Read_ptt</property </activationAgent <activationAgent className="com.oracle.bpel.activation.LifecycleManagerActivationAgent" partnerLink="test" <property name="emailAddress"[email protected]</property </activationAgent </activationAgents </BPELProcess </BPELSuitcase em

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• Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

  - by MarkPearl

  Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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• SQLAuthority News – Random Thoughts and Random Ideas

  - by pinaldave

  There are days when I keep on wondering about SQL, and even my life overall. Today is Saturday so I decided to write about SQL Server. Just like any other mornings, I woke up at 5 and opened my blog editor. I usually do not open Twitter or Facebook when I am planning to focus on my work, as they are little distractions for me. But today I opened my Twitter account and came across a very interesting quote from a friend: ‘Can I expect you to be different today?’ Well, I think it was very powerful quote for me to read first thing on a new day. This quote froze me for a while and made me think, “Do I really want to write about an SQL Server tip, or something different?”  After a little thinking, I’ve realized that for today I would go on and write something different. I am going to write about a few of the ideas and thoughts I had yesterday. After writing all these, I realized that if I am thinking so much in a day, and if I write a blog post of my random musing of the week or month, it can be so long (and boring). Here are some of my random thoughts I’d like to share with you: When the airplane lands, why does everybody get up and try to rush out when their luggage would be coming probably 20-30 minutes later? I really do not like this question when it was asked to me: “SQL Server is not using optimal index which I just created – how can I force it?” I am not going elaborate on this statement but you are allowed to in the comment section. Why do some people wish Good Morning even when they meet us after 4 PM? Can I optimize a query so much that it gives me a result before I execute it? Is it corruption when someone does their personal household work at office? The lane where I drive is always the slowest lane. Why waste time on correcting others when there are a lot of pending improvements for ourselves? If I have to get Tattoo, which SQL Server Execution Plan symbol should I get? Why do I reach office so early that the coffee machine is yet running its daily cleaning job? Why does every laptop have a ‘Page Up’ key at different locations on the keyboard? While I like color movies, I really appreciate black and white photographs. I do not appreciate statements like, “If I receive your books in PDF, I will spread it to many people to give you much greater exposure. So would you please send them to me ASAP?” Do not tell me, “Why does the database grow back after shrinking it every day?” I suggest you use “Search this blog” for the explanation. Petrol prices are currently at INR 74. I hope the rate remains there. Let me ask you the same question which started my day today:  “Can I expect you to be different today?” Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• More Stuff less Fluff

  - by brendonpage

  Originally posted on: http://geekswithblogs.net/brendonpage/archive/2013/11/08/more-stuff-less-fluff.aspxYAGNI – "You Aren't Going To Need It". This is an acronym commonly used in software development to remind developers to only write what they need. This acronym exists because software developers have gotten into the habit of writing everything they need to solve a problem and then everything they think they're going to possibly need in the future. Since we can't predict the future this results in a large portion of the code that we write never being used. That extra code causes unnecessary complexity, which makes it harder to understand and harder to modify when we inevitably have to write something that we didn't think of. I've known about YAGNI for some time now but I never really got it. The words made sense and the idea was clear but the concept never sank in. I was one of those devs who'd happily write a ton of code in the anticipation of future needs. In my mind this was an essential part of writing high quality code. I didn't realise that in doing so I was actually writing low quality code. If you are anything like me you are probably thinking "Lies and propaganda! High quality code needs to be future proof." I agree! But what makes code future proof? If we could see into the future the answer would be simple, code that allows for or meets all future requirements. Since we can't see the future the best we can do is write code that can easily adapt to future requirements, this means writing flexible code. Flexible code is: Fast to understand. Fast to add to. Fast to modify. To be flexible code has to be simple, this means only making it as complex as it needs to be to meet those 3 criteria. That is high quality code. YAGNI! The art is in deciding where to place the seams (abstractions) that will give you flexibility without making decisions about future functionality. Robert C Martin explains it very nicely, he says a good architecture allows you to defer decisions because if you can defer a decision then you have the flexibility to change it. I've recently had a YAGNI experience which brought this all into perspective. I was working on a new project which had multiple clients that connect to a server hosted in the cloud. I was tasked with adding a feature to the desktop client that would allow users to capture items that would then be saved to the cloud. My immediate thought was "Hey we have multiple clients so I should build a web service for these items, that way we can access them from other clients", so I went to work and this is what I created.  I stood back and gazed upon what I'd created with a warm fuzzy feeling. It was beautiful! Then the time came for the team to use the design I'd created for another feature with a new entity. Let's just say that they didn't get the same warm fuzzy feeling that I did when they looked at the design. After much discussion they eventually got it through to me that I'd bloated the design based on an assumption of future functionality. After much more discussion we cut the design down to the following. This design gives us future flexibility with no extra work, it is as complex as it needs to be. It has been a couple of months since this incident and we still haven't needed to access either of the entities from other clients. Using the simpler design allowed us to do more stuff with less stuff!

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• Welcome to BlogEngine.NET 2.9 using Microsoft SQL Server

  If you see this post it means that BlogEngine.NET 2.9 is running and the hard part of creating your own blog is done. There is only a few things left to do. Write Permissions To be able to log in to the blog and writing posts, you need to enable write permissions on the App_Data folder. If you’re blog is hosted at a hosting provider, you can either log into your account’s admin page or call the support. You need write permissions on the App_Data folder because all posts, comments, and blog attachments are saved as XML files and placed in the App_Data folder.  If you wish to use a database to to store your blog data, we still encourage you to enable this write access for an images you may wish to store for your blog posts.  If you are interested in using Microsoft SQL Server, MySQL, SQL CE, or other databases, please see the BlogEngine wiki to get started. Security When you've got write permissions to the App_Data folder, you need to change the username and password. Find the sign-in link located either at the bottom or top of the page depending on your current theme and click it. Now enter "admin" in both the username and password fields and click the button. You will now see an admin menu appear. It has a link to the "Users" admin page. From there you can change the username and password.  Passwords are hashed by default so if you lose your password, please see the BlogEngine wiki for information on recovery. Configuration and Profile Now that you have your blog secured, take a look through the settings and give your new blog a title.  BlogEngine.NET 2.9 is set up to take full advantage of of many semantic formats and technologies such as FOAF, SIOC and APML. It means that the content stored in your BlogEngine.NET installation will be fully portable and auto-discoverable.  Be sure to fill in your author profile to take better advantage of this. Themes, Widgets & Extensions One last thing to consider is customizing the look of your blog.  We have a few themes available right out of the box including two fully setup to use our new widget framework.  The widget framework allows drop and drag placement on your side bar as well as editing and configuration right in the widget while you are logged in.  Extensions allow you to extend and customize the behaivor of your blog.  Be sure to check the BlogEngine.NET Gallery at dnbegallery.org as the go-to location for downloading widgets, themes and extensions. On the web You can find BlogEngine.NET on the official website. Here you'll find tutorials, documentation, tips and tricks and much more. The ongoing development of BlogEngine.NET can be followed at CodePlex where the daily builds will be published for anyone to download.  Again, new themes, widgets and extensions can be downloaded at the BlogEngine.NET gallery. Good luck and happy writing. The BlogEngine.NET team

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• How do you go from a so so programmer to a great one? [closed]

  - by Cervo

  How do you go from being an okay programmer to being able to write maintainable clean code? For example David Hansson was writing Basecamp when in the process he created Rails as part of writing Basecamp in a clean/maintainable way. But how do you know when there is value in a side project like that? I have a bachelors in computer science, and I am about to get a masters and I will say that colleges teach you to write code to solve problems, not neatly or anything. Basically you think of a problem, come up with a solution, and write it down...not necessarily the most maintainable way in the world. Also my first job was in a startup, and now my third is in a small team in a large company where the attitude was/is get it done yesterday (also most of my jobs are mainly database development with SQL with a few ASP.NET web pages/.NET apps on the side). So of course cut/paste is more favored than making things more cleanly. And they would rather have something yesterday even if you have to rewrite it next month rather than to have something in a week that lasts for a year. Also spaghetti code turns up all over the place, and it takes very smart people to write/understand/maintain spaghetti code...However it would be better to do things so simple/clean that even a caveman/woman could do maintenance. Also I get very bored/unmotivated having to go modify the same things cut/pasted in a few locations. Is this the type of skill that you need to learn by working with a serious software organization that has an emphasis on maintenance and maybe even an architect who designs a system architecture and reviews code? Could you really learn it by volunteering on an open source project (it seems to me that a full time programmer job is way more practice than a few hours a week on an open source project)? Is there some course where you can learn this? I can attest that graduate school and undergraduate school do not really emphasize clean software at all. They just teach the structures/algorithms and then send you off into the world to solve problems. Overall I think the first thing is learning to write clean/maintainable code within the bounds of the project in order to become a good programmer. Then the next thing is learning when you need to do a side project (like a framework) to make things more maintainable/clean even while you still deliver things for the deadline in order to become a great programmer. For example, you are making an SQL report and someone gives you 100 calculations for individual columns. At what point does it make sense to construct a domain specific language to encode the rules in simply and then generate all the SQL as opposed to cut/pasting the query from the table a bunch of times and then adjusting each query to do the appropriate calculations. This is the type of thing I would say a great programmer would know. He/she would maybe even know ways to avoid the domain specific language and to still do all the calculations without creating an unmaintainable mess or a ton of repetitive code to cut/paste everywhere.

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• Information Indepth Newsletter - Linux Edition

  - by Paulo Folgado

  INFORMATION INDEPTH NEWSLETTERLinux Edition February 2011 Stay Connected:  NEWS Now Available: Oracle Linux 6 Get the latest release of Oracle Linux 6, which includes Unbreakable Enterprise Kernel.Download Oracle Linux 6 Read More Customers Succeed by Using Oracle Exadata with Oracle Linux Watch IT executives from Bank of America, Linkshare, and Johns Hopkins as they talk about the business challenges they faced and why they chose to use Oracle Linux along with Oracle Exadata as the solution. Watch Now Video Interview: Oracle Senior Vice President Wim Coekaerts Watch Wim Coekaerts, senior vice president, Linux and Virtualization Engineering, as he talks about use cases for Oracle VM Templates as well as the Unbreakable Enterprise Kernel for Linux.Watch Now Hot Off the Press: Migrate Your IBM AIX Environment to Oracle Linux This new white paper provides recommendations for planning and implementing the migration of applications from an IBM Power System running AIX to Oracle's Sun Fire X4800 Server with Intel Xeon 7560 Processor running Oracle Linux 5.5.Read More  Back to Top BLOGOSPHERE Just Launched: The Oracle Linux Blog Follow our new Oracle Linux blog  to hear the latest updates, product news, upcoming events, and all the latest happenings, directly from the Linux team at Oracle. Back to Top TECH DIVE NEW: Linux/Oracle Solaris CommandComparo Site from Oracle Technology NetworkThis site gives equivalent command syntax in Oracle Solaris 10 and Oracle Enterprise Linux 5 for common administrative tasks--focusing particularly on tasks that have tricky syntax or that you frequently need to double check. It acts as a quick reference for administrators who operate in these two OS environments. Free Download: Oracle Linux Release 5.6Did you know that by using Oracle Linux 5.5 or 5.6 along with the Unbreakable Enterprise Kernel, you can get all the benefits of Linux mainline kernel 2.6.32 and more, right now, without the need to reinstall or migrate to a new operating system such as RHEL6?Read Release NotesDownload Oracle Linux 5.6 LSB 4.0 Certification Completed for Oracle Linux 5.5Oracle Linux 5.5 with Unbreakable Enterprise Kernel successfully completed the LSB 4.0 certification.  Back to Top WEBCASTS Boost Your Linux Performance with Oracle's Enhancements in Infiniband and RDSRegister to hear Director of Kernel Engineering Chris Mason cover scalability and performance improvements in Linux environment. Get the Facts Oracle's Unbreakable Enterprise KernelSVP Wim Coekaerts and Senior Director Monica Kumar cover the facts about and benefits of using Unbreakable Enterprise Kernel.  View Other Webcasts on Demand   Back to Top EVENTS Collaborate 2011April 10-14 Orlando, Florida Cloud Summit Events, WorldwideVarious dates (check the city for date/time of event) Datacenter Efficiency Events WorldwideThese events include Linux and Oracle VM sessions.Various dates (check the city for date/time of event) Virtualization Events in North America Find an Oracle Event  Back to Top EDUCATION Get Oracle Linux Certified from Oracle University Oracle University offers courses in both Oracle Linux and the administration of Oracle Database on Linux.  Back to Top CUSTOMER SPOTLIGHT Pella Corporation Improves IT Performance and Efficiency with Oracle Linux and Oracle VM To improve IT performance and efficiency and lower operational costs, Pella Corporation, has standardized on Oracle VM and Oracle Linux. Read More Disney Store Deploys POS in 330 Stores and 7 Countries on Oracle Linux Disney Store is running 1,500 registers worldwide on a broad Oracle technology software stack including Oracle Database 11g, Oracle Fusion Middleware, and Oracle Linux. Read More Back to Top PARTNER SPOTLIGHT Emulex and Oracle Announce Data Integrity Features The Unbreakable Enterprise Kernel provides data integrity checking between Oracle Database applications and Emulex 8Gb/s LightPulse Fibre Channel Host Bus Adapters. Read More Dell Inc. Dell Inc. tested and validated configurations support Oracle Linux. Back to Top STAY IN TOUCH Follow @ORCL_Linux on Twitter for the latest penguin tweets Bookmark Oracle.com/Linux Read the Oracle Linux blog Back to Top  Oracle Information InDepth newsletters bring targeted news, articles, customer stories, and special offers to business people who want to find out how to streamline enterprise information management, measure results, improve business processes, and communicate a single truth to their constituents. Please send questions or comments to [email protected]. For answers to questions about subscribing, unsubscribing, and managing your Oracle e-mail communications preferences, please see the Oracle E-Mail Communications page. Copyright © 2011, Oracle Corporation and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. This document is provided for information purposes only, and the contents hereof are subject to change without notice. This document is not warranted to be error-free, nor is it subject to any other warranties or conditions, whether expressed orally or implied in law, including implied warranties and conditions of merchantability or fitness for a particular purpose. We specifically disclaim any liability with respect to this document, and no contractual obligations are formed either directly or indirectly by this document. This document may not be reproduced or transmitted in any form or by any means, electronic or mechanical, for any purpose, without our prior written permission. 

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• Interface implementation Diferences

  - by carlos

  What is the diference of using interfaces like ... I have an interface Public Interface IProDataSource Function read() As Integer End Interface Then a class Public Class DataSource : Implements IProDataSource Function read() As Integer Implements IProDataSource.read some code... End Function End Class Then I use this the next way ... but what is the difference? ... boths approaches are working ... Dim obj As IProDataSource = New DataSource obj.read() vs Dim datas as new Datasource datas.read() The only difference I have notice is that if the method is declare private it will be visible using the first approach only. Thanks for any comments !!!

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• Eventlet client-server

  - by johannix

  I'm trying to setup a server-client interraction: Server gets a string from client Server returns data to client I got this working with socket.send and socket.recv, but was wondering how to get it working with files through socket.makefile. I've got most of the pieces working, but don't know how to force each of the pieces to read at the appropriate time. So what it looks like is happening is that both the client and server are reading on the socket at the same time. Any ideas on how to let the server complete the original read before the client starts waiting for its information? Below are the core pieces that reproduce the read lock. Server: def handle(green_socket): file_handler = green_socket.makefile('rw') print 'before server read' lines = file_handler.readlines() print "readlines: %s" % (lines) print '** Server started **' server = eventlet.listen((HOST, PORT)) pool = eventlet.GreenPool() while True: new_sock, address = server.accept() pool.spawn_n(handle, new_sock) Client: from eventlet.green import socket green_socket = eventlet.connect((HOST, PORT)) file_handler = green_socket.makefile('rw') print 'before write' file_handler.writelines('client message') file_handler.flush() print 'before client read' lines = file_handler.readlines()

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• MySQL – Scalability on Amazon RDS: Scale out to multiple RDS instances

  - by Pinal Dave

  Today, I’d like to discuss getting better MySQL scalability on Amazon RDS. The question of the day: “What can you do when a MySQL database needs to scale write-intensive workloads beyond the capabilities of the largest available machine on Amazon RDS?” Let’s take a look. In a typical EC2/RDS set-up, users connect to app servers from their mobile devices and tablets, computers, browsers, etc.  Then app servers connect to an RDS instance (web/cloud services) and in some cases they might leverage some read-only replicas.   Figure 1. A typical RDS instance is a single-instance database, with read replicas.  This is not very good at handling high write-based throughput. As your application becomes more popular you can expect an increasing number of users, more transactions, and more accumulated data.  User interactions can become more challenging as the application adds more sophisticated capabilities. The result of all this positive activity: your MySQL database will inevitably begin to experience scalability pressures. What can you do? Broadly speaking, there are four options available to improve MySQL scalability on RDS. 1. Larger RDS Instances – If you’re not already using the maximum available RDS instance, you can always scale up – to larger hardware.  Bigger CPUs, more compute power, more memory et cetera. But the largest available RDS instance is still limited.  And they get expensive. “High-Memory Quadruple Extra Large DB Instance”: 68 GB of memory 26 ECUs (8 virtual cores with 3.25 ECUs each) 64-bit platform High I/O Capacity Provisioned IOPS Optimized: 1000Mbps 2. Provisioned IOPs – You can get provisioned IOPs and higher throughput on the I/O level. However, there is a hard limit with a maximum instance size and maximum number of provisioned IOPs you can buy from Amazon and you simply cannot scale beyond these hardware specifications. 3. Leverage Read Replicas – If your application permits, you can leverage read replicas to offload some reads from the master databases. But there are a limited number of replicas you can utilize and Amazon generally requires some modifications to your existing application. And read-replicas don’t help with write-intensive applications. 4. Multiple Database Instances – Amazon offers a fourth option: “You can implement partitioning,thereby spreading your data across multiple database Instances” (Link) However, Amazon does not offer any guidance or facilities to help you with this. “Multiple database instances” is not an RDS feature.  And Amazon doesn’t explain how to implement this idea. In fact, when asked, this is the response on an Amazon forum: Q: Is there any documents that describe the partition DB across multiple RDS? I need to use DB with more 1TB but exist a limitation during the create process, but I read in the any FAQ that you need to partition database, but I don’t find any documents that describe it. A: “DB partitioning/sharding is not an official feature of Amazon RDS or MySQL, but a technique to scale out database by using multiple database instances. The appropriate way to split data depends on the characteristics of the application or data set. Therefore, there is no concrete and specific guidance.” So now what? The answer is to scale out with ScaleBase. Amazon RDS with ScaleBase: What you get – MySQL Scalability! ScaleBase is specifically designed to scale out a single MySQL RDS instance into multiple MySQL instances. Critically, this is accomplished with no changes to your application code.  Your application continues to “see” one database.   ScaleBase does all the work of managing and enforcing an optimized data distribution policy to create multiple MySQL instances. With ScaleBase, data distribution, transactions, concurrency control, and two-phase commit are all 100% transparent and 100% ACID-compliant, so applications, services and tooling continue to interact with your distributed RDS as if it were a single MySQL instance. The result: now you can cost-effectively leverage multiple MySQL RDS instance to scale out write-intensive workloads to an unlimited number of users, transactions, and data. Amazon RDS with ScaleBase: What you keep – Everything! And how does this change your Amazon environment? 1. Keep your application, unchanged – There is no change your application development life-cycle at all.  You still use your existing development tools, frameworks and libraries.  Application quality assurance and testing cycles stay the same. And, critically, you stay with an ACID-compliant MySQL environment. 2. Keep your RDS value-added services – The value-added services that you rely on are all still available. Amazon will continue to handle database maintenance and updates for you. You can still leverage High Availability via Multi A-Z.  And, if it benefits youra application throughput, you can still use read replicas. 3. Keep your RDS administration – Finally the RDS monitoring and provisioning tools you rely on still work as they did before. With your one large MySQL instance, now split into multiple instances, you can actually use less expensive, smallersmaller available RDS hardware and continue to see better database performance. Conclusion Amazon RDS is a tremendous service, but it doesn’t offer solutions to scale beyond a single MySQL instance. Larger RDS instances get more expensive.  And when you max-out on the available hardware, you’re stuck.  Amazon recommends scaling out your single instance into multiple instances for transaction-intensive apps, but offers no services or guidance to help you. This is where ScaleBase comes in to save the day. It gives you a simple and effective way to create multiple MySQL RDS instances, while removing all the complexities typically caused by “DIY” sharding andwith no changes to your applications . With ScaleBase you continue to leverage the AWS/RDS ecosystem: commodity hardware and value added services like read replicas, multi A-Z, maintenance/updates and administration with monitoring tools and provisioning. SCALEBASE ON AMAZON If you’re curious to try ScaleBase on Amazon, it can be found here – Download NOW. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• writing a custom anaylzer in pylucene/inheritance using jcc?

  - by yaniv

  Hello, I want to write a custom analyzer in pylucene. Usually in java lucene , when you write a analyzer class , your class inherits lucene's Analyzer class. but pylucene uses jcc , the java to c++/python compiler. So how do you let a python class inherit from a java class using jcc ,and especially how do you write a custom pylucene analyzer? Thanks.

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• Webdriver python bindings

  - by Ockonal

  Hello, I can't make python bindings for webdriver workable. Here is tutorial for installing. easy_install webdriver Won't find webdriver package so I have to install it manually from sources. I've downloaded source from trunk, set WEBDRIVER and PYTHONPATH variables and installed webdriver: ~$ cd ~ ~$ svn checkout http://selenium.googlecode.com/svn/trunk/ selenium-read-only ~$ cd selenium-read-only ~# python setup.py install ~$ env |grep PYT ~$> PYTHONPATH=:/home/ockonal/selenium-read-only/../../../firefox/lib-src:/home/ockonal/selenium-read-only/.. ~$ env |grep WEB ~$> WEBDRIVER=/home/ockonal/selenium-read-only Then I downloaded RemoteDriverServer.jar and ran it: java -jar RemoteDriverServer.jar 8888 Now I want to include webdriver module in python script: from selenium.firefox.webdriver import WebDriver ImportError: No module named firefox.webdriver

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• Javascript Print Script Not Working in IE

  - by TY

  Greets! I'm a noob struggling to learn html and javascript - getting there slowly. I'm trying to print a DIV served up by SimpleModal. The page is at: www.planetsarsfield.com This "Print" function is in the recipe box at the bottom. Everything works great in FF, but it doesn't work at all in IE8. I must be doing something fundamentally wrong but I can't spot it. Any ideas? Cheers, TY ++++++++++++++++++++++++++++++++++++++++++++++++ <script type="text/javascript"> function PrintElem(elem) { Popup($(elem).html()); } function Popup(data) { var mywindow = window.open('', 'basic-modal-content', 'height=400,width=600'); mywindow.document.write('<html><head><title>on the grill... latest recipe</title>'); mywindow.document.write('<link href="PATH/print.css" rel="stylesheet" type="text/css" />') mywindow.document.write('</head><body >'); mywindow.document.write(data); mywindow.document.write('</body></html>'); mywindow.document.close(); mywindow.print(); return true; } </script>

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• why my print doesn't work?

  - by udaya

  hi In this below program i am printing the contents of the div when i click the print button i am receiving an alert message printer error not available why it is so <html> <head> <script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.1.min.js" > </script> <script type="text/javascript"> function PrintElem(elem) { Popup($(elem).text()); } function Popup(data) { var mywindow = window.open('', 'my div', 'height=400,width=600'); mywindow.document.write('<html><head><title>my div</title>'); /*optional stylesheet*/ //mywindow.document.write('<link rel="stylesheet" href="main.css" type="text/css" />'); mywindow.document.write('</head><body >'); mywindow.document.write(data); mywindow.document.write('</body></html>'); mywindow.document.close(); mywindow.print(); return true; } </script> </head> <body> <div id="mydiv"> This will be printed. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque a quam at nibh adipiscing interdum. Nulla vitae accumsan ante. </div> <input type="button" value="Print Div" onclick="PrintElem('#mydiv')" /> </body> </html>

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• How can I fix "[Error 6] The handle is invalid." with PySerial

  - by alnorth29

  I'm trying to connect to my phone from my Windows 7 PC using PySerial with the following code: import wmi import serial c = wmi.WMI() modem = c.query("SELECT * FROM Win32_POTSModem").pop() ser = serial.Serial(modem.AttachedTo, modem.MaxBaudRateToSerialPort) try: ser.write('at \r\n') print ser.readline() finally: ser.close() But get the following error on the write call: Traceback (most recent call last): File "D:\Alasdair\Documents\Python Scripts\Phone Interface\test.py", line 14, in <module> ser.write('at \r\n') File "C:\Python26\Lib\site-packages\serial\serialwin32.py", line 255, in write raise SerialException("WriteFile failed (%s)" % ctypes.WinError()) SerialException: WriteFile failed ([Error 6] The handle is invalid.) I've tried connecting with TeraTerm and that works fine, so it's not a problem with the connection to the phone itself. I've been searching around for ages trying to find a solution but haven't come up with anything that works. Any ideas?

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• Whats wrong with my triple DES wrapper??

  - by Chen Kinnrot

  it seems that my code adds 6 bytes to the result file after encrypt decrypt is called.. i tries it on a mkv file.. please help here is my code class TripleDESCryptoService : IEncryptor, IDecryptor { public void Encrypt(string inputFileName, string outputFileName, string key) { EncryptFile(inputFileName, outputFileName, key); } public void Decrypt(string inputFileName, string outputFileName, string key) { DecryptFile(inputFileName, outputFileName, key); } static void EncryptFile(string inputFileName, string outputFileName, string sKey) { var outFile = new FileStream(outputFileName, FileMode.OpenOrCreate, FileAccess.ReadWrite); // The chryptographic service provider we're going to use var cryptoAlgorithm = new TripleDESCryptoServiceProvider(); SetKeys(cryptoAlgorithm, sKey); // This object links data streams to cryptographic values var cryptoStream = new CryptoStream(outFile, cryptoAlgorithm.CreateEncryptor(), CryptoStreamMode.Write); // This stream writer will write the new file var encryptionStream = new BinaryWriter(cryptoStream); // This stream reader will read the file to encrypt var inFile = new FileStream(inputFileName, FileMode.Open, FileAccess.Read); var readwe = new BinaryReader(inFile); // Loop through the file to encrypt, line by line var date = readwe.ReadBytes((int)readwe.BaseStream.Length); // Write to the encryption stream encryptionStream.Write(date); // Wrap things up inFile.Close(); encryptionStream.Flush(); encryptionStream.Close(); } private static void SetKeys(SymmetricAlgorithm algorithm, string key) { var keyAsBytes = Encoding.ASCII.GetBytes(key); algorithm.IV = keyAsBytes.Take(algorithm.IV.Length).ToArray(); algorithm.Key = keyAsBytes.Take(algorithm.Key.Length).ToArray(); } static void DecryptFile(string inputFilename, string outputFilename, string sKey) { // The encrypted file var inFile = File.OpenRead(inputFilename); // The decrypted file var outFile = new FileStream(outputFilename, FileMode.OpenOrCreate, FileAccess.ReadWrite); // Prepare the encryption algorithm and read the key from the key file var cryptAlgorithm = new TripleDESCryptoServiceProvider(); SetKeys(cryptAlgorithm, sKey); // The cryptographic stream takes in the encrypted file var encryptionStream = new CryptoStream(inFile, cryptAlgorithm.CreateDecryptor(), CryptoStreamMode.Read); // Write the new unecrypted file var cleanStreamReader = new BinaryReader(encryptionStream); var cleanStreamWriter = new BinaryWriter(outFile); cleanStreamWriter.Write(cleanStreamReader.ReadBytes((int)inFile.Length)); cleanStreamWriter.Close(); outFile.Close(); cleanStreamReader.Close(); } }

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• Java FileLock for Reading and Writing

  - by bobtheowl2

  I have a process that will be called rather frequently from cron to read a file that has certain move related commands in it. My process needs to read and write to this data file - and keep it locked to prevent other processes from touching it during this time. A completely separate process can be executed by a user to (potential) write/append to this same data file. I want these two processes to play nice and only access the file one at a time. The nio FileLock seemed to be what I needed (short of writing my own semaphore type files), but I'm having trouble locking it for reading. I can lock and write just fine, but when attempting to create lock when reading I get a NonWritableChannelException. Is it even possible to lock a file for reading? Seems like a RandomAccessFile is closer to what I need, but I don't see how to implement that. Here is the code that fails: FileInputStream fin = new FileInputStream(f); FileLock fl = fin.getChannel().tryLock(); if(fl != null) { System.out.println("Locked File"); BufferedReader in = new BufferedReader(new InputStreamReader(fin)); System.out.println(in.readLine()); ... The exception is thrown on the FileLock line. java.nio.channels.NonWritableChannelException at sun.nio.ch.FileChannelImpl.tryLock(Unknown Source) at java.nio.channels.FileChannel.tryLock(Unknown Source) at Mover.run(Mover.java:74) at java.lang.Thread.run(Unknown Source) Looking at the JavaDocs, it says Unchecked exception thrown when an attempt is made to write to a channel that was not originally opened for writing. But I don't necessarily need to write to it. When I try creating a FileOutpuStream, etc. for writing purposes it is happy until I try to open a FileInputStream on the same file.

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