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  • using threads in menu options

    - by vbNewbie
    I have an app that has a console menu with 2/3 selections. One process involves uploading a file and performing a lengthy search process on its contents, whilst another process involves SQL queries and is an interactive process with the user. I wish to use threads to allow one process to run and the menu to offer the option for the second process to run. However you cannot run the first process twice. I have created threads and corrected some compilation errors but the threading options are not working correctly. Any help appreciated. main... Dim tm As Thread = New Thread(AddressOf loadFile) Dim ts As Thread = New Thread(AddressOf reports) .... While Not response.Equals("3") Try Console.Write("Enter choice: ") response = Console.ReadLine() Console.WriteLine() If response.Equals("1") Then Console.WriteLine("Thread 1 doing work") tm.SetApartmentState(ApartmentState.STA) tm.IsBackground = True tm.Start() response = String.Empty ElseIf response.Equals("2") Then Console.WriteLine("Starting a second Thread") ts.Start() response = String.Empty End If ts.Join() tm.Join() Catch ex As Exception errormessage = ex.Message End Try End While I realize that a form based will be easier to implement with perhaps just calling different forms to handle the processes.But I really dont have that option now since the console app will be added to api later. But here are my two processes from the menu functions. Also not sure what to do with the boolean variabel again as suggested below. Private Sub LoadFile() Dim dialog As New OpenFileDialog Dim response1 As String = Nothing Dim filepath As String = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) dialog.InitialDirectory = filepath If dialog.ShowDialog() = DialogResult.OK Then fileName = dialog.FileName ElseIf DialogResult.Cancel Then Exit Sub End If Console.ResetColor() Console.Write("Begin Search -- Discovery Search, y or n? ") response1 = Console.ReadLine() If response1 = "y" Then Search() ElseIf response1 = "n" Then Console.Clear() main() End If isRunning = False End Sub and the second one Private Shared Sub report() Dim rptGen As New SearchBlogDiscovery.rptGeneration Console.WriteLine("Tread Process started") rptGen.main() Console.WriteLine("Thread Process ended") isRunning = False End Sub

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  • C#: HTTPWebResponse using application/x-www-form-urlencoded

    - by CSharpened
    So I sent an HTTPWebRequest using application/x-www-form-urlencoded as my content type. I assume that this means the reponse will be returned in a similar type? (EDIT: Have now been told this isn't the case) My question is this. How do I access the different key/value pairs returned in the response. My code so far looks like this. I can of course read the string but surely there is a better way to access the data other than ripping the string apart. HttpWebResponse response = SendPOSTRequest("https://site/page?Service=foo", content.ToString(), "", "", true); string responseCode = response.StatusCode.ToString(); string responseStatusDescription = response.StatusDescription; StreamReader sr = new StreamReader(response.GetResponseStream()); string result = sr.ReadToEnd(); I tried using XML/linq to read the elements into an XDocument but of course it is not being returned in XML form. Assume I have 3 or 4 different pieces of information in there how could I read them out? EDIT: I have just checked and the data is being returned as text/plain. How can this be processed easily? EDIT: The response string once retrieved via a streamreader is: VPSProtocol=2.23 Status=OK StatusDetail=Server transaction registered successfully. VPSTxId={FDC93F3D-FC64-400D-875F-0B7E855AD81F} SecurityKey=***** NextURL=https://foo.com/PaymentPage.asp?TransactionID={875F-0B7E855AD81F}

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  • Returning JSON or XML for Exceptions in Jersey

    - by Dominic
    My goal is to have an error bean returned on a 404 with a descriptive message when a object is not found, and return the same MIME type that was requested. I have a look up resource, which will return the specified object in XML or JSON based on the URI (I have setup the com.sun.jersey.config.property.resourceConfigClass servlet parameter so I dont need the Accept header. My JAXBContextResolver has the ErrorBean.class in its list of types, and the correct JAXBContext is returned for this class because I can see in the logs). eg: http://foobar.com/rest/locations/1.json @GET @Path("{id}") @Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML}) public Location getCustomer(@PathParam("id") int cId) { //look up location from datastore .... if (location == null) { throw new NotFoundException("Location" + cId + " is not found"); } } And my NotFoundException looks like this: public class NotFoundException extends WebApplicationException { public NotFoundException(String message) { super(Response.status(Response.Status.NOT_FOUND). entity(new ErrorBean( message, Response.Status.NOT_FOUND.getStatusCode() ) .build()); } } The ErrorBean is as follows: @XmlRootElement(name = "error") public class ErrorBean { private String errorMsg; private int errorCode; //no-arg constructor, property constructor, getter and setters ... } However, I'm always getting a 204 No Content response when I try this. I have hacked around, and if I return a string and specify the mime type this works fine: public NotFoundException(String message) { super(Response.status(Response.Status.NOT_FOUND). entity(message).type("text/plain").build()); } I have also tried returning an ErrorBean as a resource. This works fine: {"errorCode":404,"errorMsg":"Location 1 is not found!"}

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  • Sample twitter App

    - by Jack
    I am now running my code on a web hosting service http://xtreemhost.com/ <?php function updateTwitter($status) { $username = 'xxxxxx'; $password = 'xxxx'; $url = 'http://twitter.com/statuses/update.xml'; $postargs = 'status='.urlencode($status); $responseInfo=array(); $ch = curl_init($url); curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 2); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt ($ch, CURLOPT_POST, true); // Give CURL the arguments in the POST curl_setopt ($ch, CURLOPT_POSTFIELDS, $postargs); // Set the username and password in the CURL call curl_setopt($ch, CURLOPT_USERPWD, $username.':'.$password); // Set some cur flags (not too important) $response = curl_exec($ch); if($response === false) { echo 'Curl error: ' . curl_error($ch); } else { echo 'Operation completed without any errors<br/>'; } // Get information about the response $responseInfo=curl_getinfo($ch); // Close the CURL connection curl_close($ch); // Make sure we received a response from Twitter if(intval($responseInfo['http_code'])==200){ // Display the response from Twitter echo $response; }else{ // Something went wrong echo "Error: " . $responseInfo['http_code']; } curl_close($ch); } updateTwitter("Just finished a sweet tutorial on http://brandontreb.com"); ?> I get the following error now Curl error: Couldn't resolve host 'api.twitter.com' Error: 0 Please somebody solve my problem

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  • Getting information from servlet created html

    - by user541597
    I have a servlet that creates an html text box and then redirects to another servlet on submit. How can I access the value of the html text box from the new servlet? I am able to access servlet variables from the new servlet but I am not aware of how to access the value of the html generated code. thanks, Here is the servlet that gets the text input public class ServletB extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); String value = System.getProperty("card"); PrintWriter out = response.getWriter(); out.println("<center><h1>Your preffered method of payment is "+value+"</h1><br />"); out.println("Please Enter Card Number<input type =\"text\" name = \"number\"/><form action=\"http://codd.cs.gsu.edu:9999/cpereyra183/servlet/ServletC\"><input type =\"submit\" value=\"Continue\" /><input type=\"button\" value=\"Cancel\" /></center>"); } }} This is the servlet the first servlet redirects to all I do is try to do is output the text input public class ServletC extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); String value = System.getProperty("card"); PrintWriter out = response.getWriter(); out.println(request.getParameter("number")); } }

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  • Images won't load if they are of high size

    - by Fahim Parkar
    I have created web-application using JSF 2.0 and mysql. I am storing images in DB using MEDIUMBLOB. When I try to load image, I am able to see those images. However if the image size is big (1 MB or more), I can see half or 3/4th image on the browser. Any idea how to overcome this issue? Do I need to set any variable in JSF or MySQL? I know I should have saved the images over disk instead of DB, however this was client requirement. Client wanted to backup data and provide it to someone else and client don't want to backup DB and images also. Edit 1 Do I need to set any variables on mysql like query_cache. Edit 2 When I download same image and put below code it works perfectly. <h:graphicImage value="images/myImage4.png" width="50%" /> Edit 3 code is as below. <h:graphicImage value="DisplayImage?mainID=drawing" /> DisplayImage.java String imgLen = rs1.getString(1); int len = imgLen.length(); byte[] rb = new byte[len]; InputStream readImg = rs1.getBinaryStream(1); InputStream inputStream = readImg; int index = readImg.read(rb, 0, len); response.reset(); response.setHeader("Content-Length", String.valueOf(len)); response.setHeader("Content-disposition", "inline;filename=/file.png"); response.setContentType("image/png"); response.getOutputStream().write(rb, 0, len); response.getOutputStream().flush(); When I print len I get value as len=1548432

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  • Bind event to AJAX populated list items

    - by AnPel
    I have an unordered list with no list items. I get some information from the user, I run it through my database using AJAX and the servers sends back a JSON object response. Then I append each list item I want to display to the list using something like $('blabla').append('<li>information</li>') My question is, since the li elements were not there at the time the DOM was ready, how can I bind a click event to them? Here is my full code: $(function(){ var timer; $('#f').keyup(function(){ clearTimeout(timer); timer = setTimeout(getSuggestions, 400); }); }) function getSuggestions(){ var a = $('#f')[0].value.length; if( a < 3){ if(a == 0){ $('#ajaxerror').hide(300,function(){ $('#loading').hide(300,function(){ $('#suggest').hide(300) }) }) } return; } $('#loading').slideDown(200,function(){ $.ajax({ url: '/models/AJAX/suggest.php', dataType: 'json', data: {'data' : $('#f')[0].value }, success: function(response){ $('#ajaxerror').hide(0,function(){ $('#loading').hide(100,function(){ $('#suggest ul li').remove(); for(var b = 0; b < ( response.rows * 3); b = b + 3){ $('#suggest ul').append('<li>'+response[b]+' '+response[b+1]+' '+response[b+2]+'</li>') // MISSING SOME CODE HERE TO BIND CLICK EVENT TO NEWLY CREATED LI } $('#suggest').show(300) }) }) }, error: function(){ $('#suggest').hide(0,function(){ $('#loading').slideUp(100,function(){ $('#ajaxerror').show(300) }) }) } }) }) }

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  • Access php multidimensional array key based on a variable string

    - by ggirtsou
    I have stored the XML path to items in a string like this: response->items->item. What I need to do is to access an array called $xml_array like this: $xml_array['response']['items']['item'] When I write it in the code it works. The thing is that I want it to be done on the fly. I use this to convert response->items->item to ['response']['items']['item']: $xml_path = 'response->items->item'; $explode_path = explode('->', $xml_path); $correct_string = false; foreach($explode_path as $path) { $correct_string .= '[\''.$path.'\']'; } the problem is that I can't access $xml_array by doing this: $xml_array[$correct_string] So I end up with this: $xml_tag = 'title'; $xml_path = 'response->items->item'; $correct_string = '$items = $xml2array'; $explode_path = explode('->', $xml_path); foreach($explode_path as $path) { $correct_string .= '[\''.$path.'\']'; } $correct_string .= ';'; eval($correct_string); foreach($items as $item) { echo $item[$xml_tag].'<br />'; } and access the $xml_array array through $items array. Is there any way I can do this and avoid using eval()? Thanks in advance!

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  • ASP.NET Cookies

    - by Aamir Hasan
    Cookies are domain specific and cannot be used across different network domains. The only domain that can read a cookie is the domain that sets it. It does not matter what domain name you set.Cookies are used to store small pieces of information on a client machine. A cookie can store only up to 4 KB of information. Generally cookies are used to store data which user types frequently such as user id and password to login to a site.The HttpCookie class defined in the System.Web namespace represents a browser cookie.Creating cookies (C#)Dim cookie As HttpCookie = New HttpCookie("UID")cookie.Value = "id"cookie.Expires = #3/30/2010#Response.Cookies.Add(cookie)cookie = New HttpCookie("username")cookie.Value = "username"cookie.Expires = #3/31/2010#Response.Cookies.Add(cookie)Creating cookies (VB.NET) HttpCookie cookie = Request.Cookies["Preferences"];      if (cookie == null)      {        cookie = new HttpCookie("Preferences");      }      cookie["Name"] = txtName.Text;      cookie.Expires = DateTime.Now.AddYears(1);      Response.Cookies.Add(cookie);Creating cookies (C#)    HttpCookie MyCookie = new HttpCookie("Background");    MyCookie.Value = "value";    Response.Cookies.Add(MyCookie);Reading cookies  (VB.NET)Dim cookieCols As New HttpCookieCollectioncookieCols = Request.CookiesDim str As String' Read and add all cookies to the list boxFor Each str In cookieColsListBox1.Items.Add("Value:" Request.Cookies(str).Value)Next Reading cookies (C#) ArrayList colCookies = new ArrayList();        for (int i = 0; i < Request.Cookies.Count; i++)            colCookies.Add(Request.Cookies[i]);        grdCookies.DataSource = colCookies;        grdCookies.DataBind();Deleting cookies (VB.NET)Dim cookieCols As New HttpCookieCollectioncookieCols = Request.CookiesDim str As String' Read and add all cookies to the list boxRequest.Cookies.Remove("PASS")Request.Cookies.Remove("UID")Deleting cookies (C#)string[] cookies = Request.Cookies.AllKeys;        foreach (string cookie in cookies)        {            ListBox1.Items.Add("Deleting " + cookie);            Response.Cookies[cookie].Expires = DateTime.Now.AddDays(-1);        }

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  • Unit testing best practices for a unit testing newbie

    - by wilhil
    In recent years, I have only written small components for people in larger projects or small tools. I have never written a unit test and it always seems like learning how to write them and actually making one takes a lot longer than simply firing up the program and testing for real. I am just about to start a fairly large scale project that could take a few months to complete and whilst I will try to test elements as I write them (like always), I am wondering if unit testing could save me time. I was just wondering if anyone could give good advice: Should I be looking at unit testing at the start of the project and possibly adopt a TDD approach. Should I just write tests as I go along, after each section is complete. Should I complete the project and then write unit tests at the end.

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  • Cannot mount Android phone in Ubuntu and sync with Banshee

    - by Brett Alton
    I can't get my LG Optimus One to sync with Banshee. I read somewhere that the root needs to have an empty file called '.is_audio_player'. I did that and it still doesn't mount. I ran dmesg however and it appears that the card is unmounting before I even have a change to run Banshee. [ 7250.321359] usb 1-1.4: new high speed USB device using ehci_hcd and address 10 [ 7250.444795] scsi12 : usb-storage 1-1.4:1.0 [ 7251.567946] scsi 12:0:0:0: Direct-Access Multiple Card Reader 1.00 PQ: 0 ANSI: 0 [ 7251.568839] sd 12:0:0:0: Attached scsi generic sg3 type 0 [ 7252.232433] sd 12:0:0:0: [sdc] 15564800 512-byte logical blocks: (7.96 GB/7.42 GiB) [ 7252.233299] sd 12:0:0:0: [sdc] Write Protect is off [ 7252.233306] sd 12:0:0:0: [sdc] Mode Sense: 03 00 00 00 [ 7252.233309] sd 12:0:0:0: [sdc] Assuming drive cache: write through [ 7252.235658] sd 12:0:0:0: [sdc] Assuming drive cache: write through [ 7252.235666] sdc: sdc1 [ 7252.239132] sd 12:0:0:0: [sdc] Assuming drive cache: write through [ 7252.239140] sd 12:0:0:0: [sdc] Attached SCSI removable disk [ 7272.573437] usb 1-1.4: USB disconnect, address 10 Suggestions?

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  • Talend Enterprise Data Integration overperforms on Oracle SPARC T4

    - by Amir Javanshir
    The SPARC T microprocessor, released in 2005 by Sun Microsystems, and now continued at Oracle, has a good track record in parallel execution and multi-threaded performance. However it was less suited for pure single-threaded workloads. The new SPARC T4 processor is now filling that gap by offering a 5x better single-thread performance over previous generations. Following our long-term relationship with Talend, a fast growing ISV positioned by Gartner in the “Visionaries” quadrant of the “Magic Quadrant for Data Integration Tools”, we decided to test some of their integration components with the T4 chip, more precisely on a T4-1 system, in order to verify first hand if this new processor stands up to its promises. Several tests were performed, mainly focused on: Single-thread performance of the new SPARC T4 processor compared to an older SPARC T2+ processor Overall throughput of the SPARC T4-1 server using multiple threads The tests consisted in reading large amounts of data --ten's of gigabytes--, processing and writing them back to a file or an Oracle 11gR2 database table. They are CPU, memory and IO bound tests. Given the main focus of this project --CPU performance--, bottlenecks were removed as much as possible on the memory and IO sub-systems. When possible, the data to process was put into the ZFS filesystem cache, for instance. Also, two external storage devices were directly attached to the servers under test, each one divided in two ZFS pools for read and write operations. Multi-thread: Testing throughput on the Oracle T4-1 The tests were performed with different number of simultaneous threads (1, 2, 4, 8, 12, 16, 32, 48 and 64) and using different storage devices: Flash, Fibre Channel storage, two stripped internal disks and one single internal disk. All storage devices used ZFS as filesystem and volume management. Each thread read a dedicated 1GB-large file containing 12.5M lines with the following structure: customerID;FirstName;LastName;StreetAddress;City;State;Zip;Cust_Status;Since_DT;Status_DT 1;Ronald;Reagan;South Highway;Santa Fe;Montana;98756;A;04-06-2006;09-08-2008 2;Theodore;Roosevelt;Timberlane Drive;Columbus;Louisiana;75677;A;10-05-2009;27-05-2008 3;Andrew;Madison;S Rustle St;Santa Fe;Arkansas;75677;A;29-04-2005;09-02-2008 4;Dwight;Adams;South Roosevelt Drive;Baton Rouge;Vermont;75677;A;15-02-2004;26-01-2007 […] The following graphs present the results of our tests: Unsurprisingly up to 16 threads, all files fit in the ZFS cache a.k.a L2ARC : once the cache is hot there is no performance difference depending on the underlying storage. From 16 threads upwards however, it is clear that IO becomes a bottleneck, having a good IO subsystem is thus key. Single-disk performance collapses whereas the Sun F5100 and ST6180 arrays allow the T4-1 to scale quite seamlessly. From 32 to 64 threads, the performance is almost constant with just a slow decline. For the database load tests, only the best IO configuration --using external storage devices-- were used, hosting the Oracle table spaces and redo log files. Using the Sun Storage F5100 array allows the T4-1 server to scale up to 48 parallel JVM processes before saturating the CPU. The final result is a staggering 646K lines per second insertion in an Oracle table using 48 parallel threads. Single-thread: Testing the single thread performance Seven different tests were performed on both servers. Given the fact that only one thread, thus one file was read, no IO bottleneck was involved, all data being served from the ZFS cache. Read File ? Filter ? Write File: Read file, filter data, write the filtered data in a new file. The filter is set on the “Status” column: only lines with status set to “A” are selected. This limits each output file to about 500 MB. Read File ? Load Database Table: Read file, insert into a single Oracle table. Average: Read file, compute the average of a numeric column, write the result in a new file. Division & Square Root: Read file, perform a division and square root on a numeric column, write the result data in a new file. Oracle DB Dump: Dump the content of an Oracle table (12.5M rows) into a CSV file. Transform: Read file, transform, write the result data in a new file. The transformations applied are: set the address column to upper case and add an extra column at the end, which is the concatenation of two columns. Sort: Read file, sort a numeric and alpha numeric column, write the result data in a new file. The following table and graph present the final results of the tests: Throughput unit is thousand lines per second processed (K lines/second). Improvement is the % of improvement between the T5140 and T4-1. Test T4-1 (Time s.) T5140 (Time s.) Improvement T4-1 (Throughput) T5140 (Throughput) Read/Filter/Write 125 806 645% 100 16 Read/Load Database 195 1111 570% 64 11 Average 96 557 580% 130 22 Division & Square Root 161 1054 655% 78 12 Oracle DB Dump 164 945 576% 76 13 Transform 159 1124 707% 79 11 Sort 251 1336 532% 50 9 The improvement of single-thread performance is quite dramatic: depending on the tests, the T4 is between 5.4 to 7 times faster than the T2+. It seems clear that the SPARC T4 processor has gone a long way filling the gap in single-thread performance, without sacrifying the multi-threaded capability as it still shows a very impressive scaling on heavy-duty multi-threaded jobs. Finally, as always at Oracle ISV Engineering, we are happy to help our ISV partners test their own applications on our platforms, so don't hesitate to contact us and let's see what the SPARC T4-based systems can do for your application! "As describe in this benchmark, Talend Enterprise Data Integration has overperformed on T4. I was generally happy to see that the T4 gave scaling opportunities for many scenarios like complex aggregations. Row by row insertion in Oracle DB is faster with more than 650,000 rows per seconds without using any bulk Oracle capabilities !" Cedric Carbone, Talend CTO.

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  • Cannot format SD memory card

    - by cool
    Hello everyone I have a SD memory card which is of local manufacturer it allows to read & copy from it but not write as it is now write-protected so i want to format that card but could not. To format this card I have tried 1) DD command 2) mkfs -f vfat command 3) creating registry entry under storage device policy in window with write value 0 4) disk part command in window to clear attributes in which it show all attributes are clear ie no write protection 5) I format card in windows through control panel - administrative tools- computer management - disk management, then it show as formatted but when I tried to create new partition it give CYCLIC REDUNDANCY CHECK error 6) I downloaded a format utility from transcend site and formatted first it shows write protected again doing format it formats and tells to remove and reinsert after reinsertion it shows the previous data as it is

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  • how to send trackback and pingback using c# script

    - by anirudha
    This is a very interesting topic because if you want to search about them. you find much useless stuff even you use c# as prefix. 1. how trackback works ? Every blog who have support to trackback that in their every post they have some text comment like <rdf:/rdf></rdf:rdf>  inside this tag the attribute “trackback:ping” have a url where we can send trackback. 2. you need some information about your blog to post where you want to trackback like 1. URL where you want to send the trackback 2. your post title [may be page title] 3. your post URL [may be page url] 4.  Excerpt : information you want to send. 5. you blogname [may be sitename if you use site not blog] make the information like querystring just we use in asp.net ex: title=”pingpost&url=pingurl&excerpt=it’s me&blog=myblog” ; the information look like asp.net Querystring if you unsure that you can HTMLencode the information who you use in parameters. you need to be sure that your post have URL of post where you want to send trackback. make  a request to pingurl set the following property request.Method = “POST”; //because they support only POST request.ContentLength = param.length // choose the length of parameters we create for sending ping. request.ContentType = "application/x-www-form-urlencoded"; // required to set. now when you send the request then server respond you something about your request check that the request.statuscode is verify that’s work or not if (response.StatusCode < HttpStatusCode.OK && response.StatusCode >= HttpStatusCode.Ambiguous)                     throw new Exception(string.Format(response.StatusCode.ToString())); because you have the response in XML format you can parse the response that’s have Error tag inside them or not. i put here information not code the reason is that “i see some other blog from a week on the topic but i found that they[blogger] post code not the method and all their code are useless and not worked”. because i thing to be more declarative i post here the definition not code.

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  • Generic and type safe I/O model in any language

    - by Eduardo León
    I am looking for an I/O model, in any programming language, that is generic and type safe. By genericity, I mean there should not be separate functions for performing the same operations on different devices (read_file, read_socket, read_terminal). Instead, a single read operation works on all read-able devices, a single write operation works on all write-able devices, and so on. By type safety, I mean operations that do not make sense should not even be expressible in first place. Using the read operation on a non-read-able device ought to cause a type error at compile time, similarly for using the write operation on a non-write-able device, and so on. Is there any generic and type safe I/O model?

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  • Adding nodes to MAAS server

    - by Yasith Tharindu
    I was able to install MAAS server using ubuntu 12.04. Then boot up nodes from he PXE. Then installed maas-precise-x86-64-commissioning through pxe. Now the installation is done. but im unable to commission with the MAAS server. It does not show it as a node and neither im unable to add it manually and end up with following error. Also what is the default username password for maas-precise-x86-64-commissioning. Im unable to login. This error when adding node manually. ERROR 2012-11-20 08:32:54,500 maas.maasserver ################################ Exception: timed out ################################ ERROR 2012-11-20 08:32:54,501 maas.maasserver Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_response response = callback(request, *callback_args, **callback_kwargs) File "/usr/lib/python2.7/dist-packages/django/views/decorators/vary.py", line 22, in inner_func response = func(*args, **kwargs) File "/usr/lib/python2.7/dist-packages/piston/resource.py", line 166, in call result = self.error_handler(e, request, meth, em_format) File "/usr/lib/python2.7/dist-packages/piston/resource.py", line 164, in call result = meth(request, *args, **kwargs) File "/usr/lib/python2.7/dist-packages/maasserver/api.py", line 251, in dispatcher self, request, request.method, *args, **kwargs) File "/usr/lib/python2.7/dist-packages/maasserver/api.py", line 193, in perform_api_operation return method(handler, request, *args, **kwargs) File "/usr/lib/python2.7/dist-packages/maasserver/api.py", line 493, in new node = create_node(request) File "/usr/lib/python2.7/dist-packages/maasserver/api.py", line 418, in create_node return form.save() File "/usr/lib/python2.7/dist-packages/maasserver/forms.py", line 234, in save node = super(NodeWithMACAddressesForm, self).save() File "/usr/lib/python2.7/dist-packages/django/forms/models.py", line 363, in save fail_message, commit, construct=False) File "/usr/lib/python2.7/dist-packages/django/forms/models.py", line 85, in save_instance instance.save() File "/usr/lib/python2.7/dist-packages/maasserver/models.py", line 114, in save return super(CommonInfo, self).save(*args, **kwargs) File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 460, in save self.save_base(using=using, force_insert=force_insert, force_update=force_update) File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 570, in save_base created=(not record_exists), raw=raw, using=using) File "/usr/lib/python2.7/dist-packages/django/dispatch/dispatcher.py", line 172, in send response = receiver(signal=self, sender=sender, **named) File "/usr/lib/python2.7/dist-packages/maasserver/provisioning.py", line 485, in provision_post_save_Node profile, power_type, preseed_data) File "/usr/lib/python2.7/dist-packages/maasserver/provisioning.py", line 245, in call result = self.method(*args) 259,1 93% result = self.method(*args) File "/usr/lib/python2.7/xmlrpclib.py", line 1224, in call return self._send(self._name, args) File "/usr/lib/python2.7/xmlrpclib.py", line 1578, in _request verbose=self._verbose File "/usr/lib/python2.7/xmlrpclib.py", line 1264, in request return self.single_request(host, handler, request_body, verbose) File "/usr/lib/python2.7/xmlrpclib.py", line 1294, in single_request response = h.getresponse(buffering=True) File "/usr/lib/python2.7/httplib.py", line 1030, in getresponse response.begin() File "/usr/lib/python2.7/httplib.py", line 407, in begin version, status, reason = self._read_status() File "/usr/lib/python2.7/httplib.py", line 365, in _read_status line = self.fp.readline() File "/usr/lib/python2.7/socket.py", line 447, in readline data = self._sock.recv(self._rbufsize) timeout: timed out

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  • Writing cross-platforms Types, Interfaces and Classes/Methods in C++

    - by user827992
    I'm looking for the best solution to write cross-platform software, aka code that I write and that I have to interface with different libraries and platforms each time. What I consider the easiest part, correct me if I'm wrong, is the definition of new types, all I have to do is to write an hpp file with a list of typedefs, I can keep the same names for each new type across the different platforms so my codebase can be shared without any problem. typedefs also helps me to redefine a better scope for my types in my code. I will probably end up having something like this: include |-windows | |-types.hpp |-linux | |-types.hpp |-mac |-types.hpp For the interfaces I'm thinking about the same solution used for the types, a series of hpp files, probably I will write all the interfaces only once since they rely on the types and all "cross-platform portability" is ensured by the work done on the types. include | |-interfaces.hpp | |-windows | |-types.hpp |-linux | |-types.hpp |-mac | |-types.hpp For classes and methods I do not have a real answer, I would like to avoid 2 things: the explicit use of pointers the use of templates I want to avoid the use of the pointers because they can make the code less readable for someone and I want to avoid templates just because if I write them, I can't separate the interface from the definition. What is the best option to hide the use of the pointers? I would also like some words about macros and how to implement some OS-specifics calls and definitions.

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  • Is this kind of Design by Contract useless?

    - by Charlie Pigarelli
    I've just started informatics university and I'm attending a programming course about C(++). The programming professor prefers to teach very few things (in 3 month we have just reached the functions topic) and connect every topic with a type of programming design that somehow is similar to the Design by Contract design. Basically what he ask us to do is to write every exercise with comments Pre-conditions, Post-conditions and Invariants that should prove the correctness of each program we write. But this doesn't make any sense to me. I mean, ok: maybe writing down your thoughts prevent you from doing some mistakes, but if this is all an abstract thing, then if your program intuition is wrong you'll write your program wrong and then you'll also write pre and post conditions wrong probably auto convincing your self about its correctness. Most of the time, both me and other students have written programs that seemed ok and that had correct pre and post condition too. But at the moment of testing it was just completely wrong. I had some experience before this course of programming and I had written a lot of line of code before and I found myself comfortably with just writing a program and unit test it. It take less time to accomplish and is less "abstract" than just thinking about what every single piece of your program should do in every case (which is kinda like mentally testing it). Finally, all this pre and post conditions takes me like 80% of the total time of the exercise. It's harder to think about putting down this pre and post correct than to write the program itself. Since we are like the only course of the only university probably in the entire world that makes this things, could someone please tell me how should I manage this thing? Am I right thinking that this doesn't worth anything? Should I change university? (there are like double of the people attending that course and it seems that usually very few people passes the exam the first year). Should I convince myself it's method is right?

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  • Should I be using Lua for game logic on mobile devices?

    - by Rob Ashton
    As above really, I'm writing an android based game in my spare time (android because it's free and I've no real aspirations to do anything commercial). The game logic comes from a very typical component based model whereby entities exist and have components attached to them and messages are sent to and fro in order to make things happen. Obviously the layer for actually performing that is thin, and if I were to write an iPhone version of this app, I'd have to re-write the renderer and core driver (of this component based system) in Objective C. The entities are just flat files determining the names of the components to be added, and the components themselves are simple, single-purpose objects containing the logic for the entity. Now, if I write all the logic for those components in Java, then I'd have to re-write them on Objective C if I decided to do an iPhone port. As the bulk of the application logic is contained within these components, they would, in an ideal world, be written in some platform-agnostic language/script/DSL which could then just be loaded into the app on whatever platform. I've been led to believe however that this is not an ideal world though, and that Lua performance etc on mobile devices still isn't up to scratch, that the overhead is too much and that I'd run into troubles later if I went down that route? Is this actually the case? Obviously this is just a hypothetical question, I'm happy writing them all in Java as it's simple and easy get things off the ground, but say I actually enjoy making this game (unlikely, given how much I'm currently disliking having to deal with all those different mobile devices) and I wanted to make a commercially viable game - would I use Lua or would I just take the hit when it came to porting and just re-write all the code?

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  • Creating a Training Lab on Windows Azure

    - by Michael Stephenson
    Originally posted on: http://geekswithblogs.net/michaelstephenson/archive/2013/06/17/153149.aspxThis week we are preparing for a training course that Alan Smith will be running for the support teams at one of my customers around Windows Azure. In order to facilitate the training lab we have a few prerequisites we need to handle. One of the biggest ones is that although the support team all have MSDN accounts the local desktops they work on are not ideal for running most of the labs as we want to give them some additional developer background training around Azure. Some recent Azure announcements really help us in this area: MSDN software can now be used on Azure VM You don't pay for Azure VM's when they are no longer used  Since the support team only have limited experience of Windows Azure and the organisation also have an Enterprise Agreement we decided it would be best value for money to spin up a training lab in a subscription on the EA and then we can turn the machines off when we are done. At the same time we would be able to spin them back up when the users need to do some additional lab work once the training course is completed. In order to achieve this I wanted to create a powershell script which would setup my training lab. The aim was to create 18 VM's which would be based on a prebuilt template with Visual Studio and the Azure development tools. The script I used is described below The Start & Variables The below text will setup the powershell environment and some variables which I will use elsewhere in the script. It will also import the Azure Powershell cmdlets. You can see below that I will need to download my publisher settings file and know some details from my Azure account. At this point I will assume you have a basic understanding of Azure & Powershell so already know how to do this. Set-ExecutionPolicy Unrestrictedcls $startTime = get-dateImport-Module "C:\Program Files (x86)\Microsoft SDKs\Windows Azure\PowerShell\Azure\Azure.psd1"# Azure Publisher Settings $azurePublisherSettings = '<Your settings file>.publishsettings'  # Subscription Details $subscriptionName = "<Your subscription name>" $defaultStorageAccount = "<Your default storage account>"  # Affinity Group Details $affinityGroup = '<Your affinity group>' $dataCenter = 'West Europe' # From Get-AzureLocation  # VM Details $baseVMName = 'TRN' $adminUserName = '<Your admin username>' $password = '<Your admin password>' $size = 'Medium' $vmTemplate = '<The name of your VM template image>' $rdpFilePath = '<File path to save RDP files to>' $machineSettingsPath = '<File path to save machine info to>'    Functions In the next section of the script I have some functions which are used to perform certain actions. The first is called CreateVM. This will do the following actions: If the VM already exists it will be deleted Create the cloud service Create the VM from the template I have created Add an endpoint so we can RDP to them all over the same port Download the RDP file so there is a short cut the trainees can easily access the machine via Write settings for the machine to a log file  function CreateVM($machineNo) { # Specify a name for the new VM $machineName = "$baseVMName-$machineNo" Write-Host "Creating VM: $machineName"       # Get the Azure VM Image      $myImage = Get-AzureVMImage $vmTemplate   #If the VM already exists delete and re-create it $existingVm = Get-AzureVM -Name $machineName -ServiceName $serviceName if($existingVm -ne $null) { Write-Host "VM already exists so deleting it" Remove-AzureVM -Name $machineName -ServiceName $serviceName }   "Creating Service" $serviceName = "bupa-azure-train-$machineName" Remove-AzureService -Force -ServiceName $serviceName New-AzureService -Location $dataCenter -ServiceName $serviceName   Write-Host "Creating VM: $machineName" New-AzureQuickVM -Windows -name $machineName -ServiceName $serviceName -ImageName $myImage.ImageName -InstanceSize $size -AdminUsername $adminUserName -Password $password  Write-Host "Updating the RDP endpoint for $machineName" Get-AzureVM -name $machineName -ServiceName $serviceName ` | Add-AzureEndpoint -Name RDP -Protocol TCP -LocalPort 3389 -PublicPort 550 ` | Update-AzureVM    Write-Host "Get the RDP File for machine $machineName" $machineRDPFilePath = "$rdpFilePath\$machineName.rdp" Get-AzureRemoteDesktopFile -name $machineName -ServiceName $serviceName -LocalPath "$machineRDPFilePath"   WriteMachineSettings "$machineName" "$serviceName" }    The delete machine settings function is used to delete the log file before we start re-running the process.  function DeleteMachineSettings() { Write-Host "Deleting the machine settings output file" [System.IO.File]::Delete("$machineSettingsPath"); }    The write machine settings function will get the VM and then record its details to the log file. The importance of the log file is that I can easily provide the information for all of the VM's to our infrastructure team to be able to configure access to all of the VM's    function WriteMachineSettings([string]$vmName, [string]$vmServiceName) { Write-Host "Writing to the machine settings output file"   $vm = Get-AzureVM -name $vmName -ServiceName $vmServiceName $vmEndpoint = Get-AzureEndpoint -VM $vm -Name RDP   $sb = new-object System.Text.StringBuilder $sb.Append("Service Name: "); $sb.Append($vm.ServiceName); $sb.Append(", "); $sb.Append("VM: "); $sb.Append($vm.Name); $sb.Append(", "); $sb.Append("RDP Public Port: "); $sb.Append($vmEndpoint.Port); $sb.Append(", "); $sb.Append("Public DNS: "); $sb.Append($vmEndpoint.Vip); $sb.AppendLine(""); [System.IO.File]::AppendAllText($machineSettingsPath, $sb.ToString());  } # end functions    Rest of Script In the rest of the script it is really just the bit that orchestrates the actions we want to happen. It will load the publisher settings, select the Azure subscription and then loop around the CreateVM function and create 16 VM's  Import-AzurePublishSettingsFile $azurePublisherSettings Set-AzureSubscription -SubscriptionName $subscriptionName -CurrentStorageAccount $defaultStorageAccount Select-AzureSubscription -SubscriptionName $subscriptionName  DeleteMachineSettings    "Starting creating Bupa International Azure Training Lab" $numberOfVMs = 16  for ($index=1; $index -le $numberOfVMs; $index++) { $vmNo = "$index" CreateVM($vmNo); }    "Finished creating Bupa International Azure Training Lab" # Give it a Minute Start-Sleep -s 60  $endTime = get-date "Script run time " + ($endTime - $startTime)    Conclusion As you can see there is nothing too fancy about this script but in our case of creating a small isolated training lab which is not connected to our corporate network then we can easily use this to provision the lab. Im sure if this is of use to anyone you can easily modify it to do other things with the lab environment too. A couple of points to note are that there are some soft limits in Azure about the number of cores and services your subscription can use. You may need to contact the Azure support team to be able to increase this limit. In terms of the real business value of this approach, it was not possible to use the existing desktops to do the training on, and getting some internal virtual machines would have been relatively expensive and time consuming for our ops team to do. With the Azure option we are able to spin these machines up for a temporary period during the training course and then throw them away when we are done. We expect the costing of this test lab to be very small, especially considering we have EA pricing. As a ball park I think my 18 lab VM training environment will cost in the region of $80 per day on our EA. This is a fraction of the cost of the creation of a single VM on premise.

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  • Motherboard/PSU crippling USB and Sata

    - by celebdor
    I very recently bought a new desktop computer. The motherboard is: Z77MX-D3H and the power supply is ocz zs series 550w. The issue I have is that once I boot to the operating system (I have tried with fedora and Ubuntu with kernels 2.6.38 - 3.4.0), my hard drive (2.5" Magnetic) occasionally makes a power switch noise and it resets. Needless to say, when this drive is the OS drive, the OS crashes. I also have a SSD that works fine with the same OS configurations, but if I have the magnetic hard drive attached as second drive, it works erratically and the reconnects result in corrupted data. I also noticed that whenever I plug an external hard drive USB2.0 or USB3.0 to the computer the issue with the reconnects is even worse: [ 52.198441] sd 7:0:0:0: [sdc] Spinning up disk... [ 57.955811] usb 4-3: USB disconnect, device number 3 [ 58.023687] .ready [ 58.023914] sd 7:0:0:0: [sdc] READ CAPACITY(16) failed [ 58.023919] sd 7:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 58.023932] sd 7:0:0:0: [sdc] Sense not available. [ 58.024061] sd 7:0:0:0: [sdc] READ CAPACITY failed [ 58.024063] sd 7:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 58.024064] sd 7:0:0:0: [sdc] Sense not available. [ 58.024099] sd 7:0:0:0: [sdc] Write Protect is off [ 58.024101] sd 7:0:0:0: [sdc] Mode Sense: 00 00 00 00 [ 58.024135] sd 7:0:0:0: [sdc] Asking for cache data failed [ 58.024137] sd 7:0:0:0: [sdc] Assuming drive cache: write through [ 58.024400] sd 7:0:0:0: [sdc] READ CAPACITY(16) failed [ 58.024402] sd 7:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 58.024405] sd 7:0:0:0: [sdc] Sense not available. [ 58.024448] sd 7:0:0:0: [sdc] READ CAPACITY failed [ 58.024450] sd 7:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 58.024451] sd 7:0:0:0: [sdc] Sense not available. [ 58.024469] sd 7:0:0:0: [sdc] Asking for cache data failed [ 58.024471] sd 7:0:0:0: [sdc] Assuming drive cache: write through [ 58.024472] sd 7:0:0:0: [sdc] Attached SCSI disk [ 58.407725] usb 4-3: new SuperSpeed USB device number 4 using xhci_hcd [ 58.424921] scsi8 : usb-storage 4-3:1.0 [ 59.424185] scsi 8:0:0:0: Direct-Access WD My Passport 0740 1003 PQ: 0 ANSI: 6 [ 59.424406] scsi 8:0:0:1: Enclosure WD SES Device 1003 PQ: 0 ANSI: 6 [ 59.425098] sd 8:0:0:0: Attached scsi generic sg2 type 0 [ 59.425176] ses 8:0:0:1: Attached Enclosure device [ 59.425248] ses 8:0:0:1: Attached scsi generic sg3 type 13 [ 61.845836] sd 8:0:0:0: [sdc] 976707584 512-byte logical blocks: (500 GB/465 GiB) [ 61.845838] sd 8:0:0:0: [sdc] 4096-byte physical blocks [ 61.846336] sd 8:0:0:0: [sdc] Write Protect is off [ 61.846338] sd 8:0:0:0: [sdc] Mode Sense: 47 00 10 08 [ 61.846718] sd 8:0:0:0: [sdc] No Caching mode page present [ 61.846720] sd 8:0:0:0: [sdc] Assuming drive cache: write through [ 61.848105] sd 8:0:0:0: [sdc] No Caching mode page present [ 61.848106] sd 8:0:0:0: [sdc] Assuming drive cache: write through [ 61.857147] sdc: sdc1 [ 61.858915] sd 8:0:0:0: [sdc] No Caching mode page present [ 61.858916] sd 8:0:0:0: [sdc] Assuming drive cache: write through [ 61.858918] sd 8:0:0:0: [sdc] Attached SCSI disk [ 69.875809] usb 4-3: USB disconnect, device number 4 [ 70.275816] usb 4-3: new SuperSpeed USB device number 5 using xhci_hcd [ 70.293063] scsi9 : usb-storage 4-3:1.0 [ 71.292257] scsi 9:0:0:0: Direct-Access WD My Passport 0740 1003 PQ: 0 ANSI: 6 [ 71.292505] scsi 9:0:0:1: Enclosure WD SES Device 1003 PQ: 0 ANSI: 6 [ 71.293527] sd 9:0:0:0: Attached scsi generic sg2 type 0 [ 71.293668] ses 9:0:0:1: Attached Enclosure device [ 71.293758] ses 9:0:0:1: Attached scsi generic sg3 type 13 [ 73.323804] usb 4-3: USB disconnect, device number 5 [ 101.868078] ses 9:0:0:1: Device offlined - not ready after error recovery [ 101.868124] ses 9:0:0:1: Failed to get diagnostic page 0x50000 [ 101.868131] ses 9:0:0:1: Failed to bind enclosure -19 [ 101.868288] sd 9:0:0:0: [sdc] READ CAPACITY(16) failed [ 101.868292] sd 9:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 101.868296] sd 9:0:0:0: [sdc] Sense not available. [ 101.868428] sd 9:0:0:0: [sdc] READ CAPACITY failed [ 101.868434] sd 9:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 101.868439] sd 9:0:0:0: [sdc] Sense not available. [ 101.868468] sd 9:0:0:0: [sdc] Write Protect is off [ 101.868473] sd 9:0:0:0: [sdc] Mode Sense: 00 00 00 00 [ 101.868580] sd 9:0:0:0: [sdc] Asking for cache data failed [ 101.868584] sd 9:0:0:0: [sdc] Assuming drive cache: write through [ 101.868845] sd 9:0:0:0: [sdc] READ CAPACITY(16) failed [ 101.868849] sd 9:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 101.868854] sd 9:0:0:0: [sdc] Sense not available. [ 101.868894] sd 9:0:0:0: [sdc] READ CAPACITY failed [ 101.868898] sd 9:0:0:0: [sdc] Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK [ 101.868903] sd 9:0:0:0: [sdc] Sense not available. [ 101.868961] sd 9:0:0:0: [sdc] Asking for cache data failed [ 101.868966] sd 9:0:0:0: [sdc] Assuming drive cache: write through [ 101.868969] sd 9:0:0:0: [sdc] Attached SCSI disk Now, if I plug the same drive to the powered usb 2.0 hub of my monitor, the issue is not reproduced (at least on a 20h long operation). Also the issue of the usb reconnects is less frequent if the hard drive is plugged before I switch on the computer. Does anybody have some advice as to what I could do? Which is the faulty part/s that I should replace? As for me, I really don't know if to point my finger to the PSU or the Motherboard (I have updated to the latest firmware and checked the BIOS settings several times). EDIT: The reconnects are happening both in the Sata connected drives and the USBX connected drives.

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  • Help with "Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral." needed

    - by rFactor
    Hi, I have this irritating problem in XNA that I have spent my Saturday with: Cannot find ContentTypeReader BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral. It throws me that when I do (within the game assembly's Renderer.cs class): this.terrain = this.game.Content.Load<Model>("heightmap"); There is a heightmap.bmp and I don't think there's anything wrong with it, because I used it in a previous version which I switched to this new better system. So, I have a GeneratedGeometryPipeline assembly that has these classes: HeightMapInfoContent, HeightMapInfoWriter, TerrainProcessor. The GeneratedGeometryPipeline assembly does not reference any other assemblies under the solution. Then I have the game assembly that neither references any other solution assemblies and has these classes: HeightMapInfo, HeightMapInfoReader. All game assembly classes are under namespace BB and the GeneratedGeometryPipeline classes are under the namespace GeneratedGeometryPipeline. I do not understand why it does not find it. Here's some code from the GeneratedGeometryPipeline.HeightMapInfoWriter: /// <summary> /// A TypeWriter for HeightMapInfo, which tells the content pipeline how to save the /// data in HeightMapInfo. This class should match HeightMapInfoReader: whatever the /// writer writes, the reader should read. /// </summary> [ContentTypeWriter] public class HeightMapInfoWriter : ContentTypeWriter<HeightMapInfoContent> { protected override void Write(ContentWriter output, HeightMapInfoContent value) { output.Write(value.TerrainScale); output.Write(value.Height.GetLength(0)); output.Write(value.Height.GetLength(1)); foreach (float height in value.Height) { output.Write(height); } foreach (Vector3 normal in value.Normals) { output.Write(normal); } } /// <summary> /// Tells the content pipeline what CLR type the /// data will be loaded into at runtime. /// </summary> public override string GetRuntimeType(TargetPlatform targetPlatform) { return "BB.HeightMapInfo, BB, Version=1.0.0.0, Culture=neutral"; } /// <summary> /// Tells the content pipeline what worker type /// will be used to load the data. /// </summary> public override string GetRuntimeReader(TargetPlatform targetPlatform) { return "BB.HeightMapInfoReader, BB, Version=1.0.0.0, Culture=neutral"; } } Can someone help me out?

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  • Gödel, Escher, Bach - Gödel's string

    - by Brad Urani
    In the book Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter, the author gives us a representation of the precursor to Gödel's string (Gödel's string's uncle) as: ~Ea,a': (I don't have the book in front of me but I think that's right). All that remains to get Gödel's string is to plug the Gödel number for this string into the free variable a''. What I don't understand is how to get the Gödel number for the functions PROOF-PAIR and ARITHMOQUINE. I understand how to write these functions in a programming language like FlooP (from the book) and could even write them myself in C# or Java, but the scheme that Hofstadter defines for Gödel numbering only applies to TNT (which is just his own syntax for natural number theory) and I don't see any way to write a procedure in TNT since it doesn't have any loops, variable assignments etc. Am I missing the point? Perhaps Gödel's string is not something that can actually be printed, but rather a theoretical string that need not actually be defined? I thought it would be neat to write a computer program that actually prints Gödel's string, or Gödel's string encoded by Gödel numbering (yes, I realize it would have a gazillion digits) but it seems like doing so requires some kind of procedural language and a Gödel numbering system for that procedural language that isn't included in the book. Of course once you had that, you could write a program that plugs random numbers into variable "a" and run procedure PROOF-PAIR on it to test for theoromhood of Gödel's string. If you let it run for a trillion years you might find a derivation that proves Gödel's string.

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  • NVRAM for journals on Linux?

    - by symcbean
    I've been thinking about ways of speeding up disk I/O, and one of the bottlenecks I keep coming back to is the journal. There's an obvious benefit to using an SSD for the journal - over and above just write caching unless of course I just disable the journal with the write cache (after all devicemapper doesn't seem to support barriers). In order to get the benefits from using a BB write cache on the controller, then I'd need to disable journalling - but then the OS should try to fsck the system after an outage. Of course if the OS knows what's in the batter-backed memory then it could use it as the journal - but that means it must be exposed as a block device and only be under the control of the operating system. However I've not been able to find a suitable low-cost device (no, write-levelling for Flash is not adequate for a journal, at least one which uses Smartmedia). While there's no end of flash devices, disk/array controllers with BB write caches, so far I've not found anything which just gives me non-volatile memory addressable as a block storage device.

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