Search Results

Search found 2676 results on 108 pages for 'spam blocking'.

Page 71/108 | < Previous Page | 67 68 69 70 71 72 73 74 75 76 77 78  | Next Page >

• Fix mail that has been put in deferred folder

  - by Safado

  So we have a little more than usual deferred mail on our Postfix server, so I started to look through the messages to make sure we weren't hacked and sending out spam. Everything is fine and it turns out that a bot had filled out our Request Info form multiple times with bad info. However, I did find one that was a legitimate request for more information about our company and I noticed that it isn't sending because they fat-fingered the address with gmal.com. Is there a way I can correct that and have Postfix send it out? This is on a CentOS server.

  Read the article

• Security against IP spoofing [on hold]

  - by user1369975

  I am pursuing a college project, in which I am running three fake services on three ports to protect the main service (say running at port 80). The concept is that if the user is malicious, he'll try to bring the services down and access the fake services. These ports adopt a blocking process of a connection request and record the IP and port of the client. These are logged and aren't granted access on service on port 80. But what to do if the client spoofs his IP? How can I modify my system?

  Read the article

• Getting much higher than usual brute-force attempts on cPanel

  - by UserZer0

  Although I have many client accounts on my cPanel based server I'm really the only one who has login information to any of the accounts. I have cPhulk setup to alert me and blocking after 4 failed attempts. I usually have only a handful of bots trying to get in each day(2 hosts ago I never had any), but Today the rate has significantly increased, every 10 minutes or so(no not like clockwork, just averaging). Should I be concerned? Is there anything extra I should be doing, is there any automated reporting services I can use? Thanks.

  Read the article

• Need help sending mass emails [closed]

  - by Jose

  Possible Duplicate: Prevent mail being marked as spam I have an Ubuntu server that I want to be able to send out several thousand emails each containing a generic header and an unique pdf attachment containing an invoice. What I want to know is what would be the best way to accomplish this? Also, are there any other programs I need to install such as anti-virus / verification tools? I would like to be able to know what the procedures for this normally are as I would prefer that the emails are not send to the junk folder of the clients receiving the emails. Any tips would be appreciated. Thanks

  Read the article

• How do I set up a mailing list for over 2000 people?

  - by John Hoffman

  I manage IT for a large organization with over 2000 people. The administration would like to send an email (often with up to 5 word document attachments) about once per week. They also want to categorize people. For instance, about 40 people are "teachers," about 1800 people are "students," and about 10 people are "board members." They may send an email to any combination of these categories. Here's what I have tried: I bought a server, installed Ubuntu server edition on it, and wrote a python script to send out their emails. However, pretty soon, mail services such as Gmail and Yahoo began to treat the mail I send out as SPAM. I'm guessing this is because I am sending an email with 2000+ people in the "bcc" field. Maintaining this server also takes a lot of time. How do I set up a mailing list for over 2000 people? Must I defer to paid services?

  Read the article

• Cannot Create New Team Project TFS2010 TF249063 TF218017

  - by Kodicus

  Server: Windows 2008 R2 Standard Team Foundation Server 2010 WSS 3.0 TFS Configuration: Single Server instalation (including SharePoint) The following error occurs when trying to create a new team project from my local machine. The ://sourcecontrol site and ://sourcecontrol/sites/DefaultCollection/ site appears to be functioning fine and my user is a Site collection administrator on both. I can navigate both sites through a browser on my local machine. Thanks for your help! 2010-04-23T10:01:42 | Module: Internal | Team Foundation Server proxy retrieved | Completion time: 0 seconds 2010-04-23T10:01:42 | Module: Wizard | Retrieved IAuthorizationService proxy | Completion time: 0 seconds 2010-04-23T10:01:42 | Module: Wizard | TF30227: Project creation permissions retrieved | Completion time: 0.109382 seconds 2010-04-23T10:01:42 | Module: Internal | The template information for Team Foundation Server "sourcecontrol\DefaultCollection" was retrieved from the Team Foundation Server. | Completion time: 0.15626 seconds ---begin Exception entry--- Time: 2010-04-23T10:03:24 Module: Wizard Exception Message: TF218017: A SharePoint site could not be created for use as the team project portal. The following error occurred: TF249063: The following Web service is not available: ://sourcecontrol/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. The underlying error is: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.. Verify that the following URL points to a valid SharePoint Web application and that the application is available: ://sourcecontrol. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServerException) Exception Stack Trace: at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.CheckCreateSite(TfsTeamProjectCollection tfsServer, Uri adminUri, Uri siteUri) at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.ValidateSettings(ProjectCreationContext context) at Microsoft.VisualStudio.TeamFoundation.PortfolioProjectForm.OnFinish() Inner Exception Details: Exception Message: TF249063: The following Web service is not available: ://sourcecontrol/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. The underlying error is: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.. Verify that the following URL points to a valid SharePoint Web application and that the application is available: ://sourcecontrol. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServiceUnavailableException) Exception Stack Trace: at Microsoft.TeamFoundation.Client.SharePoint.SharePointTeamFoundationIntegrationService.HandleException(Exception e) at Microsoft.TeamFoundation.Client.SharePoint.SharePointTeamFoundationIntegrationService.CheckUrl(String absolutePath, CheckUrlOptions options, Guid configurationServerId, Guid projectCollectionId) at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.CheckUrl(ICredentials credentials, Uri adminUrl, Uri siteUrl, CheckUrlOptions options, Guid configurationServerId, Guid projectCollectionId) at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.CheckCreateSite(TfsConnection tfs, Uri adminUrl, Uri siteUrl) at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.CheckCreateSite(TfsTeamProjectCollection tfsServer, Uri adminUri, Uri siteUri) Inner Exception Details: Exception Message: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. (type WebException) Exception Stack Trace: at System.Net.WebRequest.GetResponse() at Microsoft.TeamFoundation.Client.TeamFoundationClientProxyBase.AsyncWebRequest.ExecRequest(Object obj) Inner Exception Details: Exception Message: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. (type IOException) Exception Stack Trace: at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.Connection.SyncRead(WebRequest request, Boolean userRetrievedStream, Boolean probeRead) Inner Exception Details: Exception Message: An existing connection was forcibly closed by the remote host (type SocketException) Exception Stack Trace: at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) --- end Exception entry ---

  Read the article

• Issues writing to serial port on MAC OSX using unistd.h in c

  - by Schuyler

  I am trying to write to a bluetooth device on MAC OSX using the unistd.h Linux functions in c. I am connecting fine and writing the first few bytes with success. When I try to write other commands to it (there are bytes added to the write buffer every 15ms), I don't see any results even though the write() function returns 1 (write success). If you start a write and it doesn't finish by the time you try to start another write (since it is non-blocking), could that possibly screw up the initial write? (If so, is there any way to check if a write has completed?) That is the only thing I can think of since the writes are occurring fairly frequently and the first two are successfully sent. qwbyte() simply adds a byte to the output array and increments its length The open port function: BAMid = -1; struct termios options; struct termios originalTTYAttrs; // Open the serial port read/write, nonblocking, with no controlling terminal, and don't wait for a connection. BAMid = open(strPath, O_RDWR | O_NOCTTY | O_NONBLOCK); if (BAMid == -1) { printf("Error opening serial port %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // Issue TIOCEXCL ioctl to prevent additional opens except by root-owned processes. if (ioctl(BAMid, TIOCEXCL) == -1) { printf("Error setting TIOCEXCL on %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // Get the current options and save them so we can restore the default settings later. if (tcgetattr(BAMid, &originalTTYAttrs) == -1) { printf("Error getting tty attributes %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } // The serial port attributes such as timeouts and baud rate are set by modifying the termios // structure and then calling tcsetattr() to cause the changes to take effect. Note that the // changes will not become effective without the tcsetattr() call. options = originalTTYAttrs; // Set raw input (non-canonical) mode, with reads blocking until either a single character // has been received or a one second timeout expires. [should be moot since we are leaving it as nonblocking] cfmakeraw(&options); options.c_cc[VMIN] = 1; options.c_cc[VTIME] = 10; cfsetspeed(&options, B57600); // Set 57600 baud options.c_cflag |= CS8; // Use 8 bit words // Cause the new options to take effect immediately. if (tcsetattr(BAMid, TCSANOW, &options) == -1) { printf("Error setting tty attributes %s - %s(%d).\n", strPath, strerror(errno), errno); goto error; } //flush old transmissions if (tcflush(BAMid,TCIOFLUSH) == -1) { printf("Error flushing BAM serial port - %s(%d).\n", strerror(errno), errno); } oBufLength = 0; // Ask it to start if (! qwbyte(CmdStart) ) { goto error; } if (! qwbyte(CmdFull) ) { goto error; } //this transmit works txbytes(); printf("success opening port!"); return -1; // Failure path error: if (BAMid != -1) { close(BAMid); } printf("returning an error--%d",errno); return errno; } The write function (txbytes): int i, bufSize, numBytes; if(oBufLength != 0) { //if the output array isn't empty //duplicating the output array and its size so it can //be overwritten while this write is occuring printf("about to transmit: "); for(i = 0; i < oBufLength; i++) { printf(" %u",oBuf[i]); tempBuf[i] = oBuf[i]; } printf("\n"); bufSize = oBufLength; oBufLength = 0; numBytes = write(BAMid, &tempBuf, bufSize); printf("bytes written = %d\n",numBytes); if (numBytes == -1) { printf("Error writing to port - %s(%d).\n", strerror(errno), errno); } return (numBytes 0); } else { return 0; }

  Read the article

• Cannot Create New Team Project TFS2010 TF249063 TF218017

  - by Kodicus

  Server: Windows 2008 R2 Standard Team Foundation Server 2010 WSS 3.0 TFS Configuration: Single Server instalation (including SharePoint) The following error occurs when trying to create a new team project from my local machine. The ://sourcecontrol site and ://sourcecontrol/sites/DefaultCollection/ site appears to be functioning fine and my user is a Site collection administrator on both. I can navigate both sites through a browser on my local machine. Thanks for your help! 2010-04-23T10:01:42 | Module: Internal | Team Foundation Server proxy retrieved | Completion time: 0 seconds 2010-04-23T10:01:42 | Module: Wizard | Retrieved IAuthorizationService proxy | Completion time: 0 seconds 2010-04-23T10:01:42 | Module: Wizard | TF30227: Project creation permissions retrieved | Completion time: 0.109382 seconds 2010-04-23T10:01:42 | Module: Internal | The template information for Team Foundation Server "sourcecontrol\DefaultCollection" was retrieved from the Team Foundation Server. | Completion time: 0.15626 seconds ---begin Exception entry--- Time: 2010-04-23T10:03:24 Module: Wizard Exception Message: TF218017: A SharePoint site could not be created for use as the team project portal. The following error occurred: TF249063: The following Web service is not available: ://sourcecontrol/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. The underlying error is: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.. Verify that the following URL points to a valid SharePoint Web application and that the application is available: ://sourcecontrol. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServerException) Exception Stack Trace: at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.CheckCreateSite(TfsTeamProjectCollection tfsServer, Uri adminUri, Uri siteUri) at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.ValidateSettings(ProjectCreationContext context) at Microsoft.VisualStudio.TeamFoundation.PortfolioProjectForm.OnFinish() Inner Exception Details: Exception Message: TF249063: The following Web service is not available: ://sourcecontrol/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. The underlying error is: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.. Verify that the following URL points to a valid SharePoint Web application and that the application is available: ://sourcecontrol. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServiceUnavailableException) Exception Stack Trace: at Microsoft.TeamFoundation.Client.SharePoint.SharePointTeamFoundationIntegrationService.HandleException(Exception e) at Microsoft.TeamFoundation.Client.SharePoint.SharePointTeamFoundationIntegrationService.CheckUrl(String absolutePath, CheckUrlOptions options, Guid configurationServerId, Guid projectCollectionId) at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.CheckUrl(ICredentials credentials, Uri adminUrl, Uri siteUrl, CheckUrlOptions options, Guid configurationServerId, Guid projectCollectionId) at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.CheckCreateSite(TfsConnection tfs, Uri adminUrl, Uri siteUrl) at Microsoft.VisualStudio.TeamFoundation.WssSiteCreator.CheckCreateSite(TfsTeamProjectCollection tfsServer, Uri adminUri, Uri siteUri) Inner Exception Details: Exception Message: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server. (type WebException) Exception Stack Trace: at System.Net.WebRequest.GetResponse() at Microsoft.TeamFoundation.Client.TeamFoundationClientProxyBase.AsyncWebRequest.ExecRequest(Object obj) Inner Exception Details: Exception Message: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. (type IOException) Exception Stack Trace: at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.Connection.SyncRead(WebRequest request, Boolean userRetrievedStream, Boolean probeRead) Inner Exception Details: Exception Message: An existing connection was forcibly closed by the remote host (type SocketException) Exception Stack Trace: at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) --- end Exception entry ---

  Read the article

• Variable mysteriously changing value

  - by Eitan

  I am making a simple tcp/ip chat program for practicing threads and tcp/ip. I was using asynchronous methods but had a problem with concurrency so I went to threads and blocking methods (not asynchronous). I have two private variables defined in the class, not static: string amessage = string.Empty; int MessageLength; and a Thread private Thread BeginRead; Ok so I call a function called Listen ONCE when the client starts: public virtual void Listen(int byteLength) { var state = new StateObject {Buffer = new byte[byteLength]}; BeginRead = new Thread(ReadThread); BeginRead.Start(state); } and finally the function to receive commands and process them, I'm going to shorten it because it is really long: private void ReadThread(object objectState) { var state = (StateObject)objectState; int byteLength = state.Buffer.Length; while (true) { var buffer = new byte[byteLength]; int len = MySocket.Receive(buffer); if (len <= 0) return; string content = Encoding.ASCII.GetString(buffer, 0, len); amessage += cleanMessage.Substring(0, MessageLength); if (OnRead != null) { var e = new CommandEventArgs(amessage); OnRead(this, e); } } } Now, as I understand it only one thread at a time will enter BeginRead, I call Receive, it blocks until I get data, and then I process it. The problem: the variable amessage will change it's value between statements that do not touch or alter the variable at all, for example at the bottom of the function at: if (OnRead != null) "amessage" will be equal to 'asdf' and at if (OnRead != null) "amessage" will be equal to qwert. As I understand it this is indicative of another thread changing the value/running asynchronously. I only spawn one thread to do the receiving and the Receive function is blocking, how could there be two threads in this function and if there is only one thread how does amessage's value change between statements that don't affect it's value. As a side note sorry for spamming the site with these questions but I'm just getting a hang of this threading story and it's making me want to sip cyanide. Thanks in advance. EDIT: Here is my code that calls the Listen Method in the client: public void ConnectClient(string ip,int port) { client.Connect(ip,port); client.Listen(5); } and in the server: private void Accept(IAsyncResult result) { var client = new AbstractClient(MySocket.EndAccept(result)); var e = new CommandEventArgs(client, null); Clients.Add(client); client.Listen(5); if (OnClientAdded != null) { var target = (Control) OnClientAdded.Target; if (target != null && target.InvokeRequired) target.Invoke(OnClientAdded, this, e); else OnClientAdded(this, e); } client.OnRead += OnRead; MySocket.BeginAccept(new AsyncCallback(Accept), null); } All this code is in a class called AbstractClient. The client inherits the Abstract client and when the server accepts a socket it create's it's own local AbstractClient, in this case both modules access the functions above however they are different instances and I couldn't imagine threads from different instances combining especially as no variable is static.

  Read the article

• I can't upload mp3 files using Codeigniter

  - by Drew

  There are lots of suggested fixes for this but none of them work for me. I have tried making the upload class (using the following methods: http://codeigniter.com/forums/viewthread/148605/ and http://codeigniter.com/forums/viewthread/125441/). When i try to upload an mp3 i get the error message "The filetype you are attempting to upload is not allowed". Below is my code for my model and my form (i've got a very skinny controller). If someone could help me out with this I would be eternally grateful. --Model-- function do_upload() { $soundfig['upload_path'] = './uploads/nav'; $soundfig['allowed_types'] = 'mp3'; $this->load->library('upload', $soundfig); if ( ! $this->upload->do_upload()) { $error = array('error' => $this->upload->display_errors()); return $error; } else { /* $data = $this->upload->data('userfile'); */ $sound = $this->upload->data(); /* $full_path = 'uploads/nav/' . $data['file_name']; */ $sound_path = 'uploads/nav/' . $sound['file_name']; if($this->input->post('active') == '1'){ $active = '1'; }else{ $active = '0'; } $spam = array( /* 'image_url' => $full_path, */ 'sound' => $sound_path, 'active' => $active, 'url' => $this->input->post('url') ); $id = $this->input->post('id'); $this->db->where('id', $id); $this->db->update('NavItemData', $spam); return true; } } --View - Form-- <?php echo form_open_multipart('upload/do_upload');?> <?php if(isset($buttons)) : foreach($buttons as $row) : ?> <h2><?php echo $row->name; ?></h2> <!-- <input type="file" name="userfile" size="20" /><br /> --> <input type="file" name="userfile" size="20" /> <input type="hidden" name="oldfile" value="<?php echo $row->image_url; ?>" /> <input type="hidden" name="id" value="<?php echo $row->id; ?>" /> <br /><br /> <label>Url: </label><input type="text" name="url" value="<?php echo $row->url; ?>" /><br /> <input type="checkbox" name="active" value="1" <?php if($row->active == '1') { echo 'checked'; } ?> /><br /><br /> <input type="submit" value="submit" /> </form> <?php endforeach; ?> <?php endif; ?>

  Read the article

• Problems uploading different file types in codeigniter

  - by Drew

  Below is my script that i'm using to upload different files. All the solutions I've found deal only with multiple image uploads. I am totally stumped for a solution on this. Can someone tell me what it is i'm supposed to be doing to upload different files in the same form? Thanks function do_upload() { $config['upload_path'] = './uploads/nav'; $config['allowed_types'] = 'gif|jpg|png'; $config['max_size'] = '2000'; $this->load->library('upload', $config); if ( ! $this->upload->do_upload('userfile')) { $error = array('error' => $this->upload->display_errors()); return $error; } else { $soundfig['upload_path'] = './uploads/nav'; $soundfig['allowed_types'] = 'mp3|wav'; $this->load->library('upload', $soundfig); if ( ! $this->upload->do_upload('soundfile')) { $error = array('error' => $this->upload->display_errors()); return $error; } else { $data = $this->upload->data('userfile'); $sound = $this->upload->data('soundfile'); $full_path = 'uploads/nav/' . $data['file_name']; $sound_path = 'uploads/nav/' . $sound['file_name']; if($this->input->post('active') == '1'){ $active = '1'; }else{ $active = '0'; } $spam = array( 'image_url' => $full_path, 'sound' => $sound_path, 'active' => $active, 'url' => $this->input->post('url') ); $id = $this->input->post('id'); $this->db->where('id', $id); $this->db->update('NavItemData', $spam); return true; } } } Here is my form: <?php echo form_open_multipart('upload/do_upload');?> <?php if(isset($buttons)) : foreach($buttons as $row) : ?> <h2><?php echo $row->name; ?></h2> <input type="file" name="userfile" size="20" /><br /> <input type="file" name="soundfile" size="20" /> <input type="hidden" name="oldfile" value="<?php echo $row->image_url; ?>" /> <input type="hidden" name="id" value="<?php echo $row->id; ?>" /> <br /><br /> <label>Url: </label><input type="text" name="url" value="<?php echo $row->url; ?>" /><br /> <input type="checkbox" name="active" value="1" <?php if($row->active == '1') { echo 'checked'; } ?> /><br /><br /> <input type="submit" value="submit" /> </form> <?php endforeach; ?> <?php endif; ?>

  Read the article

• Lock free multiple readers single writer

  - by dummzeuch

  I have got an in memory data structure that is read by multiple threads and written by only one thread. Currently I am using a critical section to make this access threadsafe. Unfortunately this has the effect of blocking readers even though only another reader is accessing it. There are two options to remedy this: use TMultiReadExclusiveWriteSynchronizer do away with any blocking by using a lock free approach For 2. I have got the following so far (any code that doesn't matter has been left out): type TDataManager = class private FAccessCount: integer; FData: TDataClass; public procedure Read(out _Some: integer; out _Data: double); procedure Write(_Some: integer; _Data: double); end; procedure TDataManager.Read(out _Some: integer; out _Data: double); var Data: TDAtaClass; begin InterlockedIncrement(FAccessCount); try // make sure we get both values from the same TDataClass instance Data := FData; // read the actual data _Some := Data.Some; _Data := Data.Data; finally InterlockedDecrement(FAccessCount); end; end; procedure TDataManager.Write(_Some: integer; _Data: double); var NewData: TDataClass; OldData: TDataClass; ReaderCount: integer; begin NewData := TDataClass.Create(_Some, _Data); InterlockedIncrement(FAccessCount); OldData := TDataClass(InterlockedExchange(integer(FData), integer(NewData)); // now FData points to the new instance but there might still be // readers that got the old one before we exchanged it. ReaderCount := InterlockedDecrement(FAccessCount); if ReaderCount = 0 then // no active readers, so we can safely free the old instance FreeAndNil(OldData) else begin /// here is the problem end; end; Unfortunately there is the small problem of getting rid of the OldData instance after it has been replaced. If no other thread is currently within the Read method (ReaderCount=0), it can safely be disposed and that's it. But what can I do if that's not the case? I could just store it until the next call and dispose it there, but Windows scheduling could in theory let a reader thread sleep while it is within the Read method and still has got a reference to OldData. If you see any other problem with the above code, please tell me about it. This is to be run on computers with multiple cores and the above methods are to be called very frequently. In case this matters: I am using Delphi 2007 with the builtin memory manager. I am aware that the memory manager probably enforces some lock anyway when creating a new class but I want to ignore that for the moment. Edit: It may not have been clear from the above: For the full lifetime of the TDataManager object there is only one thread that writes to the data, not several that might compete for write access. So this is a special case of MREW.

  Read the article

• Looking for best practise for writing a serial device communication app in C#

  - by cdotlister

  I am pretty new to serial comms, but would like advise on how to best achieve a robust application which speak to and listens to a serial device. I have managed to make use of System.IO.serialport, and successfully connected to, sent data to and recieved from my device. The way things work is this. My application connects to the Com Port and opens the port.... I then connect my device to the com port, and it detects a connectio to the PC, so sends a bit of text. it's really just copyright info, as well as the version of the firmware. I don't do anything with that, except display it in my 'activity' window. The device then waits. I can then query information, but sending a command such as 'QUERY PARAMETER1'. It then replies with something like: 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n' I then process that. I can then update it by sending 'SET PARAMETER1 12345', and it will reply with 'QUERY PARAMETER1\r\n\r\n12345\r\n\r\n'. All pretty basic. So, what I have done is created a Communication Class. this call is called in it's own thread, and sends data back to the main form... and also allows me to send messages to it. Sending data is easy. Recieving is a bit more tricky. I have employed the use of the datarecieved event, and when ever data comes in, I echo that to my screen. My problem is this: When I send a command, I feel I am being very dodgy in my handling. What I am doing is, lets say I am sending 'QUERY PARAMETER1'. I send the command to the device, I then put 'PARAMETER1' into a global variable, and I do a Thread.Sleep(100). On the data recieved, I then have a bit of logic that checks the incoming data, and sees if the string CONTAINS the value in the gloabl variable. As the reply may be 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n', it sees that it contains my parameter, parses the string, and returns the value I am looking for, but placing it into another global variable. My sending method was sleeping for 100ms. It then wakes, and checks the returned global variable. If it has data... then I'm happy, and I process the data. Problem is... if the sleep is too short.. it will fail. And I feel it's flakey.. putting stuff into variables.. then waiting... The other option is to use ReadLine instead, but that's very blocking. So I remove the datarecieved method, and instead... just send the data... then call ReadLine(). That may give me better results. There's no time, except when we connect initially, that data comes from the device, without me requesting it. So, maybe readline will be simpler and safer? Is this known as 'Blocking' reads? Also, can I set a timeout? Hopefully someone can guide me.

  Read the article

• Listening for TCP and UDP requests on the same port

  - by user339328

  I am writing a Client/Server set of programs Depending on the operation requested by the client, I use make TCP or UDP request. Implementing the client side is straight-forward, since I can easily open connection with any protocol and send the request to the server-side. On the servers-side, on the other hand, I would like to listen both for UDP and TCP connections on the same port. Moreover, I like the the server to open new thread for each connection request. I have adopted the approach explained in: link text I have extended this code sample by creating new threads for each TCP/UDP request. This works correctly if I use TCP only, but it fails when I attempt to make UDP bindings. Please give me any suggestion how can I correct this. tnx Here is the Server Code: public class Server { public static void main(String args[]) { try { int port = 4444; if (args.length > 0) port = Integer.parseInt(args[0]); SocketAddress localport = new InetSocketAddress(port); // Create and bind a tcp channel to listen for connections on. ServerSocketChannel tcpserver = ServerSocketChannel.open(); tcpserver.socket().bind(localport); // Also create and bind a DatagramChannel to listen on. DatagramChannel udpserver = DatagramChannel.open(); udpserver.socket().bind(localport); // Specify non-blocking mode for both channels, since our // Selector object will be doing the blocking for us. tcpserver.configureBlocking(false); udpserver.configureBlocking(false); // The Selector object is what allows us to block while waiting // for activity on either of the two channels. Selector selector = Selector.open(); tcpserver.register(selector, SelectionKey.OP_ACCEPT); udpserver.register(selector, SelectionKey.OP_READ); System.out.println("Server Sterted on port: " + port + "!"); //Load Map Utils.LoadMap("mapa"); System.out.println("Server map ... LOADED!"); // Now loop forever, processing client connections while(true) { try { selector.select(); Set<SelectionKey> keys = selector.selectedKeys(); // Iterate through the Set of keys. for (Iterator<SelectionKey> i = keys.iterator(); i.hasNext();) { SelectionKey key = i.next(); i.remove(); Channel c = key.channel(); if (key.isAcceptable() && c == tcpserver) { new TCPThread(tcpserver.accept().socket()).start(); } else if (key.isReadable() && c == udpserver) { new UDPThread(udpserver.socket()).start(); } } } catch (Exception e) { e.printStackTrace(); } } } catch (Exception e) { e.printStackTrace(); System.err.println(e); System.exit(1); } } } The UDPThread code: public class UDPThread extends Thread { private DatagramSocket socket = null; public UDPThread(DatagramSocket socket) { super("UDPThread"); this.socket = socket; } @Override public void run() { byte[] buffer = new byte[2048]; try { DatagramPacket packet = new DatagramPacket(buffer, buffer.length); socket.receive(packet); String inputLine = new String(buffer); String outputLine = Utils.processCommand(inputLine.trim()); DatagramPacket reply = new DatagramPacket(outputLine.getBytes(), outputLine.getBytes().length, packet.getAddress(), packet.getPort()); socket.send(reply); } catch (IOException e) { e.printStackTrace(); } socket.close(); } } I receive: Exception in thread "UDPThread" java.nio.channels.IllegalBlockingModeException at sun.nio.ch.DatagramSocketAdaptor.receive(Unknown Source) at server.UDPThread.run(UDPThread.java:25) 10x

  Read the article

• Looking for best practise for writing a serial device communication app

  - by cdotlister

  I am pretty new to serial comms, but would like advise on how to best achieve a robust application which speak to and listens to a serial device. I have managed to make use of System.IO.SerialPort, and successfully connected to, sent data to and recieved from my device. The way things work is this. My application connects to the Com Port and opens the port.... I then connect my device to the com port, and it detects a connection to the PC, so sends a bit of text. it's really just copyright info, as well as the version of the firmware. I don't do anything with that, except display it in my 'activity' window. The device then waits. I can then query information, but sending a command such as 'QUERY PARAMETER1'. It then replies with something like: 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n' I then process that. I can then update it by sending 'SET PARAMETER1 12345', and it will reply with 'QUERY PARAMETER1\r\n\r\n12345\r\n\r\n'. All pretty basic. So, what I have done is created a Communication Class. this call is called in it's own thread, and sends data back to the main form... and also allows me to send messages to it. Sending data is easy. Recieving is a bit more tricky. I have employed the use of the datarecieved event, and when ever data comes in, I echo that to my screen. My problem is this: When I send a command, I feel I am being very dodgy in my handling. What I am doing is, lets say I am sending 'QUERY PARAMETER1'. I send the command to the device, I then put 'PARAMETER1' into a global variable, and I do a Thread.Sleep(100). On the data received, I then have a bit of logic that checks the incoming data, and sees if the string CONTAINS the value in the global variable. As the reply may be 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n', it sees that it contains my parameter, parses the string, and returns the value I am looking for, but placing it into another global variable. My sending method was sleeping for 100ms. It then wakes, and checks the returned global variable. If it has data... then I'm happy, and I process the data. Problem is... if the sleep is too short.. it will fail. And I feel it's flaky.. putting stuff into variables.. then waiting... The other option is to use ReadLine instead, but that's very blocking. So I remove the data received method, and instead... just send the data... then call ReadLine(). That may give me better results. There's no time, except when we connect initially, that data comes from the device, without me requesting it. So, maybe ReadLine will be simpler and safer? Is this known as 'Blocking' reads? Also, can I set a timeout? Hopefully someone can guide me.

  Read the article

• How do you send a named pipe string from umnanaged to managed code space?

  - by billmcf

  I appear to have a named pipes 101 issue. I have a very simple set up to connect a simplex named pipe transmitting from a C++ unmanaged app to a C# managed app. The pipe connects, but I cannot send a "message" through the pipe unless I close the handle which appears to flush the buffer and pass the message through. It's like the message is blocked. I have tried reversing the roles of client/server and invoking them with different Flag combinations without any luck. I can easily send messages in the other direction from C# managed to C++ unmanaged. Does anyone have any insight. Can any of you guys successfully send messages from C++ unmanaged to C# managed? I can find plenty of examples of intra amanged or unmanaged pipes but not inter managed to/from unamanged - just claims to be able to do it. In the listings, I have omitted much of the wrapper stuff for clarity. The key bits I believe that are relevant are the pipe connection/creation/read and write methods. Don't worry too much about blocking/threading here. C# Server side // This runs in its own thread and so it is OK to block private void ConnectToClient() { // This server will listen to the sending client if (m_InPipeStream == null) { m_InPipeStream = new NamedPipeServerStream("TestPipe", PipeDirection.In, 1); } // Wait for client to connect to our server m_InPipeStream.WaitForConnection(); // Verify client is running if (!m_InPipeStream.IsConnected) { return; } // Start listening for messages on the client stream if (m_InPipeStream != null && m_InPipeStream.CanRead) { ReadThread = new Thread(new ParameterizedThreadStart(Read)); ReadThread.Start(m_InPipeStream); } } // This runs in its own thread and so it is OK to block private void Read(object serverObj) { NamedPipeServerStream pipeStream = (NamedPipeServerStream)serverObj; using (StreamReader sr = new StreamReader(pipeStream)) { while (true) { string buffer = "" ; try { // Blocks here until the handle is closed by the client-side!! buffer = sr.ReadLine(); // <<<<<<<<<<<<<< Sticks here } catch { // Read error break; } // Client has disconnected? if (buffer == null || buffer.Length == 0) break; // Fire message received event if message is non-empty if (MessageReceived != null && buffer != "") { MessageReceived(buffer); } } } } C++ client side // Static - running in its own thread. DWORD CNamedPipe::ListenForServer(LPVOID arg) { // The calling app (this) is passed as the parameter CNamedPipe* app = (CNamedPipe*)arg; // Out-Pipe: connect as a client to a waiting server app->m_hOutPipeHandle = CreateFile("\\\\.\\pipe\\TestPipe", GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); // Could not create handle if (app->m_hInPipeHandle == NULL || app->m_hInPipeHandle == INVALID_HANDLE_VALUE) { return 1; } return 0; } // Sends a message to the server BOOL CNamedPipe::SendMessage(CString message) { DWORD dwSent; if (m_hOutPipeHandle == NULL || m_hOutPipeHandle == INVALID_HANDLE_VALUE) { return FALSE; } else { BOOL bOK = WriteFile(m_hOutPipeHandle, message, message.GetLength()+1, &dwSent, NULL); //FlushFileBuffers(m_hOutPipeHandle); // <<<<<<< Tried this return (!bOK || (message.GetLength()+1) != dwSent) ? FALSE : TRUE; } } // Somewhere in the Windows C++/MFC code... ... // This write is non-blocking. It just passes through having loaded the pipe. m_pNamedPipe->SendMessage("Hi de hi"); ...

  Read the article

• SQL SERVER – Generate Report for Index Physical Statistics – SSMS

  - by pinaldave

  Few days ago, I wrote about SQL SERVER – Out of the Box – Activity and Performance Reports from SSSMS (Link). A user asked me a question regarding if we can use similar reports to get the detail about Indexes. Yes, it is possible to do the same. There are similar type of reports are available at Database level, just like those available at the Server Instance level. You can right click on Database name and click Reports. Under Standard Reports, you will find following reports. Disk Usage Disk Usage by Top Tables Disk Usage by Table Disk Usage by Partition Backup and Restore Events All Transactions All Blocking Transactions Top Transactions by Age Top Transactions by Blocked Transactions Count Top Transactions by Locks Count Resource Locking Statistics by Objects Object Execute Statistics Database Consistency history Index Usage Statistics Index Physical Statistics Schema Change history User Statistics Select the Reports with name Index Physical Statistics. Once click, a report containing all the index names along with other information related to index will be visible, e.g. Index Type and number of partitions. One column that caught my interest was Operation Recommended. In some place, it suggested that index needs to be rebuilt. It is also possible to click and expand the column of partitions and see additional details about index as well. DBA and Developers who just want to have idea about how your index is and its physical statistics can use this tool. Click to Enlarge Note: Please note that I will rebuild my indexes just because this report is recommending it. There are many other parameters you need to consider before rebuilding indexes. However, this tool gives you the accurate stats of your index and it can be right away exported to Excel or PDF writing by clicking on the report. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, SQL Utility, T SQL, Technology

  Read the article

• Upgrading from TFS 2010 RC to TFS 2010 RTM done

  - by Martin Hinshelwood

  Today is the big day, with the Launch of Visual Studio 2010 already done in Asia, and rolling around the world towards us, we are getting ready for the RTM (Released). We have had TFS 2010 in Production for nearly 6 months and have had only minimal problems. Update 12th April 2010  – Added Scott Hanselman’s tweet about the MSDN download release time. SSW was the first company in the world outside of Microsoft to deploy Visual Studio 2010 Team Foundation Server to production, not once, but twice. I am hoping to make it 3 in a row, but with all the hype around the new version, and with it being a production release and not just a go-live, I think there will be a lot of competition. Developers: MSDN will be updated with #vs2010 downloads and details at 10am PST *today*! @shanselman - Scott Hanselman Same as before, we need to Uninstall 2010 RC and install 2010 RTM. The installer will take care of all the complexity of actually upgrading any schema changes. If you are upgrading from TFS 2008 to TFS2010 you can follow our Rules To Better TFS 2010 Migration and read my post on our successes.   We run TFS 2010 in a Hyper-V virtual environment, so we have the advantage of running a snapshot as well as taking a DB backup. Done - Snapshot the hyper-v server Microsoft does not support taking a snapshot of a running server, for very good reason, and Brian Harry wrote a post after my last upgrade with the reason why you should never snapshot a running server. Done - Uninstall Visual Studio Team Explorer 2010 RC You will need to uninstall all of the Visual Studio 2010 RC client bits that you have on the server. Done - Uninstall TFS 2010 RC Done - Install TFS 2010 RTM Done - Configure TFS 2010 RTM Pick the Upgrade option and point it at your existing “tfs_Configuration” database to load all of the existing settings Done - Upgrade the SharePoint Extensions Upgrade Build Servers (Pending) Test the server The back out plan, and you should always have one, is to restore the snapshot. Upgrading to Team Foundation Server 2010 – Done The first thing you need to do is off the TFS server and then log into the Hyper-v server and create a snapshot. Figure: Make sure you turn the server off and delete all old snapshots before you take a new one I noticed that the snapshot that was taken before the Beta 2 to RC upgrade was still there. You should really delete old snapshots before you create a new one, but in this case the SysAdmin (who is currently tucked up in bed) asked me not to. I guess he is worried about a developer messing up his server Turn your server on and wait for it to boot in anticipation of all the nice shiny RTM’ness that is coming next. The upgrade procedure for TFS2010 is to uninstal the old version and install the new one. Figure: Remove Visual Studio 2010 Team Foundation Server RC from the system.   Figure: Most of the heavy lifting is done by the Uninstaller, but make sure you have removed any of the client bits first. Specifically Visual Studio 2010 or Team Explorer 2010.  Once the uninstall is complete, this took around 5 minutes for me, you can begin the install of the RTM. Running the 64 bit OS will allow the application to use more than 2GB RAM, which while not common may be of use in heavy load situations. Figure: It is always recommended to install the 64bit version of a server application where possible. I do not think it is likely, with SharePoint 2010 and Exchange 2010  and even Windows Server 2008 R2 being 64 bit only, I do not think there will be another release of a server app that is 32bit. You then need to choose what it is you want to install. This depends on how you are running TFS and on how many servers. In our case we run TFS and the Team Foundation Build Service (controller only) on out TFS server along with Analysis services and Reporting Services. But our SharePoint server lives elsewhere. Figure: This always confuses people, but in reality it makes sense. Don’t install what you do not need. Every extra you install has an impact of performance. If you are integrating with SharePoint you will need to run this install on every Front end server in your farm and don’t forget to upgrade your Build servers and proxy servers later. Figure: Selecting only Team Foundation Server (TFS) and Team Foundation Build Services (TFBS)   It is worth noting that if you have a lot of builds kicking off, and hence a lot of get operations against your TFS server, you can use a proxy server to cache the source control on another server in between your TFS server and your build servers. Figure: Installing Microsoft .NET Framework 4 takes the most time. Figure: Now run Windows Update, and SSW Diagnostic to make sure all your bits and bobs are up to date. Note: SSW Diagnostic will check your Power Tools, Add-on’s, Check in Policies and other bits as well. Configure Team Foundation Server 2010 – Done Now you can configure the server. If you have no key you will need to pick “Install a Trial Licence”, but it is only £500, or free with a MSDN subscription. Anyway, if you pick Trial you get 90 days to get your key. Figure: You can pick trial and add your key later using the TFS Server Admin. Here is where the real choices happen. We are doing an Upgrade from a previous version, so I will pick Upgrade the same as all you folks that are using the RC or TFS 2008. Figure: The upgrade wizard takes your existing 2010 or 2008 databases and upgraded them to the release.   Once you have entered your database server name you can click “List available databases” and it will show what it can upgrade. Figure: Select your database from the list and at this point, make sure you have a valid backup. At this point you have not made ANY changes to the databases. At this point the configuration wizard will load configuration from your existing database if you have one. If you are upgrading TFS 2008 refer to Rules To Better TFS 2010 Migration. Mostly during the wizard the default values will suffice, but depending on the configuration you want you can pick different options. Figure: Set the application tier account and Authentication method to use. We use NTLM to keep things simple as we host our TFS server externally for our remote developers.  Figure: Setting your TFS server URL’s to be the remote URL’s allows the reports to be accessed without using VPN. Very handy for those remote developers. Figure: Detected the existing Warehouse no problem. Figure: Again we love green ticks. It gives us a warm fuzzy feeling. Figure: The username for connecting to Reporting services should be a domain account (if you are on a domain that is). Figure: Setup the SharePoint integration to connect to your external SharePoint server. You can take the option to connect later.   You then need to run all of your readiness checks. These check can save your life! it will check all of the settings that you have entered as well as checking all the external services are configures and running properly. There are two reasons that TFS 2010 is so easy and painless to install where previous version were not. Microsoft changes the install to two steps, Install and configuration. The second reason is that they have pulled out all of the stops in making the install run all the checks necessary to make sure that once you start the install that it will complete. if you find any errors I recommend that you report them on http://connect.microsoft.com so everyone can benefit from your misery.   Figure: Now we have everything setup the configuration wizard can do its work.  Figure: Took a while on the “Web site” stage for some point, but zipped though after that.  Figure: last wee bit. TFS Needs to do a little tinkering with the data to complete the upgrade. Figure: All upgraded. I am not worried about the yellow triangle as SharePoint was being a little silly Exception Message: TF254021: The account name or password that you specified is not valid. (type TfsAdminException) Exception Stack Trace:    at Microsoft.TeamFoundation.Management.Controls.WizardCommon.AccountSelectionControl.TestLogon(String connectionString)    at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument) [Info   @16:10:16.307] Benign exception caught as part of verify: Exception Message: TF255329: The following site could not be accessed: http://projects.ssw.com.au/. The server that you specified did not return the expected response. Either you have not installed the Team Foundation Server Extensions for SharePoint Products on this server, or a firewall is blocking access to the specified site or the SharePoint Central Administration site. For more information, see the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=161206). (type TeamFoundationServerException) Exception Stack Trace:    at Microsoft.TeamFoundation.Client.SharePoint.WssUtilities.VerifyTeamFoundationSharePointExtensions(ICredentials credentials, Uri url)    at Microsoft.TeamFoundation.Admin.VerifySharePointSitesUrl.Verify() Inner Exception Details: Exception Message: TF249064: The following Web service returned an response that is not valid: http://projects.ssw.com.au/_vti_bin/TeamFoundationIntegrationService.asmx. This Web service is used for the Team Foundation Server Extensions for SharePoint Products. Either the extensions are not installed, the request resulted in HTML being returned, or there is a problem with the URL. Verify that the following URL points to a valid SharePoint Web application and that the application is available: http://projects.ssw.com.au. If the URL is correct and the Web application is operating normally, verify that a firewall is not blocking access to the Web application. (type TeamFoundationServerInvalidResponseException) Exception Data Dictionary: ResponseStatusCode = InternalServerError I’ll look at SharePoint after, probably the SharePoint box just needs a restart or a kick If there is a problem with SharePoint it will come out in testing, But I will definatly be passing this on to Microsoft.   Upgrading the SharePoint connector to TFS 2010 You will need to upgrade the Extensions for SharePoint Products and Technologies on all of your SharePoint farm front end servers. To do this uninstall  the TFS 2010 RC from it in the same way as the server, and then install just the RTM Extensions. Figure: Only install the SharePoint Extensions on your SharePoint front end servers. TFS 2010 supports both SharePoint 2007 and SharePoint 2010.   Figure: When you configure SharePoint it uploads all of the solutions and templates. Figure: Everything is uploaded Successfully. Figure: TFS even remembered the settings from the previous installation, fantastic.   Upgrading the Team Foundation Build Servers to TFS 2010 Just like on the SharePoint servers you will need to upgrade the Build Server to the RTM. Just uninstall TFS 2010 RC and then install only the Team Foundation Build Services component. Unlike on the SharePoint server you will probably have some version of Visual Studio installed. You will need to remove this as well. (Coming Soon) Connecting Visual Studio 2010 / 2008 / 2005 and Eclipse to TFS2010 If you have developers still on Visual Studio 2005 or 2008 you will need do download the respective compatibility pack: Visual Studio Team System 2005 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 Visual Studio Team System 2008 Service Pack 1 Forward Compatibility Update for Team Foundation Server 2010 If you are using Eclipse you can download the new Team Explorer Everywhere install for connecting to TFS. Get your developers to check that you have the latest version of your applications with SSW Diagnostic which will check for Service Packs and hot fixes to Visual Studio as well.   Technorati Tags: TFS,TFS2010,TFS 2010,Upgrade

  Read the article

• Sharing a texture resource from DX11 to DX9 to WPF, need to wait for DeviceContext.Flush() to finish

  - by Rei Miyasaka

  I'm following these instructions on TheCodeProject for rendering from DirectX to WPF using D3DImage. The trouble is that now that I have no swap chain to call Present() on -- which according to the article shouldn't be a problem, but it definitely wasn't copying my back buffer. An additional step that I have to take before I can copy the texture to WPF is to share it with a second D3D9Ex device, since D3DImage only works with DX9 (which is understandable, as WPF is built on DX9). To that end, I've modified some SlimDX code to work with DirectX 11. I tried calling DeviceContext.Flush() (the Immediate one) at the end of each render cycle, which kind of works -- most of the time it'll show my renderings, but maybe for maybe 3 or 4 out of 60 frames each second, it'll draw my clear color instead. This makes sense -- Flush() is non-blocking; it doesn't wait for the GPU to do its thing the way SwapChain.Present does. Any idea what the proper solution is? I have a feeling it has something to do with my texture parameters for the back buffer, but I don't know.

  Read the article

• Holiday 2010 Personas Themes for Firefox

  - by Asian Angel

  Does your Firefox browser need a touch of holiday spirit to brighten it up? Then sit back and enjoy looking through these 20 wonderful holiday Personas themes that we have collected together for you. Note: The names and links for the themes are located above each image. Snoopy Christmas Tribute A Charlie Brown Christmas Celebration Winnie and Tigger Topping the Tree mickey & minnie – happy christmas Foxkeh as Rudolph the Red Nosed Rein-fox Santa and Frosty Ski Fun Santas Sleigh Ride Envol du traineau – christmas Adorable Santa Santas Hat 3 Frosty the Snowmans Christmas Eve Snowmans Village Warm For Christmas Believe – Snow Christmas in the Forest Christmas Aurora Violet Xmas Homestead Christmas ANIMATED Christmas Window Christmas Tree Lights More Holiday Personas Themes Fun Brighten Up Firefox for the Holidays *Our Holiday 2009 Personas Themes Collection Winter Time Christmas Personas Theme for Firefox Snowy Christmas House Personas Theme for Firefox Latest Features How-To Geek ETC The Complete List of iPad Tips, Tricks, and Tutorials The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Deathwing the Destroyer – WoW Cataclysm Dragon Wallpaper Drag2Up Lets You Drag and Drop Files to the Web With Ease The Spam Police Parts 1 and 2 – Goodbye Spammers [Videos] Snow Angels Theme for Windows 7 Exploring the Jungle Ruins Wallpaper Protect Your Privacy When Browsing with Chrome and Iron Browser

  Read the article

• Remove a Digital Camera’s IR Filter for IR Photography on the Cheap

  - by Jason Fitzpatrick

  Whether you have a DSLR or a point-and-shoot, this simple hack allows you to shoot awesome IR photographs without the expense of a high-quality IR filter (or the accompanying loss of light that comes with using it). How does it work? You’ll need to take apart your camera and remove a single fragile layer of IR blocking glass from the CCD inside the camera body. After doing so, you’ll have a camera that sees infrared light by default, no special add-on filters necessary. Because it sees the IR light without the filters you’ll also skip out on the light loss that occurs with the addition of the add-on IR filter. The downside? You’re altering the camera in permanent and warranty-voiding way. This is most definitely not a hack for your brand new $2,000 DSLR, but it is a really fun hack to try out on an old point and shoot camera or your circa-2004 depreciated DSLR. Hit up the link below to see the process performed on an old Canon point and shoot–we’d strongly recommend searching for a break down guide for your specific camera model before attempting the trick on your own gear. Are You Brave Enough to IR-ize Your Camera [DIY Photography] HTG Explains: How Windows Uses The Task Scheduler for System Tasks HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows? Java is Insecure and Awful, It’s Time to Disable It, and Here’s How

  Read the article

• Chennai Metro Water [Indian Websites]

  - by samsudeen

  If you are living in Chennai definitely you will have this question in your mind “Does Chennai 0survive this summer without any water crisis?”. The Chennai Metro Water maintains a website where in you can know all the details about the water storage, supply. This site has all the information about water supply  especially matters for  Chennai residents. I have given some of the uses of this site Water Sewer Application Status If you are a new resident and applied for water sewer application status. You can check your application (Water Sewer Application Status) by entering your WA No (Water Application No). You can also download all the required application forms. Register Complaints You can register complaints (Register Complaints) about  water supply / defective water meter and sewage blocking online. Pay Water & Sewage Tax You can pay your water & sewage tax (Pay Tax) online including the dues /arrears if any left out. Lake Level This site also maintains the current (Lake Level) and historic water levels of the Chennai water reservoirs including the daily inflow /out flow of water. You can also know the daily / month rainfall levels of these water reservoirs from 1965 onwards. Hope this  information little  useful for those who are planning / building a new house in Chennai corporation. Join us on Facebook to read all our stories right inside your Facebook news feed.

  Read the article

• Option Trading: Getting the most out of the event session options

  - by extended_events

  You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

  Read the article

• Desktop Fun: Merry Christmas Wallpaper Collection [Bonus Edition]

  - by Asian Angel

  Are you ready for all of the gifts, assorted goodies, and great food that are a part of Christmas? As part of the build-up to the festivities, we have a larger than normal set of wallpapers to help add those final bits of holiday cheer and decoration to your desktops. Note: Click on the picture to see the full-size image—these wallpapers vary in size so you may need to crop, stretch, or place them on a colored background in order to best match them to your screen’s resolution. For more Christmas desktop goodness be sure to check out our Merry Christmas icon packs & fonts collections (links at bottom)! Note: You can download an additional wallpaper of Rudolph by himself here. Note: There are two wallpapers from “Frosty Returns” available here and here. Note: The Garfield image will need to be slightly sharpened in a photo program and placed on a background to increase the height. Desktop Fun: Merry Christmas Icon Packs Desktop Fun: Merry Christmas Fonts Looking for more Merry Christmas wallpapers? Browse through our 2009 collection here: Awesome Holiday Themed Desktop Wallpapers For more wallpapers be certain to see our great collections in the Desktop Fun section. Latest Features How-To Geek ETC The Complete List of iPad Tips, Tricks, and Tutorials The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor The Spam Police Parts 1 and 2 – Goodbye Spammers [Videos] Snow Angels Theme for Windows 7 Exploring the Jungle Ruins Wallpaper Protect Your Privacy When Browsing with Chrome and Iron Browser Free Shipping Day is Friday, December 17, 2010 – National Free Shipping Day Find an Applicable Quote for Any Programming Situation

  Read the article

• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

  Read the article

< Previous Page | 67 68 69 70 71 72 73 74 75 76 77 78  | Next Page >