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  • Low noise sites to keep track of news related to computers & programming?

    - by Sridhar Ratnakumar
    I am aware of sites like Slashdot and Ars Technica. Unfortunately they publish way too many articles per day. Ars Technical: 100 posts per week Slashdot: 179 posts per week And I prefer not to waste my attention over reading about 180 posts (even if I were to skim) every week. Is there a site that provides only important news - excluding not-so-important news items like top 6 iPad apps that someone is dying to try out (but haven't done yet; still thinks their readers/advertisers care about it)?

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  • I would like to build an app that alerts me when road traffic is high or low. Where can I get the r

    - by MedicineMan
    I'm sitting at work, waiting for traffic to die down. The thought occurred to me. I know when I want to go home, why don't I have an app that watches traffic for me? I also know that there are a lot of smart people on stackoverflow. Where can I get live traffic data for the san francisco bay area region? The data source should be timely, accurate, and as high resolution as possible. I would like to build an app on top of a service, rather than watch google maps or watch another website. I would prefer that I not have to scrape the data, but I have been know to do this in the past when no other option exists.

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  • Opinions on Dual-Salt authentication for low sensitivity user accounts?

    - by Heleon
    EDIT - Might be useful for someone in the future... Looking around the bcrypt class in php a little more, I think I understand what's going on, and why bcrypt is secure. In essence, I create a random blowfish salt, which contains the number of crypt rounds to perform during the encryption step, which is then hashed using the crypt() function in php. There is no need for me to store the salt I used in the database, because it's not directly needed to decrypt, and the only way to gain a password match to an email address (without knowing the salt values or number of rounds) would be to brute force plain text passwords against the hash stored in the database using the crypt() function to verify, which, if you've got a strong password, would just be more effort than it's worth for the user information i'm storing... I am currently working on a web project requiring user accounts. The application is CodeIgniter on the server side, so I am using Ion Auth as the authentication library. I have written an authentication system before, where I used 2 salts to secure the passwords. One was a server-wide salt which sat as an environment variable in the .htaccess file, and the other was a randomly generated salt which was created at user signup. This was the method I used in that authentication system for hashing the password: $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; //create a random string to be used as the random salt for the password hash $size = strlen($chars); for($i = 0; $i < 22; $i++) { $str .= $chars[rand(0, $size - 1)]; } //create the random salt to be used for the crypt $r_blowfish_salt = "$2a$12$" . $str . "$"; //grab the website salt $salt = getenv('WEBSITE_SALT'); //combine the website salt, and the password $password_to_hash = $pwd . $salt; //crypt the password string using blowfish $password = crypt($password_to_hash, $r_blowfish_salt); I have no idea whether this has holes in it or not, but regardless, I moved over to Ion Auth for a more complete set of functions to use with CI. I noticed that Ion only uses a single salt as part of its hashing mechanism (although does recommend that encryption_key is set in order to secure the database session.) The information that will be stored in my database is things like name, email address, location by country, some notes (which will be recommended that they do not contain sensitive information), and a link to a Facebook, Twitter or Flickr account. Based on this, i'm not convinced it's necessary for me to have an SSL connection on the secure pages of my site. My question is, is there a particular reason why only 1 salt is being used as part as the Ion Auth library? Is it implied that I write my own additional salting in front of the functionality it provides, or am I missing something? Furthermore, is it even worth using 2 salts, or once an attacker has the random salt and the hashed password, are all bets off anyway? (I assume not, but worth checking if i'm worrying about nothing...)

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  • Can SHA-1 algorithm be computed on a stream? With low memory footprint?

    - by raoulsson
    I am looking for a way to compute SHA-1 checksums of very large files without having to fully load them into memory at once. I don't know the details of the SHA-1 implementation and therefore would like to know if it is even possible to do that. If you know the SAX XML parser, then what I look for would be something similar: Computing the SHA-1 checksum by only always loading a small part into memory at a time. All the examples I found, at least in Java, always depend on fully loading the file/byte array/string into memory. If you even know implementations (any language), then please let me know!

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  • Can I prevent Flash's Input Events from stacking up when my framerate low?

    - by Matt W
    My Flash game targets 24 fps, but slows to 10 on slower machines. This is fine, except Flash decides to throttle the queue of incoming MouseEvent and KeyboardEvents, and they stack up and the Events fall behind. Way behind. It's so bad that, at 10 fps, if I spam the Mouse and Keyboard for a few seconds not much happens, then, after I stop, the game seems to play itself for the next 5 seconds as the Events trickle in. Spooky, I know. Does anyone know a way around this? I basically need to say to Flash, "I know you think we're falling behind, but throttling the input events won't help. Give them to me as soon as you get them, please."

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  • How do I handle a low job offer for an entry level position?

    - by user229269
    Hi guys! I recently graduated with MS in CS and I am excited because I just received a job offer from a company I really like for an entry-level sw engineer position. The thing is that, although the salary is not my priority and I care way more about gaining experience, their offer unfortunately is way below of what I expected. Actually after I did some research I realized that, comparing to the average salary range for the entry-level sw engineering positions in my area (one of the most expensive areas in the US) supposedly [X - Y]$ (where X is the lowest average and Y the highest), their offer is 20% below X! I wouldnt have a problem accepting an offer around X but this one is even lower than the lowest. Can I counter offer the X which is 20% more than what they offered me but at the same time is the minimum average? -- And mind you that I didnt even take under consideration the fact that I hold a MS degree which in many cases yields to a 5-10% more pay.

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  • Application shows low memory warning and crashes while loading images?

    - by Bhoomi
    I am using following code for loading images from server using following code.When i scroll UITableView application crashes. AsynchrohousImageView class .m file - (void)dealloc { [connection cancel]; //in case the URL is still downloading [connection release]; [data release]; [_imageView release]; [_activityIndicator release]; [super dealloc]; } - (void)loadImageFromURL:(NSURL*)url defaultImageName:(NSString *)defaultImageName showDefaultImage:(BOOL)defaultImageIsShown showActivityIndicator:(BOOL)activityIndicatorIsShown activityIndicatorRect:(CGRect)activityIndicatorRect activityIndicatorStyle:(UIActivityIndicatorViewStyle)activityIndicatorStyle { if (connection!=nil) { [connection release]; } if (data!=nil) { [data release]; } if ([[self subviews] count]>0) { [[[self subviews] objectAtIndex:0] removeFromSuperview]; // } if (defaultImageIsShown) { self.imageView = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:defaultImageName]] autorelease]; } else { self.imageView = [[[UIImageView alloc] init] autorelease]; } [self addSubview:_imageView]; _imageView.frame = self.bounds; [_imageView setNeedsLayout]; [self setNeedsLayout]; if (activityIndicatorIsShown) { self.activityIndicator = [[[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:activityIndicatorStyle] autorelease]; [self addSubview:_activityIndicator]; _activityIndicator.frame = activityIndicatorRect; _activityIndicator.center = CGPointMake(_imageView.frame.size.width/2, _imageView.frame.size.height/2); [_activityIndicator setHidesWhenStopped:YES]; [_activityIndicator startAnimating]; } NSURLRequest* request = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0]; connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; } - (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData { if (data==nil) { data = [[NSMutableData alloc] initWithCapacity:2048]; } [data appendData:incrementalData]; } - (void)connectionDidFinishLoading:(NSURLConnection*)theConnection { [connection release]; connection=nil; _imageView.image = [UIImage imageWithData:data]; if (_activityIndicator) { [_activityIndicator stopAnimating]; } [data release]; data=nil; } - (UIImage*) image { UIImageView* iv = [[self subviews] objectAtIndex:0]; return [iv image]; } In ViewController Class Which loads image - (UITableViewCell *)tableView:(UITableView *)tV cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *reuseIdentifier =@"CellIdentifier"; ListCell *cell = (ListCell *)[tableView dequeueReusableCellWithIdentifier:reuseIdentifier]; if (cell==nil) { cell = [[ListCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier]; NSMutableDictionary *dicResult = [arrResults objectAtIndex:indexPath.row]; NSURL *url=[NSURL URLWithString:[dicResult objectForKey:@"Image"]]; AsynchronousImageView *asyncImageView = [[AsynchronousImageView alloc] initWithFrame:CGRectMake(5, 10,80,80)]; [asyncImageView loadImageFromURL:url defaultImageName:@"DefaultImage.png" showDefaultImage:NO showActivityIndicator:YES activityIndicatorRect:CGRectMake(5, 10,30,30) activityIndicatorStyle:UIActivityIndicatorViewStyleGray]; // load our image with URL asynchronously [cell.contentView addSubview:asyncImageView]; // cell.imgLocationView.image = [UIImage imageNamed:[dicResult valueForKey:@"Image"]]; [asyncImageView release]; } if([arrResults count]==1) { UITableViewCell *cell1=[tableView dequeueReusableCellWithIdentifier:reuseIdentifier]; if(cell1==nil) cell1=[[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier] autorelease]; NSMutableDictionary *dicResult = [arrResults objectAtIndex:0]; cell1.textLabel.text=[dicResult valueForKey:@"NoResults"]; return cell1; } else { NSMutableDictionary *dicResult = [arrResults objectAtIndex:indexPath.row]; NSString *title = [NSString stringWithFormat:@"%@ Bedrooms-%@", [dicResult valueForKey:KEY_NUMBER_OF_BEDROOMS],[dicResult valueForKey:KEY_PROPERTY_TYPE]]; NSString *strAddress = [dicResult valueForKey:KEY_DISPLAY_NAME]; NSString *address = [strAddress stringByReplacingOccurrencesOfString:@", " withString:@"\n"]; NSString *price = [dicResult valueForKey:KEY_PRICE]; NSString *distance = [dicResult valueForKey:KEY_DISTANCE]; cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; cell.lblTitle.text = title; cell.lblAddress.text = address; if ([price length]>0) { cell.lblPrice.text = [NSString stringWithFormat:@"£%@",price]; }else{ cell.lblPrice.text = @""; } if ([distance length]>0) { cell.lblmiles.text = [NSString stringWithFormat:@"%.2f miles",[distance floatValue]]; }else{ cell.lblmiles.text = @""; } } return cell; } How can i resolve this? I have attached heapshot analysis screen shot of it.Here non Object consumes so much of memory what is that?

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  • Will C++/CLI give me control over low-level devices like audio?

    - by schmoopy
    I was wondering - how much limitation is there to C++/CLI compared to classic C++ (chuckle) - I was wanting to write an application that I cannot do with c# -- I was wanting to be able to connect to the PC's audio device and detect audio (for example) - Is this something I can do with C++/CLI? I have tried using NAudio with c#, but i have been able to do this. What other advantages would C++/CLI or C++ give me over c#?

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  • Are there free, low cost, or open source tools for matching name/address data?

    - by luiscolorado
    This question is related to Tools for matching name/address data. There is a number commercial tools provided by SAS, Oracle, Microsoft, etc., that allow to de-duplicate or merging names of individuals or companies coming from multiple sources. However, after reading the answers to the question mentioned before, I wondered why a seemingly interesting problem didn't receive any answers mentioning open source projects that could tackle the problem. Are you aware of any open source projects or algorithms to implement the so called "record linking", "record merging", or "clustering"?

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  • How to catch this low level MySQL (?) error in PHP/Magento

    - by andnil
    When I'm executing the following statement in Magento with a really large $sku, the execution terminates without any errors thrown what so ever. There are no errors in either Magento's, Apache's or PHP's error logs. Mage::getModel('catalog/product')-loadByAttribute('sku', $sku); Question: How do I catch the error? I've tried to set custom error handlers, and for testing purposes I've also managed to trigger error situations where each of the error handler functions are invoked. But when running the previously mentioned Magento code with a large $sku, none of the error handling functions are executed. error_reporting( -1 ); set_error_handler( array( 'Error', 'captureNormal' ) ); set_exception_handler( array( 'Error', 'captureException' ) ); register_shutdown_function( array( 'Error', 'captureShutdown' ) ); For completeness, this is the $sku I'm passing to loadByAttribute(). (The sku is invalid, but that is not the issue) 1- 9685 0102046|1- 9685 1212100|1- 9685 1212092|1- 9685 1212096|1- 9685 1102100|1- 9685 1102108|1- 9685 1102112|1- 9685 1102092|1- 9685 0102048|1- 9685 0102054|1- 9685 0102056|1- 9685 0102058|1- 9685 1212104|1- 9685 1212108|1- 9685 0212058|1- 9685 0104050|1- 9685 0212050|1- 9685 0212056|1- 9685 0212044|1- 9685 0212048|1- 9685 0212052|1- 9685 0212054|1- 9685 1102104|1- 9685 1102124 Any insight into this matter is much appreciated! Update: Upon further investigation, this is the exact point in the code where execution terminates. when the foreach is executed I guess Magento goes into MySQL world and starts loading up data from the database. \Mage\Catalog\Model\Abstract.php public function loadByAttribute($attribute, $value, $additionalAttributes = '*') { $collection = $this->getResourceCollection() ->addAttributeToSelect($additionalAttributes) ->addAttributeToFilter($attribute, $value) ->setPage(1,1); foreach ($collection as $object) { // <--------------- HERE return $object; } return false; } Note, I'm ONLY interested in finding out how to properly CATCH these kinds of errors, not "fix" the logic. This is so that I can present a proper error message to the user. The example above with the malformed sku is contrived and I have no desire to make my Magento app work with those erroneous skus.

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  • Low-overhead way to access the memory space of a traced process?

    - by vovick
    Hello all. I'm looking for an efficient way to access(for both read and write operations) the memory space of my ptraced child process. The size of blocks being accessed may vary from several bytes up to several megabytes in size, so using the ptrace call with PTRACE_PEEKDATA and PTRACE_POKEDATA which read only one word at a time and switch context every time they're called seems like a pointless waste of resources. The only one alternative solution I could find, though, was the /proc/<pid>/mem file, but it has long since been made read only. Is there any other (relatively simple) way to do that job? The ideal solution would be to somehow share the address space of my child process with its parent and then use the simple memcpy call to copy data I need in both directions, but I have no clues how to do it and where to begin. Any ideas?

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  • Expanding on requestaudit - Tracing who is doing what...and for how long

    - by Kyle Hatlestad
    One of the most helpful tracing sections in WebCenter Content (and one that is on by default) is the requestaudit tracing.  This tracing section summarizes the top service requests happening in the server along with how they are performing.  By default, it has 2 different rotations.  One happens every 2 minutes (listing up to 5 services) and another happens every 60 minutes (listing up to 20 services).  These traces provide the total time for all the requests against that service along with the number of requests and its average request time.  This information can provide a good start in possibly troubleshooting performance issues or tracking a particular issue.   >requestaudit/6 12.10 16:48:00.493 Audit Request Monitor !csMonitorTotalRequests,47,1,0.39009329676628113,0.21034042537212372,1>requestaudit/6 12.10 16:48:00.509 Audit Request Monitor Request Audit Report over the last 120 Seconds for server wcc-base_4444****requestaudit/6 12.10 16:48:00.509 Audit Request Monitor -Num Requests 47 Errors 1 Reqs/sec. 0.39009329676628113 Avg. Latency (secs) 0.21034042537212372 Max Thread Count 1requestaudit/6 12.10 16:48:00.509 Audit Request Monitor 1 Service FLD_BROWSE Total Elapsed Time (secs) 3.5320000648498535 Num requests 10 Num errors 0 Avg. Latency (secs) 0.3531999886035919 requestaudit/6 12.10 16:48:00.509 Audit Request Monitor 2 Service GET_SEARCH_RESULTS Total Elapsed Time (secs) 2.694999933242798 Num requests 6 Num errors 0 Avg. Latency (secs) 0.4491666555404663requestaudit/6 12.10 16:48:00.509 Audit Request Monitor 3 Service GET_DOC_PAGE Total Elapsed Time (secs) 1.8839999437332153 Num requests 5 Num errors 1 Avg. Latency (secs) 0.376800000667572requestaudit/6 12.10 16:48:00.509 Audit Request Monitor 4 Service DOC_INFO Total Elapsed Time (secs) 0.4620000123977661 Num requests 3 Num errors 0 Avg. Latency (secs) 0.15399999916553497requestaudit/6 12.10 16:48:00.509 Audit Request Monitor 5 Service GET_PERSONALIZED_JAVASCRIPT Total Elapsed Time (secs) 0.4099999964237213 Num requests 8 Num errors 0 Avg. Latency (secs) 0.051249999552965164requestaudit/6 12.10 16:48:00.509 Audit Request Monitor ****End Audit Report***** To change the default rotation or size of output, these can be set as configuration variables for the server: RequestAuditIntervalSeconds1 – Used for the shorter of the two summary intervals (default is 120 seconds)RequestAuditIntervalSeconds2 – Used for the longer of the two summary intervals (default is 3600 seconds)RequestAuditListDepth1 – Number of services listed for the first request audit summary interval (default is 5)RequestAuditListDepth2 – Number of services listed for the second request audit summary interval (default is 20) If you want to get more granular, you can enable 'Full Verbose Tracing' from the System Audit Information page and now you will get an audit entry for each and every service request.  >requestaudit/6 12.10 16:58:35.431 IdcServer-68 GET_USER_INFO [dUser=bob][StatusMessage=You are logged in as 'bob'.] 0.08765099942684174(secs) What's nice is it reports who executed the service and how long that particular request took.  In some cases, depending on the service, additional information will be added to the tracing relevant to that  service. >requestaudit/6 12.10 17:00:44.727 IdcServer-81 GET_SEARCH_RESULTS [dUser=bob][QueryText=%28+dDocType+%3cmatches%3e+%60Document%60+%29][StatusCode=0][StatusMessage=Success] 0.4696030020713806(secs) You can even go into more detail and insert any additional data into the tracing.  You simply need to add this configuration variable with a comma separated list of variables from local data to insert. RequestAuditAdditionalVerboseFieldsList=TotalRows,path In this case, for any search results, the number of items the user found is traced: >requestaudit/6 12.10 17:15:28.665 IdcServer-36 GET_SEARCH_RESULTS [TotalRows=224][dUser=bob][QueryText=%28+dDocType+%3cmatches%3e+%60Application%60+%29][Sta... I also recently ran into the case where services were being called from a client through RIDC.  All of the services were being executed as the same user, but they wanted to correlate the requests coming from the client to the ones being executed on the server.  So what we did was add a new field to the request audit list: RequestAuditAdditionalVerboseFieldsList=ClientToken And then in the RIDC client, ClientToken was added to the binder along with a unique value that could be traced for that request.  Now they had a way of tracing on both ends and identifying exactly which client request resulted in which request on the server.

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  • Fast Data - Big Data's achilles heel

    - by thegreeneman
    At OOW 2013 in Mark Hurd and Thomas Kurian's keynote, they discussed Oracle's Fast Data software solution stack and discussed a number of customers deploying Oracle's Big Data / Fast Data solutions and in particular Oracle's NoSQL Database.  Since that time, there have been a large number of request seeking clarification on how the Fast Data software stack works together to deliver on the promise of real-time Big Data solutions.   Fast Data is a software solution stack that deals with one aspect of Big Data, high velocity.   The software in the Fast Data solution stack involves 3 key pieces and their integration:  Oracle Event Processing, Oracle Coherence, Oracle NoSQL Database.   All three of these technologies address a high throughput, low latency data management requirement.   Oracle Event Processing enables continuous query to filter the Big Data fire hose, enable intelligent chained events to real-time service invocation and augments the data stream to provide Big Data enrichment. Extended SQL syntax allows the definition of sliding windows of time to allow SQL statements to look for triggers on events like breach of weighted moving average on a real-time data stream.    Oracle Coherence is a distributed, grid caching solution which is used to provide very low latency access to cached data when the data is too big to fit into a single process, so it is spread around in a grid architecture to provide memory latency speed access.  It also has some special capabilities to deploy remote behavioral execution for "near data" processing.   The Oracle NoSQL Database is designed to ingest simple key-value data at a controlled throughput rate while providing data redundancy in a cluster to facilitate highly concurrent low latency reads.  For example, when large sensor networks are generating data that need to be captured while analysts are simultaneously extracting the data using range based queries for upstream analytics.  Another example might be storing cookies from user web sessions for ultra low latency user profile management, also leveraging that data using holistic MapReduce operations with your Hadoop cluster to do segmented site analysis.  Understand how NoSQL plays a critical role in Big Data capture and enrichment while simultaneously providing a low latency and scalable data management infrastructure thru clustered, always on, parallel processing in a shared nothing architecture. Learn how easily a NoSQL cluster can be deployed to provide essential services in industry specific Fast Data solutions. See these technologies work together in a demonstration highlighting the salient features of these Fast Data enabling technologies in a location based personalization service. The question then becomes how do these things work together to deliver an end to end Fast Data solution.  The answer is that while different applications will exhibit unique requirements that may drive the need for one or the other of these technologies, often when it comes to Big Data you may need to use them together.   You may have the need for the memory latencies of the Coherence cache, but just have too much data to cache, so you use a combination of Coherence and Oracle NoSQL to handle extreme speed cache overflow and retrieval.   Here is a great reference to how these two technologies are integrated and work together.  Coherence & Oracle NoSQL Database.   On the stream processing side, it is similar as with the Coherence case.  As your sliding windows get larger, holding all the data in the stream can become difficult and out of band data may need to be offloaded into persistent storage.  OEP needs an extreme speed database like Oracle NoSQL Database to help it continue to perform for the real time loop while dealing with persistent spill in the data stream.  Here is a great resource to learn more about how OEP and Oracle NoSQL Database are integrated and work together.  OEP & Oracle NoSQL Database.

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  • Multi Player game using Nodejs and Socket IO

    - by Kishorevarma
    I am trying out multi player racing game using Node and Socket IO ,express . So I have tried simple example to see the latency between node server and the clients. I have a draggable image in client . when I move the image ienter code heren one client ,it has to move in all clients. so basically when I am moving the image I am sending the image position to the node server in a json format , then from there I am broadcasting to all clients. there is a ~approx 300ms latency from the time. following are the results. Client 1 sending data to server at : 286136 (timestamp) Server received at : 286271 Client2 received data at : 286470 Client3 received data at : 286479 Client4 received data at : 286487 Client5 received data at : 286520 the latency between move from client1 to client5 is 384ms. its too hight for a racing game .. here is my server code. var app = require('express').createServer(); var io = require('socket.io'); var http = require('http'); var http_server = http.createServer(); var server = http.createServer(app); server.listen(3000); var socket = io.listen(server,{ log: false }); socket.sockets.on('connection', function (client) { client.on('message', function (data){ console.log("data arrived to server",new Date().getTime()); // Below both statements are giving same latency between the client 1 and client 5 client.broadcast.emit('message',data); //socket.sockets.emit('message',data); }); }); 1) Is there any way to optimize the server code to reduce the latency? 2) is this expected latency using node and websockets ? 3) is socket io can't broadcast the data asynchronously (I mean at a same time) ? Thanks Kishorevarma

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  • Internet Explorer stores working data under %TEMP% instead of normal locations

    - by SWB
    Internet Explorer normally stores its working data in various special locations. For example: Cookies - %APPDATA%\Microsoft\Windows\Cookies History - %LOCALAPPDATA%\Microsoft\Windows\History Cache - %LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files However, for some reason, Internet Explorer occasionally stops using the normal locations and instead creates new folders under %TEMP% and/or %TEMP%\Low for this data. For example: Cookies - %TEMP%\Cookies %TEMP%\Low\Cookies History - %TEMP%\History %TEMP%\Low\History Cache - %TEMP%\Temporary Internet Files %TEMP%\Low\Temporary Internet Files Why does Internet Explorer do this, and how can make it use the normal locations again?

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  • a question on common lisp

    - by kostas
    Hello people, I'm getting crazy with a small problem here, I keep getting an error and I cant seem to figure out why, the code is supposed to change the range of a list, so if we give it a list with values (1 2 3 4) and we want to change the range in 11 to fourteen the result would be (11 12 13 14) the problem is that the last function called scale-list will give back an error saying: Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p nil) anybody has a clue why? I use aquamacs as an editor thanks in advance ;;finds minimum in a list (defun minimum(list) (car (sort list #'<))) ;;finds maximum in a list (defun maximum(list) (car (sort list #'>))) ;;calculates the range of a list (defun range(list) (- (maximum list) (minimum list))) ;;this codes scales a value from a list (defun scale-value(list low high n) (+ (/ (* (- (nth (- n 1) list) (minimum list)) (- high low)) (range list)) low)) ;and this code is supposed to scale the whole list (defun scale-list(list low high n) (unless (= n 0) (cons (scale-value list low high n) (scale-list list low high (- n 1))))) (scale-list '(0.1 0.3 0.5 0.9) 20 30 4)

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  • Python: does it make sense to refactor this check into it's own method?

    - by Jeff Fry
    I'm still learning python. I just wrote this method to determine if a player has won a game of tic-tac-toe yet, given a board state like:'[['o','x','x'],['x','o','-'],['x','o','o']]' def hasWon(board): players = ['x', 'o'] for player in players: for row in board: if row.count(player) == 3: return player top, mid, low = board for i in range(3): if [ top[i],mid[i],low[i] ].count(player) == 3: return player if [top[0],mid[1],low[2]].count(player) == 3: return player if [top[2],mid[1],low[0]].count(player) == 3: return player return None It occurred to me that I check lists of 3 chars several times and could refactor the checking to its own method like so: def check(list, player): if list.count(player) == 3: return player ...but then realized that all that really does is change lines like: if [ top[i],mid[i],low[i] ].count(player) == 3: return player to: if check( [top[i],mid[i],low[i]], player ): return player ...which frankly doesn't seem like much of an improvement. Do you see a better way to refactor this? Or in general a more Pythonic option? I'd love to hear it!

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  • Multiplying matrices: error: expected primary-expression before 'struct'

    - by justin
    I am trying to write a program that is supposed to multiply matrices using threads. I am supposed to fill the matrices using random numbers in a thread. I am compiling in g++ and using PTHREADS. I have also created a struct to pass the data from my command line input to the thread so it can generate the matrix of random numbers. The sizes of the two matrices are also passed in the command line as well. I keep getting: main.cpp:7: error: expected primary-expression before 'struct' my code @ line 7 =: struct a{ int Arow; int Acol; int low; int high; }; My inpust are : Sizes of two matrices ( 4 arguments) high and low ranges in which o generate the random numbers between. Complete code: [headers] using namespace std; void *matrixACreate(struct *); void *status; int main(int argc, char * argv[]) { int Arow = atoi(argv[1]); // Matrix A int Acol = atoi(argv[2]); // WxX int Brow = atoi(argv[3]); // Matrix B int Bcol = atoi(argv[4]); // XxZ, int low = atoi(argv[5]); // Range low int high = atoi(argv[6]); struct a{ int Arow; // Matrix A int Acol; // WxX int low; // Range low int high; }; pthread_t matrixAthread; //pthread_t matrixBthread; pthread_t runner; int error, retValue; if (Acol != Brow) { cout << " This matrix cannot be multiplied. FAIL" << endl; return 0; } error = pthread_create(&matrixAthread, NULL, matrixACreate, struct *a); //error = pthread_create(&matrixAthread, NULL, matrixBCreate, sendB); retValue = pthread_join(matrixAthread, &status); //retValue = pthread_join(matrixBthread, &status); return 0; } void matrixACreate(struct * a) { struct a *data = (struct a *) malloc(sizeof(struct a)); data->Arow = Arow; data->Acol = Acol; data->low = low; data->high = high; int range = ((high - low) + 1); cout << Arow << endl<< Acol << endl; }// just trying to print to see if I am in the thread

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  • Convert 2 char into 1 int

    - by Leo
    I have 2 chars: HIGH and LOW and I'd like to convert them to an int corresponding to HIGH + the 2 left bits from LOW. I tried somethine like : char *HIGH; char *LOW; HIGH = 152; LOW = 12; int result; result += (LOW + 6); result += (LOW + 7)*2; result += HIGH*4; result += (HIGH + 1)*8; result += (HIGH + 2)*16; result += (HIGH + 3)*32; result += (HIGH + 4)*64; result += (HIGH + 5)*128; result += (HIGH + 6)*256; result += (HIGH + 7)*512; return result; But it doesn't work and I don't understand why.

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  • Slow performance on VMWare Linux server after Tomcat install

    - by Loftx
    We have a VMWare ESXi 4.1 server hosting a number of Linux and Windows guests. Recently a new Linux guest was added to this server and seemed to be performing well. Tomcat and some other applications on this server were then installed which seem to have caused the server to run really slowly without any obvious resource issues. Slow performance include: The time taken to bring up the password prompt over ssh takes a few seconds when it was previously instantaneous. The time taken to unzip a zip file which was previously a few seconds now takes around 30 seconds The time taken to compile vmware tools has increased by similar factors Both the VMWare console and monitoring commands don't report any issues with high CPU or memory usage but something is obviously slowing the server down somehow. Does anyone have any ideas what may be causing this issue and how it can be resolved? Thanks, Tom Edit As per your questions I’ve looked at some of the performance indicators on both the VM host and VM guest indicated. Firstly I tried reserving the full amount of memory (3gb) for this VM – no other machines on this server have any memory reservation. The swap in rate and swap out rate for the VM host and guest are now both zero. Balloon memory on the guest is zero and on the host is 3.5gb (total memory on the host is 12gb) The swap rate for the guest is also zero. Swap used by the host is 200mb on average. Compression and decompression rates for the host and guest are zero. Command aborts for the host are zero. Read latency is very low – maximum 10ms average 0.8ms. Write latency is higher – a few spikes to 170ms but mostly around 25ms – is this bad? Queue command latency is zero . Physical disk read latency averages 5ms but often 10ms Physical disk write latency averages 15ms but is often 20ms I hope this helps - let me know if you need any more information.

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