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  • Speed vs security vs compatibility over methods to do string concatenation in Python

    - by Cawas
    Similar questions have been brought (good speed comparison there) on this same subject. Hopefully this question is different and updated to Python 2.6 and 3.0. So far I believe the faster and most compatible method (among different Python versions) is the plain simple + sign: text = "whatever" + " you " + SAY But I keep hearing and reading it's not secure and / or advisable. I'm not even sure how many methods are there to manipulate strings! I could count only about 4: There's interpolation and all its sub-options such as % and format and then there's the simple ones, join and +. Finally, the new approach to string formatting, which is with format, is certainly not good for backwards compatibility at same time making % not good for forward compatibility. But should it be used for every string manipulation, including every concatenation, whenever we restrict ourselves to 3.x only? Well, maybe this is more of a wiki than a question, but I do wish to have an answer on which is the proper usage of each string manipulation method. And which one could be generally used with each focus in mind (best all around for compatibility, for speed and for security). Thanks.

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  • Serial.begin(speed, config) not compiling for Leonardo Board

    - by forgemo
    I would like to configure my serial communication to have no parity, 1 start- and 2 stop-bits. The documentation for Serial.begin(speed, config) states: (...) An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit. The documentation also lists the possible configuration-values. According to my (limited) understanding, I need SERIAL_7N2 or SERIAL_8N2 to meet my requirements. (I'm not sure how the data-bits relate to the the 1-start-bit that I need.) However, I can't even compile because I have no idea how to supply that config value to the begin method. (I don't have much Arduino/C++ experience) I've tried in my code the following two variants: Serial.begin(9600, SERIAL_8N2); Serial.begin(9600, "SERIAL_8N2"); Am I missing something? Additional Information: Serial.begin(speed, config) has been introduced with the latest Arduino 1.0.2 IDE version. The code defining/implementing the begin methods can be found here. HardwareSerial.h HardwareSerial.cpp Edit: According to the replies from PeterJ and borges, the following variant is correct. Serial.begin(9600, SERIAL_8N2); However, it's still not working. I found that the compile error doesn't occur if I change the configured board from my Arduino Leonardo to Arduino uno. Therefore, it could be a bug occurring only with a subset of boards ... or maybe it's not supported?!

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  • Analyzing Web Application Speed

    - by Amy
    I'm a bit confused because the logical/programmer brain in me says that if all things are constant, the speed of a function must be constant. I am working on a PHP web application with jqGrid as a front end for showing the data. I am testing on my personal computer, so network traffic does not apply. I make an HTTP request to a PHP function, it returns the data, and then jqGrid renders it. What has me befuddled is that sometimes, Firebug reports that this is taking 300-600 milliseconds sometimes, and sometimes, it's taking 3.68 seconds. I can run the request over and over again, with very radically different response times. The query is the same. The number of users on the system is the same. No network latency. Same code. I'm not running other applications on the computer while testing. I could understand query caching improving performance on subsequent requests, but the speed is just fluctuating wildly with no rhyme or reason. So, my question is, what else can cause such variability in the response time? How can I determine what's doing it? More importantly, is there any way to get things more consistent?

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  • Which is faster: Appropriate data input or appropriate data structure?

    - by Anon
    I have a dataset whose columns look like this: Consumer ID | Product ID | Time Period | Product Score 1 | 1 | 1 | 2 2 | 1 | 2 | 3 and so on. As part of a program (written in C) I need to process the product scores given by all consumers for a particular product and time period combination for all possible combinations. Suppose that there are 3 products and 2 time periods. Then I need to process the product scores for all possible combinations as shown below: Product ID | Time Period 1 | 1 1 | 2 2 | 1 2 | 2 3 | 1 3 | 2 I will need to process the data along the above lines lots of times ( 10k) and the dataset is fairly large (e.g., 48k consumers, 100 products, 24 time periods etc). So speed is an issue. I came up with two ways to process the data and am wondering which is the faster approach or perhaps it does not matter much? (speed matters but not at the cost of undue maintenance/readability): Sort the data on product id and time period and then loop through the data to extract data for all possible combinations. Store the consumer ids of all consumers who provided product scores for a particular combination of product id and time period and process the data accordingly. Any thoughts? Any other way to speed up the processing? Thanks

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  • Data transmission through USB

    - by ASHOK
    I want to develop code to transmit data from system to PIC through USB. Can anybody give good link regarding data transmission through USB. because i am new to this. NOTE: Very simple is code is enough to me. Thanks in Advance

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  • Node.js vs PHP processing speed

    - by Cody Craven
    I've been looking into node.js recently and wanted to see a true comparison of processing speed for PHP vs Node.js. In most of the comparisons I had seen, Node trounced Apache/PHP set ups handily. However all of the tests were small 'hello worlds' that would not accurately reflect any webpage's markup. So I decided to create a basic HTML page with 10,000 hello world paragraph elements. In these tests Node with Cluster was beaten to a pulp by PHP on Nginx utilizing PHP-FPM. So I'm curious if I am misusing Node somehow or if Node is really just this bad at processing power. Note that my results were equivalent outputting "Hello world\n" with text/plain as the HTML, but I only included the HTML as it's closer to the use case I was investigating. My testing box: Core i7-2600 Intel CPU (has 8 threads with 4 cores) 8GB DDR3 RAM Fedora 16 64bit Node.js v0.6.13 Nginx v1.0.13 PHP v5.3.10 (with PHP-FPM) My test scripts: Node.js script var cluster = require('cluster'); var http = require('http'); var numCPUs = require('os').cpus().length; if (cluster.isMaster) { // Fork workers. for (var i = 0; i < numCPUs; i++) { cluster.fork(); } cluster.on('death', function (worker) { console.log('worker ' + worker.pid + ' died'); }); } else { // Worker processes have an HTTP server. http.Server(function (req, res) { res.writeHead(200, {'Content-Type': 'text/html'}); res.write('<html>\n<head>\n<title>Speed test</title>\n</head>\n<body>\n'); for (var i = 0; i < 10000; i++) { res.write('<p>Hello world</p>\n'); } res.end('</body>\n</html>'); }).listen(80); } This script is adapted from Node.js' documentation at http://nodejs.org/docs/latest/api/cluster.html PHP script <?php echo "<html>\n<head>\n<title>Speed test</title>\n</head>\n<body>\n"; for ($i = 0; $i < 10000; $i++) { echo "<p>Hello world</p>\n"; } echo "</body>\n</html>"; My results Node.js $ ab -n 500 -c 20 http://speedtest.dev/ This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Licensed to The Apache Software Foundation, http://www.apache.org/ Benchmarking speedtest.dev (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Finished 500 requests Server Software: Server Hostname: speedtest.dev Server Port: 80 Document Path: / Document Length: 190070 bytes Concurrency Level: 20 Time taken for tests: 14.603 seconds Complete requests: 500 Failed requests: 0 Write errors: 0 Total transferred: 95066500 bytes HTML transferred: 95035000 bytes Requests per second: 34.24 [#/sec] (mean) Time per request: 584.123 [ms] (mean) Time per request: 29.206 [ms] (mean, across all concurrent requests) Transfer rate: 6357.45 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.2 0 2 Processing: 94 547 405.4 424 2516 Waiting: 0 331 399.3 216 2284 Total: 95 547 405.4 424 2516 Percentage of the requests served within a certain time (ms) 50% 424 66% 607 75% 733 80% 813 90% 1084 95% 1325 98% 1843 99% 2062 100% 2516 (longest request) PHP/Nginx $ ab -n 500 -c 20 http://speedtest.dev/test.php This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Licensed to The Apache Software Foundation, http://www.apache.org/ Benchmarking speedtest.dev (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Finished 500 requests Server Software: nginx/1.0.13 Server Hostname: speedtest.dev Server Port: 80 Document Path: /test.php Document Length: 190070 bytes Concurrency Level: 20 Time taken for tests: 0.130 seconds Complete requests: 500 Failed requests: 0 Write errors: 0 Total transferred: 95109000 bytes HTML transferred: 95035000 bytes Requests per second: 3849.11 [#/sec] (mean) Time per request: 5.196 [ms] (mean) Time per request: 0.260 [ms] (mean, across all concurrent requests) Transfer rate: 715010.65 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.2 0 1 Processing: 3 5 0.7 5 7 Waiting: 1 4 0.7 4 7 Total: 3 5 0.7 5 7 Percentage of the requests served within a certain time (ms) 50% 5 66% 5 75% 5 80% 6 90% 6 95% 6 98% 6 99% 6 100% 7 (longest request) Additional details Again what I'm looking for is to find out if I'm doing something wrong with Node.js or if it is really just that slow compared to PHP on Nginx with FPM. I certainly think Node has a real niche that it could fit well, however with these test results (which I really hope I made a mistake with - as I like the idea of Node) lead me to believe that it is a horrible choice for even a modest processing load when compared to PHP (let alone JVM or various other fast solutions). As a final note, I also tried running an Apache Bench test against node with $ ab -n 20 -c 20 http://speedtest.dev/ and consistently received a total test time of greater than 0.900 seconds.

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  • Reading from an USB barcode scanner

    - by roman
    Hi, I've got this nice USB barcode scanner and I'd like to readthe input using the USB driver and not the keyboard input. How can this be accomplished using .NET? any ready libraries? I couldn't find anything of real use... Thanks!

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  • Stress test speed on a gateway?

    - by TheLQ
    I'm interested in stress testing my gateway server but am lost on how. Most of the stress testing applications I've seen only see how much load an app like Apache can handle, but not this. Essentially I want to send as many packets I can into this box with one computer on one card and see how many come out the other in another computer just to get an idea of what kind of load this can handle. I'm also interested how Snort will perform. I'm not really sure how to do this though. What tools could you recommend that could do this?

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  • High quality / high speed dvd reader for Mac Pro

    - by deadprogrammer
    I have a high end Mac pro, but one thing in is that I'm unhappy with is a DVD drive. It's a Hitachi GH41N. Apple calls it a "superdrive", but it's anything but. The damn thing makes an amazing amount of noise, and isn't too fast either. What I want is a state of the art, fast, quiet DVD reader, preferably not even a burner. What should I get?

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  • How to speed up a HP M9517C

    - by Jen
    I bought a system with 8GB RAM, 1TB HD, Quad-Core AMD Phenom 9550, Nvidia Geforce 9300GE, 64-bit Windows Vista Machine. Bought it primarily because it was cheap and came with 25.5 inch screen. Problem: It's slow - if you can believe it. My Dell laptop 1525 is faster and more stable! I tried installing and dual-booting Linux Mint and ran into video and audio troubles. I need fast and stable and I'm going for awesome. Anyone have some suggestions on making this thing smoking hot? Vista is fine, but slows over time - suspect virus/spyware/etc.. But I need to use Photoshop, Fireworks, Dreamweaver, Illustrator. I've tried the alternatives and I just don't like them. When you've got deadlines looming you want to work with what you know. Also use Skype (and I had audio problems with it in Linux), gotomeeting, gotowebinar. Don't need MS Office. Tried VMWare, Virtualbox and again - I keep getting audio/video problems. I'd love someone's input on THEIR setup and how they got there. I'm sure I need to upgrade my video card, but what should I go to?

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  • What can I do to speed up createrepo?

    - by jsd
    We are using a yum repository to distribute our software to our production instances. Unfortunately, createrepo is becoming a bottleneck, and we only have 469 packages in the repository. $ time createrepo /opt/tm-yum-repo Spawning worker 0 with 469 pkgs Workers Finished Gathering worker results Saving Primary metadata Saving file lists metadata Saving other metadata Generating sqlite DBs Sqlite DBs complete real 0m43.188s user 0m37.798s sys 0m1.296s What can I do to make it faster?

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  • Nginx's speed, and how to replicate it [migrated]

    - by Mediocre Gopher
    I'm interested in this from more than an academic standpoint rather than a practical standpoint; I don't plan on creating a production webserver to compete with nginx. What I'm wondering is how exactly nginx is so fast. The top google response for this is this thread, but it merely links to a cryptic slideshow and a general covering of different io strategies. All other results seem to simply describe how fast nginx is, rather then the reason. I tried building a simple erlang server to try to compete with nginx, but to no avail; nginx won out. All my server does is spawn a new process for each request, uses that process to read the file to a socket, then closes the file and kills the thread. It's not complicated, but given erlang's lightweight processes and underlying aio structure I thought it would compete, but nginx still wins out by a consistent 300 ms average under a heavy stress test. What is nginx doing that my simple server isn't? My first thought would be keeping files in main memory instead of tossing them between requests, but the filesystem cache does this already so I didn't think it would make that great of difference. Am I wrong? Or is there something else that I'm missing?

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  • Mac OS X CD ripping speed

    - by SlimSCSI
    I am using vobcopy (installed via macports) to rip DVDs on a mac. I have been doing this for a while on linux with no problems. On the mac however, it is VERY slow. I am guessing that somehow the DVD drive is being limited to 1x in order to keep noise and power consumption down during playback. Is there a way to over ride this? Update: It is MUCH slower than 1x. It has taken me about an hour to copy 300MB Notes: While I appreciate all suggestions, I am not looking for "Have you tried HandBrake?". I am looking for a solution to copy the contents of a DVD, not transcode them. Also, I am launching vobcopy from an apple script that gets executed on DVD insertion, so a GUI solution is not desirable.

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  • Speed of TrueCrypt whole disk encryption

    - by Gareth
    I'm getting a new development laptop soon, and I'm thinking of using TrueCrypt to encrypt the whole disk. What kind of performance drop can I expect? 10%? 30%? more? Also, assuming the workload has an effect, would compiling/using Visual Studio be affected much? I cannot seem to find anything like this on the web.

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  • Stress test speed on a gateway?

    - by TheLQ
    I'm interested in stress testing my gateway server but am lost on how. Most of the stress testing applications I've seen only see how much load an app like Apache can handle, but not this. Essentially I want to send as many packets I can into this box with one computer on one card and see how many come out the other in another computer just to get an idea of what kind of load this can handle. I'm also interested how Snort will perform. I'm not really sure how to do this though. What tools could you recommend that could do this?

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  • Does the speed of memory define its voltage?

    - by Zak
    What I'm asking here is, if I order PC3200 memory is it all going to be 1.8V, or will some be 2.5, some 1.8, etc... I don't mean variation within a specific part #, but rather across part numbers, is there a variation where some PC 3200 memory would be incompatible with others because it is 2.5 v 1.8V .

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  • Two internet connections coming in, one Sonicwall Tz170 (enhanced os), and slow speed

    - by Development 4.0
    I work a lot from my home office and being in general a tad paranoid I have cable and DSL pipes coming into my house. I have used an Ebay bought Sonicwall Tz170 with the enhanced OS for a good while. I believe it does failover and has a feature for doing round robin on which connection is used. I get the impression from using it that I might not be getting the most out of this setup. Is it possible/likely that my router could be a cause of the slowdown? Are there more appropriate choices?

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  • Ubuntu Keyboard response speed problem.

    - by Asaf
    Hello, I have Ubuntu Lucid Lynx installed, Using Gnome 2.30.0 I'm using a Laptop, HP Pavilion dv9000 I've stumbled on responsiveness issues with my keyboard, Sometimes it's really obvious - the keyboard doesn't respond fast enough to my typing. Checked sticky keys and all that, it's all disabled of course. Now, I also checked on Windows to see if the problem is Hardware or something, and there are no responsiveness issues there... I'm thinking it's Gnome (or the X). Thanks.

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  • How To Speed Up Adding Column To Large Table In Sql Server

    - by Chris
    I want to add a column to a Sql Server table with about 10M rows. I think this query would eventually finish adding the column I want: alter table T add mycol bit not null default 0 but it's been going for several hours already. Is there any shortcut to get a "not null default 0" column inserted into a large table? Or is this inherently really slow? This is Sql Server 2000. Later on I have to do something similar on Sql Server 2008.

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  • Windows 7 Loading speed

    - by Sergiy Byelozyorov
    I have installed Windows 7 64-bit about two week ago. Since then everything was working alright, but yesterday Windows started to load much slower. Main delay comes while Windows logo is glowing -- it used to be around 10-15 seconds and now it's around 2 minutes. As far as I remember, I have only installed Microsoft IntelliMouse driver recently and removed it today. Unfortunately I found out that I have switched off System Restore some time long ago, so can't even test if the problem can be fixed by restoring old version. How can I troubleshoot the problem? Can I somehow find out what's causing the delay? P.S. Please don't suggest to reinstall Windows. I know that will help, but reinstalling all software and settings is a pain and requires a lot of time.

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