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  • Downloading content greater than 2000 bytes from local network hangs in browser on Windows XP

    - by artplastika
    We have web application that runs under Tomcat in a local network. Our customers experience strange problem using this web application. Let's say Tomcat server runs on host1 and we open webapp URL in browser on host2. Any browser on host 2 starts opening page and downloading of content "hangs" for hours. We've made bunch of experiments and found that any content larger than 2000 bytes makes browser request hang. Tried in Internet Explorer 8, Opera 12, Firefox. At the same time if user opens website from internet, it works. Opening webapp from the same host1 where Tomcat is running works normally. Local network is organized with D-Link DGS-3120-48TC switch. Additional info. During experiments we've noticed XP Tweaker installed on hosts. Network settings from that tool: MTU is manually set to 1500 RWIN = 14600 Support of TCP frames larger than 64 KB is on Time to Live = 32 SACK is on

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  • Infrastructure to effectively set up experiements and learn from them

    - by David
    Open-org.com is in the early stages of creating our first product, a place on the web, where one can ask lawyers questions at a fraction of their normal costs. An early stage front page can be found here. I got inspired by this video, which is recommended by Jeff Atwood, which talks about getting feedback faster, which is the reason for this question. The problem Needless to say, we want our conversion rates to be as high as possible. Therefore, we want to be able to rapidly set up a new experiment where we change something on the site (like moving an image slightly, rewriting a sentence etc.). We then want to present the modified page to a random subset of the users. After that we will compare the conversion rates of the experiment with another version. I could very well imagine that we want to run 10-100 experiments simultaneously and it would be nice to have features, where experiments that obviously have worse results will be ended before schedule. My question Does infrastructure to support the whole process exist? A short description of our infrastructure... We use EC2 and PHP and have a script to automatically start up new instances with all needed software. Still, starting up a new server for every experiment, seems like a bit of overkill, so I am wondering what other options exist. Btw. If you feel like working for Open-org.com, you can pick a task, and start working, or suggest a new task. All profits are given out to the contributors.

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  • Nginx A/B testing

    - by Alex
    Hey, I'm trying to do A/B testing and I'm using Nginx fo this purpose. My Nginx config file looks like this: events { worker_connections 1024; } error_log /usr/local/experiments/apps/reddit_test/error.log notice; http { rewrite_log on; server { listen 8081; access_log /usr/local/experiments/apps/reddit_test/access.log combined; location / { if ($remote_addr ~ "[02468]$") { rewrite ^(.+)$ /experiment$1 last; } rewrite ^(.+)$ /main$1 last; } location /main { internal; proxy_pass http://www.reddit.com/r/lisp; } location /experiment { internal; proxy_pass http://www.reddit.com/r/haskell; } } } This is kind of working, but css and js files woon't load. Can anyone tell me what's wrong with this config file or what would be the right way to do it? Thanks, Alex

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  • Use bug tracker to get things done and manage personal tasks?

    - by Frank
    This is slightly off-topic, but can only be answered by programmers and is useful to many programmers: Do you think it is useful to use a bug tracking system to keep track of personal todo items and to Get Things Done? I have not tried that; in fact, I don't have much experience with bug tracking systems. For my todo lists, I have played around with Google Tasks and Remember The Milk, but both of them have shortcomings: Google Tasks: I like that you can create todo lists easily, can reorder items in the list and easily create hierarchies. But it is way too simplistic and does not allow to tag tasks or move tasks from one list to another. Remember The Milk: It is nice and sleek, but you cannot create hierarchies of tasks, cannot arbitrarily reorder tasks and cannot set dependencies of tasks. That's where a bug tracking system should come in: Since I think (maybe too much?) like a programmer, my tasks have a natural hierarchy and a tree of dependencies, like in a Makefile. Here are two examples: The task of writing my thesis is done when several milestones are done. Some of these milestones can run in parallel (writing background chapter, running experiments A, running experiments B), others depend on each other (writing main chapter depends on first getting results from experiments A). The same is true for more personal goals: I want to host a dinner party, which requires finding a good date, finishing the guest list, making invitations, finding nice recipes, cooking, ... For me, all these tasks involve hierarchical dependencies and milestones that bug tracking systems should be able to handle? Here is an article that explains how to do advanced GTD with Remember The Milk, but he has to use several workarounds: (1) add a general tag 'wait' to tasks that are waiting for others to be completed but you cannot enter the IDs of the tasks that they are waiting for, (2) starting some special tasks with "." so that they are at the top of the alphabetically sorted list and signal that others are 'below' it as subgoals. Bug tracking systems should be able to handle these things much more naturally? Does anyone have experience and can recommend a lightweight bug tracking system that might be good for this? Other requirements: Should run as web app, should allow me to tag a task with several tags (like 'work', 'fun', 'short-task', 'errands', ...).

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  • Is there anything for Python that is like readability.js?

    - by Emre Sevinç
    Hi, I'm looking for a package / module / function etc. that is approximately the Python equivalent of Arc90's readability.js http://lab.arc90.com/experiments/readability http://lab.arc90.com/experiments/readability/js/readability.js so that I can give it some input.html and the result is cleaned up version of that html page's "main text". I want this so that I can use it on the server-side (unlike the JS version that runs only on browser side). Any ideas? PS: I have tried Rhino + env.js and that combination works but the performance is unacceptable it takes minutes to clean up most of the html content :( (still couldn't find why there is such a big performance difference).

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  • Writing csv files with python with exact formatting parameters

    - by Ben Harrison
    I'm having trouble with processing some csv data files for a project. The project's programmer has moved onto greener pastures, and now I'm trying to finish the data analysis up (I did/do the statistical analysis.) The programmer suggested using python/csv reader to help break down the files, which I've had some success with, but not in a way I can use. This code is a little different from what I was trying before. I am essentially attempting to create an array. In the raw data format, the first 7 rows contain no data, and then each column contains 50 experiments, each with 4000 rows, for 200000 some rows total. What I want to do is take each column, and make it an individual csv file, with each experiment in its own column. So it would be an array of 50 columns and 4000 rows for each data type. The code here does break down the correct values, I think the logic is okay, but it is breaking down the opposite of how I want it. I want the separators without quotes (the commas and spaces) and I want the element values in quotes. Right now it is doing just the opposite for both, element values with no quotes, and the separators in quotes. I've spent several hours trying to figure out how to do this to no avail, import csv ifile = open('00_follow_maverick.csv') epistemicfile = open('00_follower_maverick_EP.csv', 'w') reader = csv.reader(ifile) colnum = 0 rownum = 0 y = 0 z = 8 for column in reader: rownum = 4000 * y + z for element in column: writer = csv.writer(epistemicfile) if y <= 50: y = y + 1 writer.writerow([element]) writer.writerow(',') rownum = x * y + z if y > 50: y = 0 z = z + 1 writer.writerow(' ') rownum = x * y + z if z >= 4008: break What is going on: I am taking each row in the raw data file in iterations of 4000, so that I can separate them with commas for the 50 experiments. When y, the experiment indicator here, reaches 50, it resets back to experiment 0, and adds 1 to z, which tells it which row to look at, by the formula of 4000 * y + z. When it completes the rows for all 50 experiments, it is finished. The problem here is that I don't know how to get python to write the actual values in quotes, and my separators outside of quotes. Any help will be most appreciated. Apologies if this seems a stupid question, I have no programming experience, this is my first attempt ever. Thank you.

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  • How should I use random.jumpahead in Python

    - by Peter Smit
    I have a application that does a certain experiment 1000 times (multi-threaded, so that multiple experiments are done at the same time). Every experiment needs appr. 50.000 random.random() calls. What is the best approach to get this really random. I could copy a random object to every experiment and do than a jumpahead of 50.000 * expid. The documentation suggests that jumpahead(1) already scrambles the state, but is that really true? Or is there another way to do this in 'the best way'? (No, the random numbers are not used for security, but for a metropolis hasting algorithm. The only requirement is that the experiments are independent, not whether the random sequence is somehow predictable or so)

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  • Database Design: A proper table design for large number of column values.

    - by Jake
    I wish to perform an experiment many different times. After every trial, I am left with a "large" set of output statistics -- let's say, 1000. I would like to store the outputs of my experiments in a table, but what's the best way...? Option 1 Have a table with 1000 columns. Seems like a bad idea. What if the number of statistics one day exceeds the maximum number of columns? Option 2 Have a table with three columns. Let's say, ID, StatisticType, and StatisticValue. That way, you can have as many statistics as you want. However, reading a single experiments statistics becomes more complicated. Moreover, what if different statistics are different data types?? Any suggestions?

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  • How do browsers/PHP handle characters outside the set characterset?

    - by Maarten
    I'm looking into how characters are handled that are outside of the set characterset for a page. In this case the page is set to iso-8859-1, and the previous programmer decided to escape input using htmlentities($string,ENT_COMPAT). This is then stored into Latin1 tables in Mysql. As the table is set to the same character set as the page, I am wondering if that htmlentities step is needed. I did some experiments on http://floris.workingweb.nl/experiments/characters.php and it seems that for stuff inside Latin1 some characters are escaped, but for example with a Czech name they are not. Is this because those characters are outside of Latin1? If so, then the htmlentities can be removed, as it doesn't help for stuff outside of Latin1 anyway, and for within Latin1 it is not needed as far as I can see now...

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  • Microsoft Press Deal of the Day - 5/April/2012 - Windows® Internals, Part 1, Sixth Edition

    - by TATWORTH
    Today's Deal of the day from Microsoft Press at http://shop.oreilly.com/product/0790145305930.do is Windows® Internals, Part 1, Sixth Edition."Delve inside Windows architecture and internals—guided by a team of internationally renowned internals experts. Fully updated for Windows 7 and Windows Server 2008 R2, this classic guide delivers key architectural insights on system design, debugging, performance, and support—along with hands-on experiments to experience Windows internal behavior firsthand."

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  • Feature (de)activation error “The web or site was not found” and Application Pool

    - by panjkov
    I am using Microsoft IW Demo VM (2010-10A) for my experiments related to SharePoint, in all cases when I don’t have time (read: when I’m lazy) to create complete SharePoint Dev environment. Problem This particular time I was playing around with site-scoped features and newly created site collection. So here is my workflow: Create feature with feature receiver Deploy to Site Collection from Visual Studio using “No Activation” deployment profile Activate feature from “Site Collection Features” interface...(read more)

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  • A new name for unit tests

    - by Will
    I never used to like unit testing. I always thought it increased the amount of work I had to do. Turns out, that's only true in terms of the actual number of lines of code you write and furthermore, this is completely offset by the increase in the number of lines of useful code that you can write in an hour with tests and test driven development. Now I love unit tests as they allow me to write useful code, that quite often works first time! (knock on wood) I have found that people are reluctant to do unit tests or start a project with test driven development if they are under strict time-lines or in an environment where others don't do it, so they don't. Kinda like, a cultural refusal to even try. I think one of the most powerful things about unit testing is the confidence that it gives you to undertake refactoring. It also gives new found hope, that I can give my code to someone else to refactor/improve, and if my unit tests still work, I can use the new version of the library that they modified, pretty much, without fear. It's this last aspect of unit testing that I think needs a new name. The unit test is more like a contract of what this code should do now, and in the future. When I hear the word testing, I think of mice in cages, with multiple experiments done on them to see the effectiveness of a compound. This is not what unit testing is, we're not trying out different code to see what is the most affective approach, we're defining what outputs we expect with what inputs. In the mice example, unit tests are more like the definitions of how the universe will work as opposed to the experiments done on the mice. Am I on crack or does anyone else see this refusal to do testing and do they think it's a similar reason they don't want to do it? What reasons do you / others give for not testing? What do you think their motivations are in not unit testing? And as a new name for unit testing that might get over some of the objections, how about jContract? (A bit Java centric I know :), or Unit Contracts?

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  • SQL SERVER – Fix: Error: 10920 Cannot drop user-defined function. It is being used as a resource governor classifier

    - by pinaldave
    If you have not read my SQL SERVER – Simple Example to Configure Resource Governor – Introduction to Resource Governor yesterday’s detailed primer on Resource Governor, I suggest you go ahead and read it before continuing this article. After reading the article the very first email I received was as follows: “Pinal, I configured resource governor on my development server and it worked fine with tests I ran. After doing some tests, I decided to remove the resource governor and as a first step I disabled it however, I was not able to drop the classification function during the process of the clean up. It was continuously giving me following error. Msg 10920, Level 16, State 1, Line 1 Cannot drop user-defined function myudfname. It is being used as a resource governor classifier. Would you please give me solution?” The original email was really this short and there is no other information. I am glad he has done experiments on development server and not on the production server. Production server must not be the playground of the experiments. I think I have covered the answer of this error in an earlier blog post. If the user disables the Resource Governor it is still not possible to drop the function because it can be enabled again and when enabled it can still use the same function. Here is the simple resolution of the how one can drop the classifier function (do this only if you are not going to use the function). The reason the classifier function can’t be dropped because it is associated with resource governor. Create a new classified function for your resource governor or just assign NULL as described in the following T-SQL Script and you will be able to drop the function without error. ALTER RESOURCE GOVERNOR WITH (CLASSIFIER_FUNCTION = NULL) GO ALTER RESOURCE GOVERNOR DISABLE GO DROP FUNCTION dbo.UDFClassifier GO I am glad that user asked me question instead of doing something radically different, which can leave the server in the unusable state. I am aware of this only method to avoid this error. Is there any better way to achieve the same? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • lowering the use of the memory controller in OpenCL based applications

    - by user827992
    With my first experiments I noticed that OpenCL is a good technology but often hampered by the X86 architecture and finding a mid-range VGA driven by a low-end chipset is not that unusual in the real world scenarios, sometimes this can happen with some high-end VGA too. Are there some caching techniques? Something that can bypass this inconvenience in some ways. The amount of dedicated memory on today's VGA is usually high, it's possible to use this memory to create some kind of buffer with instructions.

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  • Watch syntax help

    - by Jason
    In my Systems Programming class, there are weekly programming experiments, and I'm having trouble with the current one. The objective is to write a C program that slowly writes a string of text to a file, metered by usleep() in a 100 count for loop. The goal of the experiment is to observe the file size buffer in action via the watch command. However, I can't get it to work using watch -d ./output What syntax do I need for the watch command to see the changes made to the file size?

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  • The Important Relationship Between SEO and Google - Google Dominates

    Let's face it when it comes to SEO, Google (commonly known as the Big G) has its final say. After all, when it comes to searching some information online people would always go for Google. All they do is key-in the keyword on the search box and click the search button. Few seconds after, results will be given. Google is a big company and has been the subject of a lot of experiments when it comes to SEO.

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  • cloning a kvm guest os to a vmdk file

    - by Bond
    I have a production environment where I am having 4 Guest OS running on a Ubuntu server which uses kvm. These OS are in an LVM based setup.I want these Virtual Machines to be in a vmdk format also.Where people would do experiments with these Virtual Machines so this in a vmware environment (or it can be Xen too) would be different from the kvm server.I would not have any control on that other environment so I want to give people vmdk images of these virtual machines. The production Virtual Machines will still keep running on kvm server but the VMs on which experiments would be done would be of type vmdk.(vmdk is a constraint) Here is output of lvscan ACTIVE '/dev/abcd/lvm1' [100.00 GiB] inherit ACTIVE '/dev/abcd/lvm2' [150.00 GiB] inherit ACTIVE '/dev/abcd/lvm3' [50.00 GiB] inherit ACTIVE '/dev/abcd/lvm4' [100.00 GiB] inherit I was reading man page of qemu-img and what I understand is I need to first create a qcow image file which I need to populate and then convert that to a vmdk file. Is that understanding correct? Now suppose /dev/abcd/lvm4 is the virtual machine with which I am going to start this experiment.I can shutdown the production VMs for some time to do this. So is the following way correct to go on server 1 (where kvm is running) qemu-img convert -c -f raw -O vmdk /dev/abcd/lvm4 /backup/lvm4.img or it will affect the lvm4 on kvm server 1. I do not want the VM running on original server to at all loose its any of the content but also have a vmdk file for each of the Guest OS on kvm. Before I proceed with any of the above things on the production machine I just want to make sure that I am doing the correct thing so I asking here.

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  • Psychology researcher wants to learn new language

    - by user273347
    I'm currently considering R, matlab, or python, but I'm open to other options. Could you help me pick the best language for my needs? Here are the criteria I have in mind (not in order): Simple to learn. I don't really have a lot of free time, so I'm looking for something that isn't extremely complicated and/or difficult to pick up. I know some C, FWIW. Good for statistics/psychometrics. I do a ton of statistics and psychometrics analysis. A lot of it is basic stuff that I can do with SPSS, but I'd like to play around with the more advanced stuff too (bootstrapping, genetic programming, data mining, neural nets, modeling, etc). I'm looking for a language/environment that can help me run my simpler analyses faster and give me more options than a canned stat package like SPSS. If it can even make tables for me, then it'll be perfect. I also do a fair bit of experimental psychology. I use a canned experiment "programming" software (SuperLab) to make most of my experiments, but I want to be able to program executable programs that I can run on any computer and that can compile the data from the experiments in a spreadsheet. I know python has psychopy and pyepl and matlab has psychtoolbox, but I don't know which one is best. If R had something like this, I'd probably be sold on R already. I'm looking for something regularly used in academe and industry. Everybody else here (including myself, so far) uses canned stat and experiment programming software. One of the reasons I'm trying to learn a programming language is so that I can keep up when I move to another lab. Looking forward to your comments and suggestions. Thank you all for your kind and informative replies. I appreciate it. It's still a tough choice because of so many strong arguments for each language. Python - Thinking about it, I've forgotten so much about C already (I don't even remember what to do with an array) that it might be better for me to start from scratch with a simple program that does what it's supposed to do. It looks like it can do most of the things I'll need it to do, though not as cleanly as R and MATLAB. R - I'm really liking what I'm reading about R. The packages are perfect for my statistical work now. Given the purpose of R, I don't think it's suited to building psychological experiments though. To clarify, what I mean is making a program that presents visual and auditory stimuli to my specifications (hundreds of them in a preset and/or randomized sequence) and records the response data gathered from participants. MATLAB - It's awesome that cognitive and neuro folk are recommending MATLAB, because I'm preparing for the big leap from social and personality psychology to cognitive neuro. The problem is the Uni where I work doesn't have MATLAB licenses (and 3750 GBP for a compiler license is not an option for me haha). Octave looks like a good alternative. PsychToolbox is compatible with Octave, thankfully. SQL - Thanks for the tip. I'll explore that option, too. Python will be the least backbreaking and most useful in the short term. R is well suited to my current work. MATLAB is well suited to my prospective work. It's a tough call, but I think I am now equipped to make a more well-informed decision about where to go next. Thanks again!

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  • Inside Red Gate - Exercises in Leanness

    - by simonc
    There's a new movement rumbling around Red Gate Towers - the Lean Startup. At its core is the idea that you don't have to be in a company with single-digit employees to be an entrepreneur; you simply have to (being blunt) not know what you should be doing. Specifically, you accept that you don't know everything you need to know in order to create a useful, successful & profitable product. This is something that Red Gate has had problems with in the past; we've created products that weren't aimed at the correct market, or didn't solve the problem the user had (although they solved the problem we thought the users had, or the problem the users thought they had). As a result, these products weren't as successful as they could have been. The ideas at the core of the Lean Startup help to combat this tendency to build large, well-engineered products that solve the wrong problem. You need to actually test your hypotheses about what the users and the market needs, rather than just running a project based on those untested assumptions. Furthermore, these tests need to be done as fast as possible (on the order of a week) so that, if necessary, you can change the direction of the project without wasting effort going down a dead end. Over time, as more tests are done and more hypotheses are confirmed or refuted, the project moves towards something that solves users' actual problems. However, re-aligning the development teams that operate within Red Gate along these lines does itself have some issues; we've got very good at doing large, monolithic releases, with a feature set decided well in advance. Currently it takes about 2 weeks to do install & release testing before a release; this is clearly not practicable for a team doing weekly, or even daily releases. There's also many infrastructure issues to be solved; in our source control, build system, release mechanism, support pages & documentation, licensing system, update system, and download pages. All these need modifications to allow the fast releases necessary for each experiment. Not only do we have to change our infrastructure, we have to change our mindset. Doing daily releases means each release won't get nearly as much testing as 'standard' releases. As a team, we have to be prepared that there will be releases that have bugs and issues with them; not only do we have to be prepared to change direction with every experiment we do, but we have to be ready to fix any bugs that are reported very quickly as well. The SmartAssembly team is spearheading this move towards leanness within the company, using Feature Usage Reporting (FUR). We think this is a cracking feature that will really help developers learn how people use their products, but we need to confirm this hypothesis. So, over the next few weeks, we'll be running a variety of experiments on SmartAssembly to either confirm or refute our hypotheses concerning how people use SmartAssembly and apply FUR to their own products. In the rest of this series, I'll be documenting how the experiments we perform get on, and our experiences with applying the Lean Startup model to a mature product like SmartAssembly. Cross posted from Simple Talk.

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  • Inside Red Gate - Exercises in Leanness

    - by Simon Cooper
    There's a new movement rumbling around Red Gate Towers - the Lean Startup. At its core is the idea that you don't have to be in a company with single-digit employees to be an entrepreneur; you simply have to (being blunt) not know what you should be doing. Specifically, you accept that you don't know everything you need to know in order to create a useful, successful & profitable product. This is something that Red Gate has had problems with in the past; we've created products that weren't aimed at the correct market, or didn't solve the problem the user had (although they solved the problem we thought the users had, or the problem the users thought they had). As a result, these products weren't as successful as they could have been. The ideas at the core of the Lean Startup help to combat this tendency to build large, well-engineered products that solve the wrong problem. You need to actually test your hypotheses about what the users and the market needs, rather than just running a project based on those untested assumptions. Furthermore, these tests need to be done as fast as possible (on the order of a week) so that, if necessary, you can change the direction of the project without wasting effort going down a dead end. Over time, as more tests are done and more hypotheses are confirmed or refuted, the project moves towards something that solves users' actual problems. However, re-aligning the development teams that operate within Red Gate along these lines does itself have some issues; we've got very good at doing large, monolithic releases, with a feature set decided well in advance. Currently it takes about 2 weeks to do install & release testing before a release; this is clearly not practicable for a team doing weekly, or even daily releases. There's also many infrastructure issues to be solved; in our source control, build system, release mechanism, support pages & documentation, licensing system, update system, and download pages. All these need modifications to allow the fast releases necessary for each experiment. Not only do we have to change our infrastructure, we have to change our mindset. Doing daily releases means each release won't get nearly as much testing as 'standard' releases. As a team, we have to be prepared that there will be releases that have bugs and issues with them; not only do we have to be prepared to change direction with every experiment we do, but we have to be ready to fix any bugs that are reported very quickly as well. The SmartAssembly team is spearheading this move towards leanness within the company, using Feature Usage Reporting (FUR). We think this is a cracking feature that will really help developers learn how people use their products, but we need to confirm this hypothesis. So, over the next few weeks, we'll be running a variety of experiments on SmartAssembly to either confirm or refute our hypotheses concerning how people use SmartAssembly and apply FUR to their own products. In the rest of this series, I'll be documenting how the experiments we perform get on, and our experiences with applying the Lean Startup model to a mature product like SmartAssembly.

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  • How the SPARC T4 Processor Optimizes Throughput Capacity: A Case Study

    - by Ruud
    This white paper demonstrates the architected latency hiding features of Oracle’s UltraSPARC T2+ and SPARC T4 processors That is the first sentence from this technical white paper, but what does it exactly mean? Let's consider a very simple example, the computation of a = b + c. This boils down to the following (pseudo-assembler) instructions that need to be executed: load @b, r1 load @c, r2 add r1,r2,r3 store r3, @a The first two instructions load variables b and c from an address in memory (here symbolized by @b and @c respectively). These values go into registers r1 and r2. The third instruction adds the values in r1 and r2. The result goes into register r3. The fourth instruction stores the contents of r3 into the memory address symbolized by @a. If we're lucky, both b and c are in a nearby cache and the load instructions only take a few processor cycles to execute. That is the good case, but what if b or c, or both, have to come from very far away? Perhaps both of them are in the main memory and then it easily takes hundreds of cycles for the values to arrive in the registers. Meanwhile the processor is doing nothing and simply waits for the data to arrive. Actually, it does something. It burns cycles while waiting. That is a waste of time and energy. Why not use these cycles to execute instructions from another application or thread in case of a parallel program? That is exactly what latency hiding on the SPARC T-Series processors does. It is a hardware feature totally transparent to the user and application. As soon as there is a delay in the execution, the hardware uses these otherwise idle cycles to execute instructions from another process. As a result, the throughput capacity of the system improves because idle cycles are no longer wasted and therefore more jobs can be run per unit of time. This feature has been in the SPARC T-series from the beginning, so why this paper? The difference with previous publications on this topic is in the amount of detail given. How this all works under the hood is fully explained using two example programs. Starting from the assembly language instructions, it is demonstrated in what way these programs execute. To really see what is happening we go down to the processor pipeline level, where the gaps in the execution are, and show in what way these idle cycles are filled by other copies of the same program running simultaneously. Both the SPARC T4 as well as the older UltraSPARC T2+ processor are covered. You may wonder why the UltraSPARC T2+ is included. The focus of this work is on the SPARC T4 processor, but to explain the basic concept of latency hiding at this very low level, we start with the UltraSPARC T2+ processor because it is architecturally a much simpler design. From the single issue, in-order pipelines of this processor we then shift gears and cover how this all works on the much more advanced dual issue, out-of-order architecture of the T4. The analysis and performance experiments have been conducted on both processors. The results depend on the processor, but in all cases the theoretical estimates are confirmed by the experiments. If you're interested to read a lot more about this and find out how things really work under the hood, you can download a copy of the paper here. A paper like this could not have been produced without the help of several other people. I want to thank the co-author of this paper, Jared Smolens, for his very valuable contributions and our highly inspiring discussions. I'm also indebted to Thomas Nau (Ulm University, Germany), Shane Sigler and Mark Woodyard (both at Oracle) for their feedback on earlier versions of this paper. Karen Perkins (Perkins Technical Writing and Editing) and Rick Ramsey at Oracle were very helpful in providing editorial and publishing assistance.

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  • Why does Clojure hang after hacing performed my calculations?

    - by Thomas
    Hi all, I'm experimenting with filtering through elements in parallel. For each element, I need to perform a distance calculation to see if it is close enough to a target point. Never mind that data structures already exist for doing this, I'm just doing initial experiments for now. Anyway, I wanted to run some very basic experiments where I generate random vectors and filter them. Here's my implementation that does all of this (defn pfilter [pred coll] (map second (filter first (pmap (fn [item] [(pred item) item]) coll)))) (defn random-n-vector [n] (take n (repeatedly rand))) (defn distance [u v] (Math/sqrt (reduce + (map #(Math/pow (- %1 %2) 2) u v)))) (defn -main [& args] (let [[n-str vectors-str threshold-str] args n (Integer/parseInt n-str) vectors (Integer/parseInt vectors-str) threshold (Double/parseDouble threshold-str) random-vector (partial random-n-vector n) u (random-vector)] (time (println n vectors (count (pfilter (fn [v] (< (distance u v) threshold)) (take vectors (repeatedly random-vector)))))))) The code executes and returns what I expect, that is the parameter n (length of vectors), vectors (the number of vectors) and the number of vectors that are closer than a threshold to the target vector. What I don't understand is why the programs hangs for an additional minute before terminating. Here is the output of a run which demonstrates the error $ time lein run 10 100000 1.0 [null] 10 100000 12283 [null] "Elapsed time: 3300.856 msecs" real 1m6.336s user 0m7.204s sys 0m1.495s Any comments on how to filter in parallel in general are also more than welcome, as I haven't yet confirmed that pfilter actually works.

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  • Rexml - Parsing Data

    - by Paddy
    I have a XML File in the following format: <?xml version='1.0' encoding='UTF-8'?> <entry xmlns='http://www.w3.org/2005/Atom' xmlns:gwo='http://schemas.google.com/analytics/websiteoptimizer/2009' xmlns:app='http://www.w3.org/2007/app' xmlns:gd='http://schemas.google.com/g/2005' gd:etag='W/&quot;DUYGRX85fCp7I2A9WxFWEkQ.&quot;'><id>https://www.google.com/analytics/feeds/websiteoptimizer/experiments/1025910</id><updated>2010-05-31T02:12:04.124-07:00</updated><app:edited>2010-05-31T02:12:04.124-07:00</app:edited><title>Flow Experiment</title><link rel='gwo:goalUrl' type='text/html' href='http://cart.personallifemedia.com/dlg/download.php'/><link rel='alternate' type='text/html' href='https://www.google.com/websiteoptimizer'/><link rel='self' type='application/atom+xml' href='https://www.google.com/analytics/feeds/websiteoptimizer/experiments/1025910'/><gwo:analyticsAccountId>16334726</gwo:analyticsAccountId><gwo:autoPruneMode>None</gwo:autoPruneMode><gwo:controlScript>..... I have to parse and get the data for gd:etag and how do I do it? I was able to get the value using SimpleXML, but i wanted to achieve it in ReXML. Please do advice.

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  • how do i upload virtual pc into a wesite using virtual server.

    - by ragu88
    dear friends, my school has given me a project on virtual pc and server. i am supposed to create a website with multiple virtual pcs in it.. students are supposed to go to the website and than to the virtual pc and do their lab experiments there... can i no how m i to do that and how do i upload a virtual pc into the website.. i m using ms virtual server 2005 r2.. Ragu

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  • New Google Chrome Beta?

    - by Tyilo
    I currently have Google Chrome dev version installed, however visting http://www.soundstep.com/blog/experiments/jsdetection/, it said I needed to install Google Chrome Beta. Isn't dev higher than beta? I thought there was these versions of Google Chrome, from lowest to highest version: Stable Beta Dev Canary (Chromium) Is the detection of my browser failing on the website, or have Google Chrome changed their versioning system? Download link for the "new" chrome beta: https://www.google.com/landing/chrome/beta/

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