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  • Problem with all fn Keys for Thinkpad W520

    - by Ludwig
    I have a problem with the fn. I used a live version of Ubuntu 11.10 on a USB stick to install Ubuntu on my Thinkpad W520. The fn keys worked perfectly in the live version, but do not work in the installed version. I would like to know what I have messed up. I can't seem to find the fix on google, except for inserting the shortcuts by hand, which seems a little brutal, since I know they can work without prior configuration. Thanks in Advance. Edit: The keys just started working out of the blue. I don't really know what my system did or what maybe I did. However all keys work fine now. Sorry for putting this now useless question here.

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  • Should the number of developers be considered when estimating a task?

    - by Ludwig Magnusson
    I am pretty inexperienced with working in agile projects but I have tried it a few times and I always run into this problem when estimating a task. Do we bring into the estimate the number of developers that will work on the task? Let me explain: Task A is estimated to one time unit and developer 1 will work on it. Task B is also estimated to one time unit and developer 2 and 3 will work on it together. I.e. if developer 1 begins to work on task A at the same time developer 2 and 3 begins to work on task B they will all finish at the same time according to the estimate. Should the estimate for task B be twice of that for task A or the same? The problem as I see it is that when a task is received and estimated, it is not always possible to know how many people will work on it. And if you assumed that two developers would work on the task for one time unit but it turns out that only one developer will actually do it, this will not automatically mean that that developer will work on it for two time units. Is there any standard practice for this?

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  • Linux Software RAID: How to fsck on hard drive?

    - by Rick-Rainer Ludwig
    We have a Linux server running with Software RAID1. We see some issues in /var/log/messages like: unreadable sector. I want to perform a complete fsck on the drive to get some more information, but a fsck /dev/md0 brings a clean due to the Software RAID layer in between. How can I check the real hard drive? Do I need to disassemble the whole RAID? How do I deal with the inconsistency in the partition due to the additional Software RAID header? Does anyone have a good idea for this?

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  • MySQL port 3306 became filtered when configured with Keepalived on Ubuntu server 12.04 lts

    - by Ludwig
    I'm configuring two load balancer (lb01 & lb02) with keepalived for my two mysql server (db01 & db02) with standard port 3306. There is virtual ip address (192.168.205.10) to access it also act as failover, but somehow the web server in the front can't access this mysql server using vip. Here is my config: Keepalived: Only the mysql part that i added here. LB01: virtual_server 192.168.205.10 3306 { delay_loop 6 lb_algo rr lb_kind DR protocol TCP real_server 192.168.205.4 3306 { weight 10 TCP_CHECK { connect_port 3306 connect_timeout 2 } } } LB02: virtual_server 192.168.205.10 3306 { delay_loop 6 lb_algo rr lb_kind DR protocol TCP real_server 192.168.205.6 3306 { weight 10 TCP_CHECK { connect_port 3306 connect_timeout 2 } } } I already comment out the "bind-address=127.0.0.1" part in both server my.cnf. Also, remove all the firewall prog from my ubuntu server (ufw or iptables). Any help? thanks.

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  • How do I parse JSON from a Java HTTPResponse?

    - by Joe Ludwig
    I have an HttpResponse object for a web request I just made. The response is in the JSON format, so I need to parse it. I can do it in an absurdly complex way, but it seems like there must be a better way. Is this really the best I can do? HttpResponse response; // some response object Reader in = new BufferedReader( new InputStreamReader(response.getEntity().getContent(), "UTF-8")); StringBuilder builder= new StringBuilder(); char[] buf = new char[1000]; int l = 0; while (l >= 0) { builder.append(buf, 0, l); l = in.read(buf); } JSONTokener tokener = new JSONTokener( builder.toString() ); JSONArray finalResult = new JSONArray( tokener ); I'm on Android if that makes any difference.

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  • What is the worst programming language you ever worked with? [closed]

    - by Ludwig Weinzierl
    If you have an interesting story to share, please post an answer, but do not abuse this question for bashing a language. We are programmers, and our primary tool is the programming language we use. While there is a lot of discussion about the best one, I'd like to hear your stories about the worst programming languages you ever worked with and I'd like to know exactly what annoyed you. I'd like to collect this stories partly to avoid common pitfalls while designing a language (especially a DSL) and partly to avoid quirky languages in the future in general. This question is not subjective. If a language supports only single character identifiers (see my own answer) this is bad in a non-debatable way. EDIT Some people have raised concerns that this question attracts trolls. Wading through all your answers made one thing clear. The large majority of answers is appropriate, useful and well written. UPDATE 2009-07-01 19:15 GMT The language overview is now complete, covering 103 different languages from 102 answers. I decided to be lax about what counts as a programming language and included anything reasonable. Thank you David for your comments on this. Here are all programming languages covered so far (alphabetical order, linked with answer, new entries in bold): ABAP, all 20th century languages, all drag and drop languages, all proprietary languages, APF, APL (1), AS400, Authorware, Autohotkey, BancaStar, BASIC, Bourne Shell, Brainfuck, C++, Centura Team Developer, Cobol (1), Cold Fusion, Coldfusion, CRM114, Crystal Syntax, CSS, Dataflex 2.3, DB/c DX, dbase II, DCL, Delphi IDE, Doors DXL, DOS batch (1), Excel Macro language, FileMaker, FOCUS, Forth, FORTRAN, FORTRAN 77, HTML, Illustra web blade, Informix 4th Generation Language, Informix Universal Server web blade, INTERCAL, Java, JavaScript (1), JCL (1), karol, LabTalk, Labview, Lingo, LISP, Logo, LOLCODE, LotusScript, m4, Magic II, Makefiles, MapBasic, MaxScript, Meditech Magic, MEL, mIRC Script, MS Access, MUMPS, Oberon, object extensions to C, Objective-C, OPS5, Oz, Perl (1), PHP, PL/SQL, PowerDynamo, PROGRESS 4GL, prova, PS-FOCUS, Python, Regular Expressions, RPG, RPG II, Scheme, ScriptMaker, sendmail.conf, Smalltalk, Smalltalk , SNOBOL, SpeedScript, Sybase PowerBuilder, Symbian C++, System RPL, TCL, TECO, The Visual Software Environment, Tiny praat, TransCAD, troff, uBasic, VB6 (1), VBScript (1), VDF4, Vimscript, Visual Basic (1), Visual C++, Visual Foxpro, VSE, Webspeed, XSLT The answers covering 80386 assembler, VB6 and VBScript have been removed.

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  • Pros and cons of distributed revision control systems?

    - by Ludwig Weinzierl
    What are the advantages and disadvantages of distributed revision control systems? If you have any experience with distributed systems like Git, Mercurial, Plastic SCM, etc. please share your experience. Tell us what worked well and where problems arose. I'm particularly interested to hear about the use of distributed systems in traditional, commercial, non-open source projects but answers about other uses are also welcome.

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  • AppEngine BlobStore upload failing when request is programmatic

    - by Joe Ludwig
    I have an AppEngine application that uses the blobstore to store user-provided image data. When I upload images to that application from a form in Chrome it works fine. When I try to upload an image from an Android application it fails. Both methods work fine if I am running against the development server, but the Android upload doesn't work against the live service. This is the request from Chrome: POST /_ah/upload/?userToken=11001/AMmfu6ZCyMQQ9YdiXal3SmSXIRTQIuSRXkNc-i3JmU0fqx_kJbUJ2OMLcS2lXhVJSK4qs7regViTKzOPz5ejoZYi0nAD5o8vNltiOViQw6DZO7_byZz3Ut0/ALBNUaYAAAAAS_lusgPMAGmpPrg0BuNsJyymX-57ob4i/ HTTP/1.1 Host: photohuntservice.appspot.com Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.1.249.1064 Safari/532.5 Referer: http://photohuntservice.appspot.com/debug_newpuzzle?userToken=11001 Content-Length: 60360 Cache-Control: max-age=0 Origin: http://photohuntservice.appspot.com Content-Type: multipart/form-data; boundary=----WebKitFormBoundarybl05YLmLbFRf2MzN Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="userToken" 11001 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="img"; filename="Photo_020908_001.jpg" Content-Type: image/jpeg <image data> ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="longitude" -122.084095 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="latitude" 37.422006 ------WebKitFormBoundarybl05YLmLbFRf2MzN-- This is the request from my client (which is written in Java on Android, but I don't think that's relevant): POST /_ah/upload/?userToken=11001/AMmfu6Zf9an6AU4lT9UuhIpxOZyOYb1LMwimFpeSh8zr6J1sX9F2ddJW3Qlsw0kwV3oALv-TNPWRQ6g4_Dgwk0UTwF47bbc78Yl44kDeV69MydTuR3N46S4/ALBNUaYAAAAAS_mMr3CYqTg3aVBDjhRxP0DyyRdvotyG/ HTTP/1.1 Content-Type: multipart/form-data;boundary=----WebKitFormBoundaryhdyNAhmOouRDGErG Cache-Control: max-age=0 Accept: */* Origin: http://photohuntservice.appspot.com Connection: keep-alive Referer: http://photohuntservice.appspot.com/getuploadurl?userToken=11001 Content-Length: 2638 Host: photohuntservice.appspot.com User-Agent: Apache-HttpClient/UNAVAILABLE (java 1.4) Expect: 100-Continue ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="userToken" 11001 ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="img";filename="PhotoHunt.jpg" Content-Type: image/jpeg <image data> ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="latitude" 37.422006 ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="longitude" -122.084095 ------WebKitFormBoundaryhdyNAhmOouRDGErG-- In both cases the AppEngine Python code to catch the request is the same: class UploadPuzzle( blobstore_handlers.BlobstoreUploadHandler ): def post(self): upload_files = self.get_uploads( ) The problem is that when running on the production AppEngine service self.get_uploads() returns an empty list when the request is made from my client app. Both requests return what I expect (a list with one blob_info in it) on the development server, and Chrome returns what I expect in both cases.

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  • AppEngine BlobStore upload failing with a request that works in the Development Environment

    - by Joe Ludwig
    I have an AppEngine application that uses the blobstore to store user-provided image data. When I upload images to that application from a form in Chrome it works fine. When I try to upload an image from an Android application it fails. Both methods work fine if I am running against the development server, but the Android upload doesn't work against the live service. This is the request from Chrome: POST /_ah/upload/?userToken=11001/AMmfu6ZCyMQQ9YdiXal3SmSXIRTQIuSRXkNc-i3JmU0fqx_kJbUJ2OMLcS2lXhVJSK4qs7regViTKzOPz5ejoZYi0nAD5o8vNltiOViQw6DZO7_byZz3Ut0/ALBNUaYAAAAAS_lusgPMAGmpPrg0BuNsJyymX-57ob4i/ HTTP/1.1 Host: photohuntservice.appspot.com Connection: keep-alive User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US) AppleWebKit/532.5 (KHTML, like Gecko) Chrome/4.1.249.1064 Safari/532.5 Referer: http://photohuntservice.appspot.com/debug_newpuzzle?userToken=11001 Content-Length: 60360 Cache-Control: max-age=0 Origin: http://photohuntservice.appspot.com Content-Type: multipart/form-data; boundary=----WebKitFormBoundarybl05YLmLbFRf2MzN Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="userToken" 11001 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="img"; filename="Photo_020908_001.jpg" Content-Type: image/jpeg <image data> ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="longitude" -122.084095 ------WebKitFormBoundarybl05YLmLbFRf2MzN Content-Disposition: form-data; name="latitude" 37.422006 ------WebKitFormBoundarybl05YLmLbFRf2MzN-- This is the request from my client (which is written in Java on Android, but I don't think that's relevant): POST /_ah/upload/?userToken=11001/AMmfu6Zf9an6AU4lT9UuhIpxOZyOYb1LMwimFpeSh8zr6J1sX9F2ddJW3Qlsw0kwV3oALv-TNPWRQ6g4_Dgwk0UTwF47bbc78Yl44kDeV69MydTuR3N46S4/ALBNUaYAAAAAS_mMr3CYqTg3aVBDjhRxP0DyyRdvotyG/ HTTP/1.1 Content-Type: multipart/form-data;boundary=----WebKitFormBoundaryhdyNAhmOouRDGErG Cache-Control: max-age=0 Accept: */* Origin: http://photohuntservice.appspot.com Connection: keep-alive Referer: http://photohuntservice.appspot.com/getuploadurl?userToken=11001 Content-Length: 2638 Host: photohuntservice.appspot.com User-Agent: Apache-HttpClient/UNAVAILABLE (java 1.4) Expect: 100-Continue ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="userToken" 11001 ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="img";filename="PhotoHunt.jpg" Content-Type: image/jpeg <image data> ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="latitude" 37.422006 ------WebKitFormBoundaryhdyNAhmOouRDGErG Content-Disposition: form-data; name="longitude" -122.084095 ------WebKitFormBoundaryhdyNAhmOouRDGErG-- In both cases the AppEngine Python code to catch the request is the same: class UploadPuzzle( blobstore_handlers.BlobstoreUploadHandler ): def post(self): upload_files = self.get_uploads( ) The problem is that when running on the production AppEngine service self.get_uploads() returns an empty list when the request is made from my client app. Both requests return what I expect (a list with one blob_info in it) on the development server, and Chrome returns what I expect in both cases.

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  • How can I detect the Android emulator?

    - by Joe Ludwig
    I would like to have my code run slightly differently when running on the emulator than when running on a device. (For example, using 10.0.2.2 instead of a public URL to run against a development server automatically.) What is the best way to detect when an Android application is running in the emulator?

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  • SetCursor reverts after a mouse move

    - by Joe Ludwig
    I am using SetCursor to set the system cursor to my own image. The code looks something like this: // member on some class HCURSOR _cursor; // at init time _cursor = LoadCursorFromFile("somefilename.cur"); // in some function SetCursor(_cursor); When I do this the cursor does change, but on the first mouse move message it changes back to the default system arrow cursor. This is the only code in the project that is setting the cursor. What do I need to do to make the cursor stay the way I set it?

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  • Git: How to find all commits in branch A that originated in derived branch B merged back into A?

    - by Michael Ludwig
    In Git, given (1) a branch A and (2) a branch B derived from A at some point in the past and then merged back into A, how can I find all the commits now in A that originated in B? The intent is to identify the changeset of work performed in B now in A to more quickly track down issues. A squash commit would obviously and conveniently pack the entire changeset in one commit for easy reference, but the drawbacks (such as loss of information and individual attributability) make this option undesirable for us. Hence my question.

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  • How to calculate 2^n-1 efficiently without overflow?

    - by Ludwig Weinzierl
    I want to calculate 2^n-1 for a 64bit integer value. What I currently do is this for(i=0; i<n; i++) r|=1<<i; and I wonder if there is more elegant way to do it. The line is in an inner loop, so I need it to be fast. I thought of r=(1ULL<<n)-1; but it doesn't work for n=64, because << is only defined for values of n up to 63.

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  • How do I make Subversion (SVN) send email on checkins?

    - by Joe Ludwig
    I've always found checkin mails to be very useful for keeping track of what work other people are doing in the codebase. How do I set up SVN to email a distribution list on each checkin? Edit: I'm running clients on Windows and the server on Linux. The answers below for various platforms will likely be useful to other people though.

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  • ArchBeat Link-o-Rama Top 10 - September 16-22, 2012

    - by Bob Rhubart
    The Top 10 most popular items shared on the OTN ArchBeat Facebook Page for the week of September 16-22, 2012. The Real Architects of LA: OTN Architect Day in Los Angeles - Oct 25No gossip. No drama. No hair pulling. Just a full day of technical sessions and peer interaction focused on using Oracle technologies in today's cloud and SOA architectures. The event is free, but seating is limited, so register now. Thursday October 25, 2012. 8:00 a.m. – 5:00 p.m. Sofitel Los Angeles, 8555 Beverly Boulevard, Los Angeles, CA 90048. OIM-OAM-OAAM integration using TAP – Request Flow you must understand!! | Atul KumarAtul Kumar's post addresses "key points and request flow that you must understand" when integrating three Oracle Identity Management product Oracle Identity Management, Oracle Access Management, and Oracle Adaptive Access Manager. Cloud, automation drive new growth in SOA governance market | ZDNet "SOA governance tools and processes learned over the past decade are now underpinning cloud projects as they scale across enterprises," reports Joe McKendrick. But there remains a lack of understanding about SOA Governance. DevOps Basics: Track Down High CPU Thread with ps, top and the new JDK7 jcmd Tool | Frank Munz "The approach is very generic and works for WebLogic, Glassfish or any other Java application," say Frank Munz. "UNIX commands in the example are run on CentOS, so they will work without changes for Oracle Enterprise Linux or RedHat. Creating the thread dump at the end of the video is done with the jcmd tool from JDK7." Frank has captured the process in the posted video. Oracle OpenWorld 2012 Hands-on Lab: "Leading Your Everyday Application Integration Projects with Enterprise SOA" Yet another session to squeeze into your already-jammed Oracle OpenWorld schedule. This hands-on lab focuses on how "Oracle Enterprise Repository, Oracle Application Integration Architecture (AIA) Foundation Pack, and Oracle SOA Suite work together to help you drive your enterprisewide integration projects." Loving VirtualBox 4.2… | The ORACLE-BASE Blog Is it wrong for a man to love a technology? Oracle ACE Director Tim Hall has several very good reasons for his feelings… ADF Create and CreateInsert Operations for ADF Table | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis answers the question, "What operation is best to use to insert a new row into an ADF table, Create or CreateInsert?" Fault Handling Slides and Q&A | Ronald van Luttikhuizen Oracle ACE Director Ronald van Luttikhuizen shares the slides and a Q&A transcript from a presentation he and fellow ACE Director Guido Schmutz gave at the recent Oracle OpenWorld and JavaOne preview event organized by AMIS Technology. Why IT is a profession in 'flux' | ZDNet I usuallly don't post two items from the same person in one day, but this post from ZDNet blogger Joe McKendrick deals with some critical issues affecting those in IT. As McKendrick puts it: "IT professionals are under considerable pressure to deliver more value to the business, versus being good at coding and testing and deploying and integrating." Running RichFaces on WebLogic 12c | Markus Eisele "With all the JMS magic and the different provider checks in the showcase this has become some kind of a challenge to simply build and deploy it," says Oracle ACE Director Markus Eisele. His detailed post will help you to meet that challenge. Thought for the Day "Less is more." — Ludwig Mies van der Rohe (March 27, 1886 – August 17, 1969) Source: BrainyQuote.com

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  • A Guided Tour of Complexity

    - by JoshReuben
    I just re-read Complexity – A Guided Tour by Melanie Mitchell , protégé of Douglas Hofstadter ( author of “Gödel, Escher, Bach”) http://www.amazon.com/Complexity-Guided-Tour-Melanie-Mitchell/dp/0199798109/ref=sr_1_1?ie=UTF8&qid=1339744329&sr=8-1 here are some notes and links:   Evolved from Cybernetics, General Systems Theory, Synergetics some interesting transdisciplinary fields to investigate: Chaos Theory - http://en.wikipedia.org/wiki/Chaos_theory – small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for chaotic systems, rendering long-term prediction impossible. System Dynamics / Cybernetics - http://en.wikipedia.org/wiki/System_Dynamics – study of how feedback changes system behavior Network Theory - http://en.wikipedia.org/wiki/Network_theory – leverage Graph Theory to analyze symmetric  / asymmetric relations between discrete objects Algebraic Topology - http://en.wikipedia.org/wiki/Algebraic_topology – leverage abstract algebra to analyze topological spaces There are limits to deterministic systems & to computation. Chaos Theory definitely applies to training an ANN (artificial neural network) – different weights will emerge depending upon the random selection of the training set. In recursive Non-Linear systems http://en.wikipedia.org/wiki/Nonlinear_system – output is not directly inferable from input. E.g. a Logistic map: Xt+1 = R Xt(1-Xt) Different types of bifurcations, attractor states and oscillations may occur – e.g. a Lorenz Attractor http://en.wikipedia.org/wiki/Lorenz_system Feigenbaum Constants http://en.wikipedia.org/wiki/Feigenbaum_constants express ratios in a bifurcation diagram for a non-linear map – the convergent limit of R (the rate of period-doubling bifurcations) is 4.6692016 Maxwell’s Demon - http://en.wikipedia.org/wiki/Maxwell%27s_demon - the Second Law of Thermodynamics has only a statistical certainty – the universe (and thus information) tends towards entropy. While any computation can theoretically be done without expending energy, with finite memory, the act of erasing memory is permanent and increases entropy. Life & thought is a counter-example to the universe’s tendency towards entropy. Leo Szilard and later Claude Shannon came up with the Information Theory of Entropy - http://en.wikipedia.org/wiki/Entropy_(information_theory) whereby Shannon entropy quantifies the expected value of a message’s information in bits in order to determine channel capacity and leverage Coding Theory (compression analysis). Ludwig Boltzmann came up with Statistical Mechanics - http://en.wikipedia.org/wiki/Statistical_mechanics – whereby our Newtonian perception of continuous reality is a probabilistic and statistical aggregate of many discrete quantum microstates. This is relevant for Quantum Information Theory http://en.wikipedia.org/wiki/Quantum_information and the Physics of Information - http://en.wikipedia.org/wiki/Physical_information. Hilbert’s Problems http://en.wikipedia.org/wiki/Hilbert's_problems pondered whether mathematics is complete, consistent, and decidable (the Decision Problem – http://en.wikipedia.org/wiki/Entscheidungsproblem – is there always an algorithm that can determine whether a statement is true).  Godel’s Incompleteness Theorems http://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems  proved that mathematics cannot be both complete and consistent (e.g. “This statement is not provable”). Turing through the use of Turing Machines (http://en.wikipedia.org/wiki/Turing_machine symbol processors that can prove mathematical statements) and Universal Turing Machines (http://en.wikipedia.org/wiki/Universal_Turing_machine Turing Machines that can emulate other any Turing Machine via accepting programs as well as data as input symbols) that computation is limited by demonstrating the Halting Problem http://en.wikipedia.org/wiki/Halting_problem (is is not possible to know when a program will complete – you cannot build an infinite loop detector). You may be used to thinking of 1 / 2 / 3 dimensional systems, but Fractal http://en.wikipedia.org/wiki/Fractal systems are defined by self-similarity & have non-integer Hausdorff Dimensions !!!  http://en.wikipedia.org/wiki/List_of_fractals_by_Hausdorff_dimension – the fractal dimension quantifies the number of copies of a self similar object at each level of detail – eg Koch Snowflake - http://en.wikipedia.org/wiki/Koch_snowflake Definitions of complexity: size, Shannon entropy, Algorithmic Information Content (http://en.wikipedia.org/wiki/Algorithmic_information_theory - size of shortest program that can generate a description of an object) Logical depth (amount of info processed), thermodynamic depth (resources required). Complexity is statistical and fractal. John Von Neumann’s other machine was the Self-Reproducing Automaton http://en.wikipedia.org/wiki/Self-replicating_machine  . Cellular Automata http://en.wikipedia.org/wiki/Cellular_automaton are alternative form of Universal Turing machine to traditional Von Neumann machines where grid cells are locally synchronized with their neighbors according to a rule. Conway’s Game of Life http://en.wikipedia.org/wiki/Conway's_Game_of_Life demonstrates various emergent constructs such as “Glider Guns” and “Spaceships”. Cellular Automatons are not practical because logical ops require a large number of cells – wasteful & inefficient. There are no compilers or general program languages available for Cellular Automatons (as far as I am aware). Random Boolean Networks http://en.wikipedia.org/wiki/Boolean_network are extensions of cellular automata where nodes are connected at random (not to spatial neighbors) and each node has its own rule –> they demonstrate the emergence of complex  & self organized behavior. Stephen Wolfram’s (creator of Mathematica, so give him the benefit of the doubt) New Kind of Science http://en.wikipedia.org/wiki/A_New_Kind_of_Science proposes the universe may be a discrete Finite State Automata http://en.wikipedia.org/wiki/Finite-state_machine whereby reality emerges from simple rules. I am 2/3 through this book. It is feasible that the universe is quantum discrete at the plank scale and that it computes itself – Digital Physics: http://en.wikipedia.org/wiki/Digital_physics – a simulated reality? Anyway, all behavior is supposedly derived from simple algorithmic rules & falls into 4 patterns: uniform , nested / cyclical, random (Rule 30 http://en.wikipedia.org/wiki/Rule_30) & mixed (Rule 110 - http://en.wikipedia.org/wiki/Rule_110 localized structures – it is this that is interesting). interaction between colliding propagating signal inputs is then information processing. Wolfram proposes the Principle of Computational Equivalence - http://mathworld.wolfram.com/PrincipleofComputationalEquivalence.html - all processes that are not obviously simple can be viewed as computations of equivalent sophistication. Meaning in information may emerge from analogy & conceptual slippages – see the CopyCat program: http://cognitrn.psych.indiana.edu/rgoldsto/courses/concepts/copycat.pdf Scale Free Networks http://en.wikipedia.org/wiki/Scale-free_network have a distribution governed by a Power Law (http://en.wikipedia.org/wiki/Power_law - much more common than Normal Distribution). They are characterized by hubs (resilience to random deletion of nodes), heterogeneity of degree values, self similarity, & small world structure. They grow via preferential attachment http://en.wikipedia.org/wiki/Preferential_attachment – tipping points triggered by positive feedback loops. 2 theories of cascading system failures in complex systems are Self-Organized Criticality http://en.wikipedia.org/wiki/Self-organized_criticality and Highly Optimized Tolerance http://en.wikipedia.org/wiki/Highly_optimized_tolerance. Computational Mechanics http://en.wikipedia.org/wiki/Computational_mechanics – use of computational methods to study phenomena governed by the principles of mechanics. This book is a great intuition pump, but does not cover the more mathematical subject of Computational Complexity Theory – http://en.wikipedia.org/wiki/Computational_complexity_theory I am currently reading this book on this subject: http://www.amazon.com/Computational-Complexity-Christos-H-Papadimitriou/dp/0201530821/ref=pd_sim_b_1   stay tuned for that review!

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  • What to Do When Windows Won’t Boot

    - by Chris Hoffman
    You turn on your computer one day and Windows refuses to boot — what do you do? “Windows won’t boot” is a common symptom with a variety of causes, so you’ll need to perform some troubleshooting. Modern versions of Windows are better at recovering from this sort of thing. Where Windows XP might have stopped in its tracks when faced with this problem, modern versions of Windows will try to automatically run Startup Repair. First Things First Be sure to think about changes you’ve made recently — did you recently install a new hardware driver, connect a new hardware component to your computer, or open your computer’s case and do something? It’s possible the hardware driver is buggy, the new hardware is incompatible, or that you accidentally unplugged something while working inside your computer. The Computer Won’t Power On At All If your computer won’t power on at all, ensure it’s plugged into a power outlet and that the power connector isn’t loose. If it’s a desktop PC, ensure the power switch on the back of its case — on the power supply — is set to the On position. If it still won’t power on at all, it’s possible you disconnected a power cable inside its case. If you haven’t been messing around inside the case, it’s possible the power supply is dead. In this case, you’ll have to get your computer’s hardware fixed or get a new computer. Be sure to check your computer monitor — if your computer seems to power on but your screen stays black, ensure your monitor is powered on and that the cable connecting it to your computer’s case is plugged in securely at both ends. The Computer Powers On And Says No Bootable Device If your computer is powering on but you get a black screen that says something like “no bootable device” or another sort of “disk error” message, your computer can’t seem to boot from the hard drive that Windows was installed on. Enter your computer’s BIOS or UEFI firmware setup screen and check its boot order setting, ensuring that it’s set to boot from its hard drive. If the hard drive doesn’t appear in the list at all, it’s possible your hard drive has failed and can no longer be booted from. In this case, you may want to insert Windows installation or recovery media and run the Startup Repair operation. This will attempt to make Windows bootable again. For example, if something overwrote your Windows drive’s boot sector, this will repair the boot sector. If the recovery environment won’t load or doesn’t see your hard drive, you likely have a hardware problem. Be sure to check your BIOS or UEFI’s boot order first if the recovery environment won’t load. You can also attempt to manually fix Windows boot loader problems using the fixmbr and fixboot commands. Modern versions of Windows should be able to fix this problem for you with the Startup Repair wizard, so you shouldn’t actually have to run these commands yourself. Windows Freezes or Crashes During Boot If Windows seems to start booting but fails partway through, you may be facing either a software or hardware problem. If it’s a software problem, you may be able to fix it by performing a Startup Repair operation. If you can’t do this from the boot menu, insert a Windows installation disc or recovery disk and use the startup repair tool from there. If this doesn’t help at all, you may want to reinstall Windows or perform a Refresh or Reset on Windows 8. If the computer encounters errors while attempting to perform startup repair or reinstall Windows, or the reinstall process works properly and you encounter the same errors afterwards, you likely have a hardware problem. Windows Starts and Blue Screens or Freezes If Windows crashes or blue-screens on you every time it boots, you may be facing a hardware or software problem. For example, malware or a buggy driver may be loading at boot and causing the crash, or your computer’s hardware may be malfunctioning. To test this, boot your Windows computer in safe mode. In safe mode, Windows won’t load typical hardware drivers or any software that starts automatically at startup. If the computer is stable in safe mode, try uninstalling any recently installed hardware drivers, performing a system restore, and scanning for malware. If you’re lucky, one of these steps may fix your software problem and allow you to boot Windows normally. If your problem isn’t fixed, try reinstalling Windows or performing a Refresh or Reset on Windows 8. This will reset your computer back to its clean, factory-default state. If you’re still experiencing crashes, your computer likely has a hardware problem. Recover Files When Windows Won’t Boot If you have important files that will be lost and want to back them up before reinstalling Windows, you can use a Windows installer disc or Linux live media to recover the files. These run entirely from a CD, DVD, or USB drive and allow you to copy your files to another external media, such as another USB stick or an external hard drive. If you’re incapable of booting a Windows installer disc or Linux live CD, you may need to go into your BIOS or UEFI and change the boot order setting. If even this doesn’t work — or if you can boot from the devices and your computer freezes or you can’t access your hard drive — you likely have a hardware problem. You can try pulling the computer’s hard drive, inserting it into another computer, and recovering your files that way. Following these steps should fix the vast majority of Windows boot issues — at least the ones that are actually fixable. The dark cloud that always hangs over such issues is the possibility that the hard drive or another component in the computer may be failing. Image Credit: Karl-Ludwig G. Poggemann on Flickr, Tzuhsun Hsu on Flickr     

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