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  • "Priming" a whole database in MSSQL for first-hit speed

    - by David Spillett
    For a particular apps I have a set of queries that I run each time the database has been restarted for any reason (server reboot usually). These "prime" SQL Server's page cache with the common core working set of the data so that the app is not unusually slow the first time a user logs in afterwards. One instance of the app is running on an over-specced arrangement where the SQL box has more RAM than the size of the database (4Gb in the machine, the DB is under 1.5Gb currently and unlikely to grow too much relative to that in the near future). Is there a neat/easy way of telling SQL Server to go away and load everything into RAM? It could be done the hard way by having a script scan sysobjects & sysindexes and running SELECT * FROM <table> WITH(INDEX(<index_name>)) ORDER BY <index_fields> for every key and index found, which should cause every used page to be read at least once and so be in RAM, but is there a cleaner or more efficient way? All planned instances where the database server is stopped are out-of-normal-working-hours (all the users are at most one timezone away and unlike me none of them work at silly hours) so such a process (until complete) slowing down users more than the working set not being primed at all would is not an issue.

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  • Project Euler problem 214, How can i make it more efficient?

    - by Once
    I am becoming more and more addicted to the Project Euler problems. However since one week I am stuck with the #214. Here is a short version of the problem: PHI() is Euler's totient function, i.e. for any given integer n, PHI(n)=numbers of k<=n for which gcd(k,n)=1. We can iterate PHI() to create a chain. For example starting from 18: PHI(18)=6 = PHI(6)=2 = PHI(2)=1. So starting from 18 we get a chain of length 4 (18,6,2,1) The problem is to calculate the sum of all primes less than 40e6 which generate a chain of length 25. I built a function that calculates the chain length of any number and I tested it for small values: it works well and fast. sum of all primes<=20 which generate a chain of length 4: 12 sum of all primes<=1000 which generate a chain of length 10: 39383 Unfortunately my algorithm doesn't scale well. When I apply it to the problem, it takes several hours to calculate... so I stop it because the Project Euler problems must be solved in less than one minute. I thought that my prime detection function might be slow so I fed the program with a list of primes <40e6 to avoid the primality test... The code runs now a little bit faster, but there is still no way to get a solution in less than a few hours (and I don't want this). So is there any "magic trick" that I am missing here ? I really don't understand how to be more efficient on this one... I am not asking for the solution, because fighting with optimization is all the fun of Project Euler. However, any small hint that could put me on the right track would be welcome. Thanks !

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  • How to "reduce" a hash?

    - by Julien Lebosquain
    Suppose I have any "long" hash, like a 16 bytes MD5 or a 20 bytes SHA1. I want to reduce this hash to fit on 4 bytes, for GetHashCode() purposes. First, I'm perfectly aware that I'll get more collisions. That's totally fine in my case, but I'd still prefer to get the less possible collisions. There are several solutions to my problem: I could take the 4 first bytes of the hash. I could take the 4 last bytes of the hash. I could take 4 random bytes of the hash. I could generate a hash of the hash, involving classic prime numbers multiplications. Are there other solutons I didn't think about? And more importantly, what method will give me the most unique hash code? I'm currently supposing they're almost equivalent. Microsoft choose that the public key token of an assembly is the last 8 bytes of the SHA1 hash of its public key, so I'll probably go for this solution but I'd like to know why.

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  • Project Euler, Problem 10 java solution not working

    - by Dennis S
    Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

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  • Javascript CS-PRNG - 64-bit random

    - by Jack
    Hi, I need to generate a cryptographically secure 64-bit unsigned random integer in Javascript. The first problem is that Javascript only allows 64-bit signed integers, so 9223372036854775808 is the biggest supported integer without going into floating point use I think? To fix this I can use a big number library, no problem. My Method: var randNum = SHA256( randBigInt(128, 0) ) % 2^64; Where SHA256() is a secure hash function and randBigInt() is defined below as a non-crypto PRNG, im giving it a 128bit seed so brute force shouldn't be a problem. randBigInt(n,s) //return an n-bit random BigInt (n>=1). If s=1, then the most significant of those n bits is set to 1. Is this a secure method to generate a cryptographically secure 64-bit random int? And importantly does taking the 2^64 mod guarantee 100% I have a 64-bit number? An abstract example, say this number is prime (it isn't i know), I will use it in the Galois Field [2^p], where p must be 64bits so that every possible 1-63bit number is a field element. In this query, my random int must be larger than any 63-bit number. And Im not sure im correct in taking the 2^64 mod of a 256bit hash output. Thanks (hope that makes sense)

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  • Why isn't my submit button centered?

    - by William
    For some reason my submit button isn't centered. http://prime.programming-designs.com/test_forum/viewboard.php?board=0 #submitbutton{ margin: auto; border: 1px solid #DBFEF8; background-color: #DBFEF8; color: #000000; margin-top: 5px; width: 100px; height: 20px; } here's the html. <form method=post action=add_thread.php?board=<?php echo''.$board.''; ?>> <div id="formdiv"> <div class="fieldtext1">Name</div> <div class="fieldtext1">Trip</div> <input type="text" name=name size=25 /> <input type="text" name=trip size=25 /> <div class="fieldtext2">Comment</div> <textarea name=post rows="4" cols="70"></textarea> <div class="fieldtext2">Fortune</div> <input type="checkbox" name="fortune" value="fortune" /> </div> <input type=submit value="Submit" id="submitbutton"> </form>

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  • Problem with Boost::Asio for C++

    - by Martin Lauridsen
    Hi there, For my bachelors thesis, I am implementing a distributed version of an algorithm for factoring large integers (finding the prime factorisation). This has applications in e.g. security of the RSA cryptosystem. My vision is, that clients (linux or windows) will download an application and compute some numbers (these are independant, thus suited for parallelization). The numbers (not found very often), will be sent to a master server, to collect these numbers. Once enough numbers have been collected by the master server, it will do the rest of the computation, which cannot be easily parallelized. Anyhow, to the technicalities. I was thinking to use Boost::Asio to do a socket client/server implementation, for the clients communication with the master server. Since I want to compile for both linux and windows, I thought windows would be as good a place to start as any. So I downloaded the Boost library and compiled it, as it said on the Boost Getting Started page: bootstrap .\bjam It all compiled just fine. Then I try to compile one of the tutorial examples, client.cpp, from Asio, found (here.. edit: cant post link because of restrictions). I am using the Visual C++ compiler from Microsoft Visual Studio 2008, like this: cl /EHsc /I D:\Downloads\boost_1_42_0 client.cpp But I get this error: /out:client.exe client.obj LINK : fatal error LNK1104: cannot open file 'libboost_system-vc90-mt-s-1_42.lib' Anyone have any idea what could be wrong, or how I could move forward? I have been trying pretty much all week, to get a simple client/server socket program for c++ working, but with no luck. Serious frustration kicking in. Thank you in advance.

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  • SVG rotation animation having problems on chrome for jelly bean, is there a workaround?

    - by Metalskin
    I've got a strange problem with chrome on jellybean running svg animations triggered from javascript. This JSFiddle example works fine on chrome and firefox on linux, but when I run it on android with chrome I get the final step of the animation painted at the beginning of the animation. I've tried this on both an Nexus 7 and Transformer Prime, they both have the problem. I've tested using firefox on the android devices and the problem doesn't exist. So I'm presuming that it's a defect with chrome. However I've seen other animations using svg that do not have this problem in chrome on jellybean. Is anyone aware of a way to get around this problem, or is there something that I'm doing in my animation/js that is a possible cause of the problem? I've now created a bug report at code.google.com, however I still need a workaround, if anyone can help me (or in case I'm doing something stupid). I've now discovered that this is reproducible on chrome for linux (and I suspect windows). If you click on the button to start the animation before the previous animation has completed then the problem occurs. In this case the hand is drawn at the end of the 45 degree sweep before it starts the sweep. I now suspect that I should be calling something to stop the animation before I change the animation. Anyway, hopefully someone can resolve this problem.

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  • List of Big-O for PHP functions?

    - by Kendall Hopkins
    After using PHP for a while now, I've noticed that not all PHP built in functions as fast as expected. Consider the below two possible implementations of a function that finds if a number is prime using a cached array of primes. //very slow for large $prime_array $prime_array = array( 2, 3, 5, 7, 11, 13, .... 104729, ... ); $result_array = array(); foreach( $array_of_number => $number ) { $result_array[$number] = in_array( $number, $large_prime_array ); } //still decent performance for large $prime_array $prime_array => array( 2 => NULL, 3 => NULL, 5 => NULL, 7 => NULL, 11 => NULL, 13 => NULL, .... 104729 => NULL, ... ); foreach( $array_of_number => $number ) { $result_array[$number] = array_key_exists( $number, $large_prime_array ); } This is because in_array is implemented with a linear search O(n) which will linearly slow down as $prime_array grows. Where the array_key_exists function is implemented with a hash lookup O(1) which will not slow down unless the hash table gets extremely populated (in which case it's only O(logn)). So far I've had to discover the big-O's via trial and error, and occasionally looking at the source code. Now for the question... I was wondering if there was a list of the theoretical (or practical) big O times for all* the PHP built in functions. *or at least the interesting ones For example find it very hard to predict what the big O of functions listed because the possible implementation depends on unknown core data structures of PHP: array_merge, array_merge_recursive, array_reverse, array_intersect, array_combine, str_replace (with array inputs), etc.

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  • Questions about the Backpropogation Algorithm

    - by Colemangrill
    I have a few questions concerning backpropogation. I'm trying to learn the fundamentals behind neural network theory and wanted to start small, building a simple XOR classifier. I've read a lot of articles and skimmed multiple textbooks - but I can't seem to teach this thing the pattern for XOR. Firstly, I am unclear about the learning model for backpropogation. Here is some pseudo-code to represent how I am trying to train the network. [Lets assume my network is setup properly (ie: multiple inputs connect to a hidden layer connect to an output layer and all wired up properly)]. SET guess = getNetworkOutput() // Note this is using a sigmoid activation function. SET error = desiredOutput - guess SET delta = learningConstant * error * sigmoidDerivative(guess) For Each Node in inputNodes For Each Weight in inputNodes[n] inputNodes[n].weight[j] += delta; // At this point, I am assuming the first layer has been trained. // Then I recurse a similar function over the hidden layer and output layer. // The prime difference being that it further divi's up the adjustment delta. I realize this is probably not enough to go off of, and I will gladly expound on any part of my implementation. Using the above algorithm, my neural network does get trained, kind of. But not properly. The output is always XOR 1 1 [smallest number] XOR 0 0 [largest number] XOR 1 0 [medium number] XOR 0 1 [medium number] I can never train the [1,1] [0,0] to be the same value. If you have any suggestions, additional resources, articles, blogs, etc for me to look at I am very interested in learning more about this topic. Thank you for your assistance, I appreciate it greatly!

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  • Project Euler, Problem 10 java solution now working

    - by Dennis S
    Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

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  • Int - number too large. How to get program to fail?

    - by Dave
    Hi Problem: How do you get a program to fail if a number goes beyond the bounds of its type? This code below gives the wrong answer for sum of primes under 2 million as I'd used an int instead of a long. [TestMethod] public void CalculateTheSumOfPrimesBelow2million() { int result = PrimeTester.calculateTheSumOfPrimesBelow(2000000); // 2million Assert.AreEqual(1, result); // 1,179,908,154 .. this was what I got with an int... // correct answer was 142,913,828,922 with a long } public static class PrimeTester { public static int calculateTheSumOfPrimesBelow(int maxPrimeBelow) { // we know 2 is a prime number int sumOfPrimes = 2; int currentNumberBeingTested = 3; while (currentNumberBeingTested < maxPrimeBelow) { double squareRootOfNumberBeingTested = (double)Math.Sqrt(currentNumberBeingTested); bool isPrime = true; for (int i = 2; i <= squareRootOfNumberBeingTested; i++) { if (currentNumberBeingTested % i == 0) { isPrime = false; break; } } if (isPrime) sumOfPrimes += currentNumberBeingTested; currentNumberBeingTested += 2; // as we don't want to test even numbers } return sumOfPrimes; } }

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  • Why is my php script freezing?

    - by William
    What is causing my php code to freeze? I know it's cause of the while loop, but I have $max_threads--; at the end so it shouldn't do that. <html> <head> <?php $db = mysql_connect("host","name","pass") or die("Can't connect to host"); mysql_select_db("dbname",$db) or die("Can't connect to DB"); $sql_result = mysql_query("SELECT MAX(Thread) FROM test_posts", $db); $rs = mysql_fetch_row($sql_result); $max_threads = $rs[0]; $board = $_GET['board']; ?> </head> <body> <?php While($max_threads >= 0) { $sql_result = mysql_query("SELECT MIN(ID) FROM test_posts WHERE Thread=".$max_threads."", $db); $rs = mysql_fetch_row($sql_result); $sql_result = mysql_query("SELECT post FROM test_posts WHERE ID=".$rs[0]."", $db); $post = mysql_fetch_row($sql_result); $sql_result = mysql_query("SELECT name FROM test_posts WHERE ID=".$rs[0]."", $db); $name = mysql_fetch_row($sql_result); $sql_result = mysql_query("SELECT trip FROM test_posts WHERE ID=".$rs[0]."", $db); $trip = mysql_fetch_row($sql_result); if(!empty($post)) echo'<div class="postbox"><h4>'.$name[0].'['.$trip[0].']</h4><hr />' . $post[0] . '<br /><hr />[<a href="http://prime.programming-designs.com/test_forum/viewthread.php?thread='.$max_threads.'">Reply</a>]</div>'; $max_threads--; } ?> </body> </html>

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  • Strange type-related error

    - by vsb
    I wrote following program: isPrime x = and [x `mod` i /= 0 | i <- [2 .. truncate (sqrt x)]] primes = filter isPrime [1 .. ] it should construct list of prime numbers. But I got this error: [1 of 1] Compiling Main ( 7/main.hs, interpreted ) 7/main.hs:3:16: Ambiguous type variable `a' in the constraints: `Floating a' arising from a use of `isPrime' at 7/main.hs:3:16-22 `RealFrac a' arising from a use of `isPrime' at 7/main.hs:3:16-22 `Integral a' arising from a use of `isPrime' at 7/main.hs:3:16-22 Possible cause: the monomorphism restriction applied to the following: primes :: [a] (bound at 7/main.hs:3:0) Probable fix: give these definition(s) an explicit type signature or use -XNoMonomorphismRestriction Failed, modules loaded: none. If I specify signature for isPrime function explicitly: isPrime :: Integer -> Bool isPrime x = and [x `mod` i /= 0 | i <- [2 .. truncate (sqrt x)]] I can't even compile isPrime function: [1 of 1] Compiling Main ( 7/main.hs, interpreted ) 7/main.hs:2:45: No instance for (RealFrac Integer) arising from a use of `truncate' at 7/main.hs:2:45-61 Possible fix: add an instance declaration for (RealFrac Integer) In the expression: truncate (sqrt x) In the expression: [2 .. truncate (sqrt x)] In a stmt of a list comprehension: i <- [2 .. truncate (sqrt x)] 7/main.hs:2:55: No instance for (Floating Integer) arising from a use of `sqrt' at 7/main.hs:2:55-60 Possible fix: add an instance declaration for (Floating Integer) In the first argument of `truncate', namely `(sqrt x)' In the expression: truncate (sqrt x) In the expression: [2 .. truncate (sqrt x)] Failed, modules loaded: none. Can you help me understand, why am I getting these errors?

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  • Interpretation of range(n) and boolean list, one-to-one map, simpler?

    - by HH
    #!/usr/bin/python # # Description: bitwise factorization and then trying to find # an elegant way to print numbers # Source: http://forums.xkcd.com/viewtopic.php?f=11&t=61300#p2195422 # bug with large numbers such as 99, but main point in simplifying it # def primes(n): # all even numbers greater than 2 are not prime. s = [False]*2 + [True]*2 + [False,True]*((n-4)//2) + [False]*(n%2) i = 3; while i*i < n: # get rid of ** and skip even numbers. s[i*i : n : i*2] = [False]*(1+(n-i*i)//(i*2)) i += 2 # skip non-primes while not s[i]: i += 2 return s # TRIAL: can you find a simpler way to print them? # feeling the overuse of assignments but cannot see a way to get it simpler # p = 49 boolPrimes = primes(p) numbs = range(len(boolPrimes)) mydict = dict(zip(numbs, boolPrimes)) print([numb for numb in numbs if mydict[numb]]) Something I am looking for, can you get TRIAL to be of the extreme simplicity below? Any such method? a=[True, False, True] b=[1,2,3] b_a # any such simple way to get it evaluated to [1,3] # above a crude way to do it in TRIAL

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  • Which Android hardware devices should I test on? [closed]

    - by Tchami
    Possible Duplicate: What hardware devices do you test your Android apps on? I'm trying to compile a list of Android hardware devices that it would make sense to buy and test against if you want to target an as broad audience as possible, while still not buying every single Android device out there. I know there's a lot of information regarding screen sizes and Android versions available elsewhere, but: when developing for Android it's not terribly useful to know if the screen size of a device is 480x800 or 320x240, unless you feel like doing the math to convert that into Android "units" (i.e. small, normal, large or xlarge screens, and ldpi, mdpi, hdpi or xhdpi densities). Even knowing the dimensions of a device, you cannot be sure of the actual Android units as there's some overlap, see Range of screens supported in the Android documentation Taking into account the distribution of Platform versions and Screen Sizes and Densities, below is my current list based on information from the Wikipedia article on Comparison of Android devices. I'm fairly sure the information in this list is correct, but I'd welcome any suggestions/changes. Phones | Model | Android Version | Screen Size | Density | | HTC Wildfire | 2.1/2.2 | Normal | mdpi | | HTC Tattoo | 1.6 | Normal | mdpi | | HTC Hero | 2.1 | Normal | mdpi | | HTC Legend | 2.1 | Normal | mdpi | | Sony Ericsson Xperia X8 | 1.6/2.1 | Normal | mdpi | | Motorola Droid | 2.0-2.2 | Normal | hdpi | | Samsung Galaxy S II | 2.3 | Normal | hdpi | | Samsung Galaxy Nexus | 4.0 | Normal | xhdpi | | Samsung Galaxy S III | 4.0 | Normal | xhdpi | **Tablets** | Model | Android Version | Screen Size | Density | | Samsung Galaxy Tab 7" | 2.2 | Large | hdpi | | Samsung Galaxy Tab 10" | 3.0 | X-Large | mdpi | | Asus Transformer Prime | 4.0 | X-Large | mdpi | | Motorola Xoom | 3.1/4.0 | X-Large | mdpi | N.B.: I have seen (and read) other posts on SO on this subject, e.g. Which Android devices should I test against? and What hardware devices do you test your Android apps on? but they don't seem very canonical. Maybe this should be marked community wiki?

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  • Configuring Windows 2003 As A Router

    - by Sean M
    I am trying to configure a Windows 2003 server to act as a router, so that the two subnetworks that I'm dealing with can communicate with one another without NAT. I am mostly sure that I have configured Windows 2003 incorrectly, and I'm finding it very difficult to drill down through Google results to something helpful. I have a 192.168.1.0/24 network that is my "production" network (in the sense that I'm in trouble if I screw it up) and a 10.0.0.0/8 network that is my test network. The 192.168.1.0 network is ruled by a gateway whose routing table looks like this (my address redacted): The Windows 2003 server, "prime," is multihomed. Its network adapters are at 192.168.1.122, (as seen above), 10.0.0.1, and 10.0.0.2. I added the Routing and Remote Access role to it, and enabled LAN routing. I do not have it using RIP or other routing protocols. Its current routing table is shown below. To me, it looks like all of the right routes are there for traffic to pass between the 192.168.1.0 network and the 10.0.0.0 network. However, traffic does not pass. The 10.0.0.11 and .12 clients cannot be contacted from the 192.168.1.0 network. When I use traceroute to try to get to them, the trace gets to the Windows 2003 server's 192.168.1.122 address, then produces nothing but "* * *" timeouts. When I try to traceroute to 192.168.1.1 from a 10.0.0.0-network client, I get "destination host unreachable." However, I know that the routing is working at least a little, because from the 192.168.1.0 network, I can connect to the Windows server just fine by referring to it as 10.0.0.1. What static routes would allow me to contact 10.0.0.11 and .12 from the 192.168.1.0 network? Is it possible to tell the Windows server "since you are a DHCP/DNS server, you already know routes to get to machines that are getting IP addresses from you, please add those to your routing table" ? Will using RIP or OSPF on the Windows server actually be helpful in this situation?

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  • Setting up a home server - what to use? (ZFS vs btrfs, BSD vs Linux, misc other requirements)

    - by monch1962
    I need to get all our home content off individual machines and onto a central server. What I'd like to have is the metaphorical "server under the stairs". Stuff we need: expandable storage. I want to be able to add extra disc as we go along, with minimal maintenance required. Currently we've got about 3Tb of files we need to host, and that's likely to grow by another Tb every 6-12 months based on recent history. I need to be able to add additional disc with minimal pain needs to store all the media (i.e. photos, video, music) we have, and run services to serve the various devices we have in the house to playback (e.g. DAAP so we can play stuff through iTunes, ccxstream so we can play stuff over XBMC). DAAP and ccxstream are needed now, but we also need to support new standards as they emerge (so a closed-box solution isn't going to work) RAID 5, or something broadly equivalent (e.g. RAID-Z) BitTorrent client ssh, NFS, Samba access snapshot capability (as in ZFS), so we can snapshot individual file systems regularly and rollback when my kids delete their school assignments the day before they're due... ability to recover quickly from power outages (it's not unusual for us to have power outages that last longer than our UPS' batteries) FOSS software a modern distributed version control system running on the box, such as Mercurial Stuff I'd like to have on the server, but can live without: PVR capability, so I could record TV to the box Web server. We currently run a small Web server on a very old box, and I'd ideally like to turn the old box off and move the content to the new server just to save some electricity Nagios + mrtg I've been looking at using a EEE Box as the server, primarily because I can get them cheap and they don't consume much power. The choice of OS and file system is more difficult, from what I've found: I've got most experience with various Linux distros, but am happy to use another Unix FreeBSD and OpenSolaris seem to be the best choices for hosting ZFS OpenSolaris' hardware support is nowhere near as good as e.g. Ubuntu btrfs, while looking very good, doesn't seem ready for prime-time yet ZFS doesn't let you (easily?) add new discs to a RAID5 or RAID-Z reading around, it seems that ZFS is a bit short of tools for recovering lost data At the moment, I'm leaning towards running FreeNAS+ZFS, but I'm concerned about the requirement to be able to add new disc on a fairly regular basis to an existing RAID-Z. Can anyone provide some recommendations, or share experiences? Thanks in advance

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  • Setting up a home server - what to use? (ZFS vs btrfs, BSD vs Linux, misc other requirements)

    - by monch1962
    I need to get all our home content off individual machines and onto a central server. What I'd like to have is the metaphorical "server under the stairs". Stuff we need: expandable storage. I want to be able to add extra disc as we go along, with minimal maintenance required. Currently we've got about 3Tb of files we need to host, and that's likely to grow by another Tb every 6-12 months based on recent history. I need to be able to add additional disc with minimal pain needs to store all the media (i.e. photos, video, music) we have, and run services to serve the various devices we have in the house to playback (e.g. DAAP so we can play stuff through iTunes, ccxstream so we can play stuff over XBMC). DAAP and ccxstream are needed now, but we also need to support new standards as they emerge (so a closed-box solution isn't going to work) RAID 5, or something broadly equivalent (e.g. RAID-Z) BitTorrent client ssh, NFS, Samba access snapshot capability (as in ZFS), so we can snapshot individual file systems regularly and rollback when my kids delete their school assignments the day before they're due... ability to recover quickly from power outages (it's not unusual for us to have power outages that last longer than our UPS' batteries) FOSS software a modern distributed version control system running on the box, such as Mercurial Stuff I'd like to have on the server, but can live without: PVR capability, so I could record TV to the box Web server. We currently run a small Web server on a very old box, and I'd ideally like to turn the old box off and move the content to the new server just to save some electricity Nagios + mrtg I've been looking at using a EEE Box as the server, primarily because I can get them cheap and they don't consume much power. The choice of OS and file system is more difficult, from what I've found: I've got most experience with various Linux distros, but am happy to use another Unix FreeBSD and OpenSolaris seem to be the best choices for hosting ZFS OpenSolaris' hardware support is nowhere near as good as e.g. Ubuntu btrfs, while looking very good, doesn't seem ready for prime-time yet ZFS doesn't let you (easily?) add new discs to a RAID5 or RAID-Z reading around, it seems that ZFS is a bit short of tools for recovering lost data At the moment, I'm leaning towards running FreeNAS+ZFS, but I'm concerned about the requirement to be able to add new disc on a fairly regular basis to an existing RAID-Z. Can anyone provide some recommendations, or share experiences? Thanks in advance

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  • Setting up a home server - what to use? (ZFS vs btrfs, BSD vs Linux, misc other requirements)

    - by monch1962
    I need to get all our home content off individual machines and onto a central server. What I'd like to have is the metaphorical "server under the stairs". Stuff we need: expandable storage. I want to be able to add extra disc as we go along, with minimal maintenance required. Currently we've got about 3Tb of files we need to host, and that's likely to grow by another Tb every 6-12 months based on recent history. I need to be able to add additional disc with minimal pain needs to store all the media (i.e. photos, video, music) we have, and run services to serve the various devices we have in the house to playback (e.g. DAAP so we can play stuff through iTunes, ccxstream so we can play stuff over XBMC). DAAP and ccxstream are needed now, but we also need to support new standards as they emerge (so a closed-box solution isn't going to work) RAID 5, or something broadly equivalent (e.g. RAID-Z) BitTorrent client ssh, NFS, Samba access snapshot capability (as in ZFS), so we can snapshot individual file systems regularly and rollback when my kids delete their school assignments the day before they're due... ability to recover quickly from power outages (it's not unusual for us to have power outages that last longer than our UPS' batteries) FOSS software a modern distributed version control system running on the box, such as Mercurial Stuff I'd like to have on the server, but can live without: PVR capability, so I could record TV to the box Web server. We currently run a small Web server on a very old box, and I'd ideally like to turn the old box off and move the content to the new server just to save some electricity Nagios + mrtg I've been looking at using a EEE Box as the server, primarily because I can get them cheap and they don't consume much power. The choice of OS and file system is more difficult, from what I've found: I've got most experience with various Linux distros, but am happy to use another Unix FreeBSD and OpenSolaris seem to be the best choices for hosting ZFS OpenSolaris' hardware support is nowhere near as good as e.g. Ubuntu btrfs, while looking very good, doesn't seem ready for prime-time yet ZFS doesn't let you (easily?) add new discs to a RAID5 or RAID-Z reading around, it seems that ZFS is a bit short of tools for recovering lost data At the moment, I'm leaning towards running FreeNAS+ZFS, but I'm concerned about the requirement to be able to add new disc on a fairly regular basis to an existing RAID-Z. Can anyone provide some recommendations, or share experiences? Thanks in advance

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  • Wifi network stopped being visible (and usable) (Linksys wag320n)

    - by s427
    Basically, my wifi network simply stopped working for no apparent reason. It doesn't appear in the list of the available networks anymore. I can see all my neighbors' networks, but not mine. It's as if it doesn't exist anymore. The internet connection (non-wifi), which goes through the same modem/router, is fine though. I already had a similar problem about one year ago (see here: Wifi network SSID not visible ), just after buying this very modem. I finally got it to work after performing two factory resets and getting rid of the Cisco "Magic" software; but this time it's not working. I use a linksys router-modem (WAG320N) which is directly connected (via network cable) to my desktop computer (Windows 7). I have (mainly) two devices that use the wifi network: my phone (Samsung Galaxy Nexus) and an Asus tablet (TF201, aka Transformer Prime). I also resurrected an old laptop computer (Dell, running Windows XP) to test that, and it doesn't see anything either (apart from the 20 other wifi networks, of course ^^). This wifi network was working just fine and has been for about a year. I haven't touched the modem settings so I have no idea what's causing the problem. I tried: making my phone "forget" about my network, hoping it would see it again after that: no luck. re-entering the network informations (SSID/password) manually on my phone: still no luck (says it's not in range) exporting the modem configuration, resetting the modem (factory reset, via modem admin), restarting it, importing the configuration: nope. factory reset, turning it off for 15 minutes, restarting, re-factory reset, and entering the configuration manually: still nothing. Has anybody experienced something similar before? Have you any suggestion to fix that? Thanks in advance. PS: to clear things up, here are the settings of my modem regarding wifi: Basic wireless settings: Configuration: manual Radio Band: 2.4GHz Wireless Network Mode: B/G/N-Mixed SSID: s427 Channel Bandwidth: Wide - 40 MHz Channel Wide Channel: 9 - 2.452GHz Standard Channel: 11 - 2.462GHz SSID Broadcast: Enable Advanced Wireless Settings AP Isolation: Disable Authentication Type: Auto Basic Rate: Default Transmission Rate: Auto N Transmission Rate: Auto CTS Protection Mode: Disable Beacon Interval: 100 DTIM Interval: 1 Fragmentation Threshold: 2346 RTS Threshold: 2346

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  • Gene Hunt Says:

    - by BizTalk Visionary
    "She's as nervous as a very small nun at a penguin shoot"   "He's got fingers in more pies than a leper on a cookery course" "You so much as belch out of line and I'll have your scrotum on a barbed wire plate" "Let's go play slappyface" "your surrounded by armed barstewards" “Right, get out and find this murdering scum right now!” [pause] “Scratch that, we start 9am sharp tomorrow, it's beer-o-clock.” "So then Cartwright, you're such a good Detective.... Go and Detect me a packet of Garibaldies" "You're not the one who is going to have to knit himself a new arsehole after 25 years of aggressive male love in prison" “A dream for me is Diana Dors and a bottle of chip fat." “A dream for me is Diana Dors and a bottle of chip fat." “They reckon you've got concussion - but personally, I couldn't give a tart's furry cup if half your brains are falling out. Don't ever waltz into my kingdom playing king of the jungle.” “You great... soft... sissy... girlie... nancy... french... bender... Man-United supporting POOF!!” “Drugs eh? What's the point. They make you forget, make you talk funny, make you see things that aren't there. My old grandma got all of that for free when she had a stroke.” “He's Dead! It's quite serious!” “Fanny in the flat...Nice Work” “SoopaDoopa” “Tits in a Jumper!” “Drop your weapons! You are surrounded by armed bastards!” “It's 1973, almost dinnertime. I'm 'avin 'oops!” “Trust the Gene Genie!” “I wanna hump Britt Ekland...What're we gonna do...!” “Was that 'E' and you don't know the rest?! or you going 'Eeee, I Dunno'” “Good Girl! Prostate probe and no jelly. “ “Give over, it's nothing like Spain!” “I'll come over your houses and stamp on all your toys!” “The Wizard will sort it out. It's cos of the wonderful things he does” “Cartwright can jump up and down on his knackers!” “It's not a windup love, he really thinks like this!” “Women! You can't say two words to them” “I was thinking, maybe, a Berni Inn!” “If I wanted a bollocking for drinking too much...!” “Shhhh...hear that...that's the sound of this case being closed! “Chicken!? In a basket!?” “Seems a large quantity of cocaine...” “You probably thought he kept his cock in his keks!” “The tail-end of Rays demotion speech!” “Stephen Warren is gay!?” “You're a smart boy, use your initiative!” “Don't be such a Jessie!” “I find the idea of a bird brushing her teeth...!” “Never been tempted to the Magic talcum powder?” “Make sure she's got nice tits!” “You're more likely to find an ostrich with a plum up it's arse!” “Drink this lot under the table and have a pint on the way home!” “Never be a female Prime Minister!” “Pub? Pub! pub!.....Pub!” “Thou shalt not suck off rent boys!” “The number for the special clinic is on the notice board!” “If me uncle had tits, would he be me auntie!” “Got your vicars in a twist!” “We Done?!” “Your mates got balls...If they were any bigger he'd need a wheelbarrow!” “The Ending - from 'I want to go home' to the end music.”

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  • How do I prove or disprove "god" objects are wrong?

    - by honestduane
    Problem Summary: Long story short, I inherited a code base and an development team I am not allowed to replace and the use of God Objects is a big issue. Going forward, I want to have us re-factor things but I am getting push-back from the teams who want to do everything with God Objects "because its easier" and this means I would not be allowed to re-factor. I pushed back citing my years of dev experience, that I'm the new boss who was hired to know these things, etc, and so did the third party offshore companies account sales rep, and this is now at the executive level and my meeting is tomorrow and I want to go in with a lot of technical ammo to advocate best practices because I feel it will be cheaper in the long run (And I personally feel that is what the third party is worried about) for the company. My issue is from a technical level, I know its good long term but I'm having trouble with the ultra short term and 6 months term, and while its something I "know" I cant prove it with references and cited resources outside of one person (Robert C. Martin, aka Uncle Bob), as that is what I am being asked to do as I have been told having data from one person and only one person (Robert C Martin) is not good enough of an argument. Question: What are some resources I can cite directly (Title, year published, page number, quote) by well known experts in the field that explicitly say this use of "God" Objects/Classes/Systems is bad (or good, since we are looking for the most technically valid solution)? Research I have already done: I have a number of books here and I have searched their indexes for the use of the words "god object" and "god class". I found that oddly its almost never used and the copy of the GoF book I have for example, never uses it (At least according to the index in front of me) but I have found it in 2 books per the below, but I want more I can use. I checked the Wikipedia page for "God Object" and its currently a stub with little reference links so although I personally agree with that it says, It doesn't have much I can use in an environment where personal experience is not considered valid. The book cited is also considered too old to be valid by the people I am debating these technical points with as the argument they are making is that "it was once thought to be bad but nobody could prove it, and now modern software says "god" objects are good to use". I personally believe that this statement is incorrect, but I want to prove the truth, whatever it is. In Robert C Martin's "Agile Principles, Patterns, and Practices in C#" (ISBN: 0-13-185725-8, hardcover) where on page 266 it states "Everybody knows that god classes are a bad idea. We don't want to concentrate all the intelligence of a system into a single object or a single function. One of the goals of OOD is the partitioning and distribution of behavior into many classes and many function." -- And then goes on to say sometimes its better to use God Classes anyway sometimes (Citing micro-controllers as an example). In Robert C Martin's "Clean Code: A Handbook of Agile Software Craftsmanship" page 136 (And only this page) talks about the "God class" and calls it out as a prime example of a violation of the "classes should be small" rule he uses to promote the Single Responsibility Principle" starting on on page 138. The problem I have is all my references and citations come from the same person (Robert C. Martin), and am from the same single person/source. I am being told that because he is just one guy, my desire to not use "God Classes" is invalid and not accepted as a standard best practice in the software industry. Is this true? Am I doing things wrong from a technical perspective by trying to keep to the teaching of Uncle Bob? God Objects and Object Oriented Programming and Design: The more I think of this the more I think this is more something you learn when you study OOP and its never explicitly called out; Its implicit to good design is my thinking (Feel free to correct me, please, as I want to learn), The problem is I "know" this, but but not everybody does, so in this case its not considered a valid argument because I am effectively calling it out as universal truth when in fact most people are statistically ignorant of it since statistically most people are not programmers. Conclusion: I am at a loss on what to search for to get the best additional results to cite, since they are making a technical claim and I want to know the truth and be able to prove it with citations like a real engineer/scientist, even if I am biased against god objects due to my personal experience with code that used them. Any assistance or citations would be deeply appreciated.

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  • How to Tell If Your Computer is Overheating and What to Do About It

    - by Chris Hoffman
    Heat is a computer’s enemy. Computers are designed with heat dispersion and ventilation in mind so they don’t overheat. If too much heat builds up, your computer may become unstable or suddenly shut down. The CPU and graphics card produce much more heat when running demanding applications. If there’s a problem with your computer’s cooling system, an excess of heat could even physically damage its components. Is Your Computer Overheating? When using a typical computer in a typical way, you shouldn’t have to worry about overheating at all. However, if you’re encountering system instability issues like abrupt shut downs, blue screens, and freezes — especially while doing something demanding like playing PC games or encoding video — your computer may be overheating. This can happen for several reasons. Your computer’s case may be full of dust, a fan may have failed, something may be blocking your computer’s vents, or you may have a compact laptop that was never designed to run at maximum performance for hours on end. Monitoring Your Computer’s Temperature First, bear in mind that different CPUs and GPUs (graphics cards) have different optimal temperature ranges. Before getting too worried about a temperature, be sure to check your computer’s documentation — or its CPU or graphics card specifications — and ensure you know the temperature ranges your hardware can handle. You can monitor your computer’s temperatures in a variety of different ways. First, you may have a way to monitor temperature that is already built into your system. You can often view temperature values in your computer’s BIOS or UEFI settings screen. This allows you to quickly see your computer’s temperature if Windows freezes or blue screens on you — just boot the computer, enter the BIOS or UEFI screen, and check the temperatures displayed there. Note that not all BIOSes or UEFI screens will display this information, but it is very common. There are also programs that will display your computer’s temperature. Such programs just read the sensors inside your computer and show you the temperature value they report, so there are a wide variety of tools you can use for this, from the simple Speccy system information utility to an advanced tool like SpeedFan. HWMonitor also offer this feature, displaying a wide variety of sensor information. Be sure to look at your CPU and graphics card temperatures. You can also find other temperatures, such as the temperature of your hard drive, but these components will generally only overheat if it becomes extremely hot in the computer’s case. They shouldn’t generate too much heat on their own. If you think your computer may be overheating, don’t just glance as these sensors once and ignore them. Do something demanding with your computer, such as running a CPU burn-in test with Prime 95, playing a PC game, or running a graphical benchmark. Monitor the computer’s temperature while you do this, even checking a few hours later — does any component overheat after you push it hard for a while? Preventing Your Computer From Overheating If your computer is overheating, here are some things you can do about it: Dust Out Your Computer’s Case: Dust accumulates in desktop PC cases and even laptops over time, clogging fans and blocking air flow. This dust can cause ventilation problems, trapping heat and preventing your PC from cooling itself properly. Be sure to clean your computer’s case occasionally to prevent dust build-up. Unfortunately, it’s often more difficult to dust out overheating laptops. Ensure Proper Ventilation: Put the computer in a location where it can properly ventilate itself. If it’s a desktop, don’t push the case up against a wall so that the computer’s vents become blocked or leave it near a radiator or heating vent. If it’s a laptop, be careful to not block its air vents, particularly when doing something demanding. For example, putting a laptop down on a mattress, allowing it to sink in, and leaving it there can lead to overheating — especially if the laptop is doing something demanding and generating heat it can’t get rid of. Check if Fans Are Running: If you’re not sure why your computer started overheating, open its case and check that all the fans are running. It’s possible that a CPU, graphics card, or case fan failed or became unplugged, reducing air flow. Tune Up Heat Sinks: If your CPU is overheating, its heat sink may not be seated correctly or its thermal paste may be old. You may need to remove the heat sink and re-apply new thermal paste before reseating the heat sink properly. This tip applies more to tweakers, overclockers, and people who build their own PCs, especially if they may have made a mistake when originally applying the thermal paste. This is often much more difficult when it comes to laptops, which generally aren’t designed to be user-serviceable. That can lead to trouble if the laptop becomes filled with dust and needs to be cleaned out, especially if the laptop was never designed to be opened by users at all. Consult our guide to diagnosing and fixing an overheating laptop for help with cooling down a hot laptop. Overheating is a definite danger when overclocking your CPU or graphics card. Overclocking will cause your components to run hotter, and the additional heat will cause problems unless you can properly cool your components. If you’ve overclocked your hardware and it has started to overheat — well, throttle back the overclock! Image Credit: Vinni Malek on Flickr     

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  • Specs, Form and Function – What am I Missing?

    - by Barry Shulam
    0 0 1 628 3586 08041 29 8 4206 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Friday October 26th the Microsoft Surface RT arrived at the office.  I was summoned to my boss’s office for the grand unpacking.  If I had planned ahead I could have used my iPhone 4 to film the event and post it on YouTube however the desire to hold the device and turn it ON was more inviting than becoming a proxy reviewer for Engadget’s website.  1980 was the first time we had a personal computer in our house.  It was a  Kaypro computer. It weighed 29 pounds more than any persons lap could hold.  Then the term “portable computer” meant you could remove it from the building and take it else where.  Today I am typing on this entry on a Macbook Air which weighs 2.38 pounds. This morning Amazons front page main title is: “Much More for Much Less” I was born at the right time to start with the CPM operating system on the Kaypro thru the DOS, Windows, Linux, Mac OSX and mobile phone operating systems and languages.  If you are not aware Technology is moving at a rapid pace.  The New iPad (those who are keeping score – iPad4) is replacing a 7 month old machine the New iPad (iPad 3) I have used and owned many technology devices in my life.  The main point that most of the reader who are in the USA overlook is the fact that we are in the USA.  The devices we purchase have a great digital garden to support them.  The Kaypro computer had a 7-inch screen.  It was a TV tube with two colors – Black and Green.  You could see the 80-column screen flicker with characters – have you every played Pac-Man emulated on the screen with the ABC characters. Traveling across the world you will find that not all apps on your device will function as they did back home because they are not offered outside of your country of origin. I think the main question a buyer of technology should be asking is Function.  The greatest Specs with out function limit you.  The most beautiful form with out function is the same as a crystal vase on your shelf – not a good cereal bowl in the morning. Microsoft Surface RT, Amazon Kindle Fire and Apple iPad all great devices in their respective customers hands. My advice for those looking to purchase on this year:  If the device is your only technology device you buy what you WANT and LIKE. Consider this parallel universe if its not your only device?  Ever go shopping for clothing, shoes, and accessories with your wife, girlfriend, sister or mother?  If you listen carefully you will hear the little voices coming out of there heads saying:  “This goes well with that and I can use it also with that outfit” ”Do you think this clashes with that?”  “Ohh I love how that combination looks on you”.  Portable devices such as tablets and computers can offer a whole lot more when they are combined with the digital echo system you have at home and the manufacturer offers online. Pros of each Device: Microsoft Surface RT: There is a new functionality named SmartGlass which will let you share the content off your tablet to your XBOX 360.  Microsoft office is loaded on the tablet.  You can have more than one user profile on the tablet if you share it with others.   Amazon Kindle or Kindle HD: If you are an Amazon consumer with an annual Amazon Prime service you can consume videos and read books off the Amazon site.  Its the cheapest device.  Its a step up from the kindle reader in many ways.   Apple Ipad or Ipad mini: Over 270 Thousand applications.  Airplay permits you the ability to share to your TV screen. If you are a cord cutter (a person who gets their entertainment content over the web or air vs Cable Providers) the Airplay or Smart glass are a huge bonus.  iPad mini or not: The mini will fit in a purse where the larger one will not.  Its lighter which makes it nice to hold for prolonged periods.  It has an option for LTE wireless which non of the other sub 9 inch tables offer.  The screen is non retina which means the applications are smaller.  Speaking with individuals who are above 50 in age that wear glasses they retina does not make a difference for them however they prefer the larger iPad over the new mini.   Happy Shopping this Channuka Season.   The Kosher Coder.   Follow me on twitter @KosherCoder

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