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• string s; &s+1; Legal? UB?

  - by John Dibling

  Consider the following code: #include <cstdlib> #include <iostream> #include <string> #include <vector> #include <algorithm> using namespace std; int main() { string myAry[] = { "Mary", "had", "a", "Little", "Lamb" }; const size_t numStrs = sizeof(myStr)/sizeof(myAry[0]); vector<string> myVec(&myAry[0], &myAry[numStrs]); copy( myVec.begin(), myVec.end(), ostream_iterator<string>(cout, " ")); return 0; } Of interest here is &myAry[numStrs]: numStrs is equal to 5, so &myAry[numStrs] points to something that doesn't exist; the sixth element in the array. There is another example of this in the above code: myVec.end(), which points to one-past-the-end of the vector myVec. It's perfecly legal to take the address of this element that doesn't exist. We know the size of string, so we know where the address of the 6th element of a C-style array of strings must point to. So long as we only evaluate this pointer and never dereference it, we're fine. We can even compare it to other pointers for equality. The STL does this all the time in algorithms that act on a range of iterators. The end() iterator points past the end, and the loops keep looping while a counter != end(). So now consider this: #include <cstdlib> #include <iostream> #include <string> #include <vector> #include <algorithm> using namespace std; int main() { string myStr = "Mary"; string* myPtr = &myStr; vector<string> myVec2(myPtr, &myPtr[1]); copy( myVec2.begin(), myVec2.end(), ostream_iterator<string>(cout, " ")); return 0; } Is this code legal and well-defined? It is legal and well-defined to take the address of an array element past the end, as in &myAry[numStrs], so should it be legal and well-defined to pretend that myPtr is also an array?

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• Database Schema Versioning Strategies

  - by Jack Ryan

  I work on a project that uses a reasonably large database, the live version weighing in at somewhere around 60-80GB. The live database is the only real definitive source of our schema, and because of its size duplicating this database is too slow to be done often. This means we have ended up developing our database schema in a pretty ad hoc way, using sql compare to migrate changes from dev dbs to the live system, and only wiping our dev dbs every month or two. I am hoping to get some pointers on how to improve our database development work flow so that we have a little more control. Some things to think about: Currently nobody is really in charge of the database schema, all developers can change it if they need to, though generally these decisions are talked about before they are done. There are stored procedures, functions, and views in the database. These should probably be dumped to files so they can be reloaded on every build. Schema changes should probably be checked in as scripts. We have started to do this recently. However all our scripts must then be numbered (because there may be dependencies between them), and must be re runnable (because our build script currently runs them all in order). This makes them hard to read because they are full of conditionals that check whether tables or columns already exist. This is a step that is often forgotten by developers. Getting a new database should be quick and easy. This is currently a big problem, it takes several hours to get a copy of last nights backup and restore it onto a dev machine. Some mechanism needs to be in place to allow developers to update static data. We have tables that contain data that is never updated through the application, but does potentially need to be changed when we do a new release (often this drives dropdowns). The whole thing needs to be runnable as part of a build script. Are there any tools that can be used to help to do this? Eventually I would like to be at a point where a new DB can be built from scratch without copying any data from the live system. I don't mind writing some scripts to glue all the steps together but each part should be easily editable so that we continue to use it rather than make changes directly on DBs.

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• True / false evaluation doesn't work as expected in Scheme

  - by ron

  I'm trying to compare two booleans : (if (equal? #f (string->number "123b")) "not a number" "indeed a number") When I run this in the command line of DrRacket I get "not a number" , however , when I put that piece of code in my larger code , the function doesn't return that string ("not a number") , here's the code : (define (testing x y z) (define badInput "ERROR") (if (equal? #f (string->number "123b")) "not a number" "indeed a number") (display x)) And from command line : (testing "123" 1 2) displays : 123 Why ? Furthermore , how can I return a value , whenever I choose ? Here is my "real" problem : I want to do some input check to the input of the user , but the thing is , that I want to return the error message if I need , before the code is executed , because if won't - then I would run the algorithm of my code for some incorrect input : (define (convert originalNumber s_oldBase s_newBase) (define badInput "ERROR") ; Input check - if one of the inputs is not a number then return ERROR (if (equal? #f (string->number originalNumber)) badInput) (if (equal? #f (string->number s_oldBase)) badInput) (if (equal? #f (string->number s_newBase)) badInput) (define oldBase (string->number s_oldBase)) (define newBase (string->number s_newBase)) (define outDecimal (convertIntoDecimal originalNumber oldBase)) (define result "") ; holds the new number (define remainder 0) ; remainder for each iteration (define whole 0) ; the whole number after dividing (define temp 0) (do() ((= outDecimal 0)) ; stop when the decimal value reaches 0 (set! whole (quotient outDecimal newBase)) ; calc the whole number (set! temp (* whole newBase)) (set! remainder (- outDecimal temp)) ; calc the remainder (set! result (appending result remainder)) ; append the result (set! outDecimal (+ whole 0)) ; set outDecimal = whole ) ; end of do (if (> 1 0) (string->number (list->string(reverse (string->list result))))) ) ;end of method This code won't work since it uses another method that I didn't attach to the post (but it's irrelevant to the problem . Please take a look at those three IF-s ... I want to return "ERROR" if the user put some incorrect value , for example (convert "23asb4" "b5" "9") Thanks

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• NSMutableDictionary confused over how to use keys with certain code ?

  - by Jules

  I'm getting data from a database and I need to add the string field value and the record id. However, I need this to work with some existing code... I'm replacing this (see code below) and getting data from my database. NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:path]; self.allCategories = dict; [dict release]; But needs to work with these key and value search functions. - (void)resetSearch { NSMutableDictionary *allCategoriesCopy = [self.allCategories mutableDeepCopy]; self.Categories = allCategoriesCopy; [allCategoriesCopy release]; NSMutableArray *keyArray = [[NSMutableArray alloc] init]; [keyArray addObject:UITableViewIndexSearch]; [keyArray addObjectsFromArray:[[self.allCategories allKeys] sortedArrayUsingSelector:@selector(compare:)]]; self.keys = keyArray; [keyArray release]; } . - (void)handleSearchForTerm:(NSString *)searchTerm { NSMutableArray *sectionsToRemove = [[NSMutableArray alloc] init]; [self resetSearch]; for (NSString *key in self.keys) { NSMutableArray *array = [Categories valueForKey:key]; NSMutableArray *toRemove = [[NSMutableArray alloc] init]; for (NSString *name in array) { if ([name rangeOfString:searchTerm options:NSCaseInsensitiveSearch].location == NSNotFound) [toRemove addObject:name]; } if ([array count] == [toRemove count]) [sectionsToRemove addObject:key]; [array removeObjectsInArray:toRemove]; [toRemove release]; } [self.keys removeObjectsInArray:sectionsToRemove]; [sectionsToRemove release]; [table reloadData]; } Keep getting an error from this code... NSDictionary *arrayTmp= [[NSDictionary alloc] init]; ... loop records int cid = sqlite3_column_int(statementTMP, 0); NSString *category = [[NSString alloc] initWithUTF8String:(char *)sqlite3_column_text(statementTMP, 1)]; [arrayTmp setObject:category forKey:[NSString stringWithFormat:@"%i", cid]]; Error caused by line above * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSCFString count]: unrecognized selector sent to instance 0x4d4c500' * Call stack at first throw * ... end loop self.allCategories = arrayTmp; [arrayTmp release];

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• Mutable objects and hashCode

  - by robert

  Have the following class: public class Member { private int x; private long y; private double d; public Member(int x, long y, double d) { this.x = x; this.y = y; this.d = d; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + x; result = (int) (prime * result + y); result = (int) (prime * result + Double.doubleToLongBits(d)); return result; } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj instanceof Member) { Member other = (Member) obj; return other.x == x && other.y == y && Double.compare(d, other.d) == 0; } return false; } public static void main(String[] args) { Set<Member> test = new HashSet<Member>(); Member b = new Member(1, 2, 3); test.add(b); System.out.println(b.hashCode()); b.x = 0; System.out.println(b.hashCode()); Member first = test.iterator().next(); System.out.println(test.contains(first)); System.out.println(b.equals(first)); System.out.println(test.add(first)); } } It produces the following results: 30814 29853 false true true Because the hashCode depends of the state of the object it can no longer by retrieved properly, so the check for containment fails. The HashSet in no longer working properly. A solution would be to make Member immutable, but is that the only solution? Should all classes added to HashSets be immutable? Is there any other way to handle the situation? Regards.

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• File sorting, Comparison method violates its general contract

  - by user2677383

  My file sorting comparator sometimes invoke java.lang.IllegalArgumentException in android app. I cannot figure out the reason. could you explain that? here is my code block: Comparator cc = new Comparator<File>() { @Override public int compare(File f1, File f2) { if (f1.isDirectory() && !f2.isDirectory()) { return 1; } if (f2.isDirectory() && !f1.isDirectory()) { return -1; } if ((f1.isFile() && f2.isFile()) || (f1.isDirectory() && f2.isDirectory())) { if (sort == 1) { return Util.compareFileName(f2.getName(), f1.getName()); } else if (sort == 2) { return (int) (f1.lastModified() - f2.lastModified()); } else if (sort == 3) { return (int) (f2.lastModified() - f1.lastModified()); } else if (sort == 4) { return (int) (f1.length() - f2.length()); } else if (sort == 5) { return (int) (f2.length() - f1.length()); } else return Util.compareFileName(f1.getName(), f2.getName()); } return f1.compareTo(f2); } }; Util.compareFileName is as followings: public static int compareFileName(String s1, String s2) { int thisMarker = 0; int thatMarker = 0; int s1Length = s1.length(); int s2Length = s2.length(); while (thisMarker < s1Length && thatMarker < s2Length) { String thisChunk = getChunk(s1, s1Length, thisMarker); thisMarker += thisChunk.length(); String thatChunk = getChunk(s2, s2Length, thatMarker); thatMarker += thatChunk.length(); // If both chunks contain numeric characters, sort them numerically int result = 0; if (isDigit(thisChunk.charAt(0)) && isDigit(thatChunk.charAt(0))) { // Simple chunk comparison by length. int thisChunkLength = thisChunk.length(); result = thisChunkLength - thatChunk.length(); // If equal, the first different number counts if (result == 0) { for (int i = 0; i < thisChunkLength; i++) { result = thisChunk.charAt(i) - thatChunk.charAt(i); if (result != 0) { return result; } } } } else { result = thisChunk.compareTo(thatChunk); } if (result != 0) return result; } return s1Length - s2Length; }

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• Code to generate random numbers in C++

  - by user1678927

  Basically I have to write a program to generate random numbers to simulate the rolling of a pair of dice. This program should be constructed in multiple files. The main function should be in one file, the other functions should be in a second source file, and their prototypes should be in a header file. First I write a short function that returns a random value between 1 and 6 to simulate the rolling of a single 6-sided die.Second, i write a function that pretends to roll a pair of dice by calling this function twice. My program starts by asking the user how many rolls should be made. Then I write a function to simulate rolling the dice this many times, keeping a count of exactly how many times the values 2,3,4,5,6,7,8,9,10,11,12(each number is the sum of a pair of dice) occur in an array. Later I write a function to display a small bar chart using these counts that ideally would look something like below for a sample of 144 rolls, where the number of asterisks printed corresponds to the count: 2 3 4 5 6 7 8 9 10 11 12 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Next, to see how well the random number generator is doing, I write a function to compute the average value rolled. Compare this to the ideal average of 7. Also, print out a small table showing the counts of each roll made by the program, the ideal count based on the frequencies above given the total number of rolls, and the difference between these values in separate columns. This is my incomplete code so far: "Compiler visual studio 2010" int rolling(){ //Function that returns a random value between 1 and 6 rand(unsigned(time(NULL))); int dice = 1 + (rand() %6); return dice; } int roll_dice(int num1,int num2){ //it calls 'rolling function' twice int result1,result2; num1 = rolling(); num2 = rolling(); result1 = num1; result2 = num2; return result1,result2; } int main(void){ int times,i,sum,n1,n2; int c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11;//counters for each sum printf("Please enter how many times you want to roll the dice.\n") scanf_s("%i",&times); I pretend to use counters to count each sum and store the number(the count) in an array. I know i need a loop (for) and some conditional statements (if) but m main problem is to get the values from roll_dice and store them in n1 and n2 so then i can sum them up and store the sum in 'sum'.

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• code doesnot delete specific extra files but deletes all, also no recursion for directory, help me t

  - by OM The Eternity

  I have to compare two folder structure and with reference of source folder I want to delete all the files/folders present in other destination folder which do not exist in reference source folder, how could i do this? $original = scan_dir_recursive('/var/www/html/copy2'); $mirror = scan_dir_recursive('/var/www/html/copy1'); function scan_dir_recursive($dir) { $all_paths = array(); $new_paths = scandir($dir); foreach ($new_paths as $path) { if ($path == '.' || $path == '..') { continue; } $path = $dir . DIRECTORY_SEPARATOR . $path; if (is_dir($path)) { $all_paths = array_merge($all_paths, scan_dir_recursive($path)); } else { $all_paths[] = $path; } } return $all_paths; } foreach($mirror as $mirr) { if($mirr != '.' && $mirr != '..') { if(!in_array($mirr, $original)) { unlink($mirr); // delete the file } } } The above code shows what i did.. Here My copy1 folder contains extra files than copy2 folders hence i need these extra files to be deleted. Below given output is are arrays of original Mirror and of difference of both.. Original Array ( [0] => /var/www/html/copy2/Copy (5) of New Text Document.txt [1] => /var/www/html/copy2/Copy of New Text Document.txt ) Mirror Array ( [0] => /var/www/html/copy1/Copy (2) of New Text Document.txt [1] => /var/www/html/copy1/Copy (3) of New Text Document.txt [2] => /var/www/html/copy1/Copy (5) of New Text Document.txt ) Difference Array ( [0] => /var/www/html/copy1/Copy (2) of New Text Document.txt [1] => /var/www/html/copy1/Copy (3) of New Text Document.txt [2] => /var/www/html/copy1/Copy (5) of New Text Document.txt ) when i iterate a loop to delete on difference array all files has to be deleted as per displayed output.. how can i rectify this.. the loop for deletion is given below. $dirs_to_delete = array(); foreach ($diff_path as $path) { if (is_dir($path)) { $dirs_to_delete[] = $path; } else { unlink($path); } } while ($dir = array_pop($dirs_to_delete)) { rmdir($dir); }

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• Comparator interface

  - by 1ace1

  ok I was going to edit my previous question but i wasnt sure if it was the right way to do it so i'll just give another question about Comparator, now i want to be able to sort with different ways. I have a bank checks and i want to sort with checkNumber then checkAmount i managed to do it with checkNumber but couldnt figure out how with checkAmount here is how i did it for checkNumber: import java.util.Comparator; public class Check implements Comparator { private int checkNumber; private String description; private double checkAmount; public Check() { } public Check(int newCheckNumber, double newAmountNumber) { setCheckNumber(newCheckNumber); setAmountNumber(newAmountNumber); } public String toString() { return checkNumber + "\t\t" + checkAmount; } public void setCheckNumber(int checkNumber) { this.checkNumber = checkNumber; } public int getCheckNumber() { return checkNumber; } public void setAmountNumber(double amountNumber) { this.checkAmount = amountNumber; } public double getAmountNumber() { return checkAmount; } @Override public int compare(Object obj1, Object obj2) { int value1 = ((Check) obj1).getCheckNumber(); int value2 = ((Check) obj2).getCheckNumber(); int result = 0; if (value1 > value2){ result = 1; } else if(value1 < value2){ result = -1; } return result; } } import java.util.ArrayList; import java.util.Collections; import test.CheckValue; public class TestCheck { public static void main(String[] args) { ArrayList List = new ArrayList(); List.add(new Check(445, 55.0)); List.add(new Check(101,43.12)); List.add(new Check(110,101.0)); List.add(new Check(553,300.21)); List.add(new Check(123,32.1)); Collections.sort(List, new Check()); System.out.println("Check Number - Check Amount"); for (int i = 0; i < List.size(); i++){ System.out.println(List.get(i)); } } } thank you very much in advance and please tell me if im submiting things in the wrong way.

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• Identifying if a user is in the local administrators group

  - by Adam Driscoll

  My Problem I'm using PInvoked Windows API functions to verify if a user is part of the local administrators group. I'm utilizing GetCurrentProcess, OpenProcessToken, GetTokenInformationand LookupAccountSid to verify if the user is a local admin. GetTokenInformation returns a TOKEN_GROUPS struct with an array of SID_AND_ATTRIBUTES structs. I iterate over the collection and compare the user names returned by LookupAccountSid. My problem is that, locally (or more generally on our in-house domain), this works as expected. The builtin\Administrators is located within the group membership of the current process token and my method returns true. On another domain of another developer the function returns false. The LookupAccountSid functions properly for the first 2 iterations of the TOKEN_GROUPS struct, returning None and Everyone, and then craps out complaining that "A Parameter is incorrect." What would cause only two groups to work correctly? The TOKEN_GROUPS struct indicates that there are 14 groups. I'm assuming it's the SID that is invalid. Everything that I have PInvoked I have taken from an example on the PInvoke website. The only difference is that with the LookupAccountSid I have changed the Sid parameter from a byte[] to a IntPtr because SID_AND_ATTRIBUTESis also defined with an IntPtr. Is this ok since LookupAccountSid is defined with a PSID? LookupAccountSid PInvoke [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] static extern bool LookupAccountSid( string lpSystemName, IntPtr Sid, StringBuilder lpName, ref uint cchName, StringBuilder ReferencedDomainName, ref uint cchReferencedDomainName, out SID_NAME_USE peUse); Where the code falls over for (int i = 0; i < usize; i++) { accountCount = 0; domainCount = 0; //Get Sizes LookupAccountSid(null, tokenGroups.Groups[i].SID, null, ref accountCount, null, ref domainCount, out snu); accountName2.EnsureCapacity((int) accountCount); domainName.EnsureCapacity((int) domainCount); if (!LookupAccountSid(null, tokenGroups.Groups[i].SID, accountName2, ref accountCount, domainName, ref domainCount, out snu)) { //Finds its way here after 2 iterations //But only in a different developers domain var error = Marshal.GetLastWin32Error(); _log.InfoFormat("Failed to look up SID's account name. {0}", new Win32Exception(error).Message); continue; } If more code is needed let me know. Any help would be greatly appreciated.

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• [C] Programming problem: Storing values of an array in one variable

  - by OldMacDonald

  Hello, I am trying to use md5 code to calculate checksums of file. Now the given function prints out the (previously calculated) checksum on screen, but I want to store it in a variable, to be able to compare it later on. I guess the main problem is that I want to store the content of an array in one variable. How can I manage that? Probably this is a very stupid question, but maybe somone can help. Below is the function to print out the value. I want to modify it to store the result in one variable. static void MDPrint (mdContext) MD5_CTX *mdContext; { int i; for (i = 0; i < 16; i++) { printf ("%02x", mdContext->digest[i]); } // end of for } // end of function For reasons of completeness the used struct: /* typedef a 32 bit type */ typedef unsigned long int UINT4; /* Data structure for MD5 (Message Digest) computation */ typedef struct { UINT4 i[2]; /* number of _bits_ handled mod 2^64 */ UINT4 buf[4]; /* scratch buffer */ unsigned char in[64]; /* input buffer */ unsigned char digest[16]; /* actual digest after MD5Final call */ } MD5_CTX; and the used function to calculate the checksum: static int MDFile (filename) char *filename; { FILE *inFile = fopen (filename, "rb"); MD5_CTX mdContext; int bytes; unsigned char data[1024]; if (inFile == NULL) { printf ("%s can't be opened.\n", filename); return -1; } // end of if MD5Init (&mdContext); while ((bytes = fread (data, 1, 1024, inFile)) != 0) MD5Update (&mdContext, data, bytes); MD5Final (&mdContext); MDPrint (&mdContext); printf (" %s\n", filename); fclose (inFile); return 0; }

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• Tagging the differencies in both files

  - by Hakim

  I know that comparing 2 files is a typical problem and there are many discussions on this problem. but I have a rather different problem while working with text files: I have two text files which may differ in number of lines. now I want to compare two files and find the lines which differ. after that I want to tag all the differencies in both of files. for example here are the content of my files: File1.txt: This is the first line. This line is just appeared in File1.txt. you can see this line in both files. this line is also appeared in both files. this line and, this one are mereged in File2.txt. File2.txt: This is the first line. you can see this line in both files. this line is also appeared in both files. this line and, this one are mereged in File2.txt. After processing I want both files to be like this: File1.txt: This is the first line. <Diff>This line is just appeared in File1.txt.</Diff> you can see this line in both files. this line is also appeared in both files. <Diff>this line and,</Diff> <Diff>this one are merged in File2.txt.</Diff> File1.txt: This is the first line. <Diff></Diff> you can see this line in both files. this line is also appeared in both files. <Diff>this line and, this one are mereged in File2.txt.</Diff> <Diff></Diff> How can I do this? I know that some tools such as diff could help me, but how can I convert their results in this format? Thank you in advance.

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• SSL certificates and types for securing your websites and applications

  - by Mit Naik

  Need to share few information regarding SSL certificates and there types, which SSL certificates are widely used etc. There are several SSL certificates available in the market today inorder to secure your domains, multiple subdomains, your applications and code too. Few of the details are mentioned below. CheapSSL certificates available today are Standard Rapidssl certificate, Thwate SSL 123 etc certificates which are basic level certificates. Most of these cheap SSL certificates are domain-validated only and don't provide the greatest trust for your customers. This means you shouldn't use cheap SSL certificates on e-commerce stores or other public-facing sites that require people to trust the site. EV certificates I found Geotrust Truebusinessid with EV certificate which is one of the cheapest certificate available in market today, you can also find Thwate, Versign EV version of certificates. Its designed to prevent phishing attacks better than normal SSL certificates. What makes an EV Certificate so special? An SSL Certificate Provider has to do some extensive validation to give you one including: Verifying that your organization is legally registered and active, Verifying the address and phone number of your organization, Verifying that your organization has exclusive right to use the domain specified in the EV Certificate, Verifying that the person ordering the certificate has been authorized by the organization, Verifying that your organization is not on any government blacklists. SSL WILDCARD CERTIFICATES, SSL Wildcard Certificates are big money-savers. An SSL Wildcard Certificate allows you to secure an unlimited number of first-level sub-domains on a single domain name. For example, if you need to secure the following websites: * www.yourdomain.com * secure.yourdomain.com * product.yourdomain.com * info.yourdomain.com * download.yourdomain.com * anything.yourdomain.com and all of these websites are hosted on the multiple server box, you can purchase and install one Wildcard certificate issued to *.yourdomain.com to secure all these sites. SAN CERTIFICATES, are interesting certificates and are helpfull if you want to secure multiple domains by generating single CSR and can install the same certificate on your additional sites without generating new CSRs for all the additional domains. CODE SIGNING CERTIFICATES, A code signing certificate is a file containing a digital signature that can be used to sign executables and scripts in order to verify your identity and ensure that your code has not been tampered with since it was signed. This helps your users to determine whether your software can be trusted. Scroll to the chart below to compare cheap code signing certificates. A code signing certificate allows you to sign code using a private and public key system similar to how an SSL certificate secures a website. When you request a code signing certificate, a public/private key pair is generated. The certificate authority will then issue a code signing certificate that contains the public key. A certificate for code signing needs to be signed by a trusted certificate authority so that the operating system knows that your identity has been validated. You could still use the code signing certificate to sign and distribute malicious software but you will be held legally accountable for it. You can sign many different types of code. The most common types include Windows applications such as .exe, .cab, .dll, .ocx, and .xpi files (using an Authenticode certificate), Apple applications (using an Apple code signing certificate), Microsoft Office VBA objects and macros (using a VBA code signing certificate), .jar files (using a Java code signing certificate), .air or .airi files (using an Adobe AIR certificate), and Windows Vista drivers and other kernel-mode software (using a Vista code certificate). In reality, a code signing certificate can sign almost all types of code as long as you convert the certificate to the correct format first. Also I found the below URL which provides you good suggestion regarding purchasing best SSL certificates for securing your site, as per the Financial institution, Bank, Hosting providers, ISP, Retail Merchants etc. Please vote and provide comments or any additional suggestions regarding SSL certificates.

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• Why do GPUs overheat?

  - by JAD

  About a year ago, I added a 9800GT (1 GB version) and a Corsair CX500 PSU to an HP M8000N computer. A few weeks ago, the HDD overheated and I decided to transfer the GPU & PSU to a new build, which consists of: i3 @ 3.3Ghz Gigabyte H61 Micro ATX Mobo 4GB RAM 500GB WD HDD DVD RW Drive Cooler Master Elite 430 Tower Once I had Win7 up and running, I installed all the essential drivers that came with the Gigabyte Mobo CD. However, whenever I tried installing the Graphics Media Accelerator driver, the computer would crash and enter an endless boot sequence on the next startup. I skipped installing this driver and installed the CD driver for the 9800GT, which by now is a year old. Everything was working fine, WEI rated my GPU at 6.6 graphics & aero performance. However, after updating my Nvidia drivers to the latest, the WEI dropped my rating to 3.3 for Aero, and 4.7 for graphics performance. Just to make sure that everything was ok, I ran Bad Company 2 on medium settings. The first few minutes ran just fine at a smooth framerate, so I dismissed this as Windows being Windows. About 6 hours later, I ran BC2 again. This time I averaged anywhere from 2-5 FPS. I checked the GPU temperature through GPU-Z, and it came back as 120C. The problem with this, is that the computer was on for six hours up to that point. Wouldn't the card have experienced a reactor core meltdown a lot sooner than that? Granted, the computer was "sleeping" some of the time, but still... The next day I took out a temperature gun and ran some tests. I would point the laser at a very specific area on the reverse side of the card (not the fan or "front"), and compare the temp reading with GPU-Z. After leaving the system on idle on idle for a few minutes, I ran BC2 twice. Here are the results: GPU-Z Reading / Temp Gun Reading / Time Null / 22.3°C / Comp is Off 53°C / 33.5°C / 1:49 78°C / 46°C / 1:53 - (First BC2 run; good framerate) 102°C / 64.6°C / 2:01 - (System is again on idle) 113°C / 64.8°C / 2:10 119°C / 71.8°C / 2:17 - (Second BC2 run; poor framerate) I should also mention that I also took a temp recording of another part of the GPU from 2:01-2:17. The temp in this area jumped from 75°C to 82.9°C in that time frame. This pretty much confirms that GPU-Z is reporting the temperature accurately, and the card is overheating. But I'd like to know why; the cars is doing nothing and still the temperature climbs at a steady rate. I thoroughly cleaned the GPU and PSU when I salvaged them from the old HP M8000N computer with a can of compressed air, dust cant be the issue. Similarly, the rest of the computer is brand new. I installed various Nvidia drivers, but no luck. It seems strange to me that a year-old card is suddenly failing on me; aren't they supposed to last at least two years? Could this be a driver issue? Is the motherboard faulty? Could the PSU be overfeeding the card on voltage? Neither case seems likely, as the CPU, RAM and otherwise the rest of the comp has worked flawlessly and has stayed well within respectable temp ranges (the i3 lingers around 50C, the HDD stays at 30C, so does the PSU). How can I pinpoint the issue?

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• How to export computers from Active Directory to XML using Powershell?

  - by CoDeRs

  I am trying to create a powershell scripts for Remote Desktop Connection Manager using the active directory module. My first thought was get a list of computers in AD and parse them out into XML format similar to the OU structure that is in AD. I have no problem with that, the below code will work just but not how I wanted. EG # here is a the array $OUs Americas/Canada/Canada Computers/Desktops Americas/Canada/Canada Computers/Laptops Americas/Canada/Canada Computers/Virtual Computers Americas/USA/USA Computers/Laptops Computers Disabled Accounts Domain Controllers EMEA/UK/UK Computers/Desktops EMEA/UK/UK Computers/Laptops Outside Sales and Service/Laptops Servers I wanted to have the basic XML structured like this Americas Canada Canada Computers Desktops Laptops Virtual Computers USA USA Computers Laptops Computers Disabled Accounts Domain Controllers EMEA UK UK Computers Desktops Laptops Outside Sales and Service Laptops Servers However if you run the below it does not nest the next string in the array it only restarts the from the beginning and duplicating Americas Canada Canada Computers Desktops Americas Canada Canada Computers Laptops Americas Canada Canada Computers Virtual Computers Americas USA USA Computers Laptops RDCMGenerator.ps1 #Importing Microsoft`s PowerShell-module for administering ActiveDirectory Import-Module ActiveDirectory #Initial variables $OUs = @() $RDCMVer = "2.2" $userName = "domain\username" $password = "Hashed Password+" $Path = "$env:temp\test.xml" $allComputers = Get-ADComputer -LDAPFilter "(OperatingSystem=*)" -Properties Name,Description,CanonicalName | Sort-Object CanonicalName | select Name,Description,CanonicalName $allOUObjects = $allComputers | Foreach {"$($_.CanonicalName)"} Function Initialize-XML{ ##<RDCMan schemaVersion="1"> $xmlWriter.WriteStartElement('RDCMan') $XmlWriter.WriteAttributeString('schemaVersion', '1') $xmlWriter.WriteElementString('version',$RDCMVer) $xmlWriter.WriteStartElement('file') $xmlWriter.WriteStartElement('properties') $xmlWriter.WriteElementString('name',$env:userdomain) $xmlWriter.WriteElementString('expanded','true') $xmlWriter.WriteElementString('comment','') $xmlWriter.WriteStartElement('logonCredentials') $XmlWriter.WriteAttributeString('inherit', 'None') $xmlWriter.WriteElementString('userName',$userName) $xmlWriter.WriteElementString('domain',$env:userdomain) $xmlWriter.WriteStartElement('password') $XmlWriter.WriteAttributeString('storeAsClearText', 'false') $XmlWriter.WriteRaw($password) $xmlWriter.WriteEndElement() $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('connectionSettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('gatewaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('remoteDesktop') $XmlWriter.WriteAttributeString('inherit', 'None') $xmlWriter.WriteElementString('size','1024 x 768') $xmlWriter.WriteElementString('sameSizeAsClientArea','True') $xmlWriter.WriteElementString('fullScreen','False') $xmlWriter.WriteElementString('colorDepth','32') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('localResources') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('securitySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('displaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteEndElement() } Function Create-Group ($groupName){ #Start Group $xmlWriter.WriteStartElement('properties') $xmlWriter.WriteElementString('name',$groupName) $xmlWriter.WriteElementString('expanded','true') $xmlWriter.WriteElementString('comment','') $xmlWriter.WriteStartElement('logonCredentials') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('connectionSettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('gatewaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('remoteDesktop') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('localResources') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('securitySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('displaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteEndElement() } Function Create-Server ($computerName, $computerDescription) { #Start Server $xmlWriter.WriteStartElement('server') $xmlWriter.WriteElementString('name',$computerName) $xmlWriter.WriteElementString('displayName',$computerDescription) $xmlWriter.WriteElementString('comment','') $xmlWriter.WriteStartElement('logonCredentials') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('connectionSettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('gatewaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('remoteDesktop') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('localResources') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('securitySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteStartElement('displaySettings') $XmlWriter.WriteAttributeString('inherit', 'FromParent') $xmlWriter.WriteEndElement() $xmlWriter.WriteEndElement() #Stop Server } Function Close-XML { $xmlWriter.WriteEndElement() $xmlWriter.WriteEndElement() # finalize the document: $xmlWriter.Flush() $xmlWriter.Close() notepad $path } #Strip out Domain and Computer Name from CanonicalName foreach($OU in $allOUObjects){ $newSplit = $OU.split("/") $rebildOU = "" for($i=1; $i -le ($newSplit.count - 2); $i++){ $rebildOU += $newSplit[$i] + "/" } $OUs += $rebildOU.substring(0,($rebildOU.length - 1)) } #Remove Duplicate OU's $OUs = $OUs | select -uniq #$OUs # get an XMLTextWriter to create the XML $XmlWriter = New-Object System.XMl.XmlTextWriter($Path,$UTF8) # choose a pretty formatting: $xmlWriter.Formatting = 'Indented' $xmlWriter.Indentation = 1 $XmlWriter.IndentChar = "`t" # write the header $xmlWriter.WriteStartDocument() # # 'encoding', 'utf-8' How? # # set XSL statements #Initialize Pre-Defined XML Initialize-XML ######################################################### # Start Loop for each OU-Path that has a computer in it ######################################################### foreach ($OU in $OUs){ $totalGroupName = "" #Create / Reset Total OU-Path Completed $OU.split("/") | foreach { #Split the OU-Path into individual OU's $groupName = "$_" #Current OU $totalGroupName += $groupName + "/" #Total OU-Path Completed $xmlWriter.WriteStartElement('group') #Start new XML Group Create-Group $groupName #Call function to create XML Group ################################################ # Start Loop for each Computer in $allComputers ################################################ foreach($computer in $allComputers){ $computerOU = $computer.CanonicalName #Set the computers OU-Path $OUSplit = $computerOU.split("/") #Create the Split for the OU-Path $rebiltOU = "" #Create / Reset the stripped OU-Path for($i=1; $i -le ($OUSplit.count - 2); $i++){ #Start Loop for OU-Path to strip out the Domain and Computer Name $rebiltOU += $OUSplit[$i] + "/" #Rebuild the stripped OU-Path } if ($rebiltOU -eq $totalGroupName){ #Compare the Current OU-Path with the computers stripped OU-Path $computerName = $computer.Name #Set the computer name $computerDescription = $computerName + " - " + $computer.Description #Set the computer Description Create-Server $computerName $computerDescription #Call function to create XML Server } } } ################################################### # Start Loop to close out XML Groups created above ################################################### $totalGroupName.split("/") | foreach { #Split the if ($_ -ne "" ){ $xmlWriter.WriteEndElement() #End Group } } } Close-XML

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• How to save POST&GET headers of a web page with "Wireshark"?

  - by brilliant

  Hello everybody, I've been trying to find a python code that would log in to my mail box on yahoo.com from "Google App Engine". I was given this code: import urllib, urllib2, cookielib url = "https://login.yahoo.com/config/login?" form_data = {'login' : 'my-login-here', 'passwd' : 'my-password-here'} jar = cookielib.CookieJar() opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar)) form_data = urllib.urlencode(form_data) # data returned from this pages contains redirection resp = opener.open(url, form_data) # yahoo redirects to http://my.yahoo.com, so lets go there instead resp = opener.open('http://mail.yahoo.com') print resp.read() The author of this script looked into HTML script of yahoo log-in form and came up with this script. That log-in form contains two fields, one for users' Yahoo! ID and another one is for users' password. However, when I tried this code out (substituting mu real Yahoo login for 'my-login-here' and my real password for 'my-password-here'), it just return the log-in form back to me, which means that something didn't work right. Another supporter suggested that I should send an MD5 hash of my password, rather than a plain password. He also noted that in that log-in form there are a lot other hidden fields besides login and password fields (he called them "CSRF protections") that I would also have to deal with: <input type="hidden" name=".tries" value="1"> <input type="hidden" name=".src" value="ym"> <input type="hidden" name=".md5" value=""> <input type="hidden" name=".hash" value=""> <input type="hidden" name=".js" value=""> <input type="hidden" name=".last" value=""> <input type="hidden" name="promo" value=""> <input type="hidden" name=".intl" value="us"> <input type="hidden" name=".bypass" value=""> <input type="hidden" name=".partner" value=""> <input type="hidden" name=".u" value="bd5tdpd5rf2pg"> <input type="hidden" name=".v" value="0"> <input type="hidden" name=".challenge" value="5qUiIPGVFzRZ2BHhvtdGXoehfiOj"> <input type="hidden" name=".yplus" value=""> <input type="hidden" name=".emailCode" value=""> <input type="hidden" name="pkg" value=""> <input type="hidden" name="stepid" value=""> <input type="hidden" name=".ev" value=""> <input type="hidden" name="hasMsgr" value="0"> <input type="hidden" name=".chkP" value="Y"> <input type="hidden" name=".done" value="http://mail.yahoo.com"> He said that I should do the following: Simulate normal login and save login page that I get; Save POST&GET headers with "Wireshark"; Compare login page with those headers and see what fields I need to include with my request; I really don't know how to carry out the first two of these three steps. I have just downloaded "Wireshark" and have tried capturing some packets there. However, I don't know how to "simulate normal login and save the login page". Also, I don't how to save POST$GET headers with "Wireshark". Can anyone, please, guide me through these two steps in "Wireshark"? Or at least tell me what I should start with. Thank You.

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• Performance issues when using SSD for a developer notebook (WAMP/LAMP stack)?

  - by András Szepesházi

  I'm a web application developer using my notebook as a standalone development environment (WAMP stack). I just switched from a Core2-duo Vista 32 bit notebook with 2Gb RAM and SATA HDD, to an i5-2520M Win7 64 bit with 4Gb RAM and 128 GB SDD (Corsair P3 128). My initial experience was what I expected, fast boot, quick load of all the applications (Eclipse takes now 5 seconds as opposed to 30s on my old notebook), overall great experience. Then I started to build up my development stack, both as LAMP (using VirtualBox with a debian guest) and WAMP (windows native apache + mysql + php). I wanted to compare those two. This still all worked great out, then I started to pull in my projects to these stacks. And here came the nasty surprise, one of those projects produced a lot worse response times than on my old notebook (that was true for both the VirtualBox and WAMP stack). Apache, php and mysql configurations were practically identical in all environments. I started to do a lot of benchmarking and profiling, and here is what I've found: All general benchmarks (Performance Test 7.0, HDTune Pro, wPrime2 and some more) gave a big advantage to the new notebook. Nothing surprising here. Disc specific tests showed that read/write operations peaked around 380M/160M for the SSD, and all the different sized block operations also performed very well. Started apache performance benchmarking with Apache Benchmark for a small static html file (10 concurrent threads, 500 iterations). Old notebook: min 47ms, median 111ms, max 156ms New WAMP stack: min 71ms, median 135ms, max 296ms New LAMP stack (in VirtualBox): min 6ms, median 46ms, max 175ms Right here I don't get why the native WAMP stack performed so bad, but at least the LAMP environment brought the expected speed. Apache performance measurement for non-cached php content. The php runs a loop of 1000 and generates sha1(uniqid()) inisde. Again, 10 concurrent threads, 500 iterations were used for the benchmark. Old notebook: min 0ms, median 39ms, max 218ms New WAMP stack: min 20ms, median 61ms, max 186ms New LAMP stack (in VirtualBox): min 124ms, median 704ms, max 2463ms What the hell? The new LAMP performed miserably, and even the new native WAMP was outperformed by the old notebook. php + mysql test. The test consists of connecting to a database and reading a single record form a table using INNER JOIN on 3 more (indexed) tables, repeated 100 times within a loop. Databases were identical. 10 concurrent threads, 100 iterations were used for the benchmark. Old notebook: min 1201ms, median 1734ms, max 3728ms New WAMP stack: min 367ms, median 675ms, max 1893ms New LAMP stack (in VirtualBox): min 1410ms, median 3659ms, max 5045ms And the same test with concurrency set to 1 (instead of 10): Old notebook: min 1201ms, median 1261ms, max 1357ms New WAMP stack: min 399ms, median 483ms, max 539ms New LAMP stack (in VirtualBox): min 285ms, median 348ms, max 444ms Strictly for my purposes, as I'm using a self contained development environment (= low concurrency) I could be satisfied with the second test's result. Though I have no idea why the VirtualBox environment performed so bad with higher concurrency. Finally I performed a test of including many php files. The application that I mentioned at the beginning, the one that was performing so bad, has a heavy bootstrap, loads hundreds of small library and configuration files while initializing. So this test does nothing else just includes about 100 files. Concurrency set to 1, 100 iterations: Old notebook: min 140ms, median 168ms, max 406ms New WAMP stack: min 434ms, median 488ms, max 604ms New LAMP stack (in VirtualBox): min 413ms, median 1040ms, max 1921ms Even if I consider that VirtualBox reached those files via shared folders, and that slows things down a bit, I still don't see how could the old notebook outperform so heavily both new configurations. And I think this is the real root of the slow performance, as the application uses even more includes, and the whole bootstrap will occur several times within a page request (for each ajax call, for example). To sum it up, here I am with a brand new high-performance notebook that loads the same page in 20 seconds, that my old notebook can do in 5-7 seconds. Needless to say, I'm not a very happy person right now. Why do you think I experience these poor performance values? What are my options to remedy this situation?

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• Win 7 Netbook refuses to ping JetDirect card (all other PCs work)

  - by Luke Puplett

  I have an odd thing occuring here. From a Windows 7 netbook, I cannot ping an HP printer on the network, while all other machines (Win7/Vista) can. And the netbook can also ping everything else on the LAN. Example showing that the netbook can ping 192.168.3.4 but not 3.6. C:\Users\backdoor>ping w7ue1m Pinging w7ue1m.corp.biz.co.uk [192.168.3.4] with 32 bytes of data: Reply from 192.168.3.4: bytes=32 time=7ms TTL=128 Reply from 192.168.3.4: bytes=32 time=4ms TTL=128 Reply from 192.168.3.4: bytes=32 time=2ms TTL=128 Reply from 192.168.3.4: bytes=32 time=2ms TTL=128 Ping statistics for 192.168.3.4: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 2ms, Maximum = 7ms, Average = 3ms C:\Users\backdoor>ping uktnprint1 Pinging uktnprint1.corp.biz.co.uk [192.168.3.6] with 32 bytes of data: Reply from 192.168.3.0: Destination host unreachable. Reply from 192.168.3.0: Destination host unreachable. Reply from 192.168.3.0: Destination host unreachable. Reply from 192.168.3.0: Destination host unreachable. Ping statistics for 192.168.3.6: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),`enter code here` The IPCONFIG result for the netbook is fine. IPv4 Address. . . . . . . . . . . : 192.168.3.0 Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : 192.168.1.1 Most unusual network thing I've seen in years. I must reiterate that only this netbook is having trouble pinging/printing. Thanks, Luke ** UPDATE ** Am now on a Vista box, and here's the IPCONFIG: IPv4 Address. . . . . . . . . . . : 192.168.3.3 Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : 192.168.1.1 Pinging uktnprint1.corp.biz.co.uk [192.168.3.6] with 32 bytes of data: Reply from 192.168.3.6: bytes=32 time=2ms TTL=60 Firewall is off. I'll look into the chance of an IP conflict because it's the only thing I can think of - compare arp caches of each machine. Cheers!

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• Rsyslog is not working properly, it does not log anything

  - by Victor Henriquez

  I'm running a Debian server and a couple of days ago my rsyslog started to behave very weird, the daemon is running but it doesn't seem to do anything. Many people use the system but I'm the only one with (legal) root access. I'm using the default rsyslogd configuration (if you think is relevant I'll attach it, but it's the one that comes with the package). After I rotated all the log files, they have remained empty: # ls -l /var/log/*.log -rw-r--r-- 1 root root 0 Jun 27 00:25 /var/log/alternatives.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/auth.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/daemon.log -rw-r--r-- 1 root root 0 Jun 27 00:25 /var/log/dpkg.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/kern.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/lpr.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/mail.log -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/user.log Any try to force a log writing does not have any effect: # logger hey # ls -l /var/log/messages -rw-r----- 1 root adm 0 Jun 26 13:03 /var/log/messages Lsof shows that rsyslogd does not have any log files opened: # lsof -p 1855 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME rsyslogd 1855 root cwd DIR 202,0 4096 2 / rsyslogd 1855 root rtd DIR 202,0 4096 2 / rsyslogd 1855 root txt REG 202,0 342076 21649 /usr/sbin/rsyslogd rsyslogd 1855 root mem REG 202,0 38556 32153 /lib/i386-linux-gnu/i686/cmov/libnss_nis-2.13.so rsyslogd 1855 root mem REG 202,0 79728 32165 /lib/i386-linux-gnu/i686/cmov/libnsl-2.13.so rsyslogd 1855 root mem REG 202,0 26456 32163 /lib/i386-linux-gnu/i686/cmov/libnss_compat-2.13.so rsyslogd 1855 root mem REG 202,0 297500 1061058 /usr/lib/rsyslog/imuxsock.so rsyslogd 1855 root mem REG 202,0 42628 32170 /lib/i386-linux-gnu/i686/cmov/libnss_files-2.13.so rsyslogd 1855 root mem REG 202,0 22784 1061106 /usr/lib/rsyslog/imklog.so rsyslogd 1855 root mem REG 202,0 1401000 32169 /lib/i386-linux-gnu/i686/cmov/libc-2.13.so rsyslogd 1855 root mem REG 202,0 30684 32175 /lib/i386-linux-gnu/i686/cmov/librt-2.13.so rsyslogd 1855 root mem REG 202,0 9844 32157 /lib/i386-linux-gnu/i686/cmov/libdl-2.13.so rsyslogd 1855 root mem REG 202,0 117009 32154 /lib/i386-linux-gnu/i686/cmov/libpthread-2.13.so rsyslogd 1855 root mem REG 202,0 79980 17746 /usr/lib/libz.so.1.2.3.4 rsyslogd 1855 root mem REG 202,0 18836 1061094 /usr/lib/rsyslog/lmnet.so rsyslogd 1855 root mem REG 202,0 117960 31845 /lib/i386-linux-gnu/ld-2.13.so rsyslogd 1855 root 0u unix 0xebe8e800 0t0 640 /dev/log rsyslogd 1855 root 3u FIFO 0,5 0t0 2474 /dev/xconsole rsyslogd 1855 root 4u unix 0xebe8e400 0t0 645 /var/spool/postfix/dev/log rsyslogd 1855 root 5r REG 0,3 0 4026532176 /proc/kmsg I was so frustrated that even reinstall the rsyslog package, but it still refuses to log anything: # apt-get remove --purge rsyslog # apt-get install rsyslog I thought someone had hacked the system, so run rkhunter, chkrootkit, unhide in an attempt to find hide processes / ports and nmap in a remote host to compare with the ports shown by netstat. And I know this doesn't mean anything, but all looks ok. The system also have an iptables firewall that is very restrictive with incoming / outgoing connections. This is driving me crazy, any idea what is going on here? [EDIT - disk space info] # df -h Filesystem Size Used Avail Use% Mounted on rootfs 24G 22G 629M 98% / /dev/root 24G 22G 629M 98% / devtmpfs 10M 112K 9.9M 2% /dev tmpfs 76M 48K 76M 1% /run tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 151M 40K 151M 1% /tmp tmpfs 151M 0 151M 0% /run/shm

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• Thoughts on home NAS server

  - by user826955

  I currently have a NAS with a 2x2TB HDD 1x16GB SSD layout on a mini-itx atom board. The NAS is in a Lian Li PC-Q07 case. On this system I was running freebsd 8 with a gmirror raid 1 setup, which was enough for my needs. So far I was using the NAS for: Fileserver with AFP protocol (only mac clients used) SVN server hosting all my source trees of my projects JIRA (performance was okay-ish) Timemachine backup for the macs The power consumption was about 38W, although I did not put HDDs asleep when unused (I think this is not possible in a raid setup). I liked the NAS because: the performance was good through gigabit LAN (enough for my needs) power consumption was good its a pretty small case and fits in one of my cupboards I disliked the NAS a bit because: it was a bit noisy, the Q07 case vibrated a good amount because of the HDDs. I switched the NAS off every evening I do not have a real backup of the data on the NAS, only the internal raid 1 as safety. I really dont want to loose my source trees under no circumstances, so I would really be sleeping better if I knew I had regular backups somewhere. Recently, the board seemed to have died, I can't boot anymore. Thus, I was thinking about a redesign of my NAS (I still have to find out what parts are broken, I probably need to replace the mainboard and SSD. HDDs seem to be okay). First of all, I was wondering what other users have as backup for their NAS? Are you actually using a second NAS, and regularly copying over the data to have it safe? Or is there any better solution to this? I was thinking about getting a cheap NAS like the synology DS112j with only one disk, and use rsync or something similar to regularly copy data over to the second NAS (wake the second NAS upon start, shut it down after copy). Although this approach seems somewhat weird, It would have the benefit (?) that I could use a single disk instead of raid in the main NAS, and put the disk asleep when idle, and have the NAS running 24/7 with low energy consumption (I found no way to do this with a gmirror setup). Is there any recommended backup solution for a small NAS? Then I was thinking about a different raid setup. Since I have to buy a new mainboard as well as SSD, I might as well switch over to a i3 board with more ram, and also switch to ZFS. I am not familar with ZFS, I've never used it, but I read and hear much about it. Would it be viable to set up a ZFS storage with only 2 disks? Can I easily extend this storage with more disks, once I choose to add some? I could maybe get a new case like the Fractal Design Array R2 which has more 3,5" slots. I could as well get another 2 disks, but I would prefer sticking with the existing 2 for enegery/heat/noise reasons. Should I go for a ZFS storage or stick to my gmirror setup? I would also like to keep freebsd as operating system, and also I dont need any web gui or something (that is, I dont need/want to use FreeNAS or Openfiler etc). Does anyone maybe have a sample setup in use so I can compare energy consumption/noise/software setup? Any guidance towards the NAS of my dreams (silent, low energy, safe w/ backups) much appreciated.

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• Rosewill RSV-S5 and it's transferespeeds

  - by DoomStone

  I have just bought a Rosewill RSV-S5, I have installed 5x1,5Tb Western Digital Green disks in it. After that have I created a Raid5 on them all with the software that followed with the hardware. Not the raid it self works fine, but it is SLOW, I can only obtain a maximum of 25 MB/s, and if SABnzbd+ is downloading with 5 MB/s is it having a hard time streaming a normal DIVX (700 mb) movie. Is this normal or is there something wrong? Edit: should be able to handle 3 Gbps = 384 megabytes / second Edit 2: As you can see am I only downloading with 3,76 MB/s and I'm trying to watch V s02e08 (720p), but it is completely unwatchable, as I can see 30 sec, and the it buffers for 20 sec. Edit: Other information there might be required I'm running Windows Server 2008 R2, optimized for program performance. Windows is installed on a 60GB SSD. I have a 50 Mb/s internet connection and a 1 Gb/s LAN, all connected with Cat6 Ethernet cables. The MCE is using a Gigabyte EP35C-DS3R motherboard with 2 GB DDR2 ram. Edit 3: I have used chunk sizes for 128 KB Edit 4: I found this on newegg Pros: Enclosure for 5x2TB hard drive is fine. This is basically a rebranded San Digital TR5M-B product. For support Rosewill tells you to contact San Digital. No direct support from Silicon Image for the computer raid card. Cons: Includes computer Silicon Image 3132 raid card, extremely slow raid 5 write (our tests ~10MB/s). Compare to regular internal local drive write 30-60MB/s. We basically dumped the Sil3132 card and replaced with High Point RocketRaid 622 card for extra $69.99. Note for RR622, turn off ECRC (end to end CRC check) for card to work on IBM xserver. What took 12hrs to copy now took 2-3hrs. San Digital realized the problem and has the newer model TR5M-BP TowerRaid Plus that comes with High Point RocketRaid 622 card. Rosewill should discontinue this product and go with TR5M-BP. Could not get Silicon Image raid management software to work with complicated 2008R2 server with 10 NICs, application doesn't know how to talk to localhost port with all those NICs. No updates from Silicon Image and support from San Digital ignored. Gave up on Sil3132 card. Save yourself from a lot of headaches, get the RR622 card too if you are going to buy this product. Other Thoughts: The newer model is TR5M-BP TowerRaid Plus, comes with High Point RocketRaid 622 raid card for the PC instead of Silicon Image Sil3132. According to San Digital, raid 5 performance for Sil3132 read 80MB/s write 19MB/s, and RR622 read 154MB/s write 149MB/s. Our RR622 tests gave (8TB raid 5) write ~80-110MB/s copying 40GB file took 8mins. So I have now ordered a HighPoint RocketRAID 622 2P ext SATA III and hopes that it will solve my problems.

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• Our Look at Opera 10.50 Web Browser

  - by Asian Angel

  Everyone has been talking about the newest version of Opera recently but perhaps you have not looked at it too closely yet. Today we will take a look at 10.50 and let you see what this “new browser” is all about. The New Engines Carakan JavaScript Engine: Runs web applications up to 7 times faster than its predecessor Futhark Vega Graphics Library: Enables super fast and smooth graphics on everything from tab switching to webpage animation Presto 2.5: Provides support for HTML5, CSS2.1 and the latest CSS3 standards A Look at the Features Available If you have installed or used older versions of Opera before then the default look after a clean install will probably seem rather different. The main differences in appearance are mainly located within the “glass border” areas of the browser. The “Speed Dial” setup looks and works just as well as in previous versions. You can set a favorite wallpaper or image as your background and choose the number of “dials” using the “Configure Speed Dial Command”. One of the “standout” differences is the “O Button”. All of the menus have been condensed into this single access point but it only takes a few moments to find what you are looking for. If you have used the style before in earlier versions of Opera some of the items have been moved around. For those who prefer the “Menu Bar” that can be easily restored using the “Show Menu Bar Command”. If desired you can actually “extend” the “Tab Bar” downwards to display thumbnails of your open tabs. Just use your mouse to grab the bottom of the “Tab Bar” and adjust it to suit your personal needs. The only problem with this feature is that it will quickly use up a good sized portion of your available UI and browser window space. The “Password Manager” is ready to access when needed…the background for the button will turn a shiny metallic blue when you open a webpage that you have “Login Information” saved for. One of the new features is a small “Recycle Bin Button” in the upper right corner. Clicking on this will display a list of recently closed tabs letting you have easy access to any tabs that you may have accidentally closed. This is definitely a great feature to have as an easy access button. For those who were used to how the “Zoom Feature” looked before it has a new “look” to it. Instead of the pop-up menu-type listing of “view sizes” present before you now have a slider button that you can use to adjust the zooming level. For our default setup here the “Sidebar Panels” available were: “Bookmarks, Widgets, Unite, Notes, Downloads, History, & Panels”. Additional panels such as “Links, Windows, Search, Info, etc.” are available if you want and/or need them (accessible using the “Panels Plus Sign Button”). The “Opera Link Button” makes it easy for you to synchronize your “Speed Dial, Bookmarks, Personal Bar, Custom Searches, History & Notes”. Note: “Opera Link” requires an account and can be signed up for using the link provided below. Want to share files with your family and friends? “Unite” allows you to do that and more. With “Unite” you can: “Stream Music, Show Photo Galleries, Share Files and/or Folders, & host webpages directly from your browser”. We have a more in-depth look at “Unite” in our article here. Note: Use of “Unite” requires an Opera account. Got a slow internet connection? “Opera Turbo” can help with that by running the web traffic through their “compression servers” to speed up your web browsing. Keep in mind that “Opera Turbo” will not engage if you are accessing a secure website (i.e. your bank’s website) thus preserving your security. Note: “Opera Turbo” can be set up to automatically detect slow internet connections (i.e. crowded Wi-Fi in a cafe). Opera has a built-in “Private Browsing Mode” now for those who prefer anonymous browsing and want to keep the “history records clean” on their computer. To access it go to “Tabs and windows” and select “New private tab” or “New private window” as desired. When you open your new “Private Tab or Window” you will see the following message with details on how Opera will handle browsing information and a large “door hanger symbol”. Notice that the one tab is locked into “Private Browsing Mode” while the others are still working in “Regular Browsing Mode”. Very nice! A miniature version of the “door hanger symbol” will be present on any tab that is locked into “Private Browsing Mode”. If you are using Windows 7 then you will love how things look from your “Taskbar”. Here you can see four very nice looking thumbnails for the tabs that we had open. All that you have to do is click on the desired thumbnail… The “Context Menu” looks just as lovely as the thumbnails and definitely has some terrific functionality built into it. Add Enhanced Aero Capability If you love “Aero” and want more for your new Opera install then we have the perfect theme for you. The theme’s name is Z1-AV69 and once you have downloaded it you will need to place it in the “Skins Subfolder” in Opera’s “Program Files Folder”. Note: For our example we used version 1.10 but version 2.00 is now available (link provided below). Once you have restarted Opera, go to the “O Menu” and select “Appearance”. When the “Appearance Window” opens click on “Z1-Glass Skin” and then click “OK”. All of a sudden you will have more “Aero Goodness” to enjoy. Compare this screenshot with the one at the top of this article…the only part that is not transparent now is the browser window area itself. Want even more “Aero Goodness”? Right click on the “Tab Bar” and set “Tab Bar Placement” to “Left”. Note: You can achieve the same effect by setting the “Tab Bar Placement” to “Right”. With the “Speed Dial” visible you will be able to see your wallpaper with ease. While this is obviously not for everyone it does make for a great visual trick. Portable Versions Perhaps you need this wonderful new version of Opera to go with you wherever you do during the day. Not a problem…just visit the Opera USB website to choose a version that works best for you. You can select from “Zip or Exe” setup files and if needed update an older portable version using a “Zipped Update Files Package”. If you are updating an older version keep in mind that you will need to delete the old “OperaUSB.exe. File” due to changes with the new setup files. During our tests updating older portable versions went well for the most part but we did experience a few “odd UI quirks” here and there…so we recommend setting up a clean install if possible. Conclusion The new 10.50 release is a pleasure to use and is a recommended install for your system. Whether you are considering trying Opera for the first time or have been using it for a bit we think that you will pleased with everything that the 10.50 release has to offer. For those who would like to add User Scripts to Opera be certain to look at our how-to article here. Links Download Opera 10.50 for your location (Windows) Get the latest Snapshot versions for Linux & Mac Sign up for an Opera Link account View In-Depth detail on Opera 10.50’s features Download the Z1-AV69 Aero Theme Download Portable Opera 10.50 Similar Articles Productive Geek Tips Set the Speed Dial as the Opera Startup PageSet Up User Scripts in Opera BrowserScan Files for Viruses Before You Download With Dr.WebTurn Your Computer into a File, Music, and Web Server with Opera UniteSet the Default Browser on Ubuntu From the Command Line TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier Design Your Web Pages Using the Golden Ratio Worldwide Growth of the Internet How to Find Your Mac Address Use My TextTools to Edit and Organize Text

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• Parallelism in .NET – Part 18, Task Continuations with Multiple Tasks

  - by Reed

  In my introduction to Task continuations I demonstrated how the Task class provides a more expressive alternative to traditional callbacks.  Task continuations provide a much cleaner syntax to traditional callbacks, but there are other reasons to switch to using continuations… Task continuations provide a clean syntax, and a very simple, elegant means of synchronizing asynchronous method results with the user interface.  In addition, continuations provide a very simple, elegant means of working with collections of tasks. Prior to .NET 4, working with multiple related asynchronous method calls was very tricky.  If, for example, we wanted to run two asynchronous operations, followed by a single method call which we wanted to run when the first two methods completed, we’d have to program all of the handling ourselves.  We would likely need to take some approach such as using a shared callback which synchronized against a common variable, or using a WaitHandle shared within the callbacks to allow one to wait for the second.  Although this could be accomplished easily enough, it requires manually placing this handling into every algorithm which requires this form of blocking.  This is error prone, difficult, and can easily lead to subtle bugs. Similar to how the Task class static methods providing a way to block until multiple tasks have completed, TaskFactory contains static methods which allow a continuation to be scheduled upon the completion of multiple tasks: TaskFactory.ContinueWhenAll. This allows you to easily specify a single delegate to run when a collection of tasks has completed.  For example, suppose we have a class which fetches data from the network.  This can be a long running operation, and potentially fail in certain situations, such as a server being down.  As a result, we have three separate servers which we will “query” for our information.  Now, suppose we want to grab data from all three servers, and verify that the results are the same from all three. With traditional asynchronous programming in .NET, this would require using three separate callbacks, and managing the synchronization between the various operations ourselves.  The Task and TaskFactory classes simplify this for us, allowing us to write: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAll( new[] {server1, server2, server3 }, (tasks) => { // Propogate exceptions (see below) Task.WaitAll(tasks); return this.CompareTaskResults( tasks[0].Result, tasks[1].Result, tasks[2].Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This is clean, simple, and elegant.  The one complication is the Task.WaitAll(tasks); statement. Although the continuation will not complete until all three tasks (server1, server2, and server3) have completed, there is a potential snag.  If the networkClass.GetResults method fails, and raises an exception, we want to make sure to handle it cleanly.  By using Task.WaitAll, any exceptions raised within any of our original tasks will get wrapped into a single AggregateException by the WaitAll method, providing us a simplified means of handling the exceptions.  If we wait on the continuation, we can trap this AggregateException, and handle it cleanly.  Without this line, it’s possible that an exception could remain uncaught and unhandled by a task, which later might trigger a nasty UnobservedTaskException.  This would happen any time two of our original tasks failed. Just as we can schedule a continuation to occur when an entire collection of tasks has completed, we can just as easily setup a continuation to run when any single task within a collection completes.  If, for example, we didn’t need to compare the results of all three network locations, but only use one, we could still schedule three tasks.  We could then have our completion logic work on the first task which completed, and ignore the others.  This is done via TaskFactory.ContinueWhenAny: var server1 = Task.Factory.StartNew( () => networkClass.GetResults(firstServer) ); var server2 = Task.Factory.StartNew( () => networkClass.GetResults(secondServer) ); var server3 = Task.Factory.StartNew( () => networkClass.GetResults(thirdServer) ); var result = Task.Factory.ContinueWhenAny( new[] {server1, server2, server3 }, (firstTask) => { return this.ProcessTaskResult(firstTask.Result); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, instead of working with all three tasks, we’re just using the first task which finishes.  This is very useful, as it allows us to easily work with results of multiple operations, and “throw away” the others.  However, you must take care when using ContinueWhenAny to properly handle exceptions.  At some point, you should always wait on each task (or use the Task.Result property) in order to propogate any exceptions raised from within the task.  Failing to do so can lead to an UnobservedTaskException.

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• Displaying an image on a LED matrix with a Netduino

  - by Bertrand Le Roy

  In the previous post, we’ve been flipping bits manually on three ports of the Netduino to simulate the data, clock and latch pins that a shift register expected. We did all that in order to control one line of a LED matrix and create a simple Knight Rider effect. It was rightly pointed out in the comments that the Netduino has built-in knowledge of the sort of serial protocol that this shift register understands through a feature called SPI. That will of course make our code a whole lot simpler, but it will also make it a whole lot faster: writing to the Netduino ports is actually not that fast, whereas SPI is very, very fast. Unfortunately, the Netduino documentation for SPI is severely lacking. Instead, we’ve been reliably using the documentation for the Fez, another .NET microcontroller. To send data through SPI, we’ll just need  to move a few wires around and update the code. SPI uses pin D11 for writing, pin D12 for reading (which we won’t do) and pin D13 for the clock. The latch pin is a parameter that can be set by the user. This is very close to the wiring we had before (data on D11, clock on D12 and latch on D13). We just have to move the latch from D13 to D10, and the clock from D12 to D13. The code that controls the shift register has slimmed down considerably with that change. Here is the new version, which I invite you to compare with what we had before: public class ShiftRegister74HC595 { protected SPI Spi; public ShiftRegister74HC595(Cpu.Pin latchPin) : this(latchPin, SPI.SPI_module.SPI1) { } public ShiftRegister74HC595(Cpu.Pin latchPin, SPI.SPI_module spiModule) { var spiConfig = new SPI.Configuration( SPI_mod: spiModule, ChipSelect_Port: latchPin, ChipSelect_ActiveState: false, ChipSelect_SetupTime: 0, ChipSelect_HoldTime: 0, Clock_IdleState: false, Clock_Edge: true, Clock_RateKHz: 1000 ); Spi = new SPI(spiConfig); } public void Write(byte buffer) { Spi.Write(new[] {buffer}); } } All we have to do here is configure SPI. The write method couldn’t be any simpler. Everything is now handled in hardware by the Netduino. We set the frequency to 1MHz, which is largely sufficient for what we’ll be doing, but it could potentially go much higher. The shift register addresses the columns of the matrix. The rows are directly wired to ports D0 to D7 of the Netduino. The code writes to only one of those eight lines at a time, which will make it fast enough. The way an image is displayed is that we light the lines one after the other so fast that persistence of vision will give the illusion of a stable image: foreach (var bitmap in matrix.MatrixBitmap) { matrix.OnRow(row, bitmap, true); matrix.OnRow(row, bitmap, false); row++; } Now there is a twist here: we need to run this code as fast as possible in order to display the image with as little flicker as possible, but we’ll eventually have other things to do. In other words, we need the code driving the display to run in the background, except when we want to change what’s being displayed. Fortunately, the .NET Micro Framework supports multithreading. In our implementation, we’ve added an Initialize method that spins a new thread that is tied to the specific instance of the matrix it’s being called on. public LedMatrix Initialize() { DisplayThread = new Thread(() => DoDisplay(this)); DisplayThread.Start(); return this; } I quite like this way to spin a thread. As you may know, there is another, built-in way to contextualize a thread by passing an object into the Start method. For the method to work, the thread must have been constructed with a ParameterizedThreadStart delegate, which takes one parameter of type object. I like to use object as little as possible, so instead I’m constructing a closure with a Lambda, currying it with the current instance. This way, everything remains strongly-typed and there’s no casting to do. Note that this method would extend perfectly to several parameters. Of note as well is the return value of Initialize, a common technique to add some fluency to the API and enabling the matrix to be instantiated and initialized in a single line: using (var matrix = new LedMS88SR74HC595().Initialize()) The “using” in the previous line is because we have implemented IDisposable so that the matrix kills the thread and clears the display when the user code is done with it: public void Dispose() { Clear(); DisplayThread.Abort(); } Thanks to the multi-threaded version of the matrix driver class, we can treat the display as a simple bitmap with a very synchronous programming model: matrix.Set(someimage); while (button.Read()) { Thread.Sleep(10); } Here, the call into Set returns immediately and from the moment the bitmap is set, the background display thread will constantly continue refreshing no matter what happens in the main thread. That enables us to wait or read a button’s port on the main thread knowing that the current image will continue displaying unperturbed and without requiring manual refreshing. We’ve effectively hidden the implementation of the display behind a convenient, synchronous-looking API. Pretty neat, eh? Before I wrap up this post, I want to talk about one small caveat of using SPI rather than driving the shift register directly: when we got to the point where we could actually display images, we noticed that they were a mirror image of what we were sending in. Oh noes! Well, the reason for it is that SPI is sending the bits in a big-endian fashion, in other words backwards. Now sure you could fix that in software by writing some bit-level code to reverse the bits we’re sending in, but there is a far more efficient solution than that. We are doing hardware here, so we can simply reverse the order in which the outputs of the shift register are connected to the columns of the matrix. That’s switching 8 wires around once, as compared to doing bit operations every time we send a line to display. All right, so bringing it all together, here is the code we need to write to display two images in succession, separated by a press on the board’s button: var button = new InputPort(Pins.ONBOARD_SW1, false, Port.ResistorMode.Disabled); using (var matrix = new LedMS88SR74HC595().Initialize()) { // Oh, prototype is so sad! var sad = new byte[] { 0x66, 0x24, 0x00, 0x18, 0x00, 0x3C, 0x42, 0x81 }; DisplayAndWait(sad, matrix, button); // Let's make it smile! var smile = new byte[] { 0x42, 0x18, 0x18, 0x81, 0x7E, 0x3C, 0x18, 0x00 }; DisplayAndWait(smile, matrix, button); } And here is a video of the prototype running: The prototype in action I’ve added an artificial delay between the display of each row of the matrix to clearly show what’s otherwise happening very fast. This way, you can clearly see each of the two images being displayed line by line. Next time, we’ll do no hardware changes, focusing instead on building a nice programming model for the matrix, with sprites, text and hardware scrolling. Fun stuff. By the way, can any of my reader guess where we’re going with all that? The code for this prototype can be downloaded here: http://weblogs.asp.net/blogs/bleroy/Samples/NetduinoLedMatrixDriver.zip

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• SQL SERVER – How to Recover SQL Database Data Deleted by Accident

  - by Pinal Dave

  In Repair a SQL Server database using a transaction log explorer, I showed how to use ApexSQL Log, a SQL Server transaction log viewer, to recover a SQL Server database after a disaster. In this blog, I’ll show you how to use another SQL Server disaster recovery tool from ApexSQL in a situation when data is accidentally deleted. You can download ApexSQL Recover here, install, and play along. With a good SQL Server disaster recovery strategy, data recovery is not a problem. You have a reliable full database backup with valid data, a full database backup and subsequent differential database backups, or a full database backup and a chain of transaction log backups. But not all situations are ideal. Here we’ll address some sub-optimal scenarios, where you can still successfully recover data. If you have only a full database backup This is the least optimal SQL Server disaster recovery strategy, as it doesn’t ensure minimal data loss. For example, data was deleted on Wednesday. Your last full database backup was created on Sunday, three days before the records were deleted. By using the full database backup created on Sunday, you will be able to recover SQL database records that existed in the table on Sunday. If there were any records inserted into the table on Monday or Tuesday, they will be lost forever. The same goes for records modified in this period. This method will not bring back modified records, only the old records that existed on Sunday. If you restore this full database backup, all your changes (intentional and accidental) will be lost and the database will be reverted to the state it had on Sunday. What you have to do is compare the records that were in the table on Sunday to the records on Wednesday, create a synchronization script, and execute it against the Wednesday database. If you have a full database backup followed by differential database backups Let’s say the situation is the same as in the example above, only you create a differential database backup every night. Use the full database backup created on Sunday, and the last differential database backup (created on Tuesday). In this scenario, you will lose only the data inserted and updated after the differential backup created on Tuesday. If you have a full database backup and a chain of transaction log backups This is the SQL Server disaster recovery strategy that provides minimal data loss. With a full chain of transaction logs, you can recover the SQL database to an exact point in time. To provide optimal results, you have to know exactly when the records were deleted, because restoring to a later point will not bring back the records. This method requires restoring the full database backup first. If you have any differential log backup created after the last full database backup, restore the most recent one. Then, restore transaction log backups, one by one, it the order they were created starting with the first created after the restored differential database backup. Now, the table will be in the state before the records were deleted. You have to identify the deleted records, script them and run the script against the original database. Although this method is reliable, it is time-consuming and requires a lot of space on disk. How to easily recover deleted records? The following solution enables you to recover SQL database records even if you have no full or differential database backups and no transaction log backups. To understand how ApexSQL Recover works, I’ll explain what happens when table data is deleted. Table data is stored in data pages. When you delete table records, they are not immediately deleted from the data pages, but marked to be overwritten by new records. Such records are not shown as existing anymore, but ApexSQL Recover can read them and create undo script for them. How long will deleted records stay in the MDF file? It depends on many factors, as time passes it’s less likely that the records will not be overwritten. The more transactions occur after the deletion, the more chances the records will be overwritten and permanently lost. Therefore, it’s recommended to create a copy of the database MDF and LDF files immediately (if you cannot take your database offline until the issue is solved) and run ApexSQL Recover on them. Note that a full database backup will not help here, as the records marked for overwriting are not included in the backup. First, I’ll delete some records from the Person.EmailAddress table in the AdventureWorks database.   I can delete these records in SQL Server Management Studio, or execute a script such as DELETE FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 Then, I’ll start ApexSQL Recover and select From DELETE operation in the Recovery tab.   In the Select the database to recover step, first select the SQL Server instance. If it’s not shown in the drop-down list, click the Server icon right to the Server drop-down list and browse for the SQL Server instance, or type the instance name manually. Specify the authentication type and select the database in the Database drop-down list.   In the next step, you’re prompted to add additional data sources. As this can be a tricky step, especially for new users, ApexSQL Recover offers help via the Help me decide option.   The Help me decide option guides you through a series of questions about the database transaction log and advises what files to add. If you know that you have no transaction log backups or detached transaction logs, or the online transaction log file has been truncated after the data was deleted, select No additional transaction logs are available. If you know that you have transaction log backups that contain the delete transactions you want to recover, click Add transaction logs. The online transaction log is listed and selected automatically.   Click Add if to add transaction log backups. It would be best if you have a full transaction log chain, as explained above. The next step for this option is to specify the time range.   Selecting a small time range for the time of deletion will create the recovery script just for the accidentally deleted records. A wide time range might script the records deleted on purpose, and you don’t want that. If needed, you can check the script generated and manually remove such records. After that, for all data sources options, the next step is to select the tables. Be careful here, if you deleted some data from other tables on purpose, and don’t want to recover them, don’t select all tables, as ApexSQL Recover will create the INSERT script for them too.   The next step offers two options: to create a recovery script that will insert the deleted records back into the Person.EmailAddress table, or to create a new database, create the Person.EmailAddress table in it, and insert the deleted records. I’ll select the first one.   The recovery process is completed and 11 records are found and scripted, as expected.   To see the script, click View script. ApexSQL Recover has its own script editor, where you can review, modify, and execute the recovery script. The insert into statements look like: INSERT INTO Person.EmailAddress( BusinessEntityID, EmailAddressID, EmailAddress, rowguid, ModifiedDate) VALUES( 70, 70, N'[email protected]' COLLATE SQL_Latin1_General_CP1_CI_AS, 'd62c5b4e-c91f-403f-b630-7b7e0fda70ce', '20030109 00:00:00.000' ); To execute the script, click Execute in the menu.   If you want to check whether the records are really back, execute SELECT * FROM Person.EmailAddress WHERE BusinessEntityID BETWEEN 70 AND 80 As shown, ApexSQL Recover recovers SQL database data after accidental deletes even without the database backup that contains the deleted data and relevant transaction log backups. ApexSQL Recover reads the deleted data from the database data file, so this method can be used even for databases in the Simple recovery model. Besides recovering SQL database records from a DELETE statement, ApexSQL Recover can help when the records are lost due to a DROP TABLE, or TRUNCATE statement, as well as repair a corrupted MDF file that cannot be attached to as SQL Server instance. You can find more information about how to recover SQL database lost data and repair a SQL Server database on ApexSQL Solution center. There are solutions for various situations when data needs to be recovered. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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