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• Exchange 2003 mail non-delivery (NDR), spam activity? events 7002 & 7004

  - by HighTechGeek

  Windows Server 2003 Small Business Server SP2 Exchange Version 6.5 (Build 7638.2: Service Pack 2) This network has been neglected and has been having email problems for years and was on many blacklists. I was called in after the server eventually crashed... I got the server back up and running, but email problems persist. Outgoing mail delivery is sporadic. Sometimes the mail goes through, sometimes a delayed delivery report is generated after a day or more, and sometimes it seems to go through, but the recipient never receives it. Not sure if spammers are successfully using the server as a relay (see event entries below after turning on maximum SMTP logging)... User PCs infected with viruses and server was blacklisted on many sites (I used mxtoolbox.com) I have cleaned all the PCs and changed all passwords (including administrator) I have requested removal from all of the blacklists - most have removed the listing, some take more time. I have setup rDNS pointer records with the ISP (Comcast) - that was one reason for some of the blacklistings. I have tested that it's not an open relay using telnet as described here: www.amset.info/exchange/smtp-openrelay.asp I followed the advise of a Spamhaus & Microsoft article to enable maximum SMTP logging. http://www.spamhaus.org/faq/answers.lasso?section=isp%20spam%20issues#320 which directed me to Microsoft KB article 895853, specifically, the part 2/3 down titled: "If mail relay occurs from an account on an Exchange computer that is not configured as an open relay" . The Application Event Log is filling with this type of activity (Event ID 7002, 7002 & 3018 errors): Event Type: Error Event Source: MSExchangeTransport Event Category: SMTP Protocol Event ID: 7004 Date: 1/18/2011 Time: 7:33:29 AM User: N/A Computer: SERVER Description: This is an SMTP protocol error log for virtual server ID 1, connection #621. The remote host "212.52.84.180", responded to the SMTP command "rcpt" with "550 #5.1.0 Address rejected [email protected] ". The full command sent was "RCPT TO: ". This will probably cause the connection to fail. and this: Event Type: Warning Event Source: MSExchangeTransport Event Category: SMTP Protocol Event ID: 7002 Date: 1/18/2011 Time: 7:33:29 AM User: N/A Computer: SERVER Description: This is an SMTP protocol warning log for virtual server ID 1, connection #620. The remote host "212.52.84.170", responded to the SMTP command "rcpt" with "452 Too many recipients received this hour ". The full command sent was "RCPT TO: ". This may cause the connection to fail. or a variant of: Event Type: Warning Event Source: MSExchangeTransport Event Category: SMTP Protocol Event ID: 7002 Date: 1/18/2011 Time: 8:39:21 AM User: N/A Computer: SERVER Description: This is an SMTP protocol warning log for virtual server ID 1, connection #661. The remote host "82.57.200.133", responded to the SMTP command "rcpt" with "421 Service not available - too busy ". The full command sent was "RCPT TO: ". This may cause the connection to fail. also Event Type: Error Event Source: MSExchangeTransport Event Category: NDR Event ID: 3018 Date: 1/18/2011 Time: 9:49:37 AM User: N/A Computer: SERVER Description: A non-delivery report with a status code of 5.4.0 was generated for recipient rfc822;[email protected] (Message-ID ). Causes: This message indicates a DNS problem or an IP address configuration problem Solution: Check the DNS using nslookup or dnsq. Verify the IP address is in IPv4 literal format. Data: 0000: ef 02 04 c0 ï..À Any guidance and/or suggestions and/or tests to perform would be greatly appreciated.

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• Is it possible to command a common router without using the web interface?

  - by MDeSchaepmeester

  Some background The internet arrangement in my student home is really weird. There is one ethernet outlet and several wifi hotspots. Either way requires a login through a web site to get internet access. This is annoying as each device needs to login seperately and with a PS3 for example, it is impossible to get connected at all since the web login procedure doesn't work. Therefore I have installed a D-Link DIR-635 router which is connected to the ethernet outlet. It has DHCP enabled so it uses NAT, but whatever it is connected to also uses NAT and I've read this should not work. A fellow student tried it with an Apple Airport but that keeps giving errors related to NAT after NAT. Anyway my setup does work so bonus points if you can clarify this. I need to login to the web site I mentioned earlier with any device, after which all devices in my LAN have connectivity. This is great. Except... In short From time to time, I lose internet connectivity and my D-Link DIR-635 router needs to do a DHCP renew. I can do this via the web interface but my life would be easier if I could just run a cmd file which tells my router to do this without all the hassle. This would setup a connection to my router and execute the proper command. I have tried googling but couldn't find much helpful stuff.

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• How do bots access directories on a server that are not DocumentRoot of public IP address? How do I stop them?

  - by tmsimont

  I have a local network set up with apache2 and "named" running on OpenSuse 13.1 Linux. I used the "named" service to use my computer as a domain server. I set up my router to point to ask my computer for domain lookups, so I have a chance to have it rewrite a bunch of domains on my network to its own local IP, 192.168.0.111 This works great. I use virtual host configuration to allow various domains and subdomains (re-routed to the same IP via named) to pull up different directories in my computer. For example: <VirtualHost *:80> ServerName 192.168.0.111 ServerAlias fmb.wa.net DocumentRoot /home/work/wa.net/fmb </VirtualHost> <VirtualHost *:80> ServerName 192.168.0.111 ServerAlias postrecord.wa.net DocumentRoot /home/work/wa.net/postrecord </VirtualHost> <VirtualHost *:80> ServerName 192.168.0.111 ServerAlias cvalley.wa.net DocumentRoot /home/work/wa.net/cvalley_local </VirtualHost> This makes it possible for me to hit cvalley.wa.net from any device in my network and get the site that lives in /home/work/wa.net/cvalley_local I decided to forward port 80 to this computer, so I could share a few development sites with coworkers. I can't control which site they see with the same named service, because they'd have to use my computer as their domain name server... So I added a line like this: <VirtualHost *:80> ServerName 192.168.0.111 ServerAlias MY.IP.XXX.XX DocumentRoot /home/work/wa.net/cvalley </VirtualHost> Where "MY.IP.XXX.XX" is my public IP address. This works as expected, when you hit my IP address from a public network you see the site that lives in /home/work/wa.net/cvalley. The point of confusion that I have is that there are public IP addresses in my logs in other sites. I would have expected it to be impossible to access other sites in my network, unless the public user somehow figured out what I'm calling my ServerAliases, and is mimicing my domain set up... How can public traffic be hitting my other local sites? How can I recreate this kind of access? Here are some examples of public IP's hitting my VirtualHost sites: 162.253.66.76 - - [15/Aug/2014:19:20:47 -0600] "GET /xmlrpc.php HTTP/1.0" 404 1004 "-" "-" 162.253.66.74 - - [16/Aug/2014:10:50:28 -0600] "GET / HTTP/1.0" 200 262 "-" "masscan/1.0 (https://github.com/robertdavidgraham/masscan)" 185.4.227.194 - - [16/Aug/2014:11:16:45 -0600] "GET http://24x7-allrequestsallowed.com/?PHPSESSID=1rysxtj500143WQMVT%5E_NAZ%5BQ HTTP/1.1" 200 262 "-" "-" 101.226.254.138 - - [16/Aug/2014:13:32:14 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" 162.253.66.74 - - [16/Aug/2014:14:26:19 -0600] "GET / HTTP/1.0" 200 262 "-" "masscan/1.0 (https://github.com/robertdavidgraham/masscan)" 212.129.2.119 - - [16/Aug/2014:16:00:51 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" 91.240.163.111 - - [16/Aug/2014:18:34:32 -0600] "GET / HTTP/1.0" 200 262 "-" "masscan/1.0 (https://github.com/robertdavidgraham/masscan)" 162.253.66.74 - - [16/Aug/2014:19:02:53 -0600] "GET / HTTP/1.0" 200 262 "-" "masscan/1.0 (https://github.com/robertdavidgraham/masscan)" 122.226.223.69 - - [17/Aug/2014:05:53:09 -0600] "GET http://www.k2proxy.com//hello.html HTTP/1.1" 404 1006 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/6.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)" ::1 - - [17/Aug/2014:10:19:26 -0600] "OPTIONS * HTTP/1.0" 200 - "-" "Apache/2.4.6 (Linux/SUSE) OpenSSL/1.0.1e PHP/5.4.20 (internal dummy connection)" 162.209.65.196 - - [17/Aug/2014:15:31:53 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" 111.206.199.163 - - [18/Aug/2014:11:12:56 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" 37.187.180.168 - - [18/Aug/2014:15:40:00 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" 62.210.38.226 - - [18/Aug/2014:18:35:16 -0600] "HEAD / HTTP/1.0" 200 - "-" "-" Is there anything that I can do to reliably deny public access by default, but allow it only in one VirtualHost?

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• VM automatic provisioning advice

  - by jdgregson

  In my lab we have 24 workstations, each with five technician-maintained virtual machines set up in VMware Workstation. These provide a lot of management overhead, as we have to update them as well as the host operating systems every three months (the start of the next quarter), which adds up to 144 systems to update instead of just 24. Whenever we need to reimage the hosts, the VMs add another 130GB to each image, which is over 3TB of extra data to send over the network, and a lot more time to apply each image, and then we still have to boot all 120 VMs and assign them a unique IP Address and host names. We would like to get the VMs off the hosts and onto a server, but after looking around for a few days, I still don't know where to begin looking for a solution. There may be a better way to do this, but in my mind, the ideal solution would be to replace the VMs on the host machines with five Thin Client operating systems, each configured to connect to a server and be sent or connected to a unique virtual machine. We can't have 120 VMs running on the server all the time, so the server would have to create a copy of the VM from a template whenever a student tries to boot one, and destroy the VM after the student is finished with it. If there is another client application that has to be installed on the hosts that would be fine, the only reason I'd like to keep them in VMware Workstation is because students already know to look there for the VMs when they need to use them. What, if any, virtualization software will allow this? Is there some other solution I'm not seeing?

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• Confused Why I am getting C1010 error?

  - by bluepixel

  I have three files: Main, slist.h and slist.cpp can be seen at http://forums.devarticles.com/c-c-help-52/confused-why-i-am-getting-c2143-and-c1010-error-259574.html I'm trying to make a program where main reads the list of student names from a file (roster.txt) and inserts all the names in a list in ascending order. This is the full class roster list (notCheckedIN). From here I will read all students who have come to write the exams, each checkin will transfer their name to another list (in ascending order) called present. The final product is notCheckedIN will contain a list of all those students that did not write the exam and present will contain the list of all students who wrote the exam Main File: // Exam.cpp : Defines the entry point for the console application. #include "stdafx.h" #include "iostream" #include "iomanip" #include "fstream" #include "string" #include "slist.h" using namespace std; void OpenFile(ifstream&); void GetClassRoster(SortList&, ifstream&); void InputStuName(SortList&, SortList&); void UpdateList(SortList&, SortList&, string); void Print(SortList&, SortList&); const string END_DATA = "EndData"; int main() { ifstream roster; SortList notCheckedIn; //students present SortList present; //student absent OpenFile(roster); if(!roster) //Make sure file is opened return 1; GetClassRoster(notCheckedIn, roster); //insert the roster list into the notCheckedIn list InputStuName(present, notCheckedIn); Print(present, notCheckedIn); return 0; } void OpenFile(ifstream& roster) //Precondition: roster is pointing to file containing student anmes //Postcondition:IF file does not exist -> exit { string fileName = "roster.txt"; roster.open(fileName.c_str()); if(!roster) cout << "***ERROR CANNOT OPEN FILE :"<< fileName << "***" << endl; } void GetClassRoster(SortList& notCheckedIN, ifstream& roster) //Precondition:roster points to file containing list of student last name // && notCheckedIN is empty //Postcondition:notCheckedIN is filled with the names taken from roster.txt in ascending order { string name; roster >> name; while(roster) { notCheckedIN.Insert(name); roster >> name; } } void InputStuName(SortList& present, SortList& notCheckedIN) //Precondition: present list is empty initially and notCheckedIN list is full //Postcondition: repeated prompting to enter stuName // && notCheckedIN will delete all names found in present // && present will contain names present // && names not found in notCheckedIN will report Error { string stuName; cout << "Enter last name (Enter EndData if none to Enter): "; cin >> stuName; while(stuName!=END_DATA) { UpdateList(present, notCheckedIN, stuName); } } void UpdateList(SortList& present, SortList& notCheckedIN, string stuName) //Precondition:stuName is assigned //Postcondition:IF stuName is present, stuName is inserted in present list // && stuName is removed from the notCheckedIN list // ELSE stuName does not exist { if(notCheckedIN.isPresent(stuName)) { present.Insert(stuName); notCheckedIN.Delete(stuName); } else cout << "NAME IS NOT PRESENT" << endl; } void Print(SortList& present, SortList& notCheckedIN) //Precondition: present and notCheckedIN contains a list of student Names present/not present //Postcondition: content of present and notCheckedIN is printed { cout << "Candidates Present" << endl; present.Print(); cout << "Candidates Absent" << endl; notCheckedIN.Print(); } Header File: //Specification File: slist.h //This file gives the specifications of a list abstract data type //List items inserted will be in order //Class SortList, structured type used to represent an ADT using namespace std; const int MAX_LENGTH = 200; typedef string ItemType; //Class Object (class instance) SortList. Variable of class type. class SortList { //Class Member - components of a class, can be either data or functions public: //Constructor //Post-condition: Empty list is created SortList(); //Const member function. Compiler error occurs if any statement within tries to modify a private data bool isEmpty() const; //Post-condition: == true if list is empty // == false if list is not empty bool isFull() const; //Post-condition: == true if list is full // == false if list is full int Length() const; //Post-condition: size of list void Insert(ItemType item); //Precondition: NOT isFull() && item is assigned //Postcondition: item is in list && Length() = Length()@entry + 1 void Delete(ItemType item); //Precondition: NOT isEmpty() && item is assigned //Postcondition: // IF items is in list at entry // first occurance of item in list is removed // && Length() = Length()@entry -1; // ELSE // list is not changed bool isPresent(ItemType item) const; //Precondition: item is assigned //Postcondition: == true if item is present in list // == false if item is not present in list void Print() const; //Postcondition: All component of list have been output private: int length; ItemType data[MAX_LENGTH]; void BinSearch(ItemType, bool&, int&) const; }; Source File: //Implementation File: slist.cpp //This file gives the specifications of a list abstract data type //List items inserted will be in order //Class SortList, structured type used to represent an ADT #include "iostream" #include "slist.h" using namespace std; // int length; // ItemType data[MAX_SIZE]; //Class Object (class instance) SortList. Variable of class type. SortList::SortList() //Constructor //Post-condition: Empty list is created { length=0; } //Const member function. Compiler error occurs if any statement within tries to modify a private data bool SortList::isEmpty() const //Post-condition: == true if list is empty // == false if list is not empty { return(length==0); } bool SortList::isFull() const //Post-condition: == true if list is full // == false if list is full { return (length==(MAX_LENGTH-1)); } int SortList::Length() const //Post-condition: size of list { return length; } void SortList::Insert(ItemType item) //Precondition: NOT isFull() && item is assigned //Postcondition: item is in list && Length() = Length()@entry + 1 // && list componenet are in ascending order of value { int index; index = length -1; while(index >=0 && item<data[index]) { data[index+1]=data[index]; index--; } data[index+1]=item; length++; } void SortList:elete(ItemType item) //Precondition: NOT isEmpty() && item is assigned //Postcondition: // IF items is in list at entry // first occurance of item in list is removed // && Length() = Length()@entry -1; // && list components are in ascending order // ELSE data array is unchanged { bool found; int position; BinSearch(item,found,position); if (found) { for(int index = position; index < length; index++) data[index]=data[index+1]; length--; } } bool SortList::isPresent(ItemType item) const //Precondition: item is assigned && length <= MAX_LENGTH && items are in ascending order //Postcondition: true if item is found in the list // false if item is not found in the list { bool found; int position; BinSearch(item,found,position); return (found); } void SortList::Print() const //Postcondition: All component of list have been output { for(int x= 0; x<length; x++) cout << data[x] << endl; } void SortList::BinSearch(ItemType item, bool found, int position) const //Precondition: item contains item to be found // && item in the list is an ascending order //Postcondition: IF item is in list, position is returned // ELSE item does not exist in the list { int first = 0; int last = length -1; int middle; found = false; while(!found) { middle = (first+last)/2; if(data[middle]<item) first = middle+1; else if (data[middle] > item) last = middle -1; else found = true; } if(found) position = middle; } I cannot get rid of the C1010 error: fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source? Is there a way to get rid of this error? When I included "stdafx.h" I received the following 32 errors (which does not make sense to me why because I referred back to my manual on how to use Class method - everything looks a.ok.) Error 1 error C2871: 'std' : a namespace with this name does not exist c:\..\slist.h 6 Error 2 error C2146: syntax error : missing ';' before identifier 'ItemType' c:\..\slist.h 8 Error 3 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 8 Error 4 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 8 Error 5 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 30 Error 6 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 34 Error 7 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 43 Error 8 error C2146: syntax error : missing ';' before identifier 'data' c:\..\slist.h 52 Error 9 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 52 Error 10 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int c:\..\slist.h 52 Error 11 error C2061: syntax error : identifier 'ItemType' c:\..\slist.h 53 Error 12 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 41 Error 13 error C2761: 'void SortList::Insert(void)' : member function redeclaration not allowed c:\..\slist.cpp 41 Error 14 error C2059: syntax error : ')' c:\..\slist.cpp 41 Error 15 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 45 Error 16 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 45 Error 17 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 57 Error 18 error C2761: 'void SortList:elete(void)' : member function redeclaration not allowed c:\..\slist.cpp 57 Error 19 error C2059: syntax error : ')' c:\..\slist.cpp 57 Error 20 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 65 Error 21 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 65 Error 22 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 79 Error 23 error C2761: 'bool SortList::isPresent(void) const' : member function redeclaration not allowed c:\..\slist.cpp 79 Error 24 error C2059: syntax error : ')' c:\..\slist.cpp 79 Error 25 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 83 Error 26 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 83 Error 27 error C2065: 'data' : undeclared identifier c:\..\slist.cpp 95 Error 28 error C2146: syntax error : missing ')' before identifier 'item' c:\..\slist.cpp 98 Error 29 error C2761: 'void SortList::BinSearch(void) const' : member function redeclaration not allowed c:\..\slist.cpp 98 Error 30 error C2059: syntax error : ')' c:\..\slist.cpp 98 Error 31 error C2143: syntax error : missing ';' before '{' c:\..\slist.cpp 103 Error 32 error C2447: '{' : missing function header (old-style formal list?) c:\..\slist.cpp 103

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• How to Browse Without a Trace with an Ubuntu Live CD

  - by Trevor Bekolay

  No matter how diligently you clear your cache and erase your history, web browsing leaves traces on your computer. If you need keep your browsing private, then an Ubuntu Live CD is the answer. The key to this trick is that the Live CD environment runs completely in RAM, so things like your cache, cookies, and history don’t get saved to a persistent storage location. On a hard drive, even deleted files can be recovered, but once a computer is turned off the data stored in RAM is unrecoverable. In addition, since the Ubuntu Live CD environment is the same no matter what computer you use it on, there’s very little identifying information that a website can use to track you! The first step is to either burn an Ubuntu Live CD, or prepare a non-persistent Ubuntu USB flash drive. Ubuntu treats non-persistent flash drives like CDs, so files will not be written to it, but if you’re paranoid, then using a physical CD ensures that nothing gets written to a storage device. Boot up from the CD or flash drive, and choose to Run Ubuntu from the CD or flash drive if prompted (for more detailed instructions on booting from a CD or USB drive, see this article, or our guide on booting from a flash drive even if your BIOS won’t let you). Once the graphical Ubuntu environment comes up, you can click on the Firefox icon at the top of the screen to start browsing. If your browsing requires Flash, then you can install it by clicking on System at the top-left of the screen, then Administration > Synaptic Package Manager. Click on Settings at the top of the Synaptic window, and then select Repositories. Add a check in the checkbox with the label ending in “multiverse”. Click Close. Click the Reload button in the main Synaptic window. The list of available packages will reload. When they’ve reloaded, type “restricted” in the Quick search box. Right-click on ubuntu-restricted-extras and select Mark for Installation. It will note a number of other packages that will be installed. This list includes audio and video codecs, so after installing these, you should be able to play downloaded movies and songs. Click Mark to accept the installation of these other packages. Once you return to the main Synaptic window, click the Apply button and go through the dialogs to finish the installation of Flash and the other useful packages. If you open up Firefox now, you’ll have no problems using websites that use Flash. When you’re done browsing and shut down or restart your computer, all traces of your web browsing will be gone. It’s a bit of work compared to just using a privacy-centric browser, but if it’s very important that your browsing leave no traces on your hard drive, an Ubuntu Live CD is your best bet. Download Ubuntu Similar Articles Productive Geek Tips Reset Your Ubuntu Password Easily from the Live CDAdding extra Repositories on UbuntuHow to Add a Program to the Ubuntu Startup List (After Login)How to install Spotify in Ubuntu 9.10 using WineInstalling PHP4 and Apache on Ubuntu 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 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 2010 World Cup Schedule Boot Snooze – Reboot and then Standby or Hibernate Customize Everything Related to Dates, Times, Currency and Measurement in Windows 7 Google Earth replacement Icon (Icons we like) Build Great Charts in Excel with Chart Advisor tinysong gives a shortened URL for you to post on Twitter (or anywhere)

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• SQLAuthority News – Windows Efficiency Tricks and Tips – Personal Technology Tip

  - by pinaldave

  This is the second post in my series about my favorite Technology Tips, and I wanted to focus on my favorite Microsoft product.  Choosing just one topic to cover was too hard, though.  There are so many interesting things I have to share that I am forced to turn this second installment into a five-part post.  My five favorite Windows tips and tricks. 1) You can open multiple applications using the task bar. With the new Windows 7 taskbar, you can start navigating with just one click.  For example, you can launch Word by clicking on the icon on your taskbar, and if you are using multiple different programs at the same time, you can simply click on the icon to return to Word.  However, what if you need to open another Word document, or begin a new one?  Clicking on the Word icon is just going to bring you back to your original program.  Just click on the Word icon again while holding down the shift key, and you’ll open up a new document. 2) Navigate the screen with the touch of a button – and not your mouse button. Yes, we live in a pampered age.  We have access to amazing technology, and it just gets better every year.  But have you ever found yourself wishing that right when you were in the middle of something, you didn’t have to interrupt your work flow be reaching for your mouse to navigate through the screen?  Yes, we have all been guilty of this pampered wish.  But Windows has delivered!  Now you can move your application window using your arrow keys. Lock the window to the left, right hand screen: Win+left Arrow and Win+right Arrow Maximize & minimize: Win+up arrow and Win+down arrow Minimize all items on screen: Win+M Return to your original folder, or browse through all open windows: Alt+up arrow, Alt+Left Arrow, or Alt+right arrow Close down or reopen all windows: win+home 3) Are you one of the few people who still uses Command Prompt? You know who you are, and you aren’t ashamed to still use this option that so many people have forgotten about it.  You can easily access it by holding down the shift key while RIGHT clicking on any folder. 4) Quickly select multiple files without using your mouse. We all know how to select multiple files or folders by Ctrl-clicking or Shift-clicking multiple items.  But all of us have tried this, and then accidentally released Ctrl, only to lose all our precious work.  Now there is a way to select only the files you want through a check box system.  First, go to Windows Explorer, click Organize, and then “Folder and Search Options.”  Go to the View tab, and under advanced settings, you can find a box that says “Use check boxes to select items.”  Once this has been selected, you will be able to hover your mouse over any file and a check box will appear.  This makes selecting multiple, random files quick and easy. 5) Make more out of remote access. If you work anywhere in the tech field, you are probably the go-to for computer help with friends and family, and you know the usefulness of remote access (ok, some of us use this extensively at work, as well, but we all have friends and family who rely on our skills!).  Often it is necessary to restart a computer, which is impossible in remote access as the computer will not show the shutdown menu.  To force the computer to do your wishes, we return to Command Prompt.  Open Command Prompt and type “shutdown /s” for shutdown, or “shutdown /r” for restart. I hope you will find above five tricks which I use in my daily use very important. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology Tagged: Personal Technology

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• How do you install a USB CD Rom drive?

  - by Matt Allen

  Hello, I recently purchased a USB CD ROM drive, but I don't know how to get it to work with my computer which runs Ubuntu 10.04. http://www.amazon.com/gp/product/B00303H908/ref=oss_product When I issue the lsusb command, it shows up as: Bus 002 Device 016: ID 05e3:0701 Genesys Logic, Inc. USB 2.0 IDE Adapter The computer doesn't recognize it automatically. How can I get this drive to show up as an actual drive on my computer? If this particular drive can't handle Linux, can you recommended one which can and provide a link to it so I can purchase it? Thanks! Update: I was asked by Scaine to run a command and report back with the output: joe@joe-laptop:~$ tail -f /var/log/kern.log Dec 29 12:51:35 joe-laptop kernel: [103190.551437] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.551446] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.551463] end_request: I/O error, dev sr1, sector 0 Dec 29 12:51:35 joe-laptop kernel: [103190.877542] sr 7:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 12:51:35 joe-laptop kernel: [103190.877551] sr 7:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 12:51:35 joe-laptop kernel: [103190.877559] Info fld=0x0, ILI Dec 29 12:51:35 joe-laptop kernel: [103190.877562] sr 7:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 12:51:35 joe-laptop kernel: [103190.877572] sr 7:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 12:51:35 joe-laptop kernel: [103190.877588] end_request: I/O error, dev sr1, sector 0 Dec 29 13:08:46 joe-laptop kernel: [104221.558911] usb 2-2.2: USB disconnect, address 16 Then when I plugged the drive back into the computer, I got: Dec 29 13:10:29 joe-laptop kernel: [104324.668320] usb 2-2.2: new high speed USB device using ehci_hcd and address 17 Dec 29 13:10:29 joe-laptop kernel: [104324.761702] usb 2-2.2: configuration #1 chosen from 1 choice Dec 29 13:10:29 joe-laptop kernel: [104324.762700] scsi8 : SCSI emulation for USB Mass Storage devices Dec 29 13:10:29 joe-laptop kernel: [104324.762935] usb-storage: device found at 17 Dec 29 13:10:29 joe-laptop kernel: [104324.762938] usb-storage: waiting for device to settle before scanning Dec 29 13:10:34 joe-laptop kernel: [104329.760521] usb-storage: device scan complete Dec 29 13:10:34 joe-laptop kernel: [104329.761344] scsi 8:0:0:0: CD-ROM TEAC CD-224E 1.7A PQ: 0 ANSI: 0 CCS Dec 29 13:10:34 joe-laptop kernel: [104329.767425] sr1: scsi3-mmc drive: 24x/24x cd/rw xa/form2 cdda tray Dec 29 13:10:34 joe-laptop kernel: [104329.767612] sr 8:0:0:0: Attached scsi CD-ROM sr1 Dec 29 13:10:34 joe-laptop kernel: [104329.767720] sr 8:0:0:0: Attached scsi generic sg2 type 5 Dec 29 13:10:34 joe-laptop kernel: [104330.141060] sr 8:0:0:0: [sr1] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Dec 29 13:10:34 joe-laptop kernel: [104330.141069] sr 8:0:0:0: [sr1] Sense Key : Illegal Request [current] Dec 29 13:10:34 joe-laptop kernel: [104330.141077] Info fld=0x0, ILI Dec 29 13:10:34 joe-laptop kernel: [104330.141081] sr 8:0:0:0: [sr1] Add. Sense: Illegal mode for this track Dec 29 13:10:34 joe-laptop kernel: [104330.141090] sr 8:0:0:0: [sr1] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00 Dec 29 13:10:34 joe-laptop kernel: [104330.141106] end_request: I/O error, dev sr1, sector 0 Dec 29 13:10:34 joe-laptop kernel: [104330.141113] __ratelimit: 18 callbacks suppressed There was more output than this (the number of lines started growing after the drive was plugged back in, and kept growing), but this is the first few lines.

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• Read Mobi eBooks on Kindle for PC

  - by Matthew Guay

  Do you use your PC as a eBook reader?  Kindle for PC makes it easy to read thousands of books from the Kindle Store on your computer. What you may not know is that is also works with .mobi format too, so you can increase the amount of books you can read. Amazon has jumpstarted the eBook market with their popular Kindle device.  Last fall Amazon unveiled Kindle for PC, and we reviewed how you can Read Kindle Books On Your Computer with Kindle for PC.  Whether or not you own a Kindle or other eBook reader, this is a great way to take advantage of the thousands of eBooks available from the Kindle Store today. It supports azw, prc, and tpz format, which are sold from the Kindle store, but it also supports Mobipocket (.mobi) eBooks that are not DRM protected.  Here’s how you can add them to Kindle for PC so you can easily read them on your PC Getting Started: First, make sure you have Kindle for PC (link below) installed on your computer. Sign in with your Amazon account when you first run it. Kindle for PC lets you easily read eBooks downloaded from the Kindle Store, but it doesn’t have any way to add other eBooks directly from the program. To add eBooks, you can sometimes download and double-click on the books, and they will open in Kindle for PC and be automatically added to the library.  However, this does not always seem to work. So instead, browse to your Documents folder (simply click on the Documents link on your Start menu), and double-click on the My Kindle Content folder. This folder contains all the Kindle books you have downloaded.  If you have other eBooks you would like to add to Kindle for PC, simply drag-and-drop or copy and paste them into this folder.  Here we have a .mobi formatted book downloaded from the Gutenberg Project that we’re dragging into the folder. Now, close and reopen Kindle for PC.  It should now show your new eBook right beside the eBooks you have downloaded from the Kindle Store. These eBooks work just the same as the ones downloaded from the Kindle store, and you can change font size and add bookmarks just as with other eBooks. The eBooks downloaded this way may show up with either a Amazon logo or a mobile device icon.  You should only see the mobile device icon on .mobi files formatted for mobile devices; other ones should show up with the Amazon logo.  In this screen, Pilgrim’s Progress is a standard .mobi book, The Adventures of Sherlock Holmes is a mobipocket book, and the others are downloaded from the Kindle Store. Conclusion This is a great way to read eBooks from across the internet on Kindle for PC.  Wikipedia’s Kindle page has a list of websites that offer eBooks formatted for the Kindle, so be sure to check it out for more books. Links Download Kindle for PC List of websites that offer eBooks that will work on Kindle – via Wikipedia Similar Articles Productive Geek Tips Read Kindle Books On Your Computer with Kindle for PCInstall Adobe PDF Reader on Ubuntu EdgyHow to Access your Box.Net Account from Ubuntu the Easy Way 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 New Stinger from McAfee Helps Remove ‘FakeAlert’ Threats Google Apps Marketplace: Tools & Services For Google Apps Users Get News Quick and Precise With Newser Scan for Viruses in Ubuntu using ClamAV Replace Your Windows Task Manager With System Explorer Create Talking Photos using Fotobabble

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• Laptop screen blank after login when external monitor is not connected

  - by Ramon Suarez

  Ubuntu does not switch back automatically to only monitor present when booting after disconnecting external monitor. Here's a video showing what happens. I get to the login window and everything looks ok, then I type my password, the desktop image shows up and... everything goes blank. It does not happen when I just login as a guest. When possible I work with my laptop connected to an external screen via the VGA port. The problem comes when I boot the computer without that secondary screen connected: The login screen comes out ok. After login the screen goes black, but I can hear the login sound. If I hit ctr + alt + backwards-delete and login again sometimes it is fixed, but not all. If I log in as a different user everything is OK. Then I log in as my user and sometimes it works. To have a screen I have to plug a monitor. Although I have turned on the laptop display with that monitor on, if I reboot it goes blank again after login, even if I turn off the external monitor before turning off the computer. I've managed to get my screen back with my username after going into recovery mode, but only sometimes. Failsafe would not load after second screen asking me what I wanted to do (no mouse to click nor keyboard working). My computer is a LDLC Aurore BB1-i5 -8 -S1. Which is the configuration file that keeps the information about the monitors using Displays under lightgdm and where is it? I guess if I could edit it I may have a chance :) One of the things I tried following a solution in another post was removing my monitors.xml file, but it does not work and I don't know how to create a good one that I could use now. When doing DISPLAY=:0 xrandrI get: Screen 0: minimum 320 x 200, current 320 x 200, maximum 8192 x 8192 LVDS1 connected (normal left inverted right x axis y axis) 1366x768 60.0 + 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) DP1 disconnected (normal left inverted right x axis y axis) This is the full dmesg after activating sudo xdiagnoseas Bryce sugested. (If you tell me the relevant parts I will paste them here) When conecting the external monitor, only the external will work, although I can see using Displays that the computer thinks that both are working. I've asked the question in Launchpad but have it keeps on expiring without any feedback. In my opinion Ubuntu should be able to detect automatically that there is no external monitor present and switch to the laptop monitor. There's a similar question here, but it does not apply to my case External monitor set as primary even when disconnected from laptop Update: For clarification, the problem happens only with my user and once I log in. I even get to see the screensaver for about a second, and then it goes blank. Tried Bryce's example (see his answer below), but it did not work. This is the info I get from tty1 with Display=:0 xrandr: – Ramon Suarez Jul 9 at 16:36 Screen 0: minimum 320 x 200, current 320 x 200, maximum 8192 x 8192 LVDS1 connected (normal left inverted right x axis y axis) 1366x768 60.0 + 1360x768 59.8 60.0 1024x768 60.0 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) HDMI1 disconnected (normal left inverted right x axis y axis) DP1 disconnected (normal left inverted right x axis y axis)

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• Ubuntu 12.04 Bootloader failed to install

  - by Chris

  Sorry about the excessively long question, but I figured giving more information would be better. I recently bought a new desktop for myself, running Windows 7. It has two hard drives, and I wanted to install Ubuntu on a small partition on the second hard drive. I created 25GB "free space" in Windows and ran a LiveCD install. I wanted to select the install options myself but accidentally selected "Install alongside Windows 7," but it seemed to pick up the free space and installed itself there as I wanted it to. However, I was told that the bootloader installation had failed. I chose to "Cancel installation," leaving my computer unable to boot. I wiped my computer and reinstalled Windows. After that, I tried installing Ubuntu through Windows using WUBI, once using files from my LiveCD and once downloading everything again. Both times the install succeeded, but both times when I restarted and tried to load Ubuntu, it gave me an error - wubildr.mbr was corrupt or missing. I checked in Windows - it was indeed present on the C:\ drive. I went back to the LiveCD installation, this time going the custom options route. I assigned 16GB to an Ext4 journaling file system and 10GB to a swap file. I got the same bootloader error as before. Being prompted to select a different partition to install the bootloader to, I first tried the partition Ubuntu was installed on. A window came up saying that the install had succeeded, but a second window gave me the same error and choices as before. I went through every single option it gave me, including the Windows partition and the hard drives themselves (dev/sda, dev/sdb). Same result. I then chose to not install a bootloader. Windows still works fine, and I assume Ubuntu has installed but is unbootable. Knowing that my computer could potentially brick itself again - and, this time around, with a lot of data to lose and hassle to go through if I mess it up - I really don't want to do anything without some advice. So I'll ask this: a) Why did the bootloader fail to install? Can I fix the error and install Ubuntu fresh? b) Is there any way to get around the error, install the bootloader, and point it towards an existing installation of Ubuntu? c) Is there a quicker and easier solution I might have missed? EDIT: Thanks for the tip, AthloX. After testing the liveCD in Virtualbox with no installation problems, I looked around for some alternate bootloaders but had no success. I attempted another install, which installed the bootloader and Ubuntu just fine but bricked Windows 7. I wiped both hard disks clean, including some "System Reserved" partitions I hadn't noticed before, before re-installing Windows 7 on one hard drive and immediately afterwards installing Ubuntu on the other. Now the computer boots into Windows, but I can pop into the BIOS at startup to boot into Ubunbtu via it's bootloader, and I'm guessing it'll only take a bit of poking at the BIOS to swap the load order. Many thanks!

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• Ubuntu 13.04 installation issues: unable to handle kernel paging request error

  - by user173944

  I wish I could say that I’ve done more for the Linux community as of recent but I am very VERY new to all of this and I feel very much in over my head. I figured I would install Ubuntu. on my computer and then I would learn and contribute to the community simultaneously. I will try to be as detailed as I can, please ask questions if you need clarification. I installed Ubuntu. 13.04 (64-bit) on my dell Inspiron 1501. This has an AMD Turion 64-bit TL-56 1.8 Ghz mobile processor. It is a dual core. It has an ATI Radeon Xpress 1150 chipset in it as well. As of right now I only have a total of 2Ghz ram, however I was planning on upgrading that in the near future so I opted for the 64-bit Ubuntu. 13.04. I first tried the live CD and everything seemed to be functioning correctly other than the wireless (but that's not the issue at hand, there are plenty of guides on the internet on how to get that functioning). The internet worked just fine when it was plugged in so no issues there. However, once I went from that to installing 13.04 (just 13.04, no dual partitioning... I want this computer to run strictly Ubuntu.) it did not work. It took me into a shell that I could not type anything into. In this shell it said Bug: unable to handle kernel paging and then it called a bunch of traces and froze up. I had to hard reset the laptop. I tried the boot-repair program multiple times with many different settings and typically after starting up the laptop would say something along the lines of recursive errors. will attempt to fix and then it would attempt to fix a couple of things, and then the computer would freeze up after the text said end trace... so I had to hard reset it again. I'm not an impatient person either, when I say it would freeze up it would be for a period of at least 15 minutes each time before I decided to hard reset. I attempted to install 12.10 on it instead and I got the same exact message, and when I ran boot-repair it did the same exact thing as before. I am currently in the process of running memtest64+ on the computer's memory, though I really don't believe that, nor any of the hardware is at fault due to the fact that it was still running windows vista perfectly when I had decided to switch over to Ubuntu. so far the memtest has came back just fine without any errors, but I’ve only been running it for approximately an hour. So this is the situation I’m in. I did notice when I was using the live disk that the video driver needed updated so I performed that, though I’m fairly certain that has nothing to do with this. I have also attempted (though I’m not certain that my attempt was successful in accomplishing what I had planned) to manually edit the grub settings by making acpi=0 along top of adding nomodeset to the boot commands. Like I said, I’m not sure I did that correctly though, but I’m fairly certain I did. If anyone needs any more information I will be more than happy to provide it, I will post back once I get the full results of the memtest. I very much appreciate any ideas anyone else has, I’ve been at this for a few days to no avail... thank you

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• Slow Ubuntu 10.04 after long time unused

  - by Winston Ewert

  I'm at spring break so I'm back at my parent's house. I've turned my computer on which has been off since January and its unusably slow. This was not the case when I last used the computer in January. It is running 10.04, Memory: 875.5 MB CPU: AMD Athlon 64 X2 Dual Core Processor 4400+ Available Disk Space: 330.8 GB I'm not seeing a large usage of either memory or Disk I/O. If I look at my list of processes there is only a very small amount of CPU usage. However, if I hover over the CPU usage graph that I've on the top bar, I sometimes get really high readings like 100%. It took a long time to boot, to open firefox, to open a link in firefox. As far as I can tell everything that the computer tries to do is just massively slow. Right now, I'm apt-get dist-upgrading to install any updates that I will have missed since last time this computer was on. Any ideas as to what is going on here? UPDATE: I thought to check dmesg and it has a lot of entries like this: [ 1870.142201] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1870.142206] ata3.00: irq_stat 0x40000008 [ 1870.142210] ata3.00: failed command: READ FPDMA QUEUED [ 1870.142217] ata3.00: cmd 60/08:10:c0:4a:65/00:00:03:00:00/40 tag 2 ncq 4096 in [ 1870.142218] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1870.142221] ata3.00: status: { DRDY ERR } [ 1870.142223] ata3.00: error: { UNC } [ 1870.143981] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1870.146758] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1870.146761] ata3.00: configured for UDMA/133 [ 1870.146777] ata3: EH complete [ 1872.092269] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1872.092274] ata3.00: irq_stat 0x40000008 [ 1872.092278] ata3.00: failed command: READ FPDMA QUEUED [ 1872.092285] ata3.00: cmd 60/08:00:c0:4a:65/00:00:03:00:00/40 tag 0 ncq 4096 in [ 1872.092287] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1872.092289] ata3.00: status: { DRDY ERR } [ 1872.092292] ata3.00: error: { UNC } [ 1872.094050] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1872.096795] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1872.096798] ata3.00: configured for UDMA/133 [ 1872.096814] ata3: EH complete [ 1874.042279] ata3.00: exception Emask 0x0 SAct 0x7 SErr 0x0 action 0x0 [ 1874.042285] ata3.00: irq_stat 0x40000008 [ 1874.042289] ata3.00: failed command: READ FPDMA QUEUED [ 1874.042296] ata3.00: cmd 60/08:10:c0:4a:65/00:00:03:00:00/40 tag 2 ncq 4096 in [ 1874.042297] res 41/40:00:c5:4a:65/00:00:03:00:00/40 Emask 0x409 (media error) <F> [ 1874.042300] ata3.00: status: { DRDY ERR } [ 1874.042302] ata3.00: error: { UNC } [ 1874.044048] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1874.046837] ata3.00: SB600 AHCI: limiting to 255 sectors per cmd [ 1874.046840] ata3.00: configured for UDMA/133 [ 1874.046861] sd 2:0:0:0: [sda] Unhandled sense code [ 1874.046863] sd 2:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 1874.046867] sd 2:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor] [ 1874.046872] Descriptor sense data with sense descriptors (in hex): [ 1874.046874] 72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00 [ 1874.046883] 03 65 4a c5 [ 1874.046886] sd 2:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed [ 1874.046892] sd 2:0:0:0: [sda] CDB: Read(10): 28 00 03 65 4a c0 00 00 08 00 [ 1874.046900] end_request: I/O error, dev sda, sector 56969925 [ 1874.046920] ata3: EH complete I'm not certain, but that looks like my problem may be a failing hard drive. But the drive is less then a year old, it really shouldn't be failing now...

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• Communication between state machines with hidden transitions

  - by slartibartfast

  The question emerged for me in embedded programming but I think it can be applied to quite a number of general networking situations e.g. when a communication partner fails. Assume we have an application logic (a program) running on a computer and a gadget connected to that computer via e.g. a serial interface like RS232. The gadget has a red/green/blue LED and a button which disables the LED. The LEDs color can be driven by software commands over the serial interface and the state (red/green/blue/off) is read back and causes a reaction in the application logic. Asynchronous behaviour of the application logic with regard to the LED color down to a certain delay (depending on the execution cycle of the application) is tolerated. What we essentially have is a resource (the LED) which can not be reserved and handled atomically by software because the (organic) user can at any time press the button to interfere/break the software attempt to switch the LED color. Stripping this example from its physical outfit I dare to say that we have two communicating state machines A (application logic) and G (gadget) where G executes state changes unbeknownst to A (and also the other way round, but this is not significant in our example) and only A can be modified at a reasonable price. A needs to see the reaction and state of G in one piece of information which may be (slightly) outdated but not inconsistent with respect to the short time window when this information was generated on the side of G. What I am looking for is a concise method to handle such a situation in embedded software (i.e. no layer/framework like CORBA etc. available). A programming technique which is able to map the complete behaviour of both participants on classical interfaces of a classical programming language (C in this case). To complicate matters (or rather, to generalize), a simple high frequency communication cycle of A to G and back (IOW: A is rapidly polling G) is out of focus because of technical restrictions (delay of serial com, A not always active, etc.). What I currently see as a general solution is: the application logic A as one thread of execution an adapter object (proxy) PG (presenting G inside the computer), together with the serial driver as another thread a communication object between the two (A and PG) which is transactionally safe to exchange The two execution contexts (threads) on the computer may be multi-core or just interrupt driven or tasks in an RTOS. The com object contains the following data: suspected state (written by A): effectively a member of the power set of states in G (in our case: red, green, blue, off, red_or_green, red_or_blue, red_or_off...etc.) command data (written by A): test_if_off, switch_to_red, switch_to_green, switch_to_blue operation status (written by PG): operation_pending, success, wrong_state, link_broken new state (written by PG): red, green, blue, off The idea of the com object is that A writes whichever (set of) state it thinks G is in, together with a command. (Example: suspected state="red_or_green", command: "switch_to_blue") Notice that the commands issued by A will not work if the user has switched off the LED and A needs to know this. PG will pick up such a com object and try to send the command to G, receive its answer (or a timeout) and set the operation status and new state accordingly. A will take back the oject once it is no longer at operation_pending and can react to the outcome. The com object could be separated of course (into two objects, one for each direction) but I think it is convenient in nearly all instances to have the command close to the result. I would like to have major flaws pointed out or hear an entirely different view on such a situation.

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• Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

  - by Mike

  EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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• Creating a CD-burning feature for a music player based on Java

  - by jjanggoo

  Hi, I'm trying to create a CD-burning feature for a Java-based music player for my school project. Since I'm new to real-life programming (I've only learned to write codes on AP Computer Science A level), I don't know how I can apply the concepts I learned from APCS A to this task. A friend of mine who is studying computer science at graduate school told me to "look up the cd player control functions and add methods in those classes to read in data that you want to write to the CD, write it to a buffer, write everything in the buffer to the CD itself, clear the buffer and then write a new chunk of data into the buffer," but I can't quite grasp what this means, and tt's really hard to contact her right now because she's busy working on her dissertation. Can someone from this forum please guide me through & explain the general concepts? Thank you!

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• Desktop Notifications, aka Internal Alert System

  - by Refracted Paladin

  It has become apparent that where I work needs, internally, a "notification system". The issue being that we are very spread out throughout multiple buildings and the bulk of the work force regularly keeps there email closed for hours at a time. I need to create a simple way to be able to push out a message and have it "pop up" on everyones computer(or a single computer). My first thought was to write a windows service that calls a winform/wpf app that resides on each computer that simply pops up with the message. Not sure how viable an idea that is but this is just brain-storming. A different route, I thought, could be an app that resides in the systray on each computer that polls a db table and using the Query Notifications could pop up a message each time a new row is added. Then simply create an insanely basic app for writing a row to that table. So, what I am asking is if any one else has walked this path. If so, how? What things did you take into consideration? Are either of my ideas valid starting points or are "egg and my face in perfect alignment"? Is there a different way that is even simpler? Thanks

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• Best Fit Scheduling Algorithm

  - by Teegijee

  I'm writing a scheduling program with a difficult programming problem. There are several events, each with multiple meeting times. I need to find an arrangement of meeting times such that each schedule contains any given event exactly once, using one of each event's multiple meeting times. Obviously I could use brute force, but that's rarely the best solution. I'm guessing this is a relatively basic computer science problem, which I'll learn about once I am able to start taking computer science classes. In the meantime, I'd prefer any links where I could read up on this, or even just a name I could Google.

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• running bash scripts in php

  - by HDawg

  I have two computers. On the first computer I have apache running with all my web code. On the second computer I have large amounts of data stored with a retrieval script (the script usually takes hours to run). I am essentially creating a web UI to access this data without any time delay. so I call: exec("bash initial.bash"); this is a driver script that is in my Apache folder. It calls the script on the other computer. calling: ssh otherMachine temp.bash& this script invokes the data retrieval script on the second computer. If I call initial.bash in the terminal, everything works smoothly and successfully, but if I call it in my PHP file, then all my commands in initial.bash run, with the exception of ssh otherMachine temp.bash&. I put the & at the end of that, so that temp.bash will run in the background, since it does take a few hours to complete. I am not sure why the nested script is not running when invoked by Apache. Is there a better alternative than using exec or shell_exec to call a script, which ultimately calls another script. The reason I don't call a script on the second machine directly is because of the time it takes the program to run. Shell_exec does not render the php page until the script is complete.

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• can't properly shutdown ubuntu and sound problem on HP mini 311 netbook

  - by Viele

  hi, I recently bought a HP mini 311 netbook. I replaced its harddrive and installed ubuntu 10.04. Since then, I have encountered some very strange problem with its sound and shutdown/reboot. At times, when I start the computer, it will have no sound, on the GUI the sound is at max, but no sound is available. This sometimes also happen after after upgrades, hibernate, and toggling the wireless radio button. Strangely, when the sound is out the device will also refuse to be shutdown. If I shutdown the computer using the GUI, it will simply go back to the log in screen without actually shutting down. If I use "sudo shutdown 0", the computer will hang on the loading screen of the shut down process. I had to force the pc to shutdown by holding the power button down. usually (probably always) after I force a turn-off then start off again. the sound and shutdown become normal. I wonder if anyone have clues regarding to the cause of this problem. This the info about the computer: 1) installed ubuntu 10.04LTS RC, later upgraded to formal released version. 2) cat /proc/asound/version == "Advanced Linux Sound Architecture Driver Version 1.0.21." however, when doing 'alsaconf' the version displayed is 1.0.23 any help is appreciated. Thanks

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• SQL to retrieve aggregated data with computed columns

  - by Remnant

  I have a table that looks like this for about ~30 students: StudentID Course* CourseStatus 1 Math Pass 1 English Fail 1 Science Pass 2 Math Fail 2 English Pass 2 Science Fail etc. *In my actual database the 'Course' column is a CourseID e.g. (1 = Math; 2 = English etc.) which references a 'CourseName' table. I amended the table above just to make it clear the nature of the problem. I want to write a query (stored procedure) in SQL that summarises performance for a given course and returns the following: EXEC usp_GetCourseSummary 'Math' Total Students Total Pass % Pass Total Fail % Fail 25 15 60 10 40 Have been scratching my head on this one for some time. Any ideas?

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• Best Fit Scheduling Algorithim

  - by Teegijee

  I'm writing a scheduling program with a difficult programming problem. There are several events, each with multiple meeting times. I need to find an arrangement of meeting times such that each schedule contains any given event exactly once, using one of each event's multiple meeting times. Obviously I could use brute force, but that's rarely the best solution. I'm guessing this is a relatively basic computer science problem, which I'll learn about once I am able to start taking computer science classes. In the meantime, I'd prefer any links where I could read up on this, or even just a name I could Google.

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• Is it the right time to get a Master's degree?

  - by harshit

  I'm currently a software engineer in India and have been working for 3,5 years. Before recession started I decided to study further and planned for a Master of Science degree in computer science in Fall09, since I want to explore more of this field. I have got an admission in Univ of Texas @ Dallas. I am confused about whether I should go for studying at the time of recession or not and how the market will be once I graduate in 2011 Jan. Any views will be appreciated.

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• Pong: How does the paddle know where the ball will hit?

  - by Roflcoptr

  After implementing Pacman and Snake I'm implementing the next very very classic game: Pong. The implementation is really simple, but I just have one little problem remaining. When one of the paddle (I'm not sure if it is called paddle) is controlled by the computer, I have trouble to position it at the correct position. The ball has a current position, a speed (which for now is constant) and a direction angle. So I could calculate the position where it will hit the side of the computer controlled paddle. And so Icould position the paddle right there. But however in the real game, there is a probability that the computer's paddle will miss the ball. How can I implement this probability? If I only use a probability of lets say 0.5 that the computer's paddle will hit the ball, the problem is solved, but I think it isn't that simple. From the original game I think the probability depends on the distance between the current paddle position and the position the ball will hit the border. Does anybody have any hints how exactly this is calculated?

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• mysql fetch result parent id and category id by single query?

  - by Karthik

  I have the table and values like this, CREATE TABLE `category` ( `id` INT( 4 ) NOT NULL AUTO_INCREMENT PRIMARY KEY , `category` VARCHAR( 50 ) NOT NULL , `parent` INT( 4 ) NOT NULL ) INSERT INTO `category` VALUES (1, 'MCA', 9); INSERT INTO `category` VALUES (2, 'M Tech', 9); INSERT INTO `category` VALUES (3, 'B Tech', 9); INSERT INTO `category` VALUES (4, 'BioTech', 9); INSERT INTO `category` VALUES (5, 'InfoTech', 9); INSERT INTO `category` VALUES (6, 'Chemical', 10); INSERT INTO `category` VALUES (7, 'Indus', 10); INSERT INTO `category` VALUES (8, 'Physics', 10); INSERT INTO `category` VALUES (9, 'Information Science', 0); INSERT INTO `category` VALUES (10, 'Others Science', 0); I need a single query for getting the values in terms of category and subcategory. 3rd values zero as category and others are subcategory.

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