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  • Silverlight Goes Mobile!

    - by PeterTweed
    The most exciting announcements from Mix 2010 last week for me were the release of the Windows Phone 7 Series SDK and the news that the platform utilizes Silverlight for the application development technology. From the press and exposure that the platform is being given and the experience that is promised it looks like the Windows Phone 7 Series could eventually compete with the iPhone. For me this is exciting as Silverlight can now be used to develop RIA apps, easily deployed desktop apps and mobile apps. As someone who delivers enterprise technology solutions this equates to a whole bunch of opportunity knocking at the door and asking to join the party. Watch this space for future posts on developing apps on the Windows Phone 7 Series platform!

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  • Can't get Wireless to work! (Fujitsu siemens ESPRIMO Mobile u9200) Ubuntu 12.4

    - by Martin Oscarsson
    I can't get wireless to work on my computer. I have recently installed 12.04. Computer name: (Fujitsu siemens ESPRIMO Mobile u9200) Hardware button starts bluetooth - so can't start that way. Have searched the Internet for help but can't find any on my specific problem! State: connected (global) - Device: wlan0 ---------------------------------------------------------------- Type: 802.11 WiFi Driver: ath5k State: disconnected Default: no *-network beskrivning: Trådlöst gränssnitt produkt: AR242x / AR542x Wireless Network Adapter (PCI-Express) tillverkare: Atheros Communications Inc. *-network beskrivning: Ethernet interface produkt: 88E8055 PCI-E Gigabit Ethernet Controller tillverkare: Marvell Technology Group Ltd. HERE IS ALL THE NETWORK INFO: ellika@ellikas:~$ ifconfig eth0 Link encap:Ethernet HWaddr 00:1e:33:00:96:9a inet addr:192.168.1.26 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::21e:33ff:fe00:969a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13778 errors:0 dropped:0 overruns:0 frame:0 TX packets:9510 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:14022669 (14.0 MB) TX bytes:1001621 (1.0 MB) Interrupt:17 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1542 errors:0 dropped:0 overruns:0 frame:0 TX packets:1542 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:125040 (125.0 KB) TX bytes:125040 (125.0 KB) ellika@ellikas:~$ sudo ifconfig [sudo] password for ellika: eth0 Link encap:Ethernet HWaddr 00:1e:33:00:96:9a inet addr:192.168.1.26 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::21e:33ff:fe00:969a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:13801 errors:0 dropped:0 overruns:0 frame:0 TX packets:9528 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:14024965 (14.0 MB) TX bytes:1002836 (1.0 MB) Interrupt:17 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:1542 errors:0 dropped:0 overruns:0 frame:0 TX packets:1542 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:125040 (125.0 KB) TX bytes:125040 (125.0 KB) ellika@ellikas:~$ sudo ifconfig wlan0 up SIOCSIFFLAGS: Operationen inte möjlig p.g.a. RF-kill ellika@ellikas:~$ phy0 Wireless LAN phy0: command not found ellika@ellikas:~$ rfkill Usage: rfkill [options] command Options: --version show version (0.4-1ubuntu2 (Ubuntu)) Commands: help event list [IDENTIFIER] block IDENTIFIER unblock IDENTIFIER where IDENTIFIER is the index no. of an rfkill switch or one of: <idx> all wifi wlan bluetooth uwb ultrawideband wimax wwan gps fm ellika@ellikas:~$ sudo rf-kill unblock all sudo: rf-kill: kommandot hittades inte ellika@ellikas:~$ sudo rfkill unblock all ellika@ellikas:~$ sedan sudo ifconfig wlan0 sedan: command not found ellika@ellikas:~$ sudo ifconfig wlan0 wlan0 Link encap:Ethernet HWaddr 00:22:5f:3f:63:76 BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) ellika@ellikas:~$ ^C ellika@ellikas:~$ ^C ellika@ellikas:~$ sudo rfkill unblock all ellika@ellikas:~$ sudo ifconfig wlan0 up SIOCSIFFLAGS: Operationen inte möjlig p.g.a. RF-kill ellika@ellikas:~$ sudo rfkill unblock all ellika@ellikas:~$ sudo rfkill list 0: phy0: Wireless LAN Soft blocked: no Hard blocked: yes ellika@ellikas:~$ sudo rfkill unblock all ellika@ellikas:~$ echo -e "sudo lshw --class network:\n\n$(sudo lshw -c network)\n\nlspci -nnn | grep Ethernet:\n\n$(lspci -nnn | grep Ethernet)\n\nlsusb:\n\n$(lsusb)\n\niwlist wlan0 scanning:\n\n$(iwlist wlan0 scanning)\n\nrfkill list:\n\n$(rfkill list)\n\nping -c 5 google.com:\n\n$(ping -c 5 google.com)\n\nhost google.com 8.8.8.8:\n\n$(host google.com 8.8.8.8)\n\nlsb_release -a:\n\n$(lsb_release -a)\n\nuname -a:\n\n$(uname -a)" ^[[C^[[C^[[C^[[C^[[C^[[B wlan0 Failed to read scan data : Network is down No LSB modules are available. sudo lshw --class network: *-network beskrivning: Ethernet interface produkt: 88E8055 PCI-E Gigabit Ethernet Controller tillverkare: Marvell Technology Group Ltd. physical id: 0 bus info: pci@0000:04:00.0 logiskt namn: eth0 version: 14 serienummer: 00:1e:33:00:96:9a storlek: 100Mbit/s kapacitet: 1Gbit/s bredd: 64 bits klocka: 33MHz förmågor: pm vpd msi pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation konfiguration: autonegotiation=on broadcast=yes driver=sky2 driverversion=1.30 duplex=full firmware=N/A ip=192.168.1.26 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resurser: irq:44 memory:f8000000-f8003fff ioport:3000(storlek=256) memory:f2000000-f201ffff *-network INAKTIVERAD beskrivning: Trådlöst gränssnitt produkt: AR242x / AR542x Wireless Network Adapter (PCI-Express) tillverkare: Atheros Communications Inc. physical id: 0 bus info: pci@0000:06:00.0 logiskt namn: wlan0 version: 04 serienummer: 00:22:5f:3f:63:76 bredd: 64 bits klocka: 33MHz förmågor: pm msi pciexpress msix bus_master cap_list ethernet physical wireless konfiguration: broadcast=yes driver=ath5k driverversion=3.2.0-30-generic-pae firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bg resurser: irq:18 memory:fa000000-fa00ffff lspci -nnn | grep Ethernet: 04:00.0 Ethernet controller [0200]: Marvell Technology Group Ltd. 88E8055 PCI-E Gigabit Ethernet Controller [11ab:4363] (rev 14) 06:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR242x / AR542x Wireless Network Adapter (PCI-Express) [168c:001c] (rev 04) lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 05e3:0715 Genesys Logic, Inc. USB 2.0 microSD Reader Bus 001 Device 003: ID 05c8:0103 Cheng Uei Precision Industry Co., Ltd (Foxlink) FO13FF-65 PC-CAM iwlist wlan0 scanning: rfkill list: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: yes ping -c 5 google.com: PING google.com (173.194.32.34) 56(84) bytes of data. 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=1 ttl=55 time=10.6 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=2 ttl=55 time=10.5 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=3 ttl=55 time=10.4 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=4 ttl=55 time=10.4 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=5 ttl=55 time=10.4 ms --- google.com ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4004ms rtt min/avg/max/mdev = 10.451/10.517/10.631/0.062 ms host google.com 8.8.8.8: Using domain server: Name: 8.8.8.8 Address: 8.8.8.8#53 Aliases: google.com has address 173.194.32.36 google.com has address 173.194.32.38 google.com has address 173.194.32.41 google.com has address 173.194.32.37 google.com has address 173.194.32.35 google.com has address 173.194.32.39 google.com has address 173.194.32.33 google.com has address 173.194.32.34 google.com has address 173.194.32.46 google.com has address 173.194.32.32 google.com has address 173.194.32.40 google.com has IPv6 address 2a00:1450:400f:801::100e google.com mail is handled by 40 alt3.aspmx.l.google.com. google.com mail is handled by 20 alt1.aspmx.l.google.com. google.com mail is handled by 30 alt2.aspmx.l.google.com. google.com mail is handled by 50 alt4.aspmx.l.google.com. google.com mail is handled by 10 aspmx.l.google.com. lsb_release -a: Distributor ID: Ubuntu Description: Ubuntu 12.04.1 LTS Release: 12.04 Codename: precise uname -a: Linux ellikas 3.2.0-30-generic-pae #48-Ubuntu SMP Fri Aug 24 17:14:09 UTC 2012 i686 i686 i386 GNU/Linux ellika@ellikas:~$ ellika@ellikas:~$ clear ellika@ellikas:~$ echo -e "sudo lshw --class network:\n\n$(sudo lshw -c network)\n\nlspci -nnn | grep Ethernet:\n\n$(lspci -nnn | grep Ethernet)\n\nlsusb:\n\n$(lsusb)\n\niwlist wlan0 scanning:\n\n$(iwlist wlan0 scanning)\n\nrfkill list:\n\n$(rfkill list)\n\nping -c 5 google.com:\n\n$(ping -c 5 google.com)\n\nhost google.com 8.8.8.8:\n\n$(host google.com 8.8.8.8)\n\nlsb_release -a:\n\n$(lsb_release -a)\n\nuname -a:\n\n$(uname -a)" wlan0 Failed to read scan data : Network is down No LSB modules are available. sudo lshw --class network: *-network beskrivning: Ethernet interface produkt: 88E8055 PCI-E Gigabit Ethernet Controller tillverkare: Marvell Technology Group Ltd. physical id: 0 bus info: pci@0000:04:00.0 logiskt namn: eth0 version: 14 serienummer: 00:1e:33:00:96:9a storlek: 100Mbit/s kapacitet: 1Gbit/s bredd: 64 bits klocka: 33MHz förmågor: pm vpd msi pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation konfiguration: autonegotiation=on broadcast=yes driver=sky2 driverversion=1.30 duplex=full firmware=N/A ip=192.168.1.26 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s resurser: irq:44 memory:f8000000-f8003fff ioport:3000(storlek=256) memory:f2000000-f201ffff *-network INAKTIVERAD beskrivning: Trådlöst gränssnitt produkt: AR242x / AR542x Wireless Network Adapter (PCI-Express) tillverkare: Atheros Communications Inc. physical id: 0 bus info: pci@0000:06:00.0 logiskt namn: wlan0 version: 04 serienummer: 00:22:5f:3f:63:76 bredd: 64 bits klocka: 33MHz förmågor: pm msi pciexpress msix bus_master cap_list ethernet physical wireless konfiguration: broadcast=yes driver=ath5k driverversion=3.2.0-30-generic-pae firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bg resurser: irq:18 memory:fa000000-fa00ffff lspci -nnn | grep Ethernet: 04:00.0 Ethernet controller [0200]: Marvell Technology Group Ltd. 88E8055 PCI-E Gigabit Ethernet Controller [11ab:4363] (rev 14) 06:00.0 Ethernet controller [0200]: Atheros Communications Inc. AR242x / AR542x Wireless Network Adapter (PCI-Express) [168c:001c] (rev 04) lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 05e3:0715 Genesys Logic, Inc. USB 2.0 microSD Reader Bus 001 Device 003: ID 05c8:0103 Cheng Uei Precision Industry Co., Ltd (Foxlink) FO13FF-65 PC-CAM iwlist wlan0 scanning: rfkill list: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: yes ping -c 5 google.com: PING google.com (173.194.32.34) 56(84) bytes of data. 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=1 ttl=55 time=10.6 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=2 ttl=55 time=10.5 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=3 ttl=55 time=10.4 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=4 ttl=55 time=10.4 ms 64 bytes from arn06s02-in-f2.1e100.net (173.194.32.34): icmp_req=5 ttl=55 time=10.5 ms --- google.com ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4004ms rtt min/avg/max/mdev = 10.476/10.522/10.602/0.045 ms host google.com 8.8.8.8: Using domain server: Name: 8.8.8.8 Address: 8.8.8.8#53 Aliases: google.com has address 173.194.32.36 google.com has address 173.194.32.38 google.com has address 173.194.32.41 google.com has address 173.194.32.37 google.com has address 173.194.32.35 google.com has address 173.194.32.39 google.com has address 173.194.32.33 google.com has address 173.194.32.34 google.com has address 173.194.32.46 google.com has address 173.194.32.32 google.com has address 173.194.32.40 google.com has IPv6 address 2a00:1450:400f:801::100e google.com mail is handled by 40 alt3.aspmx.l.google.com. google.com mail is handled by 20 alt1.aspmx.l.google.com. google.com mail is handled by 30 alt2.aspmx.l.google.com. google.com mail is handled by 50 alt4.aspmx.l.google.com. google.com mail is handled by 10 aspmx.l.google.com. lsb_release -a: Distributor ID: Ubuntu Description: Ubuntu 12.04.1 LTS Release: 12.04 Codename: precise uname -a: Linux ellikas 3.2.0-30-generic-pae #48-Ubuntu SMP Fri Aug 24 17:14:09 UTC 2012 i686 i686 i386 GNU/Linux

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  • Top 50 ASP.Net Interview Questions & Answers

    - by Samir R. Bhogayta
    1. What is ASP.Net? It is a framework developed by Microsoft on which we can develop new generation web sites using web forms(aspx), MVC, HTML, Javascript, CSS etc. Its successor of Microsoft Active Server Pages(ASP). Currently there is ASP.NET 4.0, which is used to develop web sites. There are various page extensions provided by Microsoft that are being used for web site development. Eg: aspx, asmx, ascx, ashx, cs, vb, html, xml etc. 2. What’s the use of Response.Output.Write()? We can write formatted output  using Response.Output.Write(). 3. In which event of page cycle is the ViewState available?   After the Init() and before the Page_Load(). 4. What is the difference between Server.Transfer and Response.Redirect?   In Server.Transfer page processing transfers from one page to the other page without making a round-trip back to the client’s browser.  This provides a faster response with a little less overhead on the server.  The clients url history list or current url Server does not update in case of Server.Transfer. Response.Redirect is used to redirect the user’s browser to another page or site.  It performs trip back to the client where the client’s browser is redirected to the new page.  The user’s browser history list is updated to reflect the new address. 5. From which base class all Web Forms are inherited? Page class.  6. What are the different validators in ASP.NET? Required field Validator Range  Validator Compare Validator Custom Validator Regular expression Validator Summary Validator 7. Which validator control you use if you need to make sure the values in two different controls matched? Compare Validator control. 8. What is ViewState? ViewState is used to retain the state of server-side objects between page post backs. 9. Where the viewstate is stored after the page postback? ViewState is stored in a hidden field on the page at client side.  ViewState is transported to the client and back to the server, and is not stored on the server or any other external source. 10. How long the items in ViewState exists? They exist for the life of the current page. 11. What are the different Session state management options available in ASP.NET? In-Process Out-of-Process. In-Process stores the session in memory on the web server. Out-of-Process Session state management stores data in an external server.  The external server may be either a SQL Server or a State Server.  All objects stored in session are required to be serializable for Out-of-Process state management. 12. How you can add an event handler?  Using the Attributes property of server side control. e.g. [csharp] btnSubmit.Attributes.Add(“onMouseOver”,”JavascriptCode();”) [/csharp] 13. What is caching? Caching is a technique used to increase performance by keeping frequently accessed data or files in memory. The request for a cached file/data will be accessed from cache instead of actual location of that file. 14. What are the different types of caching? ASP.NET has 3 kinds of caching : Output Caching, Fragment Caching, Data Caching. 15. Which type if caching will be used if we want to cache the portion of a page instead of whole page? Fragment Caching: It caches the portion of the page generated by the request. For that, we can create user controls with the below code: [xml] <%@ OutputCache Duration=”120? VaryByParam=”CategoryID;SelectedID”%> [/xml] 16. List the events in page life cycle.   1) Page_PreInit 2) Page_Init 3) Page_InitComplete 4) Page_PreLoad 5) Page_Load 6) Page_LoadComplete 7) Page_PreRender 8)Render 17. Can we have a web application running without web.Config file?   Yes 18. Is it possible to create web application with both webforms and mvc? Yes. We have to include below mvc assembly references in the web forms application to create hybrid application. [csharp] System.Web.Mvc System.Web.Razor System.ComponentModel.DataAnnotations [/csharp] 19. Can we add code files of different languages in App_Code folder?   No. The code files must be in same language to be kept in App_code folder. 20. What is Protected Configuration? It is a feature used to secure connection string information. 21. Write code to send e-mail from an ASP.NET application? [csharp] MailMessage mailMess = new MailMessage (); mailMess.From = “[email protected]”; mailMess.To = “[email protected]”; mailMess.Subject = “Test email”; mailMess.Body = “Hi This is a test mail.”; SmtpMail.SmtpServer = “localhost”; SmtpMail.Send (mailMess); [/csharp] MailMessage and SmtpMail are classes defined System.Web.Mail namespace.  22. How can we prevent browser from caching an ASPX page?   We can SetNoStore on HttpCachePolicy object exposed by the Response object’s Cache property: [csharp] Response.Cache.SetNoStore (); Response.Write (DateTime.Now.ToLongTimeString ()); [/csharp] 23. What is the good practice to implement validations in aspx page? Client-side validation is the best way to validate data of a web page. It reduces the network traffic and saves server resources. 24. What are the event handlers that we can have in Global.asax file? Application Events: Application_Start , Application_End, Application_AcquireRequestState, Application_AuthenticateRequest, Application_AuthorizeRequest, Application_BeginRequest, Application_Disposed,  Application_EndRequest, Application_Error, Application_PostRequestHandlerExecute, Application_PreRequestHandlerExecute, Application_PreSendRequestContent, Application_PreSendRequestHeaders, Application_ReleaseRequestState, Application_ResolveRequestCache, Application_UpdateRequestCache Session Events: Session_Start,Session_End 25. Which protocol is used to call a Web service? HTTP Protocol 26. Can we have multiple web config files for an asp.net application? Yes. 27. What is the difference between web config and machine config? Web config file is specific to a web application where as machine config is specific to a machine or server. There can be multiple web config files into an application where as we can have only one machine config file on a server. 28.  Explain role based security ?   Role Based Security used to implement security based on roles assigned to user groups in the organization. Then we can allow or deny users based on their role in the organization. Windows defines several built-in groups, including Administrators, Users, and Guests. [xml] <AUTHORIZATION>< authorization > < allow roles=”Domain_Name\Administrators” / >   < !– Allow Administrators in domain. — > < deny users=”*”  / >                            < !– Deny anyone else. — > < /authorization > [/xml] 29. What is Cross Page Posting? When we click submit button on a web page, the page post the data to the same page. The technique in which we post the data to different pages is called Cross Page posting. This can be achieved by setting POSTBACKURL property of  the button that causes the postback. Findcontrol method of PreviousPage can be used to get the posted values on the page to which the page has been posted. 30. How can we apply Themes to an asp.net application? We can specify the theme in web.config file. Below is the code example to apply theme: [xml] <configuration> <system.web> <pages theme=”Windows7? /> </system.web> </configuration> [/xml] 31: What is RedirectPermanent in ASP.Net?   RedirectPermanent Performs a permanent redirection from the requested URL to the specified URL. Once the redirection is done, it also returns 301 Moved Permanently responses. 32: What is MVC? MVC is a framework used to create web applications. The web application base builds on  Model-View-Controller pattern which separates the application logic from UI, and the input and events from the user will be controlled by the Controller. 33. Explain the working of passport authentication. First of all it checks passport authentication cookie. If the cookie is not available then the application redirects the user to Passport Sign on page. Passport service authenticates the user details on sign on page and if valid then stores the authenticated cookie on client machine and then redirect the user to requested page 34. What are the advantages of Passport authentication? All the websites can be accessed using single login credentials. So no need to remember login credentials for each web site. Users can maintain his/ her information in a single location. 35. What are the asp.net Security Controls? <asp:Login>: Provides a standard login capability that allows the users to enter their credentials <asp:LoginName>: Allows you to display the name of the logged-in user <asp:LoginStatus>: Displays whether the user is authenticated or not <asp:LoginView>: Provides various login views depending on the selected template <asp:PasswordRecovery>:  email the users their lost password 36: How do you register JavaScript for webcontrols ? We can register javascript for controls using <CONTROL -name>Attribtues.Add(scriptname,scripttext) method. 37. In which event are the controls fully loaded? Page load event. 38: what is boxing and unboxing? Boxing is assigning a value type to reference type variable. Unboxing is reverse of boxing ie. Assigning reference type variable to value type variable. 39. Differentiate strong typing and weak typing In strong typing, the data types of variable are checked at compile time. On the other hand, in case of weak typing the variable data types are checked at runtime. In case of strong typing, there is no chance of compilation error. Scripts use weak typing and hence issues arises at runtime. 40. How we can force all the validation controls to run? The Page.Validate() method is used to force all the validation controls to run and to perform validation. 41. List all templates of the Repeater control. ItemTemplate AlternatingltemTemplate SeparatorTemplate HeaderTemplate FooterTemplate 42. List the major built-in objects in ASP.NET?  Application Request Response Server Session Context Trace 43. What is the appSettings Section in the web.config file? The appSettings block in web config file sets the user-defined values for the whole application. For example, in the following code snippet, the specified ConnectionString section is used throughout the project for database connection: [csharp] <em><configuration> <appSettings> <add key=”ConnectionString” value=”server=local; pwd=password; database=default” /> </appSettings></em> [/csharp] 44.      Which data type does the RangeValidator control support? The data types supported by the RangeValidator control are Integer, Double, String, Currency, and Date. 45. What is the difference between an HtmlInputCheckBox control and anHtmlInputRadioButton control? In HtmlInputCheckBoxcontrol, multiple item selection is possible whereas in HtmlInputRadioButton controls, we can select only single item from the group of items. 46. Which namespaces are necessary to create a localized application? System.Globalization System.Resources 47. What are the different types of cookies in ASP.NET? Session Cookie – Resides on the client machine for a single session until the user does not log out. Persistent Cookie – Resides on a user’s machine for a period specified for its expiry, such as 10 days, one month, and never. 48. What is the file extension of web service? Web services have file extension .asmx.. 49. What are the components of ADO.NET? The components of ADO.Net are Dataset, Data Reader, Data Adaptor, Command, connection. 50. What is the difference between ExecuteScalar and ExecuteNonQuery? ExecuteScalar returns output value where as ExecuteNonQuery does not return any value but the number of rows affected by the query. ExecuteScalar used for fetching a single value and ExecuteNonQuery used to execute Insert and Update statements.

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  • Educause Top-Ten IT Issues - the most change in a decade or more

    - by user739873
    The Education IT Issue Panel has released the 2012 top-ten issues facing higher education IT leadership, and instead of the customary reshuffling of the same deck, the issues reflect much of the tumult and dynamism facing higher education generally.  I find it interesting (and encouraging) that at the top of this year's list is "Updating IT Professionals' Skills and Roles to Accommodate Emerging Technologies and Changing IT Management and Service Delivery Models."  This reflects, in my view, the realization that higher education IT must change in order to fully realize the potential for transforming the institution, and therefore it's people must learn new skills, understand and accept new ways of solving problems, and not be tied down by past practices or institutional inertia. What follows in the remaining 9 top issues all speak, in some form or fashion, to the need for dramatic change, but not just in the areas of "funding IT" (code for cost containment or reduction), but rather the need to increase effectiveness and efficiency of the institution through the use of technology—leveraging the wave of BYOD (Bring Your Own Device) to the institution's advantage, rather than viewing it as a threat and a problem to be contained. Although it's #10 of 10, IT Governance (and establishment and implementation of the governance model throughout the institution) is key to effectively acting upon many of the preceding issues in this year's list.  In the majority of cases, technology exists to meet the needs and requirements to effectively address many of the challenges outlined in top-ten issues list. Which brings me to my next point. Although I try not to sound too much like an Oracle commercial in these (all too infrequent) blog posts, I can't help but point out how much confluence there is between several of the top issues this year and what my colleagues and I have been evangelizing for some time. Starting from the bottom of the list up: 1) I'm gratified that research and the IT challenges it presents has made the cut.  Big Data (or Large Data as it's phased in the report) is rapidly going to overwhelm much of what exists today even at our most prepared and well-equipped research universities.  Combine large data with the significantly more stringent requirements around data preservation, archiving, sharing, curation, etc. coming from granting agencies like NSF, and you have the brewing storm that could result in a lot of "one-off" solutions to a problem that could very well be addressed collectively and "at scale."   2) Transformative effects of IT – while I see more and more examples of this, there is still much more that can be achieved. My experience tells me that culture (as the report indicates or at least poses the question) gets in the way more than technology not being up to task.  We spend too much time on "context" and not "core," and get lost in the weeds on the journey to truly transforming the institution with technology. 3) Analytics as a key element in improving various institutional outcomes.  In our work around Student Success, we see predictive "academic" analytics as essential to getting in front of the Student Success issue, regardless of how an institution or collections of institutions defines success.  Analytics must be part of the fabric of the key academic enterprise applications, not a bolt-on.  We will spend a significant amount of time on this topic during our semi-annual Education Industry Strategy Council meeting in Washington, D.C. later this month. 4) Cloud strategy for the broad range of applications in the academic enterprise.  Some of the recent work by Casey Green at the Campus Computing Survey would seem to indicate that there is movement in this area but mostly in what has been termed "below the campus" application areas such as collaboration tools, recruiting, and alumni relations.  It's time to get serious about sourcing elements of mature applications like student information systems, HR, Finance, etc. leveraging a model other than traditional on-campus custom. I've only selected a few areas of the list to highlight, but the unifying theme here (and this is where I run the risk of sounding like an Oracle commercial) is that these lofty goals cry out for partners that can bring economies of scale to bear on the problems married with a deep understanding of the nuances unique to higher education.  In a recent piece in Educause Review on Student Information Systems, the author points out that "best of breed is back". Unfortunately I am compelled to point out that best of breed is a large part of the reason we have made as little progress as we have as an industry in advancing some of the causes outlined above.  Don't confuse "integrated" and "full stack" for vendor lock-in.  The best-of-breed market forces that Ron points to ensure that solutions have to be "integratable" or they don't survive in the marketplace. However, by leveraging the efficiencies afforded by adopting solutions that are pre-integrated (and possibly metered out as a service) allows us to shed unnecessary costs – as difficult as these decisions are to make and to drive throughout the organization. Cole

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

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

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  • links for 2011-02-11

    - by Bob Rhubart
    New Versions of Whitepapers are available (The Shorten Spot) Anthony Shorten shares the details on several recently updated Updated Oracle Utilities Application Framework white papers. (tags: oracle otn whitepapers) Energy Firms Targetted for Sensitive Documents (Oracle IRM, the official blog) Numerous multinational energy companies have been targeted by hackers who have been focusing on financial documents related to oil and gas field exploration, bidding contracts, and drilling rights, as well as proprietary industrial process documents, according to a new McAfee report. (tags: oracle otn security) Get Your Workshop Hands On! New Developer Day Cities & Dates (Oracle Technology Network Blog (aka TechBlog)) Oracle Technology Network's Justin Kestelyn share information on upcoming OTN Developer days. (tags: oracle otn events)

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  • Only One GPU Detected in the Nvidia Quadra NVS 450

    - by Kyle Brandt
    I just built myself an new workstation and now only 2 of 3 monitors are working. I built the nvidia driver by downloading it and installing with ./Nvidia... Before when I ran nvidia-settings I saw two GPUs listed but now I only see one. Xorg Config (Not sure how I ended up with 3 devices in there): # nvidia-settings: X configuration file generated by nvidia-settings # nvidia-settings: version 256.35 (buildmeister@builder101) Wed Jun 16 19:25:39 PDT 2010 Section "ServerLayout" # Removed Option "Xinerama" "1" Identifier "Layout0" Screen 0 "Screen0" 0 0 Screen 1 "Screen1" RightOf "Screen0" InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" Option "Xinerama" "0" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" # HorizSync source: edid, VertRefresh source: edid Identifier "Monitor0" VendorName "Unknown" ModelName "DELL E207WFP" HorizSync 30.0 - 83.0 VertRefresh 56.0 - 75.0 Option "DPMS" EndSection Section "Monitor" # HorizSync source: edid, VertRefresh source: edid Identifier "Monitor1" VendorName "Unknown" ModelName "DELL E207WFP" HorizSync 30.0 - 83.0 VertRefresh 56.0 - 75.0 Option "DPMS" EndSection Section "Monitor" # HorizSync source: edid, VertRefresh source: edid Identifier "Monitor2" VendorName "Unknown" ModelName "DELL E207WFP" HorizSync 30.0 - 83.0 VertRefresh 56.0 - 75.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "Quadro NVS 450" BusID "PCI:6:0:0" EndSection Section "Device" Identifier "Device1" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "Quadro NVS 450" BusID "PCI:5:0:0" EndSection Section "Device" Identifier "Device2" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "Quadro NVS 450" BusID "PCI:3:0:0" EndSection Section "Screen" # Removed Option "TwinView" "0" # Removed Option "metamodes" "DFP-0: nvidia-auto-select +0+0" # Removed Option "metamodes" "DFP-0: nvidia-auto-select +0+275, DFP-3: nvidia-auto-select +1680+0" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 Option "TwinView" "1" Option "TwinViewXineramaInfoOrder" "DFP-3" Option "metamodes" "DFP-0: nvidia-auto-select +0+0, DFP-3: nvidia-auto-select +1680+0" SubSection "Display" Depth 24 EndSubSection EndSection Section "Screen" # Removed Option "metamodes" "DFP-3: nvidia-auto-select +0+0" Identifier "Screen1" Device "Device1" Monitor "Monitor1" DefaultDepth 24 Option "TwinView" "0" Option "metamodes" "nvidia-auto-select +0+0" SubSection "Display" Depth 24 EndSubSection EndSection Section "Screen" Identifier "Screen2" Device "Device2" Monitor "Monitor2" DefaultDepth 24 Option "TwinView" "0" Option "metamodes" "nvidia-auto-select +0+0" SubSection "Display" Depth 24 EndSubSection EndSection lscpi: 00:00.0 Host bridge: Intel Corporation 5520/5500/X58 I/O Hub to ESI Port (rev 13) 00:01.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 1 (rev 13) 00:02.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 2 (rev 13) 00:03.0 PCI bridge: Intel Corporation 5520/5500/X58 I/O Hub PCI Express Root Port 3 (rev 13) 00:10.0 PIC: Intel Corporation 5520/5500/X58 Physical and Link Layer Registers Port 0 (rev 13) 00:10.1 PIC: Intel Corporation 5520/5500/X58 Routing and Protocol Layer Registers Port 0 (rev 13) 00:11.0 PIC: Intel Corporation 5520/5500 Physical and Link Layer Registers Port 1 (rev 13) 00:11.1 PIC: Intel Corporation 5520/5500 Routing & Protocol Layer Register Port 1 (rev 13) 00:13.0 PIC: Intel Corporation 5520/5500/X58 I/O Hub I/OxAPIC Interrupt Controller (rev 13) 00:14.0 PIC: Intel Corporation 5520/5500/X58 I/O Hub System Management Registers (rev 13) 00:14.1 PIC: Intel Corporation 5520/5500/X58 I/O Hub GPIO and Scratch Pad Registers (rev 13) 00:14.2 PIC: Intel Corporation 5520/5500/X58 I/O Hub Control Status and RAS Registers (rev 13) 00:15.0 PIC: Intel Corporation 5520/5500/X58 Trusted Execution Technology Registers (rev 13) 00:1a.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #4 00:1a.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #5 00:1a.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #6 00:1a.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #2 00:1b.0 Audio device: Intel Corporation 82801JI (ICH10 Family) HD Audio Controller 00:1c.0 PCI bridge: Intel Corporation 82801JI (ICH10 Family) PCI Express Root Port 1 00:1c.1 PCI bridge: Intel Corporation 82801JI (ICH10 Family) PCI Express Port 2 00:1c.3 PCI bridge: Intel Corporation 82801JI (ICH10 Family) PCI Express Root Port 4 00:1c.4 PCI bridge: Intel Corporation 82801JI (ICH10 Family) PCI Express Root Port 5 00:1d.0 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #1 00:1d.1 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #2 00:1d.2 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB UHCI Controller #3 00:1d.7 USB Controller: Intel Corporation 82801JI (ICH10 Family) USB2 EHCI Controller #1 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 90) 00:1f.0 ISA bridge: Intel Corporation 82801JIR (ICH10R) LPC Interface Controller 00:1f.2 IDE interface: Intel Corporation 82801JI (ICH10 Family) 4 port SATA IDE Controller #1 00:1f.3 SMBus: Intel Corporation 82801JI (ICH10 Family) SMBus Controller 00:1f.5 IDE interface: Intel Corporation 82801JI (ICH10 Family) 2 port SATA IDE Controller #2 01:00.0 IDE interface: Device 1b4b:91a3 (rev 11) 02:00.0 USB Controller: NEC Corporation Device 0194 (rev 03) 03:00.0 PCI bridge: nVidia Corporation PCI express bridge for Quadro Plex S4 / Tesla S870 / Tesla S1070 (rev a3) 04:00.0 PCI bridge: nVidia Corporation PCI express bridge for Quadro Plex S4 / Tesla S870 / Tesla S1070 (rev a3) 04:02.0 PCI bridge: nVidia Corporation PCI express bridge for Quadro Plex S4 / Tesla S870 / Tesla S1070 (rev a3) 05:00.0 3D controller: nVidia Corporation G98 [Quadro NVS 450] (rev a1) 06:00.0 VGA compatible controller: nVidia Corporation G98 [Quadro NVS 450] (rev a1) 08:00.0 SATA controller: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 02) 08:00.1 IDE interface: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 02) 09:00.0 SATA controller: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 03) 09:00.1 IDE interface: JMicron Technology Corp. JMB362/JMB363 Serial ATA Controller (rev 03) 0a:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06) 0b:06.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link)

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  • Hologic Ensures Regulatory Compliance & UDI with Agile PLM for the Medical Device Industry

    - by Ulf Köster
    A new success story featuring Hologic, Inc., is now available. Hologic is known for developing innovative medical technology—like the world’s first 3-D mammogram—that can quickly diagnose women’s health issues and save lives in the process.The success story features Hologic’s use of Oracle Agile PLM to ensure regulatory compliance in every phase of product development, including managing all product-related data, design history files, and device master records. Hologic is using Oracle Agile PLM as the foundation for Unique Device Identification (UDI). Thanks to Agile PLM, Hologic can easily interface with the FDA’s database (GUDID) to streamline compliance, without devoting additional time and resources towards a new solution. Hologic is one of the first 2 companies granted production accounts by the FDA for GUDID submittal, and is the first company to submit official data. This an important milestone for Oracle Agile PLM, our partner Inspirage and the Medical Device industry as a whole. Read the full story here!

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  • In-depth Coverage for Oracle Workflow

    - by Steven Chan (Oracle Development)
    I'm lucky to work with many talented people in the Applications Technology Group, and many of them contribute articles to this blog.  Some team members have their own blogs.  If you work with Oracle Workflow, here's one that you should be following: Oracle E-Business Suite - Workflow This blog is updated every few months by our development team with in-depth technical articles about Oracle Workflow-related topics.  For example, articles posted there include: Implementing a post-notification function to perform custom validation E-Business Suite Proactive Support - Workflow Analyzer Asynchronous Business Event Subscriptions - Troubleshooting Tips Oracle E-Busienss Suite RCD - Applications Technology Releases 12.1 and 12.2 SMTP Authentication Feature in R12.1.3 Configurable User LOV in Worklist UI Oracle Business Event and Subsciptions Execution Flow Understanding AQs in Workflow SSL in Oracle Workflow Leveraging Oracle Workflow for Declarative PageFlow If you have suggestions about Workflow topics that you'd like to see covered there, drop them a line.

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  • Using Custom Validation with LINQ to SQL in an ASP.Net application

    - by nikolaosk
    A friend of mine is working in an ASP.Net application and using SQL Server as the backend. He also uses LINQ to SQL as his data access layer technology. I know that Entity framework is Microsoft's main data access technology. All the money and resources are available for the evolution of Entity Framework. If you want to read some interesting links regarding LINQ to SQL roadmap and future have a look at the following links. http://blogs.msdn.com/b/adonet/archive/2008/10/29/update-on-linq-to-sql-and...(read more)

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  • Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

    - by MarkPearl
    After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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