Simple and (hopefully!) free procedures to handle unsuccessfully finalized DVDs, damaged DVDs or DVDs that have not been burned correctly by a video camcorder,recorder or burner and has some corrupt data.

It is a good idea for you to first consider other possible causes of what appear to be DVD errors such as a dirty disc surface, a dirty lens in the DVD reader or other software and hardware related problems. Prior to embarking on any of the following you need to eliminate all possible causes for having trouble with a DVD. Check to see your DVD burner has the latest firmware by going to the manufacturers website. Check to see if the media (brand and type) is compatible with your DVD burner/reader. Once you are certain that you have an unsuccessfully finalized DVD or a corrupt DVD you can get started.

Scratched DVD Disks

A simple visual inspection of the surface of the disc will tell you straight away whether your first problem is physical damage to the disc. If you can see a scratch or scratches on the surface then this may need to be addressed first. I say “may” because personally I use DVDFab to check to see if the disc will copy before I embark on any other course of action. DVDFab can read through a lot of surface errors because of its superior algorithms so I always take the lazy route and see if I can simply make a new copy. Now failing that you could go online and buy some expensive DVD scratch repair kit. Or you could do as I do and go to your local hardware store or even your own garage! All you will need is a bottle of any neutral colored (clear) car polishing product. Turtlewax happens to be the one I use. Take a VERY soft cloth (NOT paper towel), apply a little polish to the surface of the disc and GENTLY (remember, it’s not a car!) rub the disc. Use straight strokes from the centre of the disc to the outer edge and continue to do this until you can see the scratch either disappear or reduce noticeably. Then using the same motion and fresh cloth buff the disc back to its original shine. Now try it with DVDFab. If you are still unsuccessful repeat the process until you can be certain, again by visual inspection, that the problem is now not coming from a damaged disc surface.

DVD Data Repair/Recovery

The software you can use for this are DVDFab, Nero 8 (trial) and Isobuster. In the case of Isobuster you can try the free features first but failing that the full featured version needs to be purchased. A straight search of Yahoo or Google will find you the relevant sites.

Put the problem disc in the DVD drive of your computer then:

1. DVDFab. Try to use DVDFab first, as it has the best algorithms for reading anything on a DVD including how it integrates with the DVD drive, honestly sometimes I think it would read a bagel if you put it in there!

Select “DVD to DVD.” DVDFab will now try to read the contents of the disc and, if it can, write the contents to a folder on your hard drive. It is as simple as that. It is either going to work or not! If it does do it then the copy you now have on your hard drive will be fully repaired and you can then burn a new copy.

Failing that:

2. Isobuster. Using the free functions try to make a disc image file and burn to another DVD. Isobuster has three alternate methods of dealing with data corruption. It can replace the corrupted area with nothing, with fake data or with a series of zeros. It will give you the choice and just select them in order to try each until one works. Isobuster will not create the disc image file unless it knows it will be successful. If Isobuster has created the file (note where it was going to put it first!) you will have to re-name the extension to .iso. Use the disc image file to burn a new DVD disc. At this point, if you now have a new disc, you need to check that new one carefully. There is always the possibility that Isobuster has just made a perfect copy of your faulty disc! So now you have a brand new faulty disc!

Failing that: You will need to pay for the full version of Isobuster but ONLY buy it if you got this far. If Isobuster free couldn’t even read the disc then don’t bother.

>From this point forward the best you can hope for is the extraction of the MPEG video files or data files on the disc. You ARE going to lose the video menus and you may lose some of the video or data.

a. Start Isobuster then load the disc.

b. When Isobuster has detected the files on the disc run the “Find Missing Files and Folders” option under the “File” menu.

c. You will now have an entry on the left hand column of “files and folders found by their signature.”

d. Select that, then go to “File,” “Files found via their signature” then “Extract files found via their signature.” Choose a location and let it run.

Now you will have all the files where you selected them to go. The ones with the extension .VOB are the MPEG files from your disc wrapped in the VOB container. They can then be imported into a video editing program using the “Import DVD/VR” function or can be read by most DVD burning software.

Unfinalized discs.

If at all possible try to get the original device used to create the disc to finalize it. If this is not possible or the original device is failing to successfully finalize the disc you may have to resort to the Isobuster routine above.

If you have been left with an otherwise perfectly good disc, but unfinalized, do the following.

This requires Nero 8 (Trial version).

Go to the Nero website, download and install Nero 8. Yes, it’s big…sorry!

Place the unfinalized disc into the computer DVD tray. Open Nero 8 StartSmart.
Click “create and edit” at the top of the screen.
Click “author, edit and capture video.” NeroVision 5 will start.
Click on the disk tools drop down menu then click “finalize disk.”
In the option box that appears choose “no menus” and let it run.

Hopefully you now have a fully finalized disc that is readable.

Hope this helps!

When it comes to cleaning your keyboard there are many methods that can be used, some harder and more effective than others.

The easiest method is the Shake Method. It is so easy that you can do it right now. Pick up your keyboard, turn it over being careful not to press any keys, and shake it. See all of that stuff fall out? It is dirtier than you thought, isn’t it? You can use one of the following methods to clean it further.

The Blow Method - You can buy cans of pressurized air at the computer department or computer store which are made especially for cleaning your computer. They usually have either a hose and nozzle or a tube extending from the nozzle. Hold the keyboard up vertically (that means that end of the keyboard is up and the other end is down), aim towards the keys and press the button. Keep blowing until all of the debris is blown out. Be sure to get around and in between all of the keys. This can be done with the computer on, but it is better if it is off so that you do not have to worry about pressing the keys and coming up with a page of aaaaaaaaaaaaaaaaaaaaa’s.

The Vacuum Method - This is just like the Blow Method except that a vacuum is used instead of a can of pressurized air. It is quite simple. Just turn the vacuum on, pull out the hose, and run the nozzle over the keys. Before doing this make sure your keyboard does not have any loose pop off keys that could be sucked into the vacuum.

The Cotton Ball Method - This can be done in addition to the above methods and in lieu of the following methods. Take a cotton ball or cloth and wet it with rubbing alcohol. It should not be so wet that the alcohol runs down into the cracks of the keyboard. Wipe the tops and sides of the keys.

The Dishwasher Method - I hesitate to tell about this method because there is the possibility that it could fry your keyboard. When I had less experience with computers, I dunked my keyboard in a sink full of water to clean it. It did work afterwards, so I don’t doubt those who say this method will not mess up your keyboard, but if it does, don’t complain to me. I warned you. If your keyboard is not the standard membrane type of keyboard or if it is on a laptop, do not even think of trying this.

This is how you do it. Unplug the keyboard and place it face down in an empty dishwasher. Do not disassemble the keyboard and do not put it in a dishwasher that has dirty dishes in it. Some say to add soap, some say not to. Run the dishwasher through a regular cycle. Take the keyboard out, shake the water out, and stand it on end until it is completely dry (this may take several days). If it does not work after doing this, it may not be dry. Let it stand another week and try it again. If it still does not work, I warned you.

The Disassembly Method - This is the most thorough method, but it should not be done on laptop keyboards or non-standard non-membrane keyboards.

Turn off the computer and unplug the keyboard. Turn the keyboard upside down. You may want to get two books or short boards to place the keyboard on. Position them so that they hold up the keyboard on the edges when it is turned over. This should leave the keys dangling and not touching the books or the floor. This is especially needed when the keyboard’s back is off; otherwise the keys will be lifted out of their position by the floor (or whatever surface it is laying on).

Get a screwdriver and remove all of the screws from the back of the keyboard. Lay the keyboard down on the books and carefully remove the back.

Take everything apart and clean thoroughly. It is better to take the keys out one at a time and clean them so that you do not put them back in the wrong place. Wipe each one down with a wet cloth and then with a dry cloth. Any keys that may be hard to put back in, can be cleaned in place without removing them. Wipe around the keys as they sit in place and blow any debris out with your lungs (using compressed air or a vacuum may upset the keys). If you are really brave, you can remove all of the keys at once and give the frame a good wipe down too.

Do a once over and make sure that you have cleaned everything. Then reassemble it all.

Don’t forget the keyboard’s cable. Wrap a wet cloth around it and wipe it down. It may have an accumulation of grime that needs to be scrubbed off. Also if any of the letters on the keys have rubbed off, you can use a fine point permanent marker to draw the letter back on the key.

Use these cleaning methods and your keyboard will last a long time and be something you can be proud of.

I know most of you will not heed this advice, but KEYBOARDS CAN MAKE YOU SICK (how’s that for tactfulness?). Germs live on your hands and fingers. When you type, many of them jump on to the keyboard. When someone else types on your keyboard, those germs transfer to their fingers. Or when you later type on the same keyboard, those germs reconquer your fingers. Regularly disinfecting the keyboard can prevent this.

To disinfect the keyboard, turn off the computer. Then spray disinfectant on a cloth. Be sure to use disinfectant and not just any type of cleaner because not all cleaners disinfect. Also do not spray the disinfectent directly on the keys. Spray it on the cloth. Wipe down the top and sides of the keys. Give the keys a few minutes to dry off before turning the computer back on.

Now that you know how to do it, you should make it a regular practice to disinfect the keyboard. It’s one step towards a healthier you.

So you have your keyboard disinfected and life is great. Then your child spills koolaide all over it. What do you do? There are certain steps that you should take when something, like pop, beer, wine, coffee, milk, or kool-aide, is spilled on the keyboard.

The first thing to do is immediately unplug the keyboard from the back of the computer and turn the keyboard over so that its keys are down. This will allow the liquid to drain out. You will probably want to put a cloth under the keyboard or at least make sure that the surface you have put it on is washable.

Then use the mouse to shut down Windows and turn off the computer (this is important because later you will have to plug the keyboard back into the computer and you should never plug any device into a computer while it is on).

While the keyboard is upside down use a cloth to dry as much of the liquid off as you can. If you have a can of compressed air or a vacuum, while the keyboard is upside down blow or vacuum it out. Then let the keyboard set upside down for at least a night so that it can adequately dry out.

If the liquid that spilled on it was sticky, you may want to follow the extensive cleaning procedure explained in the next article, How to Clean your Keyboard - Part 2.

Liquid spilled on a laptop keyboard can easily reach the hard drive, so turn it over immediately and leave it in that position until it dries.

Keyboards are quite resilient and so it should work when you turn it on again. But if not, another attribute of keyboards is that they are cheap and so it won’t cost too much to buy another one.

With these pointers in mind and a quick reaction, you just may save your keyboard from total destruction the next time it gets coated with coffee.

Today?s telecommunications networks are a delicate blend of clients and servers that together offer virtually endless possibilities when it comes to services and applications. For every new client developed, there seems to be a score more on the way ? from mobile handsets, PDAs, terminals, telephones, video phones, IP set-top-boxes, and so on.

There are essentially two types of servers that connect between clients on large networks: Proxy servers and Back-to-Back User Agent (B2BUA) servers. The more prevalent Proxy servers feature predictable behavior ? simply connecting between clients. Effectively, B2BUA servers are much stronger and intelligent entities that perform actions which Proxy servers cannot. Moreover, B2BUA servers provide a flexible solution for a wide range of applications and services and are becoming the primary engine for more and more SIP servers in NGN and IMS networks.

The difference between Proxy servers and B2BUA servers is sometimes not fully understood. In this article, we will explore what makes B2BUA servers such an appealing alternative to standard Proxy servers. Better understanding of B2BUA servers can help managers understand the value, and the tradeoffs, of choosing a B2BUA server, as well as the frameworks needed to develop a wide range of SIP applications and SIP services using it.

Figure 1 - Architectural difference between Proxy servers and B2BUA servers

B2BUA Server Defined
B2BUA servers are used to provide value added features for point-to-point calls and manage multi-point calls. The power behind a B2BUA server is derived mostly from the fact that it has a very generic definition, which gives it almost unlimited power. However, this same characteristic is the root of the controversy surrounding it.

IETF standard (RFC 3261) defines a back-to-back user agent as ?a logical entity that receives a request and processes it as a user agent server (UAS). In order to determine how the request should be answered, it acts as a user agent client (UAC) and generates requests. Unlike a Proxy server, it maintains a dialogue state and must participate in all requests sent on the dialogues it has established.?

B2BUA servers have capabilities that far exceed those of other types of SIP servers, and answer the need for developing sophisticated value added SIP applications that cannot be implemented as Proxy applications.

Some of these capabilities, which are unique to B2BUA servers, are outlined below:

3rd Party Call Control (3PCC) Features
3rd Party Call Control (3PCC) is the ability of an entity (usually a controller) to set up and manage communication between two or more parties. 3PCC is often used for operator services and conferencing.

3PCC actions are important capabilities, exclusive to B2BUA servers since ?passive? non call-stateful elements, such as Proxy servers, cannot initiate these types of activities. Some examples of 3PCC services are online billing, QoS, resource prioritization, call transfer, click-to-dial, mid-call announcement and more.

3PCC actions can be initiated automatically by B2BUA server applications, like disconnecting a call following credit expiration in an online-billing system. Or they can be initiated by remote administrative control (OSS), e.g. invite parties to a multi-point conferencing session.

Figure 2 - Schematic outline of B2BUA server offering 3PCC functionality

Inter-working Function (IWF) for Interoperability

SIP was designed as a highly flexible and extendible protocol. The very strength of this flexibility is also an inherent weakness, since the vast array of client types in the market still need to connect.

B2BUA Inter-working Functions (IWF) defines a wide range of powerful SIP servers that connect SIP clients that ?speak? in different protocol dialects, or support different capabilities. This Inter-working function is very important in enabling connectivity between clients with different capabilities and/or protocol dialects. Or even between clients and networks ? where the B2BUA server actually acts as an access device.

Examples of what IWF can do include:

? Connecting SIP clients to IMS networks by adding and removing IMS SIP protocol extensions (AKA P-Headers) that are essential for connecting to the IMS network
? Connecting clients with different Session Timers settings
? Connecting clients with different media capabilities and with distinct Session Description Protocol (SDP) messages by relaying between the two types of control sessions
? Connecting to different types of networks (e.g. IPv4, IPv6) and support for different transport types, such as TCP/UDP/SCTP/TLS

Figure 3 - Schematic outline of a B2BUA Inter-Working Function

Multi-point Call Management

B2BUA servers an also implement multi-point call scenarios where multiple CPE devices connect to the B2BUA, and the B2BUA provides services to all CPE.

Due to these unique capabilities, B2BUA servers are widely used in the communications industry. A few examples are listed below:

? Online-billing/prepaid functions
? Servers supporting Resource Prioritization (RP) and/or Quality of Service (QoS) features
? Multi Point Conferencing servers
? IVR servers
? PBX Applications and Softswitches
? Application Layer Gateways (ALG)
? FW/NAT Traversal applications
? Privacy servers
? 3rd-Party Call Control Applications (3PCC)
? Service Creation Environment (SCE) runtime engines
? Session Boarder Controller (SBC)
? IMS S-CSCF, P-CSCF, I-CSCF
? SIP Inter-work Function (IWF) Gateway
? Security Gateway (SEG)
? Voice Call Continuity (VCC) servers

In addition, B2BUA servers play an important role in emerging IMS networks. Recent releases of 3GPP IMS specifications (3GPP TS 24.229 V8.0.0) indicate that an increasing number of IMS network element servers, such as P-CSCF, IBCF,SBC etc., are B2BUA servers. The reason for this is that value added services are usually session stateful, and feature capabilities that go beyond basic call proxying. Applications written on top of B2BUA Application servers fulfill several roles, such as SIP User Agents, SIP Proxy servers and SIP Registrars.

B2BUA Server Challenges

B2BUA application developers face many challenges, such as achieving rapid time-to-market, conformance and interoperability, offering customization for proprietary services and support for High Availability (HA) and redundancy. A comprehensive B2BUA framework can help developers overcome these challenges.

A solid B2BUA framework should have modular application building block architecture for increased flexibility, abstraction and short delivery time. Traditional architecture, which features a single configurable state machine, is not flexible enough. Also, a B2BUA framework should facilitate developing B2BUA applications by flexibly linking ?pluggable? high-level Modular Application Building Blocks (MABB). Developers should have the ability to combine these MABBs and they should be designed in a way that allows developers to further customize their behavior if needed. This type of architecture complies with contemporary Service Oriented Architecture (SOA) concepts, and is suitable for powering flexible business communication platforms. This modular architecture can save months of work. With a set of MABBs in hand, developing the application is a matter of combining existing MABBs to produce the required business logic. In addition, this architecture enhances efficiency; development of new MABBs can be done concurrently.

A B2BUA framework should facilitate developing applications that fully conform to standards and are interoperable; without restricting developers from customizing protocol behavior for special cases. Moreover, it should conform for non-standard implementations, as well as to mediate between two versions of the same standard. This type of framework allows developers to focus on their proprietary application with the confidence that their final application will be fully interoperable.

And finally, a B2BUA framework should provide the ability to configure, amend and replace application building blocks to create proprietary features. With this ability, developers can maximize existing code ? significantly reducing development time, shortening testing cycles, and reducing overall time-to-market.

Figure 4 - Traditional architecture of a B2BUA framework

RADVISION?s B2BUA Application Framework http://www.radvision.com/Products/Developer/SIPServer delivers these capabilities and more. The B2BUA Application Framework module is a part of the RADVISION SIP server Platform, a software framework that offers the essential building blocks for the development of a wide variety of high performance SIP and IMS servers. The rich set of components and modules can be flexibly combined to match customers? requirements for developing SIP servers that offer both standard and advanced SIP services.

Applications written on top of RADVISION?s B2BUA framework are developed by combining customizable modular application building blocks. This is effectively large chunks of functionality that can be strung together to form ad-hoc applications, enabling developers to focus on the high-level business logic and use building blocks that hide low-level details.

As one of the most popular IM applications, Yahoo! Messenger was the first large consumer player that adopted B2B UA. Yahoo! Messenger combined its backend scalable platform with RADVISION?s B2B UA to serve millions of monthly unique messaging users around the world. Yahoo selected RADVISION?s B2BUA due to its robust performance and scalability features.

Figure 5 - The architecture of RADVISION B2BUA Application Framework

RADVISION also offers automatic High Availability (HA) and Redundancy support. The B2BUA framework automatically replicates the run-time state of the different Services and B2BUA framework core. In the event of a server outage, a redundant server takes over seamlessly and provides uninterrupted service continuity.

B2BUA framework benefits in a nutshell

? Significantly reduces time to market developing proprietary B2B applications and services.
? Allows adding advanced services easily to retain competitive advantage and evolve to meet growing customer demands.
? Focuses on the business logic and hides low level operator communication intricacies.
? Delivers off-the-shelf conformance and interoperability.
? Enables rapid development of applications that can interoperate with different vendors.
? Enables adding high-availability features easily.