Dual layer refers to a DVD recording technology that provides users with 8.5GB of recording space (as opposed to 4.7GB of space) on a standard DVD+R discs).
Dual-layer recording (sometimes also known as double-layer recording) allows DVD-R and DVD+R discs to store significantly more data—up to 8.54 gigabytes per disc, compared with 4.7 gigabytes for single-layer discs. Along with this, DVD-DL's have slower write speeds as compared to ordinary DVD's and when played on a DVD player, a slight transition can be seen between the layers. DVD-R DL was developed for the DVD Forum by Pioneer Corporation; DVD+R DL was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM).
A dual-layer disc differs from its usual DVD counterpart by employing a second physical layer within the disc itself. The drive with dual-layer capability accesses the second layer by shining the laser through the first semitransparent layer. In some DVD players, the layer change can exhibit a noticeable pause, up to several seconds. This caused some viewers to worry that their dual-layer discs were damaged or defective, with the end result that studios began listing a standard message explaining the dual-layer pausing effect on all dual-layer disc packaging.
DVD recordable discs supporting this technology are backward-compatible with some existing DVD players and DVD-ROM drives. Many current DVD recorders support dual-layer technology, and the price is now comparable to that of single-layer drives, although the blank media remain more expensive. The recording speeds reached by dual-layer media are still well below those of single-layer media.
There are two modes for dual-layer orientation. With Parallel Track Path (PTP), used on DVD-ROM, both layers start at the inside diameter (ID) and end at the outside diameter (OD) with the lead-out. With Opposite Track Path (OTP), used on many Digital Video Discs, the lower layer starts at the ID and the upper layer starts at the OD, where the other layer ends; they share one lead-in and one lead-out. However, some DVDs also use a parallel track, such as those authored episodically, as in a disc with several separate episodes of a TV series—where more often than not, the layer change is in-between titles and therefore would not need to be authored in the opposite track path fashion.
Compact disc manufacturing is the process by which commercial compact discs (CDs) are replicated in mass quantities using a master version created from a source recording. This may be either in audio form (CD-Audio) or data form (CD-ROM). This process is used in the mastering of read-only compact discs; CD-Rs, CD-RWs, and DVDs are made somewhat differently, though the methods are broadly similar.
A CD can be used to store audio, video, and data in various standardized formats defined in the Rainbow Books. CDs are usually manufactured in a class 100 (ISO 5) or better clean room; they can usually be manufactured to quite strict manufacturing tolerances for only a few US cents per disk.
CD mastering differs from burning, as the pits and lands of a mastered CD are moulded into a CD blank, rather than being 'burn marks' in a dye layer (in CD-Rs) or areas with changed physical characteristics (in CD-RWs). In addition, CD burners write data sequentially, while a CD pressing plant 'writes' the entire disk in one physical stamping operation.
Basically the CD/DVD tower contains a bunch of IDE CD/DVD-ROM drives connected to the network. The number of DVD's is growing all the time. The result of this is that people are amassing larger and larger collections of DVD's in their home. With the introduction of BluRay DVD's this problem is only going to get worse. Pretty soon, unless you sort out a good storage solution there will be a good chance that disks will be lost, broken or damaged. In order to protect your collection, and to make sure that you can always find the DVD you want, when you want it, you really should think about buying a DVD tower to store your collection within. The DVD tower gives you great points of storage that can be kept close to your player and ensure that your DVD's are always close by.
There are many different types of DVD tower to choose from; you are far from limited to the very few models that might have characterized the market a few short years ago. The vast majority of towers are made from wood, but you can get metal versions, metallic versions and even glass in all sorts of shapes, styles and sizes which can really complement the decor of your home.
If you buy a good quality tower then you will find that they can be light to move around, if necessary and easy to clean. If you cannot find a suitable style to stand on the floor then you can also find models that will sit on shelves or even work by being bolted onto a strong wall. There are many different options to choose from and you are sure to be able to find something that is eminently suitable.
Nowadays, there are specialized disc printing devices called thermal DVD printers that are used to label and personalize DVDs. There are different types of thermal DVD printers available in the market: those that are run manually and those that work automatically.
The manual thermal DVD printer is used for manual printing of a small number of DVDs. However, when there are many DVDs to be printed, it is better to use an automatic thermal DVD printer that prints on hundreds of DVDs at a time.
In a thermal DVD printer, unlike the inkjet printers, the printer conveys solid pigment from a coated ribbon onto the surface of the disc under the influence of a combination of heat and pressure. Thermal DVD printers, which do not require special coated discs to accept the ink in the printing process, do give durable results. However, there are some DVDs that come out better after thermal printing, as the surface here is optimized for thermal transfer printing.
Writable DVD discs tend to have a raised ring in their center hub that may hamper the thermal DVD printer?s head, so be aware of this. To overcome this obstruction, it is advised to print above and below this area. However, there are some discs specially manufactured without this ring for continuous thermal printing. Thermal printing is best for text and line art colors on silver or white thermal discs. As the resolution and color processing of thermal is not that long, it is considered a cheap printing method. Moreover, as thermal printing does not require any drying time, the image here has no possibility of smearing or peeling off.
A thermal DVD printer works with a Windows or Mac compatible computer. The thermal DVD printer is connected to the computer through a USB port, and then using the supplied software, you design the appropriate design to be printed on the DVD.