Nero DiscSpeed

Slider Test length	Defines the accuracy of the transfer rate test. The higher the accuracy, the more detailed the graph is. However, higher accuracy results in a longer test duration.
Check box Show RPM	Shows the rotational speed in the graph.
Menu Maximum speed CD/DVD	Defines the maximum value shown on the vertical scale of the graph on the Create Disc tab if a CD/DVD is inserted into the optical drive. To prevent parts of the curve from extending past the edge of the graph area, we recommend that you choose a value slightly above the maximum read speed of the optical drive.
Check box Show minimum/maximum	Shows the minimum and maximum speed values recorded during the transfer rate test. In a normal curve, the lowest speed is the start speed while the highest speed is the end speed. In an uneven curve, the lowest recorded speed is displayed as the minimum value while the highest recorded speed is displayed as the maximum value.
Check box Read test	Shows the read test curve in either high or low resolution.
Check box Write test	Shows the write test curve in either high or low resolution.

Area Write mode	Selects the SAO (Session-At-Once) or TAO (Track-At-Once) write mode for discs. You can also select the Overburn CD and Overburn DVD check boxes in Session-At Once mode. Enter the exact data quantity in the corresponding input fields.
Area Disc type	Enables burning simulation for either data or audio discs.
Check box Buffer underrun protection	Enables protection against optical drive buffer underrun. Buffer underrun protection is enabled by default. We recommend that you leave this check box selected.
Check box Streaming	Streaming can more than double the write speed. However, it can have a negative effect on the quality of the disc, since the disc is not checked during the burn process and defective sectors are not re-written. This check box is cleared by default, in other words verification is enabled. If this check box is enabled, verification will be disabled for DVD-RAM and Blu-ray discs.
Check box Direct overwrite	If this check box is selected, rewritable discs will be directly overwritten without having to delete old data first. If this check box is cleared, a dialog box will notify you when a disc containing data is inserted for writing.
Check box Burning an image file	If this check box is enabled, Nero DiscSpeed will run through the Create data disc test by creating an image file (ISO or NRG). If this check box is cleared, Nero DiscSpeed will run through the same test by burning binary data until the maximum capacity of the disc is reached.
Check box Include test data	If this check box is selected, additional information about the test (information on the optical drive, the installed firmware, and the burn process graph) will be burned to the disc.

Rotational speed

Discs can be read and/or burned in different ways. As a general rule, the reading process in optical drives starts at the radius of the disc and moves from the center outwards. The two standards used to define the types of rotational speed are linear velocity and angular velocity. With constant angular velocity, the tracks at the center of the disc always travel at the slowest linear velocity. The linear velocity increases as you move away from the center towards the outer edge. Angular velocity (also called rotational speed) describes the change in the rotation angle over time independently of the radius of the disc, i.e. the velocity at which an object loops a sector.

Buffer

A buffer refers to temporary memory that records and delivers data that cannot be processed immediately as required. The buffer also allows for continuous data flow.

DVD-RAM

Digital Versatile Disc Random Access Memory is the first rewritable data carrier format developed. It is characterized by a distribution of sectors that makes it possible to achieve increased data integrity, quicker formatting, and improved error management in comparison to DVD+/-RW.

Blu-ray

Blu-ray technology refers to burning on special data carriers. In comparison to DVD’s, which use a red laser in order to read and write data, Blu-ray discs are written with a blue laser. The shorter wavelength (405 nm) of this blue laser makes it possible to position the laser with greater accuracy. Data can be written in a more compact manner and takes up less space on the disc. A Blu-ray disc can store up to 25 GB on a single layer disc and up to 50 GB on a dual layer disc.

Streaming

Streaming refers to the continuous transmission of data that can already be played during the transmission procedure. This means that it is not necessary to wait until a media file has been transmitted completely before it can be played back. A TV channel can be received and displayed at the same time without it first having to be saved to the hard drive.