Burning on the fly

Have you ever "burned on the fly?"

No -- I'm not talking about burning an insect with a magnifying glass like some of us did when we were younger (kids can be so cruel!) Burning on the fly is a technical term that essentially means writing directly to a CD recorder from another source other than your hard drive.

Usually when a CD is burned, it is read from the hard drive and then written to the CD burner. The important thing to note here is that a hard drive can retrieve information must faster than any other source-medium of information.

An example of burning on the fly might be copying a music CD using your CD ROM (source) and your CD burner (destination) at the same time. The process of burning on the fly infers that the process is done in real time -- that is, information is read from the source, and is written directly to the destination without any interruption.

Problems with burning on the fly

There are a few things to mention here. Although it is possible, it is not recommended to burn on the fly if both your CD ROM drive and CD burner are using the same I/O channel of communication -- IE: they are not physically connected using the same I/O (input/output) cable inside your computer.

The reason: the information from the source drive must travel to the motherboard (the "main" part of your computer) and then piped back up the same cable to your CD burner. Since this is an inefficient way to move information, it is possible to encounter a buffer underrun.

Although technical, the solution to this type of problem is to separate both CD drives to use different I/O channels. For example: the CD ROM drive could be connected to the hard drive, which is also connected to the Primary I/O on the mainboard. The CD burner could then be connected to the Secondary I/O, which would use a separate cable. This way, both drives are using two I/O channels of communication, instead of one.

No hiccups allowed

One thing worth mentioning is that burning on the fly requires that there are no hiccups during the recording process. Some possible causes for a read/write error are: finger-prints on the CD, scratches, defective medium, or causing resource starvation by utilizing the computer while under a heavy load.

Other physical limitations

Burning on the fly is usually I/O intensive which, in most cases, means that the process cannot be interrupted. If your system should hang -- even for a split second -- you risk the chance of burning a bad CD. This is because CD burning must be done on a continual (non-interrupted) basis, unless you've got buffer underrun protection. Even so, some buffer underrun protection schemes can cause distortion in music CDs on the destination disc.

On the other hand

While time can be saved burning on the fly, one way of ensuring that your CD burn will be 100% error-free from read-defects is to write the source information to your hard drive first, then write from the hard drive to the burner. In most cases, this preference is as simple as deselecting the "burn on the fly" option in most CD recording applications. The benefit to using this method: if there are errors along the way while reading the source CD, the process will abort without writing any bad information to the destination CD.

Long story short: you save $$ by not burning bad CDs.