There are three distinct parts to this note: some words on terminology, information on write-once media and critical data on erasable blanks. Terminology first: What's with this business of "erasable" and "write-once"; aren't "CD-RW" and "CD-R" good enough. Frankly, no, they're not.
The terms "CD-R" and "CD-RW" are applied to both the drives and the media that they write. In itself, that ambiguity is confusing, but even worse is the fact that it leads to a set of misunderstandings, particularly by newbies. I believe it's the reason that some do not recognize that you can master an erasable. There have even been some who don't know you can burn a write-once disc in a CD-RW drive. So, live with it: I use "erasable" and "write-once" for media, "CD-R" and "CD-RW" only for writers.
As noted elsewhere in this primer, there is a place in the ATIP of every blank for specifying the maximum and minimum write speeds. However, that is a capability, not a requirement. No manufacturer of media is required to fill in those data and many do not. If the blank does not establish a minimum, you are free to write - or to try to write - at 1x. If it does not specify a maximum, then you can run your drive at its max speed. The problem is that that may not produce a valid burn.
There is an optimum speed for writing any blank in any burner. Fortunately, that will tend to be a broad optimum and not to be very sensitive to the burner used. So if the optimum speed in your Yamaha is 8x then that medium will probably burn well at 4x and 12x and I'm likely to get good results in my Plextor at those speeds as well. However, that disc may not write well at 2x, might not work at all at 1x, may have high error rates at 16x and be prohibitively bad at a higher speed.
The result is that there is no blanket answer to the question of whether a blank certified for 12x will work at 16x (or 20x or ...). If it is not limited in the ATIP, you need to find out its performance for yourself or trust the reports in the newsgroups. Remembering that there are errors on every disc (though most are correctable), you can see that someone else saying it's (not) good enough for his needs doesn't promise you anything about your criteria.
When erasable discs came along, they could be written at only one speed: 2x. So the rule for writing the ATIP was different from that for write-once. If there is no value specified for minimum, the lowest write speed is 2x; if none for maximum, the highest speed is 2x. So far so good, but when the manufacturers wanted to get practical speeds on erasables, they came up with a new alloy. The dynamics of melting and freezing this metal are quite different from those for the 2x or 1x-4x media and the new stuff simply won't work below 4x. These blanks are termed "HS" for High Speed and drives suitable for writing them are similarly marked "HS". At this writing, HS media and drives are typically rated 4x-10x. Non-HS media and drives operate at 1x-4x.
Here comes the fun: the two types overlap at 4x. So someone with a non-HS writer may believe he can use HS media at 4x. Nice thought, but it's wrong. They simply won't work and if he's lucky, his software will tell him that when he tries. If he's not lucky, he may write or format without getting anything written or formatted. Even that's not as bad as using a non-HS disc in an HS drive. Typically, that does work, but only for a little while. All erasable media seem to be forgetful and to lose their data after some period of storage. The old 2x-only blanks seem to hold the information for many years; 1x-4x are less reliable; HS are pretty sad in this respect, but still should work for testing over a few months. But if you write an HS disc in a non-HS drive, you have a good chance that it will have forgotten most of that information the next day, perhaps on the next insertion.
The conclusion is that most experienced users of CD-RWs are very selective about where they use erasable media. Even more, they make sure that they use a tested brand of the right type: HS or not. Erasing is a good thing; forgetting is not.
E-mail me at cdrecording@mrichter.com
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