Does a .dmg need to be converted prior to burning to a CD?

Not with Disk Utility or Toast. You should be able to burn directly from the dmg.

just remember the resulting CD/DVD will have the same format as the original .dmg and depending on what that format is may or may not be cross platform compatible.

It's been my experience that .ISO = .Toast = .CDR

Those are raw block dumps with no headers stripped or added, no compression, and include the entire media regardless of used/free space, and are totally platform and OS independent. (any computer can burn an ISO that's meant to be used by any other computer)

.dmg can be any of an immense variety of things, even when you consider only those made by disk utility.

But .cdr is a Corel Draw file format and just an image. How do you burn an image as something special or platform-independent? It will still be an image only openable by Corel.

Like many extensions, more than one application uses the .CDR extension. It is also commonly used for disc images, which is to what V1 is referring.

Check FileExt.Com and scroll down the page for the six known uses of the .cdr extension and of 50 documented applications and variations associated with the extension. Yet one more reason Apple's type and creator meta tags are superior to the three character extension, albeit they are recognized only by Apple.

Thanks, I never used FinalCut Pro before and thought an extension should be tied to a program rather than being dispersed like this among unrelated things.
Good to know.

when you've only got three characters to use, you're gonna run out eventually.

Be thankful, that came from a system where the name to the left of the extension was restricted to eight characters...

BTW, apple (and I assume now windows also?) supports using more than three characters on an extension. (".toast", etc)

I would assume yes otherwise Microsoft wouldn't have created new formats like .docx and .xlsx