One of three CD recording methods. The other two are track-at-once and disc-at-once, but packet writing allows smaller blocks of data to be written. Fixed-length packets are commonly used with CD-RWs ...

No, you can't do it on the mac. Its not really worth it on windows either, because the discs are not compatible with non direct-cd equipped machines. IOW, its only useful for the segment of the market ...

I've seen packetwriting software bugger too many systems to possibly endorse the use of it. It's not like it's difficult to fire up Easy CD Creator or Nero and copy/paste files over then hit record.