|Every CD-R has a spiral, which starts on the inside and ends on the outer part of the CD, where the data is written (like on a harddisk). The laser-head will always follow this spiral from begin to end to read (or write) data.
The distance between the start- and end-position of the spiral are defined in the CD Red-Book and are the same for all 63, 74 & 80 minutes CD-R media. So the spiral has to be wound tighter to fit 80 minutes data in the same space were normally only 74 minutes data resides.
80 minutes CD-R's can be written by almost any CD-Writer but there are a few CD-Writer manufacturers (like HP & Sony) who say that they do NOT support 80 minutes CD-R's as these CD-R's do not comply to the CD Red-Book standard. So it is possible that the CD-Writers made by these manufacturers work with 80 minutes CD-R's but it most cases it won't. The only way to know it for sure is by writing 700 Mb data to a 80 minutes CD-R and then comparing it with the CD contents when the CD was written correctly.
For example the HP8100i & Sony CRX-100 CD-Writers will only write a 80 minutes CD-R up to 78:16 minutes.
As the 80 Minutes CD-R's are now widely available CD-Writer manufacturers will be forced to support them. Usually a firmware update will do the "trick".