Mac OS X 10.4: About improved disc burning and Burn Folders
Mac OS X 10.4 Tiger makes it even easier to burn to a writable CD or DVD but there are some things you should be aware of if you're used to burning discs in earlier versions of Mac OS X.
Tiger uses aliases for improved burning
Before Mac OS X 10.4, data was copied twice before burning—Tiger copies the data only once, accelerating the burning process. Tiger accomplishes this by creating aliases to the data to be burned.
For example, if you drag a folder to a blank disc icon to burn its contents, Tiger temporarily puts an alias on the disc. When you later burn the disc, the actual data that the alias points to is burned to the disc. This means that when you drag stuff to an blank disc's icon (or Burn Folder, see below), a temporary alias is created on the disc or in the folder.
Important: Aliases on discs that haven't been burned yet point to your actual data; data is not copied to the disc until you actually burn the disc. This means if you double-click the alias and modify the files or content, you are modifying the original data on your hard disk—not just the data on the unburned disc.
When Tiger burns the disc, it burns the original data to the disc, not the temporary aliases.
Burn Folders make disc burning easier
Mac OS X 10.4 also introduces Burn Folders in the Finder. This feature makes it easy to get your stuff ready for burning without actually having to have a disc in the computer (until you're ready to burn it, of course). You'll see a black "burn banner" inside the folder as a reminder, along with a Burn button. When you click the Burn button, you are prompted to insert a writable disc and told how much free space it must have to burn the contents of the folder.
Removing stuff from a burnable disc or Burn Folder before burning
You can delete aliases from a Burn Folder or unburned disc without affecting your original data to which the aliases point. These aliases are at the "highest" (or root) level of the Burn Folder or unburned disc. As mentioned, if you actually double-click any of these aliases, you'll be able to modify the files on your hard drive. In other words, when a Burn Banner is present, you can delete the data aliases with no consequence to the actual data on the hard disk.
Important: Do not double-click a burn alias and then delete the aliased content. This does not remove anything from the disc or Burn Folder, but does remove content from your computer!
What happens if an alias is manually copied to the disc or Burn Folder?
When the burn starts, Mac OS X 10.4 will attempt to burn the data that any alias points to, even if it's not as the root level of the unburned disc or Burn Folder. If your alias points to missing data, this alert appears:
"The item 'name of item' cannot be burned because the original item cannot be found. Skip this item and continue burning?"
To avoid this, don't create aliases on unburned discs or Burn folders. Instead, drag the original content to the disc or folder so that Mac OS X will create the alias for you.
How large is the burn folder?
To see the number of items and data size that will be burned, open the burn folder and look at the bottom of the window; or, select the folder and choose Get Info from the File menu. Also, you can click the refresh button in the bottom right corner of the burn folder window if you add or remove items from the folder.