OPS 05 - Disconnected aliases on CD-ROM and Alias Manager
Technical Q&A's
OPS 05 - Disconnected aliases on CD-ROM and Alias Manager (15-Sept-95)
Q Sometimes, after copying an HFS volume one-to-one to a CD-ROM, aliases which
look perfectly fine on the source volume are disconnected on the CD-ROM - the
Alias Manager claims that it cannot find the volume. What should I do to detect
and fix a possible disconnected alias before writing it to CD-ROM?
A Sometimes, when aliases move from hard drives to CD-ROMs, volume information
changes, rendering the alias unresolvable. The Alias Manager requires the
following pieces of information in order to identify a volume:
the volume's name
the volume's creation date (which should be a unique number)
the volume's kind (ejectable, non-ejectable, floppy disk, or foreign file
system)
The Alias Manager expects all three pieces of information to match. If all
three do not match, the Alias Manager attempts to identify the volume by
matching 2 of those 3 items, trying for a volume match in this order:
By name and creation date
By creation date and volume kind (if the volume name changed)
By name and volume kind (if the creation date is not stable, as with some
network file systems)
When pressing a CD-ROM, you are moving aliases from a hard drive (non-ejectable
volume kind) to an ejectable volume kind. If the volume name or creation date
of the hard drive changes after alias creation, the aliases may not resolve
properly.
You can avoid this problem by ensuring that the volume name of the hard disk
does not change while you are building a CD-ROM's content. Also, do not
backup, reformat, or restore a hard disk while you are building a CD-ROM
content, so the creation date does not change.
Sometimes, valid-looking aliases fail to resolve. Because the Finder creates
alias files, the Finder is responsible for resolving them. The Finder does not
always check and update aliases as carefully as you might. Additionally, the
Finder always resolves aliases using a relative search path.
You might want to test to see if installing QuickTime and/or the Multimedia
Tuner makes a difference in the cases where perfectly valid looking aliases
fail to resolve. QuickTime includes patches that make the Alias Manager work
better. See pages 4-6 and 4-7 of Inside Macintosh: Files.
