<<I need to create a new Image dataset. I want to retrieve the records in
reverse date order (LIFO). I was going to do a backwards chain read.
Someone told me that a reverse chain read was not efficient.>>


"Someone" is confused or misinformed. IMAGE detail dataset chains are
doubly-linked lists, so it is just as efficient to go backwards as to go
forwards. If the chain in use is the primary path of the set and the set
has been recently reloaded/repacked, there will be a slight advantage to
a forward-chain read courtesy of the disk subsystem's read-ahead
provisions. For most real-world situations, this advantage is minimal to
non-existent, and reverse chain traversals will not show any differences
from forward traversals.

Steve