An incremental backup theoretically copies only those files that have changed
since the last backup. In Office Systems 1.0 and 2.0, the incremental
backup does NOT work that way: it copies everything, just as if you had
selected a full backup. Because of this problem, Apple recommends in the
Lisa 2 Owner's Guide Release Notes: "Do not back up a hard disk icon to the
diskette icon. Instead, make duplicates of the tools or documents you wish to
back up, and then move the duplicates to the micro diskette icon."
At the end of an incremental backup with release 3.0 software, the error
number 941/3 may be displayed. All documents that were changed since the
last full backup are copied to the disk. These documents are accessible
only from the desktop; they may not be used to restore the ProFile using
the Office System 1 diskette's Restore routine. Lisa Office System version
3.1 corrects this problem, allowing you to restore your hard disk from
backup diskettes if you wish.