This procedure calls VixDiskLib_CreateChild() to establish a redo log. A child disk records disk sectors that changed since the parent disk or previous child. Children can be chained as a set of redo logs.
The sample program does not demonstrate use of VixDiskLib_Attach(), which you can use to access a link in the disk chain. VixDiskLib_CreateChild() establishes a redo log, with the child replacing the parent for read/write access. Given a pre-existing disk chain, VixDiskLib_Attach() creates a related child, or a cousin you might say, that is linked into some generation of the disk chain.
For a diagram of the attach operation, see Attach Child to Parent Disk.