Hitachi TrueCopy for IBM z/OS User and Reference Guide (T5211-96001, June 2007)

About TrueCopy for z/OS Operations 2-33
Hitachi Universal Storage Platform V TrueCopy for IBM z/OS User’s Guide
An application may issue update I/Os bypassing the MVS standard I/O
procedure.
The I/O time-stamping function may not be active at the primary system.