Does a defendant have to serve a term of imprisonment under a commitment issued upon his previous conviction for a similar crime?

Furthermore it should be noted, as discussed below, that any term of imprisonment under a commitment issued upon the earlier conviction must commence upon the date upon which defendant was delivered to prison under commitment for his subsequent offense, unless the term is made consecutive by order of the court. In the absence of such an order, the petitioner has in no way been prejudiced by the delays in his sentencing. (See People v. Rogers, supra, 252 Cal.App.2d 1015, 1021, 61 Cal.Rptr. 48.)