What's the difference between a Doctor of Computer Science and a Ph.D. in Computer Science?
This is the first I've heard of a "Doctor of Computer Science" degree. Not having a dissertation requirement is a clear sign that this is different from a "standard" Ph.D program. A Ph.D (in any discipline) requires you to produce an original piece of research that you defend to a committee of experts. In addition, most Ph.D programs will have course requirements, residency requirements and so on. 

Update: Some googling led me to the Wikipedia entry on 'professional doctorates', which most closely match the nature of the degree the OP describes. As Austin Henley points out, this is close in spirit to an MD (USA) and JD.