I've seen more of such on the far-eastern webs, although this is the first one which appears to be actually reachable.

Some (most?) of those - including this one - are based on Keil's MON51/FlashMON/SoftICE. This makes sense - the Windows software is most of the work on such product. However, some limitations certainly remain, and its not fair they won't say how much. Although, the same can be said on most of the almost-true-ICEs and OCDs, too.

JW