Before Intersolv was Polytron (the P in PVCS).
Was very happy with it until the then-current owner of the system attempted to charge extortionate support fees (Approx. $300/seat/year, IIRC) at a PPOE a number of years (and three jobs) ago. Forced that employer to a completely different product (which I will neither name nor recommend).
The PVCS Tracker started life as DCS (Defect Control System) from a company whose name I've forgotten (ISTR a bug on a surfboard in their ads, though). It was a great product, the best defect tracker I'd used, before or since. Haven't used it in years, though.
Regards, -=Dave