Cadence, Orcad, Pspice,Hspice etc.

Can anybody actually tell me the difference ? when i run Pspice on my computer, I notice that the startup states that it is a Cadence family. if somebody says that they are using cadence... does that mean that i can safely assume that they are using pspice ? thank you

The popularity of the SPICE circuit simulator has translated into various offerings, suited for different compute platforms. SPICE3, the latest Berkeley offering. It has the advantage of being freely available, to support a wide variety of models, and to run on all UNIX platforms. It is downloadable.

HSPICE (from Avant!) offers a more robust, commercial version of SPICE. No free copies here. If interested, contact Avant!.

PSPICE. This popular version of SPICE, available from Orcad (now Cadence) runs under the PC and Macintosh platforms. An evaluation version, which can handle small circuits with up to 10 transistors, is freely available. For a full fledged version or for more information, please contact Orcad. AIM-spice is a pc-version of SPICE with a revised user interface, simulation control, and with extra models. A student version can be downloaded. A complete list of all SPICE offerings (and software downloads for a wide range of platforms).
originates from the EECS Department of the University of California at Berkeley.
Cadence is a corporation of the series EDA software.
There the "Orcad " "Avant!" "are the names of the companies.
YOu can find more information from the intetnet such as google.