I would think HSPICE should be mentioned. (That is, unless you want to
trace only LTspice's ancestry.) In the semiconductor business community, I
believe it is one of the more significant and most used versions of SPICE.
Also one of the most expensive.
Regarding LTspice, I am not entirely certain whether it is considered in
the SPICE family. It's my understanding that it differs greatly from
Berkeley SPICE, and is not derived from either SPICE 2 or SPICE 3. Now
whether that means that so much of the Berkeley code was re-written or
replaced that it's a whole new program right from the start ... or if it
means Mike started from scratch but then borrowed from SPICE, and made it
extremely compatible with SPICE ... I can't say. I have seen it stated
that it is not an evolutionary step from SPICE, the way PSPICE was from
SPICE 2.
Andy
