analogspiceman
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[ ...continuation of email interview with PSpice founder, Paul Tuinenga... ]
On Mon, Aug 5, 2013 at 11:13 AM, Paul Tuinenga wrote:
I don't mind these questions, just surprised anyone is interested in ancient, narrow history.
Blume developed Probe mostly during the time I was designing and building the engineering version of the Turbine accelerator, which was convenient since he had nothing to develop code on until I got that working. Probe was available later in 1984 or the beginning of 1985, I forget but can look that up when I get back [...]
In my opinion, if PSpice was "good" then Probe was "great" in that it made the purchasing decision a "no brainer" for most. So no only was the simulation under the control of the user (e.g. no waiting for a batch queue; sure, maybe the mainframe sim took only 30 seconds however you had to wait in line for 2 hours to have it run), but viewing the results was interactive and high quality. I have always thought Probe was, for most customers, the real product. Certainly, PSpice was leading edge and convenient but it has a boring status screen, and just sits there working. Probe was an oscilloscope -- the visible face of PSpice and MicroSim. The early version supported CGA, VGA, and SVGA graphics, as I recall. A few times a week, we would field a call for a customer ordering PSpice/Probe and asking for opinions of computer and display to purchase -- they did not have a PC, yet, and were already buying PSpice as the app they were getting the PC to run!
Also, being first, Blume had complete freedom to make a clean user-interface. Everybody after had to purposely not-copy Probe.
The demo version of PSpice was available nearly from the start, and its limited circuit size was a delicate balance: showing it "had the goods" but not enough to get real work done. About once a month someone would call to see if we would increase it by "one more transistor". As if...
Recasting the demo software as a "student version" came about in late '85 or early '86 (as I recall, but I can check that later) when we found there was a mailing list of college "electrical engineering" professors available for purchase. We thought it would be perhaps a few thousand names/addresses but it turned out to be over 20,000 (as I remember and that was just domestic). To make the disc, label it, and mail it with a cover letter, for that volume, was a "break the bank" expense for MicroSim at the time. But we forged ahead realizing that if it was a good idea for say 2,000 names it was an even better idea for 20,000.
Genius? In retrospect, but that's always the way. We were confident it would be tried by a large percentage of professors or they would give to to someone to try (i.e. not throw it away). We knew it would give students with access to PCs something to play with and enhance their lab-bench efforts. And there was not much else useful to run on PCs back then ("Lotus 123", etc.), but engineering departments had invested in PCs as "the future" even without a plan for software that supported their course offerings. We were in the right place at the right time.
If anything, this knitted PSpice into the fabric of EE education. A few years later, we read in an industry rag (ED, or EDN, etc.) an article about circuit simulation that alluded to "...PSpice and all the other PSpices..." Then we knew we had made it -- PSpice had either replaced Berkeley SPICE, in mind share, or perhaps many people had never heard of Berkeley SPICE and assumed PSpice was the original thing.
We often could track the career of many customers. They would take a new job, or new consulting client, and order PSpice again. "Oh, it seems Joe is working at Floobydust Systems now." Some did it a half-dozen times.
Another competitive barrier-to-entry we erected was having a growing library of standard parts, e.g. 1N4001, 2N2222, uA709,... Immediately after Microsoft's Fortran compiler started supporting overlays there was a flood of alphabet-soup-SPICE-on-the-PC products. Not only did we make a library, but pushed it to over 1,000 components. A nice round number, and enough that even if a particular part was missing a suitable substitute could likely be in that library. And we released the Parts option, the software we used to make the library, so customers could make anything missing from the library. That broaden the market to board-level engineers without a clue as to Gummel-Poon, Shichman-Hodges, etc. models. It took the "IC" out of SPICE.
In the process of that, we upended the market for SPICE models for hire and fostered the expectation that models be unencrypted ("open"). I recall a printed interview with one of the Hailey brothers (the "H" in H-SPICE) bemoaning how Parts had ruined their $6,000/piece modelling business. Boo hoo.
Anything else?
- paul
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