Hmmmm.... didn't realize that there was confusion on this point.
Pentax SMC = "Pentax K" series. SMC is what Pentax named the series of lenses and was the first generation of Manual K-bayonet style lenses. This was pointed out in detail in the page linked under the Pentax-M remarks. Also the page linked has this at the bottom of the page:
Quote: Conclusion:
A, F, FA and D FA lenses work on all Pentax bayonet cameras ever produced (exception: A lenses do not work on the MZ-60/ZX-60).
FA J and DA lenses work on cameras which have Tv and Program auto-exposure mode. Av mode and manual exposure is supported on some of these camera bodies. DA should only be used on digital cameras with an APS C sized sensor (16 x 24 mm).
M and K lenses work on all cameras except the MZ/ZX-30, MZ/ZX-50 and MZ/ZX-6. They work with limitations on the *ist film camera. They work with stop-down metering on the *ist D series and K series digital SLRs provided that a custom function is set appropriately.
I had thought that most of this stuff was pretty clear. I used it when I was a beginner and I found it consise and easy to follow.