Heck, most decent buses (e.g. floppy, Multibus, GPIB)
are negative
Unibus, Omnibus, Qbus, etc...
logic. The control lines on most RAM chips are
negative (CS is
usually low-voltage=true along with WR = low, true). I don't see
EE's driving themselves to drink over it. If we'dve created TTL
using PNP transistors instead of NPN, would we be having the opposite
discussion?
Gieen that an unconnected TTL input floats high (yes, I know you
shouldnever rely o nthat, but plenty of computer companies did :-(), and
that the output sinks a lot better than it sources, I often thought it
would ahve made more sense to fice the TTL '0' an high and the '1' as
low. So a 7400 becomes aNOR gate, etc.
I guess they wanted to keep the convetions establisehd with DTL, though
-tony