Why do memory modules like flip-flops have a not q output and an r input?

Why do memory modules like flip-flops have a not q output and an r input?
What is the necessity of having either? In a d latch the r input is connected to the s input with an inverter, why is it necessary at all? The same goes for not q, if you really needed an inverted q output then you could just add an inverter when necessary. The only thing i could think of is that somehow these are used to connect individual modules sequentially (a 16x4 memory would have 16 rows of 4 bit words; how are the modules connected to form 1 word?) 

orksecurity7 years ago
Websearch "RS flipflop" will find a great deal of description of how these work. The two inputs exist because you need two lines to control the flipflop; the two outputs exist because the standard circuit (two NOR gates with feedback loops) naturally produces both Q and not-Q outputs, so you might as well expose them both and avoid requiring that the designer who needs not-Q add an inverter (which would add to the cost in dollars, power, space, and time delay from input to output).
seanroberts (author)  orksecurity7 years ago
Thanks for the reply, i think I understand a little better!