Memory for FIR and IIR I have doubt regarding memory of FIR and IIR, I have read that output of FIR depends upon present and previous inputs, while output of IIR depends upon, present and previous inputs as well as previous outputs. Can anyone explain me how FIR consumes more memory than IIR? 

Source: https://dspguru.com/dsp/faqs/iir/basics/

Thanks very much.
In order to accomplish a particular specified filtering task, the FIR filter order will almost certainly be much higher than the IIR filter order.  For instance a low-pass filter that requires a particular "sharpness" in cutoff, the transition region between the passband (at low frequencies) and the stopband (at high frequencies).  What a 4th-order IIR filter can do might correspond to what a 20th or 25th-order FIR can do.  The 4th-order IIR requires 10 coefficients and 4 states.  the 20th-order FIR requires 21 coefficients and 20 states.

Feedback can be useful.