Hello Ioannis,

I>>Does anyone have any experience with Hash Functions to code the unique iButton serial number into a memory address to find it then instantly?<<

Ouch...Unless you can use a "function" to calculate your address directly, you are talking about time. Some Hashing routines use functions as such. The other Hash routines will probably require more time in calculating , then it would be to read the data and compare. How many items will you have?

Can you store them in a ASCII logical order and do a Binary Search routine?
This will limit your number of reads down. if you have 256 items (like in a table) you would find (worse case senario) 8 reads to have your value.

Dwayne