A 16 bit system can only access RAM upto 64kbytes (normally). There is a concept of memory addresses that 16 bit system can access 2^16 numbers thus in unsigned integers it can only access 2^16 = 65536 INTEGERS (0 to 65535). Thus 16 bit sytem can only use addresses upto 64kbytes(after conclusion of small calculation). now the main que. Is that when we define an integer to be 'long int' than how can it access integers more than 65535?