So i need only two 24LC256 to store the six samples samples every 10mS (one sampled every 20mS).
As i have six EEPROMs on board can i use six of them to store, say input number 1 in EEPROM number 1 and so on. I know it is a waste of EEPROM but is it possible? If it is, we can sample faster and we can have more data to store (10mS and 20mS is the lowest rages in the requirments).

Otherwise i will have 2 of 24LC256 (i have got six of these and i wanted to use them as i explained above) as i don't have 24LC512.

I'm not quite following what you explained to me just before the last paragraph of you message. The RAM . . . can please you explain to me a bit more

Thanks,
Tom