Thanks everyone for you helpful insights! Sorry for the inconsistencies in the post example. My J understanding is obviously lacking.
my goal is to have a practical example of running calculations on data that is larger than my machines ram. I'm thinking mapped files is the only way to do that and if I understand..... I *hope* it's possible as long as I make sure the intermediate results do not exceed J session memory (i.e. perhaps close to machine ram). My J session memory limit is: 2^30 = 1,073,741,824=1GB If I want to work on floating point numbers which are 8 bytes each and I need at least a factor of 5 times the data memory. Then I should be able to work with data of size: 2.6e7 = ( (2^30)%5)%8 which is about 20 million floating point numbers in 32 bit J.... Much Thanks -Joe ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
