Question about random access file

I have no real experience in this kind of matter ^_^ I think you want to test the device(card or whatever) if it reads or writes. To test it's writing you want to fill the full space of the devices disk? And to test the reading you want to read all the data back and compare it with the data should be written on de disk? Since every device has a varying disk size you could just stick with 1 MB file and write a file that is sequence of that 1 Mb file. So if the disk is 256 MB you can write one large file wich contains the 1MB file 256 times. And read it like the same principle. It's just an idea. I don't know if this is usefull or wht you wanted to ask ^_^ Good luck Momer ^_^ regards