Detecting last page written in multi-plane non-volatile memory

A method, comprising:

• dividing a range of memory pages into R>2 contiguous sub-ranges, wherein R is a number of the contiguous sub-ranges;
• assigning a set of pages at boundaries of the sub-ranges;
• operating a storage controller to sense the set of pages at the boundaries across P=R−1 memory planes in parallel, wherein P is a number of planes, and wherein P is greater than 1;
• and
• reducing the range by a factor of P/R.

A memory system, comprising:

• a plurality of D memory die, each of the D memory die including a plurality of P memory planes;
• and
• logic configured to:
• test in parallel for either a programmed state or an erased state of a memory page on D*P word lines of a range R of word lines, each word line sensing a page from a different one of the memory planes;
• reduce the range R by a factor of (D*P)/(D*P+1);
• and
• repeat the test step and the reduce step until R satisfies a configured condition.