to beat a dead horse to death, i spent a few minutes writing a little
test program inspired by the little programming language in igbe for
bit-banging the atmel part.  a minimal primer
o	set offset (in bytes)
{}	set up timing
: n ;	loop
r/w	read/write
s	seek {n sectors, or 'r' random}
z	set sector size

so this little program times 1000 sectors of sequential read io
	{:1000 rs1 ;}
and this one skips sectors

so this little program times 1000 sectors of sequential read io
	{:1000 rs1 ;}
and this one would read every other sector
	{:1000 rs2 ;}

new# iop -p '{:1000 rs2 ;}' data
0.061
16220.14 iops
new# iop -p '{:1000 rs2 ;}' data
0.299
3340.96 iops

i think the 4k sector test would then be

	for(i in 1 2 3 4) iop -p z4096o$i^'{:1000 rs1 ;}' data

- erik