There are no stupid questions, only stupid answers... like this one :-)<p>No but seriously, if your &quot;spinning disk&quot; is even a semi-modern storage controller, it will queue and reorder your parallel requests for the most efficient access to the several, or dozens, or hundreds of physical disks it manages. So why not slam it with all the requests in a single sequence? Because a) if you are set up to handle parallel returns in your code, you don&#x27;t care about the ordering in which blocks are returned so much and b) the way this is physically implemented is n queues of d depth and you want to fill them all with work.