Once headers are loaded first there is no reason for sequential loading. 

Validation has to be sequantial, but that step can be deferred until the blocks before a point are loaded and continous.

Tamas Blummer
http://bitsofproof.com

On 07.04.2014, at 21:03, Gregory Maxwell <gmaxwell@gmail.com> wrote:

> On Mon, Apr 7, 2014 at 12:00 PM, Tamas Blummer <tamas@bitsofproof.com> wrote:
>> therefore I guess it is more handy to return some bitmap of pruned/full
>> blocks than ranges.
> 
> A bitmap also means high overhead and— if it's used to advertise
> non-contiguous blocks— poor locality, since blocks are fetched
> sequentially.
>