On Sun, Feb 28, 2021 at 10:18 AM Leo Wandersleb via bitcoin-dev > wrote: > Only headers need to be downloaded sequentially so downloading relevant blocks from one node is totally possible with gaps in between. In fact this is exactly how libbitcoin v4 works. We download and store blocks in parallel. In the case of a restart block gaps are repopulated. Given that headers are validated, we go after the most responsive nodes. Based on standard deviation, we drop the slowest peers and rebalance load to new/empty channels. We make ordered but not necessarily sequential requests. There is no distinction between “initial” block download, a restart, or a single or few blocks at the top. So it’s referred to as continuous parallel block download. But we don’t prune. Personally I consider this counterproductive. Apart from the complexity, it’s not healthy. And the chain grows linearly with storage cost falling exponentially, leading to a straightforward conclusion. e