[Someone]

> meanwhile, the front server waits for all chunks to arrive, which takes 1 minute 100 ms, then sends their concatenation to you, which takes 10 minutes

It doesn’t have to wait for all chunks to arrive, but can start streaming the moment it has the first byte (for some protocols, it may even send you chunks out of order, and start streaming the moment it has _any_ byte)

Also, if throughput from the server to you is higher than that of a single disk, the second case can get the file to you faster. As an extreme example, if that throughput is over ten times that of a single disk, sending the complete file to you can take close to 1 minute.

Having said that, if it has to combine X out of Y > X streams to produce the actual data, getting that will be slower than retrieving a single stream because retrieval times will have some variability.