Partial test could include beginning and end of file

[israel-lugo]

Some files may be very similar at the start, but different at the end. E.g. a large ISO of two similar operating system versions, or so on. Also, some media formats add their metadata headers at the end, instead of the start (cf ID3v1 tags for MP3).

The partial test could read X/2 KB from the start and X/2 from the end. This would also help against collisions, by mixing it up.

Should performance test this. It will cause more seeking in mechanical disks. Will it make a noticeable difference?