recoverdisk(1) wants to know about read errors when doing the 1MB/64k
reads as fast as possible so it can continue and retry them later with
smaller reads (down to sector size). Any retries by lower layers will
only slow it down.
Prodded by: arundel
This improves usability a little as we no longer require using touch.
Also reword the manpage wrt. parameters and fix usage() [1]
With no media in a cd(4) drive, the reads will loop producing EINVAL,
abort in that case [2].
Document the shortcoming of sectorsize and MAXPHYS (a quick solution
to this might be having MAXPHYS as the "bigsize", in short testing it
didn't make a difference on throughput).
Submitted by: arundel [1]
PR: bin/154528 [2]
o Introduce -r and -w keys which allow to load and save a worklist.
o Replace README by man page.
PR: bin/96677
Submitted by: Ulrich Spoerlein
Approved by: phk
MFC after: 1 month
