This is a program designed to speed up writing tapes on remote tape
drives. After startup it splits itself into two processes. The first
process reads (and reblocks) from stdin into a shared memory buffer.
The second writes from the shared memory buffer to stdout. Doing it this way
means that the writing side effectively sits in a tight write loop and
doesn't have to wait for input. Similarly for the input side. It is
this waiting that slows down other reblocking processes, like dd.