tbb.c v1.02

This is a double buffered copy program that works like dd(1) except
that it uses two processes to do the copy which allows overlapped
reading and writing. If you use tbb to copy to a streaming cartridge
tape you can improve the streaming performance of the drive.

tbb is written as a replacement for the tcb(1) command on A/UX 
operating systems and so is called tbb. But it should be able to
work on any UNIX system that implements semaphores.

Compile it with cc -O -o tbb tbb.c

Note: tbb uses semaphores. If you abort the program with a SIGKILL
the program will not be able to clean up the semaphores that it
has created. You can remove the semaphores manually with ipcrm(1)
else they will hang around until the next reboot. It is better to
kill the program with another signal (most users have control/C
set to do the right kill).

Tony Cooper
sramtrc@albert.dsir.govt.nz
