bang drum
I was recently perusing the /dev directory on a next when I
came upon the entry /dev/drum. This seemed a bit odd, I thought
that drum memory went out of fashion long, long ago. The man pages
didn't have anything to say about drum. Does any have any insight
on this odd device entry?
This actually has nothing to do with drum memory. It's a part
of the UUCP system.
Long, long ago, even before version 6, somebody wanted to
implement a program to copy files between two machines running
Unix. At the time there were no modems because there weren't even
any telephones. A Bell Labs researcher who had just visited Africa
seized upon the idea of communicating by beating on drums, as the
native Africans did. He added a drum interface to his PDP-11 and
the device driver was called, of course, /dev/drum. UUCP would
call a lower level program called "bang" to activate this device
driver. Messages could also be sent manually by typing "bang drum"
at your shell prompt. People soon devised shell scripts that would
take a mail message, convert it appropriately, and call bang to
send it. Soon they were sending multi-hop messages though several
sites this way, which is how the "bang path" got its name.
With the advancements in communications technology (semaphores
in particular), /dev/drum was removed from UNIX around version 6 or
7, I believe. The NeXT developers reinstated it on the NeXT
because they felt that a true multimedia machine should have as
many options as possible.
I hope this explanation helped.