whelan@huey.uhcc.Hawaii.Edu (The Obscure Guru) (11/07/90)
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? -- ------------------------------------------------------------------------------- whelan@ (uhunix.uhcc.hawaii.edu || uhccux.BITNET || nextsrv.wslab.hawaii.edu)
curt@cynic.wimsey.bc.ca (Curt Sampson) (11/08/90)
whelan@huey.uhcc.Hawaii.Edu (The Obscure Guru) writes: > 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 becuase 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. cjs curt@cynic.UUCP | "The unconscious self is the real genius. curt@cynic.wimsey.bc.ca | Your breathing goes wrong the minute your {uunet|ubc-cs}!van-bc!cynic!curt | conscious self meddles with it." --GBS
geoff@ITcorp.com (Geoff Kuenning) (11/08/90)
In article <10193@uhccux.uhcc.Hawaii.Edu> whelan@huey.uhcc.Hawaii.Edu (The Obscure Guru) writes: > 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? Well, drums used to be popular for swapping, since they were too small for useful file storage but very fast. So instead of /dev/swap, you had /dev/drum. System V now has /dev/swap, but BSD still uses /dev/drum. Since Next is BSD-derived and many applications have /dev/drum wired in, this device provides access to the swap file. -- Geoff Kuenning geoff@ITcorp.com uunet!desint!geoff
chris@iesd.auc.dk (Christian J. Callsen) (11/09/90)
> Well, drums used to be popular for swapping, since they were too small > for useful file storage but very fast. So instead of /dev/swap, you > had /dev/drum. System V now has /dev/swap, but BSD still uses > /dev/drum. Since Next is BSD-derived and many applications have > /dev/drum wired in, this device provides access to the swap file. > -- > Geoff Kuenning geoff@ITcorp.com uunet!desint!geoff Excuse me for asking, but which applications needs access to **the swap area** ? -Chris 8^> -Disclaimer: No, I'm *not* a NeXT owner - yet...