V10/vol2/ipc/fig1

.KF
.PS
boxht = boxht/1.5
arrow "user" "write"
move up boxht/2
line right boxwid/2 then down boxht then left boxwid/2
move by (boxwid/2, boxht/2)
arrow right
line up boxht/2
line right boxwid/2 
move down boxht
line left boxwid/2 then up boxht/2
move right boxwid/2
arrow "device" "out"
move down boxht
arrow left "device" "in"
move down boxht/2
line left boxwid/2 then up boxht
move down boxht/2
arrow left
move up boxht/2
line down boxht then left boxwid/2
move up boxht/2
arrow left "user" "read"
.PE
.sp .5
.ce
Figure 1.  Configuration after device open.
.sp
.KE