4.2BSD/usr/man/man4/dmf.4

.TH DMF 4 "27 July 1983"
.UC 4
.SH NAME
dmf \- DMF-32, terminal multiplexor
.SH SYNOPSIS
.B "device dmf0 at uba? csr 0170000"
.br
.ti +0.5i
.B "vector dmfsrint dmfsxint dmfdaint dmfdbint dmfrint dmfxint dmflint"
.SH DESCRIPTION
The 
.I dmf
device provides 8 lines of asynchronous serial line support with full
modem control (the DMF-32 provides other services, but these are
not supported by the driver).
.PP
Each line attached to a DMF-32 serial line port behaves as described
in
.IR tty (4).
Input and output for each line may independently be set to run at any
of 16 speeds; see
.IR tty (4)
for the encoding.
.PP
Bit
.I i
of flags may be specified for a
.I dmf
to to say that a line is not properly connected, and that the
line should be treated as hard-wired with carrier always present.
Thus specifying ``flags 0x0004'' in the specification of 
.IR dmf 0
would cause line ttyh2 to be treated in this way.
.PP
The
.I dmf
driver normally uses input silos and polls for input at each clock
tick (10 milliseconds).
.SH FILES
/dev/tty[hi][0-9a-f]
.br
/dev/ttyd[0-9a-f]
.SH SEE ALSO
tty(4)
.SH DIAGNOSTICS
.BR "dmf%d: NXM line %d" .
No response from UNIBUS on a dma transfer
within a timeout period.  This is often followed by a UNIBUS adapter
error.  This occurs most frequently when the UNIBUS is heavily loaded
and when devices which hog the bus (such as rk07's) are present.
It is not serious.
.PP
.BR "dmf%d: silo overflow" .
The character input silo overflowed
before it could be serviced.  This can happen if a hard error occurs
when the CPU is running with elevated priority, as the system will
then print a message on the console with interrupts disabled.  If the
Berknet
is running on a
.I dh
line at high speed (e.g. 9600 baud), there is only 1/15th of a second of
buffering capacity in the silo, and overrun is possible.  This may
cause a few input characters to be lost to users and a network
packet is likely to be corrupted, but the network will recover.
It is not serious.
.PP
.BR dmfsrint .
.br
.BR dmfsxint .
.br
.BR dmfdaint .
.br
.BR dmfdbint .
.br
.BR dmflint .
.br
One of the unsupported parts of the dmf interrupted; something
is amiss, check your interrupt vectors for a conflict with another
device.