dmc(4)dmc(4)Namedmc - DMC11/DMR11 communications interface
Syntax
device dmc0 at uba0 csr 0167600 flags 0x???? vector dmcrint dmcxint
Description
The interface provides access to a point-to-point communications device
that runs at either 1 Mb/s or 56 Kb/s. DMC11s communicate using the
DDCMP link layer protocol.
The interface driver also supports a DMR11 providing point-to-point
communication running at data rates from 2.4 Kb/s to 1 Mb/s. DMR11s
are a more recent design and are preferred over DMC11s.
The host address must be specified with an SIOCSIFADDR ioctl before the
interface will transmit or receive any packets.
Several protocols can be multiplexed over a link simultaneously. Con‐
versely, a can be set up such that only one protocol family can use
that device. If the latter approach is taken, an SIOCSTATE ioctl must
be issued by the protocol family requesting device ownership. The fam‐
ily address must appear in the ``if_family'' structure member, and
``if_nomuxhdr'' must be set. Before requesting ownership, make sure
that access to the device for all other protocol families is disabled.
The first byte of the flags word can be set up to indicate what mode
the device should use. The supported modes are 0 for full duplex, 1
for maintenance mode, and 2 for half duplex. In addition, if the
device is a the number of outstanding transmit buffers can be increased
from a default of 7 to a maximum of 24 buffers by specifying a hexadec‐
imal value in the second byte of the flags word. For example, if the
flags word is set to 0x1800, 24 transmit buffers will be allocated on a
device set up to run full duplex.
Restrictions
Note that maintenance mode should be used only to diagnose data link
problems. It is not intended to be used for normal data link traffic.
Diagnostics
dmcprobe: can't start device
The could not be started at boot time.
dmcinit: DMC not running
The unexpectedly stopped running.
dmc%d: done unalloc rbuf
The returned a receive or transmit buffer that was not allocated to it.
dmc%d: bad control %o
A bad parameter was passed to the dmcload routine.
dmc%d: unknown address type %d
An input packet was received that contained a type of address unknown
to the driver.
dmc%d: bad packet address 0x%x
The device returned a buffer with an unexpected buffer address.
dmc%d: can't handle af%d
The interface was handed a message that has addresses formatted in an
unsuitable address family. Formerly reported as dmc%d: af%d not sup‐
ported.
dmc%d: internal loopback enable requested
The device is being put in internal loopback at a user's request.
dmc%d: internal loopback disable requested
The device is being taken out of internal loopback at a user's request.
DMC FATAL ERROR 0%o
DMC SOFT ERROR 0%o
See Alsoinet(4f), intro(4n)
VAX dmc(4)
