You can obtain information
on controller characteristics by using the Get Device/Volume Information ($GETDVI)
system service. (Refer to the HP OpenVMS System Services Reference Manual.)
$GETDVI returns controller characteristics when you specify
the item code DVI$_DEVCHAR.
Ethernet Controller Device Characteristics lists these characteristics, which are defined by the
$DEVDEF macro and in the file SYS$LIBRARY:DEVDEF.H.
DVI$_DEVTYPE and DVI$_DEVCLASS return the device type and
device class names, which are defined by the $DCDEF macro and in
the file SYS$LIBRARY:DCDEF.H. The device class name for the LAN
Ethernet controllers listed in OpenVMS VAX LAN Devices and OpenVMS Alpha LAN Devices is always DC$_SCOM.
DVI$_DEVBUFSIZ returns
the maximum message size. The maximum send or receive message size
depends on the packet format and whether padding (NMA$C_PCLI_PAD)
is enabled (see Sections Read and Write ). DVI$_DEVDEPEND
returns the unit and line status bits and the error summary bits
in a longword field as shown in
DVI$_DEVDEPEND Returns.
Figure 11 DVI$_DEVDEPEND Returns
Ethernet Controller Unit and Line Status lists the
status values and their meanings. These values are defined by the
$XMDEF macro. XM$M_STS_ACTIVE is set when the port is started. XM$M_STS_BUFFAIL
and XM$M_STS_TIMO are dynamically set and cleared by the LAN driver.
Table 32 Ethernet Controller Unit and Line Status
Status
Meaning
XM$M_STS_ACTIVE
Port is active.
XM$M_STS_BUFFAIL
Attempt to allocate a system
receive buffer failed.
XM$M_STS_TIMO
Timeout occurred.
The error summary bits are set when an error occurs. They
are read-only bits. If an error is fatal, the Ethernet port is shut
down.
Error Summary Bits lists the
error summary bit values and their meanings.
Table 33 Error Summary Bits
Error Summary Bit
Meaning
XM$M_ERR_FATAL
Hardware or software error occurred on
the controller.