You can obtain informationon controller characteristics by using the Get Device/Volume Information ($GETDVI)system service. (Refer to the HP OpenVMS System Services Reference Manual.)
$GETDVI returns controller characteristics when you specifythe item code DVI$_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 anddevice class names, which are defined by the $DCDEF macro and inthe file SYS$LIBRARY:DCDEF.H. The device class name for the LANEthernet controllers listed in OpenVMS VAX LAN Devices and OpenVMS Alpha LAN Devices is always DC$_SCOM.
DVI$_DEVBUFSIZ returnsthe maximum message size. The maximum send or receive message sizedepends on the packet format and whether padding (NMA$C_PCLI_PAD)is enabled (see Sections Read and Write ). DVI$_DEVDEPENDreturns the unit and line status bits and the error summary bitsin a longword field as shown in DVI$_DEVDEPEND Returns.
Figure 20 DVI$_DEVDEPEND Returns
Ethernet Controller Unit and Line Status lists thestatus values and their meanings. These values are defined by the$XMDEF macro. XM$M_STS_ACTIVE is set when the port is started. XM$M_STS_BUFFAILand XM$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 systemreceive buffer failed.
XM$M_STS_TIMO
Timeout occurred.
The error summary bits are set when an error occurs. Theyare read-only bits. If an error is fatal, the Ethernet port is shutdown. Error Summary Bits lists theerror summary bit values and their meanings.
Table 33 Error Summary Bits
Error Summary Bit
Meaning
XM$M_ERR_FATAL
Hardware or software error occurred onthe controller.
HP OpenVMS I/O User's Reference Manual
Local Area Network (LAN) Device Drivers
