The VTAM DRIVER statement defines the ACF/VTAM operating characteristics and requirements to the Entire Net-Work VTAM line driver. The DRIVER statement must follow an Entire Net-Work NODE statement, but may be preceded by one or more non-VTAM DRIVER statements and their related LINK statements. Only one VTAM DRIVER statement can be specified for a node.
The VTAM DRIVER statement has the following format:
For more information about syntax conventions and rules used in this section, read Conventions.
The DRIVER statement parameters are read from a sequential file during system startup, and can be modified after startup using the ALTER operator command. Some parameters can be modified when the line driver is open or closed. Others can be modified only when the line driver is closed. See ALTER and CLOSE in the section VTAM Operator Commands. The open/closed requirement for each parameter is included in its description.
This section describes all of the parameters that can be used for the VTAM DRIVER statement.
For more information about syntax conventions and rules used in this section, read Conventions.
This optional parameter determines whether the line driver will accept connections from systems that have not been previously defined with LINK statements. The ACCEPTUI parameter can be modified when the line driver is open or closed.
Valid values are "Y" (Yes) or "N" (No).
If "Y" is specified, Entire Net-Work will accept connection requests from an undefined system and the required control blocks are built dynamically. Normal "handshaking" procedures with the new connections are performed.
If you are using the TCP/IP or VTAM line drivers, user exits can be defined to provide security for incoming connections. For more information, see the section User Exit Interface.
If "N" is specified, Entire Net-Work will reject incoming requests from unknown source nodes.
This parameter provides the 1 - 8 character application name by which the Entire Net-Work VTAM line driver identifies itself to VTAM. The name specified must match the value specified for the ACBNAME parameter of the APPL macro in the VTAMLST library. If this parameter is omitted, the node name specified in the NODE statement is used. The APPLID parameter can be modified only when the line driver is closed.
If "Y" (Yes) is specified for this parameter, all VTAM requests are issued using VTAM Authorized Path. This feature greatly reduces VTAM overhead for most requests. In GCS, the virtual machine must be authorized. In z/OS, all STEPLIB data sets must be authorized. Authorized Path is not available for z/VSE systems. The AUTHPATH parameter can be modified only when the line driver is closed.
This optional parameter specifies the name of a user exit. The default is to run no user exit. For more information, read User Exit Interface.
If EXIT is coded but the load module cannot be loaded, execution continues as if no exit were specified. The EXIT parameter can be modified only when the line driver is closed.
This parameter specifies the size, in bytes, of the internal buffer used to receive data from VTAM. This is the size of the largest request unit that VTAM will deliver to this node. This size can also be specified with the MAXRU parameter. If values are specified for both parameters, the larger value is used. The MAXBLK parameter can be modified only when the line driver is closed.
Specify a decimal value from the MAXRU table shown below. Optionally, a value followed by a multiplier of either "M" (x 1048576, or 1 MB) or "K" (x 1024, or 1 KB) can be specified. The value can be 128 - 491520. A value less than 128 is reset to 128. A value greater than 128 but not matching one of those in the MAXRU table is reduced to the nearest table value. The default value is 1024.
This parameter specifies the maximum size, in bytes, of the internal buffer used to receive data from VTAM. This is the size of the largest request unit that VTAM will deliver to this node. This size can also be specified with the MAXBLK parameter. If values are specified for both parameters, the larger value is used. The MAXRU parameter can be modified only when the line driver is closed.
The MAXRU specification is determined by the following equation:
bytes = 1st-hex-digit * (2-raised-to-the-2nd-hex-digit-power)
For example:
87 = 8 * (2 to the 7th power) = 8 * 128 = 1024
Specify a hexadecimal value from the MAXRU table shown below. The value can be 84 - FF. A value less than 84 is reset to 84. A value greater than 84 but not matching one of those in the MAXRU table is reduced to the nearest table value. The default is 87.
| Hex Value of Bits 4-7 |
8 |
9 |
A |
B |
C |
D |
E |
F |
| 4 | 128 | 144 | 160 | 176 | 192 | 208 | 224 | 240 |
| 5 | 256 | 288 | 320 | 352 | 384 | 416 | 448 | 480 |
| 6 | 512 | 576 | 640 | 704 | 768 | 832 | 896 | 960 |
| 7 | 1024 | 1152 | 1280 | 1408 | 1536 | 1664 | 1792 | 1920 |
| 8 | 2048 | 2304 | 2560 | 2816 | 3072 | 3328 | 3584 | 3840 |
| 9 | 4096 | 4608 | 5120 | 5632 | 6144 | 6656 | 7168 | 7680 |
| A | 8192 | 9216 | 10240 | 11264 | 12288 | 13312 | 14336 | 15360 |
| B | 16384 | 18432 | 20480 | 22528 | 24576 | 26624 | 28672 | 30720 |
| C | 32768 | 36864 | 40960 | 45056 | 49152 | 53248 | 57344 | 61440 |
| D | 65536 | 73728 | 81920 | 90112 | 98304 | 106496 | 114688 | 122880 |
| E | 131072 | 147456 | 163840 | 180224 | 196608 | 212992 | 229376 | 245760 |
| F | 262144 | 294912 | 327680 | 360448 | 393216 | 425984 | 458752 | 491520 |
This parameter specifies the 1 - 8 character password associated with this APPLID. The value specified for PASSWORD must be the same as that specified for the PRTCT parameter, if present, on the APPL macro in the VTAMLST library. The default is no password. The PASSWORD parameter can be modified only when the line driver is closed.
This parameter specifies the number of receive RPLs (Request Parameter Lists) to be kept active at all times. Receive RPLs are control blocks that Entire Net-Work uses to receive data from VTAM. The number of RPLs specified can be 4 - 32767 for the entire system.
The maximum allowed may be limited by storage availability. At startup time, if the storage required to support the RECVRPLS requested is not available, Entire Net-Work resets the value to RECVRPLS=4. A value less than 4 is reset to 4, which is also the default. The RECVRPLS parameter can be modified when the line driver is open or closed.
If a high number of receive overruns occurs (read about the STATS command in VTAM Operator Commands), increase the RECVRPLS specification to provide more receive RPLs, or increase the receive buffer size specified with the MAXRU/MAXBLK parameters, or do both. Increasing the number of RPLs also increases the storage requirement, which is calculated as follows:
total bytes = (240 bytes + MAXBLK/MAXRU bytes) * RECVRPLS
This optional parameter specifies the retry interval in seconds (interval) and the number of retries (retries) that Entire Net-Work will attempt to reopen the access method with the API after a shutdown due to a failure. The RESTART parameter can be modified when the line driver is open or closed.
If RESTART is not specified, or interval is specified as zero, no retry is attempted. By specifying (retries) as zero, an infinite number of retries can be requested.
If RESTART is specified on the VTAM DRIVER statement, a corresponding RESTART parameter should be specified on each VTAM LINK statement to control restart attempts on the individual link.
The RESTART parameter is particularly useful with the TCPI, VTAM, and TCPX line drivers when Entire Net-Work is started at IPL and communication with the API or VTAM ACB is unsuccessful because TCP/IP or VTAM is not yet fully initialized. Using this parameter, you can instruct Entire Net-Work to reopen the TCP/IP session or VTAM ACB, thereby giving TCP/IP or VTAM sufficient time to become active.
The TIMER parameter on the NODE statement affects the RESTART parameter (see the section Entire Net-Work NODE Statement.) The retry interval should not be less than the TIMER parameter, and should be a multiple of this value. If a retry interval other than zero is specified that is less than the value of the TIMER parameter, the TIMER value is used instead.
This parameter specifies the number of seconds that the VTAM line driver will wait before attempting to reissue any VTAM macro after VTAM indicates that it requires more storage. The default is 1 (one second). The SLEEPTIM parameter can be modified when the line driver is open or closed.
This parameter specifies whether the applid-name or the node-name will be used as the transaction program name that is passed to the partner node.
This optional parameter specifies the size, in bytes, of the driver-specific trace table.
This parameter specifies the size of the internal wrap-around trace
table for non-link-specific trace information. This trace can be formatted or
printed with the operator command VTAM # TRACE.
Valid values can range from 16384 (the default) to 4194304. A value less than 16384 is reset to 16384; a value greater than 4194304 is reset to 4194304.
The TRACESIZ parameter can be modified when the line driver is open or closed.