The DCAM DRIVER statement defines the operating characteristics of the DCAM application for the Entire Net-Work communicator. The DRIVER statement must follow an Entire Net-Work NODE statement, but could be preceded by non-DCAM DRIVER and related LINK statements.
Only one DCAM DRIVER statement can be specified for a node. If more than one driver statement is needed for DCAM connections, the driver synonyms ICAM, DCM1, or DCM2 can be used. See the section Multiple DCAM Drivers in One Entire Net-Work.
The DRIVER statement for the DCAM driver has the following format:
For more information about syntax conventions and rules used in this section, read Conventions.
This section describes all of the parameters that can be used for the DCAM 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.
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Warning: GATEWAY links must be predefined and cannot be built dynamically from an unsolicited connection request. |
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 "N" is specified, Entire Net-Work will reject incoming requests from unknown source nodes.
The default and minimum form for this parameter varies, depending on the line driver you are using, as shown in the table below:
This optional parameter provides the DCAM driver with the DCAM application name (dcam-appname) for opening the DCAM ACB. This name can be any alphanumeric string (A-Z,@,#,$) up to 8 characters. If no name is specified, the node name taken from the NODE statement is the default value.
Heterogeneous communication partners accessible via LAN are not always able to specify the application name in EBCDIC. DCAM provides some flexibility with the /BCMAP command where an ISO transport selector can be mapped to a legal DCAM application name.
GOSIGNAL=Y, the default, allows DCAM to stop Entire Net-Work from sending messages over a particular link whenever a shortage of DCAM buffers is detected. After the buffer jam is resolved, DCAM notifies Entire Net-Work to resume sending. If GOSIGNAL=N is specified, the DCAM driver retries sending in 5 seconds intervals (VPASS). During wait time, no Entire Net-Work action will be taken.
This parameter enables the Entire Net-Work DCAM application to run in ISO mode so that message exchange conforms to the international standards of OSI transport protocols for the functions used by Entire Net-Work DCAM. If ISO and non-ISO connections are to be used in parallel, a second driver statement must be coded (DRIVER ICAM)
This parameter must be set to Y (Yes) when communicating with ASCII machines such as VAX or UNIX-based systems with WAN or LAN transport protocols. The default is N (No).
Note:
ISO is an attribute of the DCAM application (that is, the DCAM
driver); therefore, it is not possible to connect to non-ISO and ISO partners
at the same time within one driver. However, if a mixed environment exists
where ISO and non-ISO partners are to be interconnected, the DCAM driver must
be doubled. For a description, see the section
Multiple DCAM Drivers in One Entire Net-Work.
This optional parameter defines the alphanumeric password with a length of four bytes which must be provided by the communication partners before connecting to this application (see the LOGPW parameter in the section DCAM LINK Statement). If you specify a value of "none" for the password, this parameter is ignored.
This parameter specifies the maximum block size, in bytes, accepted by the line driver. The line driver issues a DCAM YRECEIVE ANY request of this size. Be aware that messages with larger block sizes from other nodes cannot be received. Software AG recommends that you set this parameter according to the largest block size specified (MAXBLK) in the LINK statements in the network.
The default of this parameter is 4096 bytes. The maximum value you can specify for front-end processors (FEPs) or data exchange controllers (DASTs) is 32767 bytes. The recommended value for LAN-based connections is 65520 bytes, which is also the maximum that can be specified for this parameter.
If you intend to send large messages over a DCAM link, set the MAXBLK parameter to the maximum value. If you receive error messages that read "unexpected response 0C30 from YSEND", choose increasingly smaller values for MAXBLK until the YSEND error messages disappear.
This parameter is applicable only when ISO=Y (Yes) is set. The default is N (No).
When this parameter is set to Y (Yes), the DCAM MORE DATA option is used for sending and receiving messages on a link. This allows large messages to be passed in small pieces such that DCAM saves intermediate buffering. However, this may involve more overhead since Entire Net-Work is notified more often. For example, a message of 4 KB is broken up into 4 elements on a LAN link and 8 elements on a HDLC link. Therefore, Software AG recommends that this parameter be used only when a gateway link exists in Entire Net-Work where large messages must be handled (>4KB) and segmenting cannot be performed.
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 DCAM DRIVER statement, a corresponding RESTART parameter value on each related LINK statement should be specified to control restart attempts on the individual link.
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 indicates whether tracing for this line driver should be active (Y) or not (N). When tracing is activated, trace information is placed in the trace table. The default is N (no). The TRACE parameter can be modified when the line driver is open or closed.
This is equivalent to specifying
TRACE=linedriver-code or
TRON=linedriver-code in the
NODE statement
(for example, TRACE=CTCA).