BATCH2 (TCP/IP)

BATCH2 is the name for a program that allows a stream of Model 204 command in a sequential file to be sent to a Model 204 Online and to have the output from the Online to be saved to another sequential output file. There are basically two BATCH2 programs:

1. A BATCH2 program written in assembler and provided by Rocket Software that uses CRAM as its transport. Because CRAM is an inter-address space transport, this BATCH2 can only work if the BATCH2 program is running on the same machine and LPAR as the target Online.
2. A BATCH2 program written in C provided by Sirius Software that uses TCP/IP as its transport. Because TCP/IP allows communication between two different machines, there are no restrictions on where the BATCH2 program is relative to the target Online. This is the BATCH2 program that is the subject of this page.

The original TCP/IP BATCH2 was expected to be run on Unix. As such, it originally used Unix-style command line parameters. The TCP/IP BATCH2 was then extended to support Microsoft Windows and, finally, was extended to work on IBM mainframe operating systems VM and MVS (now known as z/OS).

The mainframe implementations of the TCP/IP BATCH2 continued to use the Unix-style parameters. Unfortunately, because the CRAM BATCH2 used a totally different parameter list, this made it difficult to easily convert programs that used the CRAM BATCH2 to use the TCP/IP BATCH2. The ability to do this would be useful at a site that had multiple mainframe LPARs or machines &emdash; it can be useful to have a BATCH2 program running on one LPAR or machine communicating with a an Online on another. Because of this, BATCH2 was modified so that there was a version that used a parameter list identical to that used by the CRAM BATCH2.

CRAM BATCH2 compatibility

Providing a TCP/IP BATCH2 that is plug compatible with the CRAM BATCH2 presents some special challenges. Most importantly, the target Online for a CRAM BATCH2 program is indicated by the first comma-delimited parameter. This parameter is an 8-byte or shorter CRAM channel name. But the TCP/IP BATCH2 requires a host name (which is often 16 bytes or longer) or IP address, and a port number. So, to provide CRAM BATCH2 compatibility, the mainframe TCP/IP BATCH2 must be linked with an assembler program that maps CRAM channel names to host names and port numbers.

This program is called BATCH2CH (for BATCH2 CHannel) and consists of pairs of null-terminated CRAM channel names, and host names or IP addresses and port numbers. The host name and port number must be separated by the space character. For example:

         ENTRY BATCH2CH
BATCH2CH RMODE ANY
BATCH2CH CSECT
         DC    C'IOCALE',AL1(0)
         DC    C'sirius-software.com 2231',AL1(0)
         DC    C'IOALE',AL1(0)
         DC    C'sirijes2.sirius-software.com 2231',AL1(0)
         DC    AL1(0)
         END

In this example, CRAM channel IOCALE is mapped to host sirius-software.com, port number 2231, and CRAM channel IOALE is mapped to host sirijes2.sirius-software.com, port 2231. The list is terminated with a single null (AL1(0)) after the last host name and port number. This allows the TCP/IP BATCH2 to be invoked with one of the CRAM channel names in BATCH2CH:

//BATCH2   EXEC PGM=BATCH2,REGION=4096K,     
//             PARM='IOCALE'                 

In the above example, if the BATCH2 program was linked with the (assembled) preceding BATCH2CH, it would try to connect to host sirius-software.com port 2231.