WRITE

Read syntax diagramSkip visual syntax diagramWRITE= channel_unit_address(channel_unit_address)

Specifies the subchannel address used to write data to the adjacent APPN node or Open Systems Adapter port. Code at least one WRITE subchannel address.

For an OSA-Express® feature, it specifies the subchannel address used to write MPC or ULP specific control data. Code exactly one WRITE subchannel address.

Subchannel addresses can be defined as a single address, as a range of addresses, or both. A range is indicated by a hyphen(-). VTAM® generates addresses for the range. For example, WRITE=(132,128-130,13A) defines the addresses 132, 128, 129, 12A, 12B, 12C, 12D, 12E, 12F, 130, and 13A.

For connections to an adjacent APPN host node:

For each address on the WRITE operand, code the corresponding address on the READ operand in the adjacent host to provide a complete path.

The WRITE subchannels are used in order, so certain subchannels can be given a higher priority by coding them first. For example, you might want to code subchannels with a higher bandwidth first.

For connections to an Open Systems Adapter or an OSA-Express feature:

You can specify only one subchannel address and that address must be an odd number that is one greater than the address specified on the corresponding READ operand. For example, if you specify 500 on the READ operand, you must specify 501 on the WRITE operand.

For an adjacent APPN node or an Open Systems Adapter port, do not code the same subchannel address for the READ operand and the WRITE operand in the same host.

For an adjacent APPN node or an Open Systems Adapter port, the WRITE subchannels are used in order, so certain subchannels can be given a higher priority by coding them first. For example, you might want to code subchannels with a higher bandwidth first.

Note: All READ and WRITE channels that you configure must have similar physical characteristics. If some channels take different physical paths with longer distances, this might result in data arriving out of order on the partner host. For connections to an adjacent APPN node, when MPCLEVEL=HPDT is specified, HPR is required to resequence the inbound packets that arrive out of order. HPR performs best when packets arrive with consistent times and data arrives in order. If the physical paths of the underlying HPDT MPC connection are different, this might lead to excessive retransmissions from HPR. The excessive retransmissions might lead to performance degradation.