Channel programs for channel-attached type 2 and type 4 physical units
The ICNCB represents type 2 and type 4 physical units,
and contains addresses and CCWs needed for channel programs. Figure 1 shows the following information:
- ICNCB
- Location in storage of various CCWs
- Write buffers required for writing three PIUs, each of which is contained in a single buffer. Write or Write-Break CCWs alternate with transfer-in-channel (TIC) CCWs.
Figure 1. Data areas used by channel programs
for PU types 2 and 4