z/OS DFSMSdfp Advanced Services
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Comparing CCW and zHPF channel programs

z/OS DFSMSdfp Advanced Services
SC23-6861-01

Table 1. Comparing CCW and zHPF channel programs
Function CCW channel programs zHPF channel programs
Devices supported All DASD only
Processors supported All EXCP and EXCPVR are only supported on a zEnterprise® 196 (z196) zEnterprise 114 (z114) or higher processor
Command set All commands for all currently supported devices Subset of DASD commands
Maximum channel program size No limit 240 bytes because of the TCA size limit
Maximum data transferred per CCW or TCW 64 KB-1 64 KB, 2 MB, or 4 GB, depending on the processor
Read and write commands in the same channel program Yes No
Skip on read CCW or MIDAW skip bit TIDAW skip bit
Indirect addressing IDAL, MIDAL TIDAL
Data Chaining Yes No, but TIDAL is equivalent to data chaining.
Status modifier/search commands Yes No
Program controlled interrupt (PCI) Yes No
Append to running channel program Yes No
Self-modifying channel programs Yes No
VIO data sets Yes No

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