IBM RT User's Setup Manual page 172

1 Level 6 is used in nonshared mode for compatibility, or levels 12 and 14 can share for a new mode.
a Optional interrupt levels and DMA channels can be set through software.
*D M A Channel 3 is only available when a second Extended ESDI Adapter is used
The enhanced graphics adapter (EGA) and 3278/79 Emulation adapter may be used together; at this printing, there is no
H
known program that uses interrupt level 9 on the EGA.
®The 5080 attachment adapter and the S/370 host interface adapter are designed to operate together at the defined default
values. If these adpaters are reconfigured for other optional DMA channels, the user must provide driver/application
software.
1.
Section Getting Started
AJZTF042
1-21