NCR S26 - Manual (Page 146)

SCSI Channel Configurations
D-6 Hot Plug Backplane
SCSI Channel Configurations
The backplane SCSI channels 1 and 2 can support eight SCSI devices. You
can configure the backplane as single-channel (combine) or dual-channel
(split) controller.
In single-channel configuration, channel 1 supports the SCSI devices plugged
into slots 1 through 8.
In a dual-channel configuration, channel 1 supports the devices in slots 1
through 4, and channel 2 supports the devices in slots 5 through 8.