The following is a sample output of the probe-scsi command showing the two internal SCSI busses.
ok probe-scsi Primary UltraSCSI bus: Target 0 Unit 0 Disk SEAGATE ST34371W SUN4.2G8254 Target 1 Unit 0 Disk SEAGATE ST34371W SUN4.2G8254 Target 2 Unit 0 Disk SEAGATE ST34371W SUN4.2G8254 Target 3 Unit 0 Disk SEAGATE ST34371W SUN4.2G8254 Removeable-Media/External SCSI bus: Target 3 Unit 0 Removable Tape ARCHIVE VIPER 150 21531-004 SUN-04.00.0 Target 4 Unit 0 Removable Tape EXABYTE EXB-8500SMBANXH10458 Target 5 Unit 0 Removable Tape EXABYTE EXB-8200 263H Target 6 Unit 0 Removable Read Only device TOSHIBA XM-5401TASUN4XCD3485