The Sun 501-4189 Microsystem 8Slot Scsi Hdd Backplane Board 501-4189 is in in stock at Calhoun Technologies. For over 10 years Calhoun Technologies has been saving companies likes your up to 80% off list price on hard to find computer hardware. Manufacturer: Sun Part Number: 501-4189 Details: Sun 501-4189 Microsystem 8Slot Scsi Hdd Backplane Board 501-4189