Service manual

C-10 Sun Ultra 2 Series Service Manual • July 1996
C.1.8 SCSI
The system unit or server provides a 20-Mbyte per second SCSI interface that is
supported by the FEPS ASIC. 20 Mbytes per second is provided by 16-bit
single-ended operation at 10 MHz. Both internal and external peripherals are
connected to the same daisy chain. External connection is provided through a 68-pin
SCSI connector (see
FIGURE C-1).
System configuration requires external devices to be connected in a daisy chain
configuration. A maximum of 12 external devices may be daisy-chained through a
maximum cable length of 19.69 feet (6 meters). The end of the daisy chain must be
terminated with an active terminator. If both 50-pin and 68-pin external devices are
connected externally, the 68-pin device must be connected earlier in the daisy chain.
A special terminator is available for the last 68-pin device that terminates the extra
signals and converts the extra signals into a 50-pin configuration. The last 50-pin
device must be terminated.
Note – When using the 535-Mbyte hard drive, contact your Sun representative to
order a 50-to-68-pin SCSI cable: for 1.2-meter (1.3-yard) external SCSI cable, order
X903A; for 2.0-meter (2.2-yard) external SCSI cable, order X904A.
C.1.8.1 SCSI Implementation
■ Single-ended
■ 16-bit (wide SCSI) with parity
■ 20 megabits-per-second (Mbps) Fast/Wide SCSI
TABLE C-1 Supported Hard Drives
Form Factor Dimension Hard Drive Capacity
Fast/Wide
SCSI RPM
Access
Time
1 inch 535 Mbytes No 4500 12 ms
1 inch 1 Gbyte Yes 5400 11 ms
1 inch 2.1 Gbytes Yes 7200 9.5 ms
1 inch 4.2 Gbytes Yes 7200 9.5 ms
1 inch 9.1 Gbytes Yes 7200 9.5 ms