Product data
time before motor startup is specified for each disk drive module. After power is
switched on, the delay time is usually SCSI ID x 12 seconds. For example, the delay for
a disk drive module whose SCSI ID is 2 is 2x12 seconds (24 seconds).
If the switch card assembly is not present when the 2104 is first switched on, or when
the 2104 receives a ‘Reset’ signal, the default logical setting for this switch is Off.
Enclosure ID switch 6: This 10-position rotary switch sets the ID of the 2104. The
software uses the setting of this switch to identify the enclosure.
If the switch card assembly is not present when the 2104 is first switched on, or when
the 2104 receives a ‘Reset’ signal, the default logical setting for this switch is 0.
Internal Switches
The following switches can be accessed only when the switch card assembly is
removed from the 2104. In service operations, these switches need be checked and, if
necessary, set only when a replacement switch card assembly is installed.
SCSI Address switch 7: This switch, when set to On, reverses the SCSI addresses
of the disk drive modules. The default setting for this switch is Off.
On a 2104 Model DU3, the leftmost disk drive module slot has the lowest SCSI
address; the rightmost slot has the highest SCSI address (see Table 1 on page 25). If
the switch is set to On, the SCSI addresses are reversed. The leftmost disk drive
module slot has the highest SCSI address; the rightmost slot has the lowest SCSI
address. Do not use reversed addresses on the 2104 Model DU3.
Note: On the 2104 Model DU3, the physical numbers of the disk drive module slots
are always 1 through 14, from left to right.
On a 2104 Model TU3, the topmost disk drive module slot has the highest SCSI
address; the bottommost slot has the lowest SCSI address (see Table 1 on page 25). If
the switch is set to On, the SCSI addresses are reversed. The topmost disk drive
module slot now has the lowest SCSI address; the bottommost slot has the highest
SCSI address. Do not use reversed addresses on the 2104 Model TU3.
Note: On the 2104 Model TU3, the physical numbers of the disk drive module slots
are always 1 through 14, from bottom to top.
If the switch card assembly is not present when the 2104 is first switched on, or when
the 2104 receives a ‘Reset’ signal, the default logical setting for this switch is Off.
2104 Orientation switch 8: This switch must be set to Off for the 2104 Model DU3,
and to On for the 2104 Model TU3:
v When the switch is set for the 2104 Model DU3, the two-color LEDs that are related
to the 2104 Power light and to the 2104 Check light are set so that the left-hand LED
becomes the green Power light, and the right-hand LED becomes the amber Check
light.
Chapter 1. Reference Information 11