Product data
External Switches
Power Control switch 1: When this switch is set to Off, the SCSI interface card can
enable the 2104 power supplies if both the following conditions exist:
v The 2104 is connected to mainline power and a DC On/Standby (on a
fan-and-power-supply assembly) is set to On.
v The ‘terminator power (TERMPWR)’ signal is active in an external SCSI connection.
Under these conditions, the SCSI interface card provides a remote power on control
function. That is, the 2104 switches off automatically when all the connected using
systems switch off; it switches on automatically when one using system switches on.
When the Power Control switch is set to On, power is not controlled by the ‘TERMPWR’
signal. The 2104 does not switch on and off automatically with the using system.
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.
Drive Autostart switch 2 : When this switch is set to On, the motors of the disk drive
modules do not start until a Start Motor command is issued. The timing sequence of
startup is under the control of the using-system software. When this switch is set to Off,
the disk drive modules are set to Delay Motor Start mode. The delay time before motor
startup is specified by the disk drive modules. 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 On.
Enable Enclosure Services switch 3: When the switch is set to On, the SCSI
enclosure services operate. When the switch is set to Off, the 2104 does not respond to
requests for enclosure services, and SCSI address 15 (the address of the SCSI
enclosure services) is not used.
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 On.
Select Enclosure Services switch 4: When the switch is set to On, the SCSI
enclosure services are selected. When the switch is set to Off, the SAF-TE enclosure
services are selected.
Note: SAF-TE services are not supported on an RS/6000 or IBM ^ pSeries
system.
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 On.
Delay Motor Start Mode switch 5: This switch selects either Delay Motor Start Mode
or Normal Start Mode when the Drive Autostart switch 2 is set to Off. When the Delay
Motor Start Mode switch is set to On, Delay Motor Start mode is selected. The delay
10 2104 Service Guide