Setting The Option Switches - IBM 2104 Model DS4 Installation Manual

Figure 34. Setting the option switches
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Expandable Storage Plus 2104 Model DS4 Installation Guide
4. Figure 34 shows the option switches. When the drive autostart switch-1 1 is
set to off, and the drive autostart switch-2 2 is set to on, the disk drive
motors do not start until you issue a START MOTOR command. The timing
sequence of disk motor startup is under the control of the host system
software.
When the drive autostart switch-1 1 is set to on and the drive autostart
switch-2 2 is set to off, the disk drives are set to delay motor start mode. The
disk motor startup delay time is different for each disk drive, and is usually
computed by multiplying its SCSI ID by 12 seconds. For example, the disk
drive motor of a disk drive with a SCSI ID equal to 2 will start 24 ( 2 x 12)
seconds after power is applied to the 2104 Model DS4.
When the drive autostart switch-1 1 is set to off, and the drive autostart
switch-2 2 is set to off, the disk drives are set to normal start mode. The disk
drive motors will start when power is applied to the 2104 Model DS4.
The effect of both this switch and the drive autostart switch-2 2 being set to
on is undefined.
5. To set the drive autostart switch-2 2 , see step 4 for an explanation about the
drive autostart switch-1 1 .
6. Ensure that the enable enclosure services switch 3 and the select enclosure
services switch 4 are both set to on to allow ANSI SCSI-3 Enclosure
Services (SES) to operate. This applies to both AIX and Linux users. Your
Linux operating system might not support SES, but the SES functions are used
when running the standalone AIX Diagnostics CD.
7. When the power control switch 5 is set to off, the 2104 Model DS4
automatically switches off or on when the host system is switched off or on.
When this switch is set to on, the 2104 Model DS4 is powered on or off by the
dc on/standby switch on a fan-and-power-supply assembly.
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