Disk Drives and
Terminal R •• lstor
• Identification of disk drives
A maximum of four disk drives can connect to the computer system, and every connected disk
drive requires drive number setting. This setting can be achieved by the 4-gang switch labelled
"DR IVE SE LECT" which is present on the back of each drive. Set only the switch corresponding
to a desired drive number to ON as shown below. Use care then to prevent the same drive number
from being assigned to two or more drives in a drive system, otherwise the drive system would
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Setting of the drive select switch
• Terminal resistor
The drive system requires to have one of its component drives provided with a terminal resistor.
It must be noted, however, that which drive should be provided with a terminal resistor depends
upon the number of connected drives. In principle, the drive remotest from the interface alone
needs a terminal resistor. If the drive system contains two or more drives with a terminal resistor,
those drives get damaged when the system is put in operation. Pay due attention to this regard.
When attaching a terminal resistor, follow the procedure given below.
Unscrew the panel under the indication "TERMINAL RESISTOR" which is secured with two
screws. You will find a socket then.
Mount a supplied terminal resistor on the socket. This resistor, having no polarity, can be
mounted in any orientation.
Make sure the resistor has correctly been mounted, then replace and screw the panel.
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Mounting of the terminal resistor