Jumper Block Information - IBM Ultrastar 18ZX Installation Manual

IBM storage products

JUMPER BLOCK INFORMATION

The jumper block is a block of pins located on the hard drive that when shorted with a shunt (jumper)
will make the drive behave in certain ways. The shunt is a small piece of plastic with metal inside that
shorts out the connection between 2 pins when placed over the pins. These can be purchased at any
local computer store. The pin pitch is 2 mm.
Additional Jumper Description
Auto Start Delay
The Auto Start and Auto Start Delay pins control when and how the drive can spin up and come ready.
When configured for Auto-Startup, the motor spins up after power is applied without the need of a SCSI
Start Unit command. For no Auto-Startup, a SCSI Start Unit comand is required to make the drive spin
and be ready for media access operations. When in Auto-Start Delay mode, the drive will delay its start
time by a period of time multiplied by its SCSI address.
External Activity (LED) Pins
The LED pins can be used to drive an external Light Emitting Diode.
Write Protect Pin
If the Write Protect pin is jumpered to ground the drive will prohibit SCSI commands that alter the
customer data area portion of the media from being performed.
Disable Synchronous Negotiation Pin
If a Disable Target Initiated Synchronous Negotiation pin is grounded, an Initiator is required to start a
negotiation handshake if wide transfers (16 bit) are desired.
Disable SCSI Partiy Pin
Grounding this pin will disable SCSI parity checking.
Disable Unit Attention Pin
Grounding this pin will disable the drive from building Unit Attention Sense information for commands
immediately following a Power On Reset or SCSI Bus Reset.
Disable Wide Negotiations
Jumpering the pins will cause the drive to operate in single byte mode. The drive will not negotiate wide
operation.
Force Single-Ended Mode
Jumpering pin 23 to pin 24 will cause the 68 pin and 80 pin SCA LVD drives to operate in single ended
mode only. The drive will not use the DIFFSENS line to determine SE or LVD modes.
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IBM Hard Disk Drive Technical Support Center version 1.0