SUMMARY Hard Drive

From: Roger D McGraw (
Date: Thu Sep 25 1997 - 11:30:22 CDT

On Thu, 25 Sep 1997, Roger D McGraw wrote:

> I am putting a new hard drive into a sparc 1 box.
> Can anyone tell me about the following jumper settings:

> parity enable

Not required (leave it disabled).

> remote start enable

Probably a good idea, but not required.

> terminator disabled

Definitely. All internal drives must not be terminated.

 1. parity enable: spec's if the controller and the device
carry along parity information with the data; provides
some low-level error checking but must be supported by both
parties (controller and device), most modern SCSI-cont's
do support parity checking.

2. remote start enable: controls the device's spindle motor
behaviour at startup time. If enabled the drive wants an
remote signal (usually provided by the controler) to spin
up. Makes sense if you run more than 1 drive and have a
weak power supply, because the drive motor 'eat' the most
power at startup and with that feature enabled they do
start with small delay and not all at the same time.

3. terminator disabled: If you have a jumper labelled like
this then your drive supports active termination (which is
resistors to
disable termination of the drive. In a SCSI chain you have
to enable termination at all devices at the end of the bus.
All other devices have to run without termination. Termination
does prevent the signals (high frequency!) to be reflected at
the endings of the cable. In a SPARC the controller is mostly
self-detecting if he is the last device on its side of the chain.

Thanks to all who responded!

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