parity checking option jumper
Gerry_Houlder at notes.seagate.com
Thu Apr 24 15:23:41 PDT 1997
* From the SCSI Reflector (scsi at symbios.com), posted by:
* Gerry Houlder <Gerry_Houlder at notes.seagate.com>
Francesco Ceci <f.ceci at alea.com> asked:
>I'd like to know what the Scsi specifications recommend about the parity
generation and checking.
>By experience, I know that all Scsi devices generate the parity, while the
parity checking is normally >controlled by a jumper that allow to
The SCSI standard is silent about the operation of the parity checking jumper.
It only says that the checking of parity and generation of parity was optional
in SCSI-1, mandatory in SCSI-3, and probably optional in SCSI-2. SCSI-1 also
suggested that all devices must to it the same (if one device is not checking
parity, the rest shouldn't either). If you follow this guideline, the jumper
can disable generation of parity as well as checking of parity.
My advice is to always use it with parity enabled - this behavior is clearly
defined in the standards and is the "mainstream" behavior.
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