SCSI Description
5–94 Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives
MODE SELECT (6) Command (15h) (continued)
Table 5–43 Quantum-Unique Page — Field Descriptions (continued)
Field Default Description
Auto Master Enable 0When this field = 0, this disk drive does not act as the master in
a storage array configuration (refer to the Hard Disk Geometry
page). When this field = 1, this disk drive becomes the master.
Not used by the drive.
Force 8 0When this field = 0, 16-bit wide data transfer responses are
allowed.
When this field = 1, negotiations are limited to 8-bit responses.
DFCP 0Delay Following Command Phase. Not used by the drive.
PXM 0Preserve Synchronous and Wide Mode. If set = 1, this bit
causes the disk drive to preserve the most recent wide and
synchronous states for all initiators across power on resets, bus
reset, and bus device reset messages. Not used by the drive.
ISN 0Initiate Synchronous Negotiation. When this field is set = 1, the
disk drive initiates a synchronous transfer negotiation with the
initiator. This is done on the first selection with ATTENTION
following a power on reset, bus reset, or bus device reset. The
negotiation is done for each initiator. Note that if both ISN and
IWN (Byte 5, bit 0) are set =1, the wide data transfer
negotiation takes place first.
IWN 0Initiate Wide Negotiation. When this field is set = 1, the disk
drive initiates a wide data transfer negotiation with the initiator.
This is done on the first selection with ATTENTION following a
power on reset, bus reset, or bus device reset. The negotiation
is done for each initiator. Note that if the disk drive is not
capable of actually transferring data on a wide bus, the
firmware will only negotiate for an 8-bit bus. If both ISN (Byte
5, bit 1) and IWN are set =1, the wide data transfer negotiation
takes place first. A wide data transfer negotiation causes the
disk drive to reset any synchronous agreement to
asynchronous mode.
(continued)