Scam; Scam Operation; Level 1; Level 2 - IBM DCAS-32160 - Ultrastar 2.1 GB Hard Drive Specifications

10.0 SCAM

10.1 SCAM operation

10.1.1 Level 1

A reset condition shall cause an exit from any state and places the drive in the Reset Delay state.
When a drive is powered-on, it immediately enters the Power-On Delay state and may perform local
initialization. The drive shall leave this state and enter the SCAM Monitor state within a SCAM
power-on to SCAM selection delay.
While in the SCAM Monitor state, a drive shall monitor the SCSI bus for both SCAM selection and
normal SCSI selection. If the drive detects the initiation of SCAM protocol, it shall enter the ID Assign-
able state.
If a SELECTION phase for the drive's current ID is continuously valid for at least a SCAM unassigned
ID selection response delay, the drive shall respond to selection and assert the BSY signal. This response
to selection implicitly causes the drive to enter the ID Assigned state just as if an explicit ID assignment
had been received. The assigned ID is set to the current ID and the drive now functions as a SCAM
tolerant device.
A drive remains in the ID Assignment state as long as SCAM protocol is maintained until explicit
SCAM functions change its state.
If a drive is isolated and receives an Assign ID action code, the ID specified becomes both the current
and assigned ID. The drive releases all SCSI bus signals and enters the Assigned ID state.
If a drive receives a Configuration Process Complete function code or if SCAM protocol is terminated
(the C/D signal is false), it shall release all SCSI bus signals and enter the ID Unassigned state.
A drive in the ID Unassigned state has not had any SCSI ID exiplicitly or implicitly assigned and shall
not respond to SCSI selections for its current ID regardless of the duration.
When the exception of a power-on or reset condition, only the detection of SCAM protocol initiation
shall cause the drive to leave the ID Unassigned state.
Once a drive has reached the ID Assigned state it functions as a SCAM tolerant device with the ID
assigned. That is, it shall respond to SCSI selection within a SCAM tolerant selection response time and
shall not recognize nor respond to SCAM selection.
A reset condition shall cause a SCAM target to enter the Reset Delay state, in which it may perform
local initialization. The drive shall leave this state and enter the SCAM monitor state within a SCAM
reset to SCAM selection time.

10.1.2 Level 2

A reset condition shall cause an exit from any state and places the drive in the Reset Delay state.
When a drive is powered-on, it immediately enters the Power-On Delay state and may perform local
initialization. The drive shall leave this state and enter the Initiate SCAM Protocol state within a SCAM
power-on to SCAM selection delay.
In the Initiate SCAM Protocol state, a drive shall arbitrate for the SCSI bus without an ID and perform
SCAM selection. After a SCAM selection delay the drive shall examine the SCSI bus to determine the
state of the C/D signal. If the C/D signal is true, there is a SCAM intiator present and the drive shall
enter the ID Assignable state. If the C/D signal is false, no SCAM initiator is present and the drive shall
Copyright IBM Corp. 1996
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