Scsi Bus Fairness; Table 1.34 System Level Requirements - Fujitsu MAW3073 SERIES Specifications

Parameter
V (except OR-tied signals) (1)
A
V (except OR-tied signals) (1)
N
V (OR-tied signals) (1)
A
V (OR-tied signals) (1)
N
Attenuation (%) (2)
Loaded media impedance (ohms)
(3)
Unloaded media impedance (ohms)
Terminator bias (mV)
Terminator impedance (ohms)
Device leakage (µA)
Number of SCSI devices
Ground offset level (mV) (4)
Note:
(1) These are the signal levels at the receiver, the system allows 60 mV crosstalk for calculating the
minimum driver level.
(2) Measured from the driver to the farthest receiver.
(3) Caused by the addition of device capacitive load.
(4) This is the difference in voltage signal commons for SCSI devices on the bus.
1.13

SCSI bus fairness

(1) Fairness Model
Implementation of the SCSI bus fairness is optional.
A SCSI device determines fairness by monitoring prior arbitration attempts by other SCSI devices.
It shall put off arbitration for itself until all lower priority SCSI devices that lost previous
arbitration either win a subsequent arbitration or discontinue their arbitration attempts (e.g., as in
the case where the initiator aborted an outstanding command thus removing the need to re-
arbitrate).
When a SCSI device does not need to arbitrate for the SCSI bus, it shall monitor the arbitration
attempts of the other SCSI devices and refresh the fairness register with the SCSI IDs of any lower
priority SCSI devices that lost arbitration.
C141-C011
Table 1.34 System level requirements
Minimum
100 mV
-3.6 V
100 mV
-1 V
85
110
100
100
-20
2
-355
Maximum
-100 mV
1 V
-100 mV
125 mV
15
135
135
125
110
20
16
355
1-139