IBM DCAS-32160 - Ultrastar 2.1 GB Hard Drive, Технические характеристики

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6.1.2 SCSI Cable
The drives comply with ANSI X3T10/1071D.
The maximum cumulative signal path length between terminators shall be 3.0 meters when using up to 4
maximum capacitance (25pF) devices.
The maximum cumulative signal path length between terminators shall be 1.5 meters when using from 5 to 8
maximum capacitance devices.
Implementation that limits the transfer rate to a maximum of 5 mega transfers per second may extend the
cumulative cable length to 6m as described in ANSI X3T10/855D.
6.1.3 SCSI Bus Terminator
The drives comply with ANSI X3T10/1071D.
Active terminator as specified in ANSI X3T10/1071D should be used.
Terminators employing a 220 ohm resistor to 5 Volts and 330 ohm resistor to ground on each signal shall
not be used. (Passive terminators should not be used for FAST-20.)
Note : The drive may not spin up while SCSI Bus is disconnected and internal terminator is disabled.
Internal terminator enabled by jumper plug is equipped in the drive except 80-pin (SCA-2) model.
The 80-pin (SCA-2) model does not have internal terminator.
6.1.4 Hot Plug / Unplug
Power supply and SCSI bus hot plug and unplug is allowed. There is no special sequence required for con-
necting 5 or 12 volts. During a hot plug-in event the drive being plugged will draw a large amount of current
at the instant of plug-in. This current spike is due to charging the bypass capacitors on the drive. This
current pulse may cause the power supply to go out of regulation. If this supply is shared by other drives
then a low voltage power on reset may be initiated on those drives. Therefore the recommendation for hot
plugging is to have one supply for each drive. Never daisy chain the power leads if hot plugging is planned.
Hot plugging should be minimized to prevent wear on the power connector.
Hot plugging of the SCSI bus may cause glitches on the bus. To minimize the chance of glitching, it is
recommended to plug in the SCSI bus before the power is applied.
During hot plugging, the supplies must not go over the upper voltage limit. In addition, proper ESD pro-
tection must be applied during the plugging event to insure that the SCSI bus ground is at the same poten-
tial as the drive ground.
If operating shock limit can be exceeded at hot un-plugging, spindle motor should be stopped using SCSI
Stop Unit command prior to the hot un-plugging.
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O E M Spec. of DCAS-34330/32160