Disk Crossover And Disk Controller Circuit Packs (Nt6M72Xx And 680-9143); General Description; Replacing Disk Crossover Circuit Pack - Nortel DMS-100 Series Manual

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Disk Crossover and Disk Controller
circuit packs (NT6M72xx and 680-9143)

General description

The Disk Crossover (Xovr) circuit packs provide the data and control paths
between the Disk Interface circuit pack in the card rack and the disk drives for
Non-Turbo DPP systems. For crossover information in Turbo DPP systems,
refer to the SCSI Crossover circuit pack section.
The Disk Crossover circuit pack is on the inside of the hinged panel, A15 and
B15, at the rear of each DPP chassis. This pack provides a crossover data
path between the processors and the disk. The program in the active
processing unit controls this pack which simultaneously routes data from the
active Disk Interface circuit pack to both disk drives.
For 380- and 760-Mbyte and 1- and 2-Gigabyte disk drives, the Disk
Controller circuit pack is inside the disk drive. For the 72- and 140-Mbyte
drives, the Disk Controller circuit pack is on the top of the disk assembly.
This circuit pack is in the data path between the Disk Xovr circuit pack and
the disk drive. The Disk Controller circuit pack is a smart circuit assembly,
containing a processor, RAM, EPROM, and additional control circuitry.
Control signals (status commands, write signals, and read signals) are passed
through this pack, which initiates the appropriate operation in the disk drive.
See Table 13-1 for the jumper option setting on the Disk II Crossover circuit
pack. Figure 13-1 shows the jumper location and circuit pack layout. The
Disk Controller options are described in Table 13-2.

Replacing Disk Crossover circuit pack

To replace the Disk Crossover circuit pack, use the following procedure.
DPP Hardware Component Replacement Guide DPP001 and up
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