Digital Equipment Prioris XL 6000 Series, Service Maintenance Manual

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Block Diagram
E-8
SCSI Controller
The PCI SCSI controller (7880) supports the ultra internal narrow and internal wide
SCSI connectors. The internal wide SCSI connector supports the storage backplane
and hard disks. The internal narrow SCSI supports tape drives and the CD-ROM.
The SCSI bus has active termination on the MLB, with each byte (high 8 bits and low
8 bits) capable of being enabled separately. This bus goes to two connectors – one
wide and one narrow.
The narrow connector transfers the lower 8 bits of the SCSI bus between the 5.25”
bays and the CD-ROM. The lower byte of the bus is terminated on the CD-ROM.
The wide connector goes from the controller to a standard 68-pin wide SCSI
connector on the backplane. The backplane “out” connector is terminated when
shipped; however, this terminator can be removed and the wide cable can be
installed to the outside of the box.
SBB Storage Drive
The Prioris MX 6200 supports “hot-swap” System Building Blocks (SBB) storage
drives through the internal wide SCSI connector. The SBB storage backplane
supports up to four 1.5” SBB hard disks. The SBB backplane also has a fault bus
monitor.
Ethernet Interface
A PCI Fast Ethernet LAN controller provides chip control and status registers for
network data reception and transmission. The controller shares a portion of CPU
memory, set up during initialization, that minimize CPU involvement. This controller
provides full-duplex network access through three network ports: Twisted-Pair
(10/100 Mb/s), Attachment Unit Interface (AUI, 10 Mb/s), and Thinwire (10 Mb/s).