IBM DU3 2104, Hardware Technical Information

Page: 11 / 36

On the back of the backplane are connectors for two fan-and-power-supply
assemblies
3
, two SCSI interface cards
4
, and a switch card
5
.
The 2104 Model DU3 has either two fan-and-power-supply assemblies or one
fan-and-power-supply assembly and one fan assembly. Either option provides all the
necessary power and cooling for the 2104 Model DU3.
The SCSI interface cards are used to connect host machines to the 2104 Model DU3.
These cards contain logic that provides information about what is happening in the
2104 Model DU3 and the status of components within it.
The switch card contains switches that control which SCSI bus mode is selected, how
the 2104 Model DU3 is supplied with power, and what enclosure services are enabled.
It also contains a rotary switch that is used to set the ID of the 2104 Model DU3.
Chapter 1. Introduction
3