2-1
Definitions

General rules

Apply the following rules for system engineering when arranging various
Universal Equipment Modules (UEMs) within an SL- 1.
Note:
This document has been updated to include new naming
conventions. Acronyms and abbreviations for the new names are
identified in the text using parentheses.
UEM and column designations
Columns of Universal Equipment Modules (UEMs) are numbered from 0 to
63. The column with CPU 0 is Column 0. Within a column, the
UEMs
are
numbered as 0 to 3 starting from the bottom UEM.
A UEM column can be built up to a maximum of four
UEMs
before moving
to the next column; however, three UEMs per column can be configured if
it is easier for installation and maintenance.
All the SL-1 Common Equipment (CPU UFMs) must be at the bottom or
one level up for proper cooling and reliability. The mass storage unit--
Multi-Disk Unit (MDU) or Floppy Disk Unit (FDU)--is usually located in a
CPU UEM and requires lower operating temperatures than the cards. For
this reason, do not install MDU/FDU in the third or fourth UEM.
The Common Equipment (CE) UEMs must be located next to each other at
the same horizontal level. The CPU/Network Modules (NT6D39AA/DC)
(CNE) must be located on top of each other.
The CPU, InterGroup, and CE UEMs must be located in the same vertical
column. For these UEMs, all inter-UEM cabling must be internal, not
System engineering 553-3001-l 51