NorthStar HORIZON Random Access Memory, User Manual

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HRAM USER/TECHNICAL MANUAL
The jumper areas consist of clusters of pins protruding
from the PC board. When a jumper plug is plugged onto a
pair of adjacent pins, it connects the pins together.
The jumper plugs are used to select various options on
the HRAM Board as described in Sections 3.2, 3.4 and
3.5.
Each of the Memory Address switches, S1 and S2,
actually a group of eight switches in a single package.
These switches are used as described in Section 3.3.
CAUTION
To reposition the jumper plugs, you must
remove the HRAM from the HORIZON. Make sure
the power is turned off and the red light on
the front panel is completely out before you
remove the HRAM.
To reconfigure the jumper plugs, lay the HRAM board
down on a flat surface with the components facing up.
You can move the jumper plugs with your fingers or a
pair of long nose pliers.
To reposition the jumper plugs, you must remove the
HRAM from the HORIZON. Make sure the power is turned
off and the red light on the front panel is completely
out before you remove the HRAM.
To reconfigure the jumper plugs, lay the HRAM board
down on a flat surface with the components facing up.
You can move the jumper plugs with your fingers or a
pair of long nose pliers.
EXAMPLE SYSTEM CONFIGURATIONS
This section shows the correct positions of the Memory
Address switches and the jumper plugs for several
example configurations of the HORIZON system.
3.1.1 EXAMPLE 1: THREE BANKS
In this example, the HORIZON contains three HRAM-64
Revision B boards, a standard Micro-Disk Controller
board at E800H, and a Floating Point board at EFFOH.
The switches and jumper plugs are shown in Figure 3-2.
On board 1, the memory between EOOOH through E7FFH and
FOOOH through FFFFH is left on permanently, to contain
the resident operating system. On the other two boards,
the whole last 8K of address space (EOOOH through
FFFFH) must be disabled, to prevent interference with
the Micro-Disk Controller, the Floating Point board,
and the 6K that contains the resident operating system.