User`s guide
2.1 INTRODUCTION
CHAPTER 2
CONSOLE SUBSYSTEM
The V
AX-II
/730
console subsystem
is
an important diagnostic tool.
It
enables the operator to perform
the following functions:
• Starts and stops the
CPU
instruction set processor
• Examines and deposits information
in
locations
in
main memory
I/O
registers, processor
registers, and internal registers
• Controls
CPU
execution
The console subsystem hardware consists of a dedicated console terminal, switches and lights on the front
panel
of
the
CPU
cabinet, the dual integral TU58 tape cartridge drives and the remote access port.
The VAX-I
1/730
console runs in two modes: the program and console
I/O
modes. These modes are
mutually exclusive.
One
of
these modes
is
always enabled while power
is
applied to the system.
In the program
I/O
mode, the console terminal functions like a user terminal on the VAX-I
1/730
system.
I t passes characters between itself and the program running
in
the CPU.
In
the console mode, the
CPU
is
in
the idle loop and receptive to console commands.
The
CPU
enters the console
I/O
mode when the front panel keyswitch
is
set to either the LOCAL or
REMOTE
position and one of the following occurs:
• Power
is
cycled with the
AUTO
RESTART
switch
in
the
OFF
position.
• Power
is
cycled with the
AUTO
RESTART
switch
in
the
ON
position, if the restart attempt
fails.
• Power
is
cycled with the
AUTO
RESTART
switch
in
the
ON
position, if the cold start fails.
• Power
is
cycled with the
AUTO
RESTART
switch
in
the
ON
position, if both the warm and
the cold start attempts fail.
• A boot, continue, or start console command fails.
• The operator types
CTRL/P
on
the console terminal.
• The instruction set processor executes a
HALT
MACRO-32 instruction. (See Table
2-1
for
HALT codes and· their meanings.)
2-1