IBM System/370 Operator's Reference Manual page 64

System/370 Model 195 (cont'd)
To Display Current PSW
1.
Press STOP; manual light turns on.
2.
Set CRT DISPLAY & TAPE OP to PROCESS.
3.
Read current PSW (bits
0-63)
displayed on panel H.
4. Press START to resume processing.
To Alter Current PSW
1.
Display current
PSW.
2. Place CBR/CXR switch to the CBR position.
3.
Set
new
information in the CXR/CBR (data) switches.
4. Press SET PSW. The current PSW is now altered; the now·current PSW data
is automatically displayed on panel H.
5.
Press START to resume instruction processing.
To Stop
on
Main Storage Address
1. Press STOP; manual light turns on.
2. Set ADDRESS COMPARE to (a) INSN SOFT STOP, (b) SCU STORAGE
SOFT STOP, or (c) CHAN S/F SOFT STOP.
3.
Set ADDRESS/ADDRESS COMPARE to the desired stop address.
4. Press START to resume processing. After the compare stop has been accom·
plished, restore switches to their normal settings, then press START.
To Clear Main Storage Only
Under normal operating-system operation, it is unnecessary to clear main storage
because the operating system provides this function as required. For certain testing
operations, however, it may be desirable to clear main storage. The following pro·
cedure clears main storage, but does not alter the contents of general or floating· point
registers.
1.
Press STOP; manual light turns
on.
2. Set
STORE/DISPLAY/STG SELECT to MAIN STORAGE.
3. Set CRT DISPLAY & TAPE OP to STORAGE.
4.
Set all CXR/CBR switches to
0
or press CBR TO ZEROS.
5.
Set (lever) STORAGE TEST to STO (up position) on panel
L
6.
Press START STORAGE TEST on panel
L
7. Restore STORAGE TEST to normal, center position. All of main storage
now contains data (zeros) in CXR/CB R switches.
8.
To resume processing, re-IPL the control program.
To Clear System
1.
Hold System Clear Enable switch (panel
U
in the down position while
depressing the System Reset switch. This will cause (1) a normal system
reset, (2) all of main storage, G RS and. F L RS, and Storage Protect keys to
be reset to zero, and (3) the data buffers to be invalidated.
2. Hold System Clear Enable switch in the down position while depressing the
Load swi tch. This will cause the machine to execute a normal system clear
and then the normal load function.
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