Figure 50. Machine Status Display [10829]
a problem occurs in which the program continually loops to the same PSW.
IPL-En-or: The legend 'IPL-Error' appears on the screen when the system was unable to load a vaJid PSW. This condition can occur when the load device is not ready, an invalid address is specified, or an interruption is incorrectly executed. The legend 'IPL-Error' occupies screen positions normally reserved for 'Sys', 'Man', and 'Wait'.
'EC-PSW En-or': The legend 'EC-PSW Error' appears on the screen when the load process has ended with an attempt to load a PSW with an invalid EC mode format, and processing cannot continue. The legend 'EC-PSW Error' occupies the screen positions normally reserved for 'Sys', 'Man', and 'Wait'. It indicates that a correct program should be loaded.
'PSW-Adr En-': The legend 'PSW-Adr Err' appears on the screen when the system cannot continue processing because the instruction address in the current PSW is not an address in physical storage. The legend occupies the screen positions normally reserved for 'Sys', 'Man', and 'Wait'. It indicates that a correct program should be loaded.
KB Field
The KB (keyboard) field shows the state of the keyboard.
Anyone of four legends can appear in this field.
Proceed: The legend 'Proceed' means that the operator can use the keyboard to type in data. All keys are unlocked and will respond.
Inhibit: The legend 'Inhibit' means that the data entry keys are disabled because the operator tried to enter data into a protected area on the screen. When 'Inhibit' is on the screen, the operator can use the KEYBD RESET key to enable the keyboard.
Lock: The legend 'Lock' means that the system has locked all keys capable of interfering with the current operation.
The operation may be, for example, a main storage transfer, or a log operation. When the 'Lock' legend is on the screen, the KEYBD RESET key has no function.
Req: The legend 'Req' (request) means that the operator has pressed the REQ key and the request has been accepted. Requests are interpreted by the operating system.
Cnsl-Prtr Field
The Cnsl-Prtr (console printer) field is used when a console printer is installed and the printer's supply of forms is
exhausted or its cover is open. The field is also used to indicate console printer errors after a system reset or IMPL operation. The 'Cnsl~Prtr' legend i~ a request for operator intervention.
Timer Field
The Timer field shows the state of the interval timer at main storage location 80. The legend 'On' or 'Off appears, depending whether the timer has been enabled or disabled.
Line 14
Line 14 consists of one field, for displaying information on two special modes: address compare and instruction step.
When neither of these modes applies, the whole line is blank. When either or both of the modes are selected, the information on the selected special mode appears on the screen.
Adr Camp
When 'Adr Comp' appears on the screen, address compare mode has been set. The following information (described in more detail under "Main Storage Address Compare" earlier in this section) is also shown.
Real: The legend 'Real' indicates that the search address is a real address.
Adr: The search address entered for the address compare operation is displayed after the legend 'Adr' (address).
Type: The legend 'Type' is followed by the indicator 'Any', 'Data Store', 'I-Count', or 'I/O' and shows the type of comparison to be made.
Act: The legend 'Act' (action) is followed by the indicator 'Stop' or 'Sync' and shows the action to be performed when an address match occurs.
I-Step
When the legend 'I-Step' appears on the screen beside 'Mode', instruction step mode has been set.
Line 15
Line 15 provides additional information on the state. of the system. From left to right, three fields are shown: the con trol mode (basic or extended) field; the address and data field; and the check control field.
Control Mode Field
The control mode field shows the current control mode of the system, as follows.
EC and BC: Either of these two legends is on the screen;
'EC' (extended control) whenever bit 12 of th{l current PSW is set, and 'BC' (basic control) whenever bit 12 of the current PSW is off.
DAT: This indicator is on the screen when the BC mode PSW bit 5 (DAT bit) is set.
Address and Data Field
The Address and Data field shows the address mode, the main storage location of the next instruction, and the associated data, as follows.
Virt: The legend 'Virt' (virtual) means that dynamic address translation (PSW bit 5) was set when the system stopped.
Real: The legend 'Real' means that dynamic address translation (PSW bit 5) was off when the ~ystem stopped.
Adr: The 'Adr' ( address) field shows the storage address of the instruction to be processed. This address is always the instruction address in the current PSW. When the &ystem is in the check-stop or wait state the address is not shown but it can be brought onto the screen by a display PSW operation.
Data: The 'Data' field shows the halfword stored at the main stotage location indicated by the address field. The first byte of this halfword is the op code of the next instruction.
Chk-Ctl Field
The Chk-Ctl (check control) field shows anyone of three selectable modes. If the check-control mode is normal, as it is after initialization of control register 14, the Chk-Ctl field is blank.
Hard Stop: The legend 'Hard Stop' means that a check-stop takes place immediately when a machine check occurs.
1/0 Stop: The legend 'I/O Stop' means that a check-stop takes place after a limited channel logout is performed.
Compatible: The legend 'Compatible' means that a check-stop takes place after a machine check interruption or a limited channel logout has occurred.
Line 16
Line: 16 is reserved for displays and special messages for the customer engineer when special modes, such as logging or in-line tests, are being run.
Usage Metering
The system usage meter is located near the diskette in the . CPU main frame. The meter covers all activity in the main storage controller, and in the subprocessors. The system usag1e meter stops if the CE meter is switched on.
The modes and conditions during which the meter runs are summarized in Figure 51.
I/O METERING
The Model 115 attachments, adapters, and multiplexer channel have no meters. Instead, most I/O devices attached other than through the multiplexer channel have a usage meter, and each channel-attached device has one, either under its own covers, or in the control unit, or both.
I/O metering is controlled by in and metering-out lines connected to the internal bus system. The metering-in line is activated when an I/O device accerts a command, and deactivated when device end is presented for the same command. The line remains inactive for instructions, such as 'test I/O', which do not generate device end. The metering-out line is active when the system meter runs.
TELEPROCESSING METERING
For teleprocessing operations, the metering-in line is activated as soon as character transfer occurs to or from main storage.
Tht, follOwing types of commands do not activate metering in:
Input/Output Enable Disable Set mode Prepare Adprep No-operation.
Power On
Manual Operations
Figure 51. Usage Metering [10830]
Run Mode
Wait State
Stopped State
Check Stop State