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PARITY
(cont)
PROGRAM
SECTION
II.
OPERATOR'S CONTROL PANEL
button.
The run requirements of each installation vary, and the
handling of error conditions is often a function of the type of run,
e. g., production or checkout.
How a parity check is to be
handled may be defined by the programmer's instructions to the
operator or by locally established policy.
In general, the opera-
tor may reset the PARITY indicator by pressing either the
SYSTEM CLEAR or the INITIALIZE button on the control panel
and, if necessary, clear memory and restart the run.
NOTE: It may be possible to effect a restart without clearing
memory.
The operator may also perform any other
set of procedures specified locally by the installation.
This check condition is caused by an illegal op code in the pro-
gram (see page 2-12).
Depending on the type of run and the
programmer's instructions to the operator, the operator may
clear the PROGRAM indicator by pressing either the SYSTEM
CLEAR or the INITIALIZE button and attempt to continue the run.
NOTE: Pressing the INITIALIZE button resets all central
processor auxiliary storage functions, thus perhaps
destroying pertinent program information.
The
operator should always exercise extreme caution in
the use of the INITIALIZE button.
To continue processing, the operator must prevent the re-extraction
of the offending op code by changing it to a No Operation (NOP) in-
struction.
Program execution resumes at the next op code identi-
fied by a word mark.
The operator may also perform any other
set of procedures specified locally by the installation for handling
a program check.
Control Panel Checkpoint Procedures
A "checkpoint" is a programmed condition whereby processing is delayed or stopped to
await an operator decision.
The operator can easily recognize the existence of a checkpoint by
observing the control panel.
Any checkpoint is denoted by the control panel lights becoming
constant to signify a machine halt.
Depending on the configuration of the control panel lights, the checkpoint (machine halt)
may indicate Simply the completion of a job or the necessity for a parameter entry by the opera-
tor.
(The occurrence of a checkpoint implies that no abnormal stop conditions have occurred,
e. g., a parity error.) The contents of the pertinent control memory register (usually the A-
,
and/or B-address registers) must be consulted in accordance with the programmer's instruc-
tions to the operator.
In this way, the operator can determine the nature of the machine halt (by
comparing the contents of specified registers with predefined checkpoint codes) and then act
accordingly.
The actions which may be taken by the operator are those which are normally as-
sociated with job completion (e. g •• demounting tapes. disposition of output. etc.) or the control
panel entry of a previously defined parameter which permits processing to continue according
to programmer-specified operating options.
2-16
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