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PDP-10 Archives
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k20v7c
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subsys/sysjob.hlp
There are 46 other files named sysjob.hlp in the archive. Click here to see a list.
SYSJOB
SYSJOB is a program which starts and controls a number of
programs which perform system functions. These programs run
continuously and do not usually require any terminal
interaction. SYSJOB is also responsible for initiating the job
which controls the set of "operator" jobs and for maintaining
control over that job in the absence of an actual operator.
SYSJOB is started automatically by the monitor and is run under
job 0 along with other monitor background functions. SYSJOB
resides in its own process and creates other processs to run
the various programs. When SYSJOB is started, it reads the
file <SYSTEM>SYSJOB.RUN which contains the initial set of
commands. These commands cause the normal background programs
and the operator job to be started. Thereafter, SYSJOB is
dormant except in the following events:
1. One of the background programs halts or crashes.
SYSJOB will report the status of the halted process on
the CTY.
2. The operator wishes to communicate with or control one
of the background programs.
Both of these events are relatively unusual. The background
programs will not halt under ordinary circumstances. The only
normal occurrance of case 2 is when the operator is going off
duty and the system is changing from attended to unattended
status. In this case, the operator will cause SYSJOB to assume
control of the operator job which had been running on the CTY.
COMMUNICATING WITH SYSJOB
Commands may be given to SYSJOB at any time via the CTRL-ESPEAK
command. All text beginning on the next line and continuing to
the next CTRL-Z will be taken as input to SYSJOB. The
CTRL-ESPEAK command writes this text into the file
<SYSTEM>SYSJOB.COMMANDS and issues a wakeup request to SYSJOB.
Upon waking up, SYSJOB reads the file and performs the
commands.
SYSJOB COMMANDS
SYSJOB commands are in the form of a keyword possibly followed
by arguments. The same command set is recognized in the
SYSJOB.RUN and SYSJOB.COMMANDS files. Several of the commands
affect an inferior process; these are RUN, KILL, RESUME,
FREEZE. Certain other commands affect a job being controlled
via a PTY; these are JOB, KILLJOB, CCJOB. Other commands are
STATUS AND RELOAD described below.
PROCESS COMMANDS
RUN filespec
This command creates an inferior process and runs the
specified program in it. The process will be
identified by a name which consists of the first six
characters of the name portion of the filespec.
KILL name
This command kills the process of the specified name.
FREEZE name
This command executes a freeze on the process of the
specified name; this may later be undone by the RESUME
command.
RESUME name
This command executes a resume on the process of the
specified name thus undoing the effect of a previous
FREEZE.
JOB COMMANDS
JOB ident textstring
This command transmits text to a job via a PTY. The
ident is an arbitrary small integer not related to the
system job number of the job being controlled. The
operator should choose the smallest number (beginning
with 0) not presently in use when a new job is desired.
Thereafter, that number will identify that job.
The textstring is an arbitrary string surrounded by any
character not occuring within the string, e.g., /a
string of characters/. The string may include carriage
returns and other control characters, and specific
control characters may be indicated by the sequence ^g
(up-arrow followed by the printing equivalent). If
there is no job in existence when a JOB command is
executed, a CTRL-C is sent ahead of the specified text
to create one. Note however that the job is not
automatically logged in, so a LOGIN command must be
given via the JOB command.
Any output from the job will be fielded by SYSJOB and
typed on the CTY. Each line will be prefixed with the
ident number of the job which produced the output.
Output will only be typed at the conclusion of a line,
so prompt characters coming from a job will not be seen
until the remainder of the line has been typed in.
KILLJOB ident
This forces a LOGOUT of the specified job.
CCJOB ident
This transmits two CTRL-Cs to the specified job and
holds any further input until the CTRL-Cs have been
handled.
OTHER COMMANDS
STATUS
This command generates a printout on the CTY of the
status of all existing subprocesss and jobs presently
known to SYSJOB.
RELOAD
This command causes SYSJOB to reload and restart
itself. This should be used with great caution since
it will cause an abrupt termination of all inferior
processs and the detaching of any controlled jobs. If
possible, all processes should be killed and all jobs
logged out before the RELOAD is executed. This command
is intended to allow a new version of SYSJOB to be put
into operation during timesharing and to provide a
possibility of recovery after severe SYSJOB
malfunction.
(End of SYSJOB.HLP)