The DLYCMD allows you to enter a command at a workstation and have it
executed at a later time. It is specifically intended for operations
at the system console that should only be run when no other jobs are
active. Some functions of the system (e.g. RCLSTG) require that the
system be in the restricted state (only a single job is active) in
order to execute.
Tools now exist for SAVSYSBCH and RCLSTGBCH which may preferable to
the use of DLYCMD for these functions.
As an example of DLYCMD, assume you want to run RCLSTG beginning at
3:00 AM tomorrow morning and then powerdown. Just prior to going
home, you would enter the following command at a workstation in the
controlling subsystem (you can prompt for the command entered in the
CMD parameter).
DLYCMD CMD(RCLSTG)
TIME(030000)
DATE(*DAY1)
TEXT('Reclaim Storage function')
RSTDSTATE(*YES)
POWERDOWN(*YES)
A display would appear as follows:
**********************************************************************
* *
* TAA Delay command in operation *
* *
* Text . . . . . . . . . . : Reclaim Storage function *
* *
* Command to be executed . : RCLSTG *
* *
* Command date . . . . . . : *DAY1 *
* Date to execute . . . . : 12/02/09 *
* Time to execute . . . . : 3:00:00 *
* Maximum active job limit : *NOMAX *
* Subsystem . . . . . . . : *ALL *
* Exit pgm after timeout : *NONE *
* Restricted state . . . . : *YES *
* Power down . . . . . . . : *YES *
* Restart . . . . . . . . : *NO *
* Signoff LOG(*LIST) . . . : *YES *
* Wait time . . . . . . . : 900 *
* *
* *
* No break messages will appear. No function keys are valid. *
* Use system request to display a Message Queue. *
* An -End Request- via System Request causes a Signoff. *
* *
**********************************************************************
You would then go home. At 3:00 AM, the DLYCMD would shutdown the
subsystems, enter the restricted state, execute the RCLSTG command
and then powerdown.
When the display occurs, there are no input fields and the program
will not respond to the enter key or a function key. You can end the
command using system request option 2 (End previous request), but a
Signoff will occur.
While the command is executing, no messages will cause a break. You
can display a message queue using the the system request function.
If you request the restricted state, DLYCMD ensures that only a
single job is active at the workstation as ending the subsystems does
not cause other jobs at the same workstation to end.
Using the defaults for Day and Time and MAXJOBS
-----------------------------------------------
There are three methods of delaying the command:
- Using a time of day
- Using a date
- Using the MAXJOBS parameter
If all defaults are taken, the DLYCMD screen appears with a status
message indicating a wait of 30 seconds. This is designed to allow
the operator time to review the specifications and cancel the
function if required. The cancel would be done by using System
Request Option 2 (End Previous Request), but will cause the job to be
signed off.
Triggering a command based on a MAXJOBS value
---------------------------------------------
In addition to triggering a command based on a time of day, you can
also trigger a command based on the number of active jobs. For
example, if you want to trigger a command when there are only 10
active jobs (or less) on the system, you would say:
MAXJOBS(10)
The default is that all subsystems would be checked. You may also
name one or more subsystems. For example, if you enter the command
from a device in the controlling subsystem and want to trigger a
command when there are no active jobs in SBSD1 or SBSD2, you would
specify:
MAXJOBS(0)
SBS(SBSD1 SBSD2)
When using MAXJOBS, the subsystem monitor (a job that appears on
WRKACTJOB) does not count toward the value.
You can specify both the TIME and the MAXJOBS triggers in which case
the command will not be triggered until both are satisfied.
For example, assume you are using the QBATCH subsystem and want to
perform RCLSTG beginning no earlier than 11:00 PM tonight and after
all work has been completed in the QBATCH subsystem. You would
specify:
DLYCMD CMD(RCLSTG)
TIME(230000)
MAXJOBS(0)
SBS(QBATCH)
TEXT('RCLSTG command')
POWERDOWN(*YES)
RESTART(*YES)
If the number of jobs you specified is greater or equal to the number
in the subsystem, the command waits 30 seconds and accesses the
number active again. This process is repeated 3 times before the
command you want is run. This repeated processing is an attempt to
ensure that a 'window of time' has not found a condition where a new
job is starting, but is not yet known to the subsystem.
Note that if you have 'never ending' batch jobs in the specified
subsystem, specifying MAXJOBS(0) will never cause the command to run.
There are two solutions:
** Determine the number of 'never ending' batch jobs and use this
number instead of 0.
** Use the RTVSBSBCH solution described later.
If you are using QBASE as the controlling subsystem for all of your
work, there will be additional jobs which are active. You will want
to review the RTVSBSBCH solution.
Triggering a command based on the TAA Tool RTVSBSBCH
----------------------------------------------------
If QBASE is used (it is the system default) rather than a separate
subsystem for batch work, the system starts several batch jobs that
exist in QBASE that remain active while they are waiting for an event
to occur. A similar condition can exist in a separate subsystem
devoted to batch work where 'never ending user jobs' are waiting for
some event.
Because these types of jobs are common, the definition of when batch
work is completed can be complex. Unless you have a very straight
forward batch subsystem with none of these types of jobs, you cannot
rely on a count of zero batch jobs to determine that there is no more
batch work to be performed.
Most installations consider that a job that is waiting for an event
can be safely terminated when it is time to reach the restricted
state or shut down the system.
To provide a solution for when there is no more 'actual batch work'
being performed, the TAA Tool RTVSBSBCH should be considered.
*RTVSBSBCH is an option for the MAXJOBS parameter.
RTVSBSBCH allows you to determine that no 'actual batch work' is
being performed based on the status values as displayed by WRKACTJOB.
If the only batch jobs still active are in a wait state, you can
decide to end the subsystem.
You should not use MAXJOBS(*RTVSBSBCH) unless you have understood the
RTVSBSBCH tool documentation and used the PRTSBSBCH command to help
determine your individual system requirements. You may describe your
own set of status conditions that should be checked for.
If *RTVSBSBCH is specified, 1 to 9 subsystems or all active
subsystems may be checked. If a TIME value is also entered,
RTVSBSBCH is not attempted until the TIME value is met.
If all subsystems specified find no jobs in the RTVSBSBCH return
variables of RUN and OTHCNT, the job delays 30 seconds and does the
same test again for all specified subsystems. This helps ensure that
a window of time has not caused a lack of batch activity. If the
loop is successful 3 consecutive times, the command you specified
will be run.
If one of the subsystems to be checked reports batch activity, an
exception spooled file is output and the job waits again for the time
specified on the WAITTIME parameter.
Setting the defaults for DLYCMD
-------------------------------
You can set the defaults for DLYCMD to your own requirements by using
the SETDLYCMD command. A user with *ALLOBJ special authority would
enter:
SETDLYCMD
and press F4. The command prompts are the same as for DLYCMD except
that *SAME is allowed for most parameters. Key over the defaults you
want to change and press Enter. The next time DLYCMD is prompted
for, you will see your default.
SETDLYCMD may also be used without prompting to change one or more
parameters.
The defaults are stored in the DLYCMD data area in TAASECURE. Both
SETDLYCMD and DLYCMD use the same prompt override program to extract
the values from the TAASECURE data area. The EXITPGM parameter does
not exist on SETDLYCMD and cannot be set as a default.
The SETDLYCMD function may also be invoked from the TAA SAVE2 menu.
The same set of defaults is used for any DLYCMD operation. If an
'exit before save program' is specified in the SAVE2 Application
Value, it is used on the DLYCMD.
Restrictions
------------
** If you have requested RSTDSTATE(*YES):
-- The command must be executed from a device in the
controlling subsystem. The default on i5/OS is for
QBASE to be the controlling subsystem and also used for
interactive and batch work. Therefore, any local
device in QBASE could perform the function. If the
QINTER/QBATCH approach is used, you must have a device
in the controlling subsystem (e.g. QCTL) to enter the
command.
-- If the restricted state cannot be reached in 10
minutes, the command fails with an escape message.
-- If POWERDOWN(*NO) is requested, the controlling
subsystem will be restarted after your command is
completed. The current controlling subsystem is used.
Not the name in the QCTLSBSD system value. You can use
an auto start job to bring up other subsystems.
** If a break message occurs at a workstation which is executing
a command, the command is interrupted and will not complete
until the message interrupt is ended. RCLSTG assigns QSYSOPR
to the requesting workstation and may send break messages.
To prevent this potential hang condition, the CHGJOB
BRKMSG(*HOLD) function is used while DLYCMD is in execution.
However, any inquiry messages caused by the DLYCMD command,
will cause the function to hang. For example, if a 'mount
media' occurs, the DLYCMD command will hang waiting for a
response.
The RCLSTG command does not normally issue any inquiry
messages. The SAVSYS command normally causes media mount
messages unless the entire save can be placed on a single
media.
Security considerations
-----------------------
The intent is that you will leave the system unattended and the
DLYCMD in execution. Because of this, there is a security exposure
since the System Request function can be used while the DLYCMD
display is being displayed.
Physical security should be used.
Two functions are automatically provided by DLYCMD.
** No Function key or Enter key can be used to end the DLYCMD
display.
** If System Request is used for -End Request-, a Signoff will
occur.
The POWERDOWN and SIGNOFF options on DLYCMD control what happens when
the command completes successfully.
Only a user with *ALLOBJ authority can use SETDLYCMD. The program
which accesses the command defaults for the prompt override program
adopts the owners authority.
Tighter security
----------------
To achieve better security, you should consider a separate profile
(e.g. QSYSOPR2) so that you can prevent certain actions. The
following user profile could be created (CURLIB should be set to the
library which contains the DLYCMD command):
CRTUSRPRF USRPRF(QSYSOPR2) PASSWORD(xxxx)
USRCLS(*SYSOPR) CURLIB(TAATOOL)
INLPGM(QSYS/QCMD) ATNPGM(*NONE)
TEXT('User profile intended for +
use with TAATOOL DLYCMD')
Note that it is important for a user class of *SYSOPR to be used so
that the user can perform save operations and power down the system.
The following commands will prevent access to certain System Request
functions.
GRTOBJAUT OBJ(QSYS/TFRSECJOB) OBJTYPE(*CMD)
USER(QSYSOPR2) AUT(*EXCLUDE)
GRTOBJAUT OBJ(QSYS/DSCJOB) OBJTYPE(*CMD)
USER(QSYSOPR2) AUT(*EXCLUDE)
The sequence of events would then be:
** Signoff the device to be used in the controlling subsystem.
** Signon as QSYSOPR2.
** Prompt for the DLYCMD.
** Enter the required values and press Enter.
** The DLYCMD display will appear (as shown earlier).
** Go home.
At that point, any user gaining access to the device could not do the
following:
** Use System Request to transfer to a secondary job.
** Use the Attention key to access a group job or a command entry
menu.
** Use System Request to -End request- to access the command
entry display. A signoff would occur.
** End the DLYCMD function and access command entry by using any
Function key or Enter key.
Any user gaining access to the device could use System Request to:
- Display the current job.
- Display any authorized message queue (including QSYSOPR).
- Send a message to a message queue.
- Signoff.
You could prevent any of the remaining valid options by using the
GRTOBJAUT command as was suggested for the TFRSECJOB command.
DLYCMD use within a CL program
------------------------------
It is possible to execute the DLYCMD within a CL program, but the
command can only be executed from an interactive job. Commands may
follow DLYCMD in a CL program, but only if you request POWERDOWN(*NO)
and SIGNOFF(*NO). For example, after the command completes, you
could start other subsystems or submit batch jobs.
DLYCMD Command parameters *CMD
-------------------------
CMD The command to be executed when the triggers are
satisfied. F4 may be used to prompt for the
command. The original default is blank (no
command). The command is optional and is intended
for those cases where you only want a PWRDWNSYS
option to occur. SETDLYCMD may be used to change
the default.
TIME The time of day trigger. It must be entered as
HHMMSS. Military time is used (2:00 PM must be
entered as 140000). The original default is *NONE.
SETDLYCMD may be used to change the default.
DATE The date trigger. A date (in job format) or the
values *TODAY, *DAY1 or *DAY2 can be entered. The
original default is *TODAY. SETDLYCMD may be used
to change the default.
If *TODAY is entered, the TIME value must be greater
than the current time. *DAY1 means the next day and
*DAY2 is the second day.
MAXJOBS The maximum number of jobs trigger. The default is
*NOMAX. The value may be from 0 to 9999. SETDLYCMD
may be used to change the default.
Note that the subsystem monitor job can be seen on
WRKACTJOB, but is not considered a job for the
MAXJOBS parameter. Thus an entry of 0 means there
is no other job, but the monitor job.
If a value is entered, it is used to compare against
all of the active jobs specified in the SBS
parameter. If the number is met, the command waits
30 seconds and tries the function twice more with
another intervening 30 seconds. This helps ensure
that no new jobs are being started.
The special value *RTVSBSBCH may be entered to use
the RTVSBSBCH tool on the specified subsystems.
This tool is designed to assist you in determining
if any 'actual batch work' is being performed in the
subsystem. Before specifying *RTVSBSBCH, review the
documentation for the RTVSBSBCH tool and try the
PRTSBSBCH command to ensure that you have the proper
status values checked for your system.
SBS The subsystems to check for the MAXJOBS parameter.
Up to 9 subsystems may be named. The original
default is *ALL. SETDLYCMD may be used to change
the default.
If MAXJOBS is other than *NOMAX and a subsystem name
is entered, the subsystem must be active.
If you name multiple subsystems, there is a
performance advantage in naming the most active
subsystem first. For example, if you want to delay
until both QINTER and QBATCH are 1 and QINTER is
more likely to have more active jobs, specify QINTER
first. If QINTER has multiple active jobs, QBATCH
is not even checked.
There is overhead involved in checking for MAXJOBS.
If you need to check for MAXJOBS, but do not need to
do so until a specific time, you should also specify
the TIME parameter. No overhead occurs while the
job is waiting for the time value to expire.
EXITPGM The name of your exit program which will be run
after any time out has occurred and before ending
any subsystems. *NONE is the default meaning there
is no exit program.
An exit program and library name may be specified to
cause the program to be run after the timeout
occurs. The intention of the program is to provide
for any cleanup before ending all subsystems.
TEXT The text that should appear on the display. The
original default is *NONE. SETDLYCMD may be used to
change the default.
RSTDSTATE Whether the restricted state should be entered
before the command entered on the CMD parameter
should be executed. The restricted state is
required for some commands. The original default is
*NO. SETDLYCMD may be used to change the default.
POWERDOWN Whether the system should be powered down after the
command is executed. The original default is *NO.
SETDLYCMD may be used to change the default.
If the restricted state is used and PWRDWNSYS(*NO)
is specified, STRSBS will be used for the
controlling subsystem when the CMD command
completes.
RESTART Whether to re-start the system if a powerdown has
occurred. This value is passed thru to the
PWRDWNSYS command RESTART parameter. The original
default is *NO. SETDLYCMD may be used to change the
default.
SIGNOFF Whether to signoff after the command is executed.
If the system is re-started without powering down,
you may choose to signoff. LOG(*LIST) is used to
provide a job log. The original default is *YES.
SETDLYCMD may be used to change the default.
An entry of *NO will cause a return when the DLYCMD
is complete. If you include the DLYCMD in a CL
program with commands following DLYCMD, you will
want to specify SIGNOFF(*NO).
WAITTIME The wait time associated with the MAXJOBS parameter.
The 5 digit 0 decimal parameter uses an original
default of 600 seconds (10 minutes). SETDLYCMD may
be used to change the default.
This value controls the frequency in which the
DLYCMD will check the number of active jobs per the
MAXJOBS and SBS parameters. There is overhead
associated with this checking. Thus the WAITTIME
should not be specified too low. If the MAXJOBS
value is reached, the DLYCMD will not recognize it
until the wait time expires.
SETDLYCMD Command parameters *CMD
----------------------------
The same parameters as used on DLYCMD are supported plus the addition
of *SAME for each parameter except CMD.
If the CMD parameter is blank, the current value is not changed. To
reset the CMD parameter to blanks, use the NOOP TAA command.
Prerequisites
-------------
The following TAA Tools must be on your system:
ADDDAT Add date
CHKALLOBJ Check *ALLOBJ special authority
CHKRSDSTE Check restricted state
CLCDATDIF2 Calculate date difference 2
CLCTIMDIF Calculate time difference
EDTVAR Edit variable
EXTLST Extract list
EXTLST2 Extract list 2
RTVIPLSTS Retrieve IPL status
RTVJOBSTS Retrieve job status
RTVSBSD Retrieve subsystem description
RTVNBRACT Retrieve number of active jobs in a subsystem
SNDCOMPMSG Send completion message
SNDESCMSG Send escape message
SNDSTSMSG Send status message
Implementation
--------------
None, the tool is ready to use.
Objects used by the tool
------------------------
Object Type Attribute Src member Src file
------ ----- --------- ---------- -----------
DLYCMD *CMD TAAJOBK QATTCMD
SETDLYCMD *CMD TAAJOBK2 QATTCMD
TAAJOBKD *FILE DSPF TAAJOBKD QATTDDS
TAAJOBKC *PGM CLP TAAJOBKC QATTCL
TAAJOBKC2 *PGM CLP TAAJOBKC2 QATTCL
TAAJOBKC11 *PGM CLP TAAJOBKC11 QATTCL
DLYCMD *DTAARA
The DLYCMD data area is in TAASECURE.
Structure
---------
DLYCMD Cmd
TAAJOBKC CL
SETDLYCMD Cmd
TAAJOBKC2 CL
The TAAJOBKC11 program is used as a prompt override program for each
command.
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