The paging operation for an MFS device depends on MFS control
block definitions, the output message content, and your input. If
the device is a printer, each physical page of each logical page is
transmitted to the device in sequence and the message is dequeued.
During output paging, if online change processing occurs that changes
the format of the output message you access, you can get an error
message or get the message in a format different from the one expected.
If operator logical paging is not specified for a 3604,
3270, SLU 2 display, or SLU P using the DPM paging option, each physical
page of each logical page can be viewed in sequence using the NEXTPP
function. Because operator logical paging is not specified, entering
NEXTPP after the last physical page of the last logical page has been
displayed causes the next message to be transmitted if only one exists
in the queue. If no message is in the queue, no action takes place.
If operator logical paging is specified for a 3604, 3270, SLU 2
display, or SLU P using the DPM paging option, the NEXTPP function
can be used to view pages sequentially. However, entering NEXTPP after
the last physical page of the last logical page causes MFS to return
an error message and reset the page position to the first page. If
you are going to view pages out of sequence, the formats should be
designed to use the PAGEREQ capability or to have the page request
edited to the first field of the first input segment. If not, the
screen must be cleared before the page request is entered as unformatted
input. For performance reasons, avoid this method.
The following tables describe IMS actions,
and the possible message and device status from your input or remote
program actions after a successful message transmission.
The following factors must be considered and are included in the
figure:
Macro/statement specifications:
TERMINAL (or TYPE) macro (IMS system
definition)
or
When you use the default (PAGEDEL=YES), your input
that invokes processing for a new transaction causes the output message
for the current transaction to be dequeued. To prevent current output
from being dequeued, OPTIONS=(...,NPGDEL,...), or PAGDEL=NO for nonswitched
3270 devices, must be specified.
MSG statement (MOD definition)
PAGE=YES specifies that operator logical paging
is permitted. PAGE=NO specifies that paging is not permitted.
Whether the last physical page of the last logical page in the
current message has been sent.
An IMS action performed automatically
after successful message transmission and before your input.
Your input or remote program action after receiving a message:
PAGE ADVANCE: NEXTPP request is entered (or you press PA1 key
on 3270 or SLU 2).
LOGICAL PAGE ADVANCE: NEXTLP request is entered.
=PAGE: specific logical page is requested.
PAGEREQ: specific logical page is requested.
MESSAGE ADVANCE: NEXTMSG request is entered (or you press the
PA2 key on a 3270 or SLU 2 device).
MESSAGE ADVANCE PROTECT: NEXTMSGP request is entered (or you press
PA3 key on 3270 or SLU 2 when PA3 is not defined for copy function).
You enter (or a remote program enters) data that does not invoke
an operator control function, followed by enter (or 3270 or SLU 2
PFK, CARD, IMMEDIATE DETECT).
3270 or SLU 2 operators can also
press the CLEAR key. The CLEAR key causes the screen to be unprotected,
and subsequent input is edited by IMS basic
edit. CLEAR does not affect the status of the current output message.
The result of any operator action after using CLEAR is the same as
if CLEAR had not been used.
The following tables use the following abbreviations to describe IMS action:
MSG DEQ
Message dequeue. IMS removes
the current output message from the message queue. The message is
available until this action takes place.
MSG ENQ
Message enqueue. IMS places
the input message in the message queue.
PROTECT
IMS prevents the device from
receiving output from IMS.
UNPROTECT
IMS makes the device eligible
to receive output from IMS. If
a message is currently queued for this device, IMS sends it (subject to controls established
by response mode, conversational or exclusive device status).
If a paged message is sent to the terminal with the unprotected
screen option set to unprotected (during system definition
or using the DSCA or SCA specification), the screen is not protected
between pages and the IMS-described actions shown in the following
tables should be ignored. If the message is sent to the terminal with
the unprotected screen option set to protect, the IMS actions shown in the following tables apply.
The following tables assume the system and message definition values
and page position in the current message that apply in the following
four cases:
Case 1
PAGE=NO and the last physical page of the last logical page of
the current message was sent.
Case 2
PAGE=NO and the last physical page of the last logical page of
the current message was not sent.
Case 3
PAGE=YES and the last physical page of the last logical page of
the current message was sent.
Case 4
PAGE=YES and the last physical page of the last logical page of
the current message was not sent.
Note: If an error message has been sent to the last page, the following
tables do not apply. The original message is still in the queue. See IMS
Version 15.2 System Utilities for
the proper response to the message.
For the following table, the IMS action,
after successful IMS transmission
of the message and terminal receipt of the message, for each of these
four cases is PROTECT, that is, IMS prevents
the device from receiving output from IMS.
For Case 1, IMS also dequeues
the message from the IMS message
queue.
Table 1. Paging operation for a device with MFS with PAGDEL specified. IMS-MFS action and resulting terminal and message status
Operator Action
IMS Action for Case 1
IMS Action for Case 2
IMS Action for Case 3
IMS Action for Case 4
Request
PAGE
ADVANCE
(NEXTPP)
Unprotected
Send next physical page unprotected
Send error message, protected1
Send next physical page, protected
Request
LOGICAL
PAGE
ADVANCE
(NEXTLP)
Unprotected
Send first physical page of next logical page
in current msg 2
Send error message, protected 1
Send first physical page of next logical page
in current msg 2
Request specific logical page using =PAGE
Send error message, protected 3
MSG DEQ, send error message protected 3
If valid, send
first physical page of requested logical page, protected. 1
If
invalid, send error message protected. 1
Request specific logical page using PAGEREQ
Send error message, protected
Send error message, protected 1
If valid, send
first physical page of requested logical page, protected. 1
If
invalid, send error message protected. 1
Request
MESSAGE
ADVANCE
(NEXTMSG)
Unprotected
MSG DEQ,
unprotected
MSG DEQ,
unprotected
MSG DEQ,
unprotected
Request
MESSAGE
ADVANCE
PROTECT
(NEXTMSGP)
Protected 4
MSG DEQ,
protected 4
MSG DEQ,
protected 4
MSG DEQ,
protected 4
Enter data
MSG ENQ,
unprotected
MSG DEQ,
MSG ENQ,
unprotected
MSG DEQ,
MSG ENQ,
unprotected
MSG DEQ,
MSG ENQ,
unprotected
Notes:
The original message is still in the queue. See IMS
Version 15.2 System Utilities for
the proper response to the message.
If the current page was the last logical page, no
new page is sent, and device status is unprotected.
If the device is preset or in conversation, the input
is queued; no error message is sent and the device status is unprotected.
If a message is in the queue and exclusive or conversational
status does not prevent it from being sent, it will be sent. If no
message can be sent, a system message is sent indicating that no output
is available.
For the following table, the IMS action,
after successful IMS transmission
of the message and terminal receipt of the message, for Cases 2, 3,
and 4 is PROTECT, that is, IMS prevents
the device from receiving output from IMS.
For Case 1, IMS dequeues the
message from the IMS message
queue.
Table 2. Paging operation for a device with MFS with NPAGDEL
specified. IMS-MFS action and resulting terminal and message
status
Operator Action
IMS Action for Case 1
IMS Action for Case 2
IMS Action for Case 3
IMS Action for Case 4
Request
PAGE
ADVANCE
(NEXTPP)
Unprotected
Send next physical page, protected
Send error message, protected 1
Send next physical page, protected
Request
LOGICAL
PAGE
ADVANCE
(NEXTLP)
Unprotected
Send first physical page of next logical page
in current msg 2
Send error message, protected 1
Send first physical page of next logical page
in current msg 2
Request specific logical page using =PAGE
Send error message, protected 3
Send error message, protected 1, 3
If valid, send
first physical page of requested logical page, protected.
If
invalid, send error message, protected. 1
Request specific logical page using PAGEREQ
Send error message, protected
Send error message, protected 1
If valid, send
first physical page of requested logical page, protected.
If
invalid, send error message, protected. 1
Request
MESSAGE
ADVANCE
(NEXTMSG)
Unprotected
MSG DEQ,
unprotected
MSG DEQ,
unprotected
MSG DEQ,
unprotected
Request
MESSAGE
ADVANCE
PROTECT
(NEXTMSGP)
Protected 4
MSG DEQ,
unprotected
MSG DEQ,
protected 4
MSG DEQ,
protected 4
Enter data
MSG ENQ,
unprotected
MSG ENQ 5
MSG ENQ 5
MSG ENQ 5
Notes:
The original message is still in the queue. See IMS
Version 15.2 System Utilities for
the proper response to the message.
If the current page was the last logical page, no
new page is sent, and device status is unprotected.
If the device is preset or in conversation, the
input is queued; no error message is sent and the device status is
unprotected.
If a message is in the queue and exclusive or conversational
status does not prevent it from being sent, it will be sent. If no
message can be sent, a system message is sent indicating that no output
is available.
The original message is still in the queue. The
first physical page of the first logical page is sent unless the device
is currently involved in an active conversation. If in conversation,
an error message is sent. To continue after a conversational response,
NEXTMSG must be entered to dequeue that response.
