gtps4m45 | System Generation |
There are a number of major differences between the base-only configuration
and the loosely coupled configuration:
- Each processor has its own system console (or its own 3270 local CU with a
CRT device) and only certain processor models are supported for inclusion in
the complex.
- The same or different processor models may be included in the complex or
as backup processors.
- If native console support is used each processor must have its
own 3270 local CU with at least one 328x printer as its RO CRAS device.
- Either native console or 1052/3215 support may be specified, and all
processors must use the same type of devices but they may have different
addresses.
- Processors may be used that have different main storage sizes but the size
of the smallest must be specified.
- Processors may be equipped with a different number of channels but SIP
must be coded with the value for the processor with the fewest number.
- If the tape devices are shared, each processor must access the tape
devices using the same addresses.
- All of the shared DASD CUs and devices are accessed from each processor
via the same addresses. In addition, all shared DASD CUs
must be equipped with either the LLF or the CFLF RPQ. Depending on the
RPQ, the following differences exist:
- For LLF, all of the shared DASD CUs must have a path to each processor
where the interface is installed in the exact same sequence on all CUs (that
is, if 1 DASD CU is connected to the first processor through interface A,
all other DASD CUs connected to the same processor must
also use interface A, and interface B would be used to connect to the second
processor, and so on).
- For CFLF, unique pathing is not required.
- Each processor has its own unique tape configuration.
- A TCU running 3705/EP is shown to emphasize the significance of an EP
processor.
- A TCU with multi-tail capability and running ACF/NCP must be connected to
all processors and can be on either a byte or block-multiplexer channel but
must be located at the same address for all processors.
- Any unit record equipment, in addition to the system printer depicted,
must not be shared but may be located at the same addresses on each
processor.
- Not shown but required is a Clock Synchronization RPQ that must be
connected to each of the processors in the complex.
- Additional processors may be generated but not used in the online
system. This is a useful technique when generating for today
but preparing for tomorrow, or for backup.
- The requirements for a backup processor are different for a loosely
coupled complex and are impacted by cost and the need both for a backup
processor and for an EP processor (if there are any 3705/EP protocols being
supported).
- In this illustration the backup processor has been configured in such a
way as to be able to replace either of the two active
processors.
- Another possible configuration would be to backup each processor in the
complex with another processor.
- A third configuration would be to generate a complex with more processors
than are required but to only have active at any one time a subset of the
total generated.
- 3270 local CUs, other than one with the system console devices, can only
be attached to the EP processor. For configuration purposes, the 3270
local considerations are the same as 3705/EP.
- The input to create a loosely coupled complex is only a single SIP input
deck regardless of the number of processors. Thus hardware, which is
unique to one processor, must be defined to all but only used by one.
Figure 31. Sample Loosely Coupled System Configuration
The SIP input required for this LC complex is:
CONFIG
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APRNT=00E,DCUSV=16,SYSID=(B,C),
PROC1=(xxxxx,yyyy,0,0),
PROC2=(wwwww,zzzz,1,1),
PROC3=(uuuuu,tttt,2,2)
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X
X
X
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- The system printer is defined as '00E' and it must be the same for
all processors in the complex.
- The type of DASD CU and devices shown utilize up to 16 device
addresses. Typically, the number of DASD devices per CU in an LC
complex will be less than a base only system due to the performance impact
that results from the sharing of CUs (busy conditions).
- The symbolic processor IDs chosen are 'B' and 'C'.
This is a critical parameter since it specifies the number of processors in
the complex. Additionally, the first subparameter value of SYSID
designates the EP processor. Although the illustration implies that SIP
assigns the IDs to a particular processor, in reality the choice is selected
at restart time. Since they are configured exactly alike, any of the
three can assume the identity of either 'B' or 'C'.
- The processor identification number must be specified for each
of the processors in the complex. The backup processor must be assigned
one of these IDs when it is actually utilized.
- The hardware selection address of the Clock Synchronization RPQ must be
specified for each processor. The backup processor must be able to
access the TOD RPQ using one of the Synch Selection Addresses.
- Defaults are accepted for all other CONFIG keywords.
CRASTB PRCRS=(1F,1F,20),ROCRS=(24,24),NCONSL=YES
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Each LC processor must have a system console. In addition, each must
have its own 3270 local CU with at least one printer if using native console
support.
- Addresses are specified sequentially by processor in the same order that
the processors were defined on the CONFIG macro (SYSID).
- All addresses specified are actually available to all processors.
All other addresses are treated as alternates by all processors.
- All system consoles must be either 3270-like or 1052/3215 devices.
They may also all have alternates. The addresses specified
('01F' and '020') are the same, but they could be
different.
- The 3270 local printer ('024') is designated as the RO CRAS device
in both cases but are physically different devices. Again, the
addresses specified can be different for each processor.
LINES ...
NETWK N2703=1,SUBCH=(1C-n)
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- These macros are coded in order to utilize the TCU depicted
('01C').
- The type of protocols and numbers of lines are specified via the LINES
macro, whereas the TCU running 3705/EP and is defined via the NETWK
macro.
- The addresses, number of TCUs, and symbolic TCU numbers are specified on
NETWK along with the channel adapter type.
- Note that the addresses of the TCUs running ACF/NCP are specified on the
SNAKEY macro (MAXALS=), not here.
- The other keywords on NETWK relate to the protocol being generated and the
appropriate ones must be coded or defaults accepted.
UNITRD UNIT=3211,ADDR=00E,SYMNO=1
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- This macro is specified to include the printer ('00E') for
application program use in addition to system use (CONFIG, APRNT).
- If there are any additional U/R devices they could be on any or all of the
processors with the same or different addresses. They are included by
defining the device to all processors. If the same address
is used, it is defined only once.
IODEV DVTYP=DASD,IOADR=03C0
IODEV DVTYP=DASD,IOADR=03C8
IODEV DVTYP=DASD,IOADR=02A0
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This series of macros defines the DASD CUs and devices.
- The DVTYP specification can be for any one of the supported DASD device
types but must utilize the 3880 CUs with the LLF RPQ or the 3990 CU with the
LLF or CFLF RPQ.
- The number of devices on a CU is dependent upon the device type but due to
both CU and device contention will probably be less than a base only system
configuration.
- All control units defined to the system must have the CFLF or LLF RPQs
installed.
IODEV DVTYP=TAPE,IOADR=48
IODEV DVTYP=TAPE,IOADR=58
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The tape configuration for each of the processors in the complex is defined
as if a single system had multiple tape CUs.
- In this case one macro is for processor 'B' and one is for
processor 'C'.
- Both processors can have a tape CU at the same address and in this case
only one set of macros is required as if there was only one CU.
- Each macro specifies 16 tape drives. Because there is a maximum of
8 drives per control unit, 2 control units are required per tape
subsystem. If the communications feature is installed between the two
control units and TPF supports multipathing to those devices, then TPF can use
both control units to communicate with any of the 16 devices. If,
however, the communications feature is not installed between the control units
or TPF does not support multipathing for those drives, then only one control
unit at a time may be used to communicate with a device.