gtpg1m0b | General Information |
To provide for system and application growth, the TPF system can increase its capacity through different hardware configurations. It can also update one or multiple databases, and update relational databases directly.
The TPF system allows open-ended growth by providing:
The remainder of this chapter describes the TPF functions and features that allow the TPF system to grow in capacity and connectivity.
The TPF system can run in a single central processing complex (CPC) or in a multiple CPC environment. A single CPC can have one (uniprocessor) or more (multiprocessor) processors. The TPF system runs on selected models of ES/3090 and ES/9000 processors. TPF configurations can be tightly coupled or loosely coupled.
A tightly coupled configuration has a single multiprocessor in which the processors are synchronized to share a single main storage. When the TPF system runs with one image of the TPF system for each CPC, regardless of the number of processors, it is referred to as a tightly coupled configuration.
A loosely coupled configuration has two or more CPCs that share a common set of DASD. Sharing a database improves the TPF system's capacity and availability. Through its loosely coupled (LC) facility, the High Performance Option (HPO) feature allows the TPF system to run in a loosely coupled configuration. When using HPO, a maximum of 8 CPCs can share a common database in a loosely coupled configuration.
Figure 5 shows an example of vertical growth from a uniprocessor CPC to a multiprocessor CPC.
Figure 5. TPF System Capacity for Vertical Growth
Figure 6 shows an example of horizontal growth that uses the HPO feature to share the same database between multiple CPCs.
Figure 6. TPF System Capacity for Horizontal Growth
Loosely coupled TPF configurations provide the following advantages over single CPC systems:
The capacity of the TPF system increases linearly with each CPC added to a loosely coupled configuration. Coupling one CPC to an existing CPC effectively doubles the capacity; coupling 2 CPCs to an existing CPC effectively triples the capacity. For example, if the capacity of a single ES/9000 CPC is not sufficient, up to eight ES/9000 CPCs can be loosely coupled together. In a loosely coupled configuration, any application can run in any CPC, and any CPC can update any part of the shared database.
Multiple CPCs share the transaction processing workload and maintain the same database, as shown in Figure 7.
Based on workload, the number of CPCs can be dynamically expanded or contracted without affecting system availability. Periodic functions such as system utilities constitute a significant drain on system resources. A CPC can be dedicated to one or several utilities while the remainder of the complex continues transaction processing unaware of concurrent utility activity.
Data integrity in a loosely coupled configuration is ensured through TPF-unique functions for IBM CPCs and disk control units. The disk control units support TPF locking functions that maintain locks on a piece of data so that multiple CPCs cannot update that data simultaneously.
The TPF system uses the hardware timers to synchronize CPC clocks throughout a loosely coupled complex.
The CPCs in a loosely coupled configuration communicate status information to each other at a very high speed using the Multi-Processor Interconnect Facility (MPIF) feature.
Figure 7. Loosely Coupled Configuration
Multiple TPF CPC configurations can be formed through:
When CPCs are connected through a loosely coupled configuration, the Multi-Processor Interconnect Facility (MPIF) feature provides an interface that allows TPF configurations to communicate at very high speeds with another TPF configuration through channel-to-channel (CTC) connections. In a loosely coupled configuration, multiple CPCs can share a database.
The MPIF feature allows one TPF CPC to request a service that is received, processed, and returned by another TPF CPC. The requesting CPC need not be aware that a different CPC provided the requested service. The MPIF feature uses CTC connections to communicate in a single loosely coupled CPC or between multiple CPCs. The TPF 4.1 system can communicate with the TPF 3.1 system using the MPIF feature.
Figure 8 shows an example of connecting configurations using the MPIF feature and SNA CTC.
Figure 8. Connecting Configurations Using The MPIF Feature and SNA CTC
Through its Multiple Database Function (MDBF), the High Performance Option (HPO) feature allows your installation to run multiple applications concurrently under one TPF system with a unique database for each application.
MDBF extends the TPF system's capabilities by supporting multiple unique databases on the same central processor complex (CPC). Your installation can define up to 64 unique databases or subsystems. A group of applications that share a database is treated as a unique TPF system. In a TPF system with multiple subsystems, a primary or basic subsystem (BSS) is required for operational control of all TPF system resources.
The BSS contains all system routines, the control program, and supporting programs. The BSS can also include application programs. The other subsystems contain all resources necessary for a stand-alone system except the control program and its supporting programs. Each subsystem relies on the BSS running all system-related tasks, including input and output message processing.
Subsystems are independent and their data is protected from other subsystems. This assures that new applications and equipment can be assimilated in a planned, orderly manner without affecting existing databases.
TPF applications can be written in IBM High Level Assembler/MVS & VM & VSE or C language. TPF application programs can directly access relational databases through structured query language (SQL) commands using the TPF Application Requester (TPFAR) feature.
IBM C/370 language is included in the Systems Application Architecture (SAA) Common Programming Interface. IBM C/370 language support and the IBM C/370 Compiler program product provide support for the C/370 language. The use of this high-level, general purpose language can increase productivity and quality in application programming shops. By writing application programs in the C/370 language, your installation can create fast and compact code with all the benefits of coding in a high-level language.
TPF C/370 language support includes the following:
In addition to the benefits provided by C/370 support, ISO-C C language support provides the following:
The TPF 4.1 system connects to the latest level IBM Systems Network Architecture (SNA) communication networks. TPF SNA networks are owned by an MVS/VTAM communication management configuration (CMC) that is attached to and owns the resources in the TPF network. The TPF system maintains all logical unit sessions with the elements in the network. In the event of a CMC failure, the existing sessions with the network are not disrupted. New sessions are established when the CMC has been recovered.
If the TPF system fails, the network remains active. The TPF system usually can be brought back online in time to prevent a loss of the network, therefore avoiding the lengthy restart procedures that are associated with very large networks.
TPF Advanced Program-to-Program Communications (TPF/APPC) is an interface that allows TPF transaction programs to communicate with remote SNA nodes that have implemented the APPC interface using LU 6.2 protocols. TPF/APPC supports all APPC base functions as well as some optional functions.
The TPF 4.1 system also supports communication with other host systems. The TPF system can communicate with other TPF, IMS, CICS, or DATABASE 2 (DB2) systems through channel-to-channel (CTC) connections and the Network Control Program (NCP).