gtpg1m13 | General Information |
The TPF 4.1 system provides the following migration aids to protect your investment:
Explains the TPF 4.1 system details as they affect your system and application code.
Provides file address reference format 4 (FARF4) as a transition step between FARF3 and FARF5. For more information, see Expanded File Addressing Capacity.
Provides limited virtual function to help your installation convert from a non-virtual to a virtual TPF system. VEQR mode allows your installation to run programs that are unchanged from the TPF 3.1 system even though the programs use data-sharing techniques that are no longer supported. When unsupported storage sharing is found, the TPF system logs the incident. Running in VEQR mode identifies illegal storage references between address spaces. By using VEQR mode in a test environment, you can test individual programs as you make changes, before modifying your entire application for the TPF 4.1 system. VEQR mode allows you to migrate your applications to the TPF 4.1 system gradually.
Marks code that uses block storage management practices that could have worked in the TPF 3.1 system but do not work in the TPF 4.1 system. Block checking mode marks coding errors such as writing beyond the end of a block, passing blocks chained to other blocks, and using storage that has already been released. Block checking mode can be turned on and off without reinitializing the TPF system.
Multiple TPF images function as both a migration aid and an auxiliary loader. Being able to define up to 8 images of the TPF system on a single processor gives your installation greater flexibility in migrating to a new release. You can maintain images of both releases and fall back to a previous program base if necessary. See Auxiliary Loader for more details and for a description of the auxiliary loader.
To improve performance in the TPF 4.1 system, virtual file access (VFA) is always present and active. Your installation can run programs directly from VFA, thereby improving system performance. The online and offline VFA performance monitoring facilities improve your installation's ability to better tune VFA candidates and VFA resources.
Enhancements to the macro decoder and supervisor call instruction (SVC) definitions increase an application's ability to request system services.
The primary interfaces for application requests of system services are through macros using the SVC and fast-link macro decoders. (Fast-link macros are macros that do not issue SVCs.) In the TPF 4.1 system, the SVCs allocated for use are increased from 128 to 255, and the SVCs reserved for customer use are increased from 1 to 32. In addition, two SVC entries (one for IBM and one for customers) can be reserved to support a second-level structure. With this secondary or indexed structure, your installation can define more than 32 000 additional macros.
One hundred fast-link macros are reserved for your application's use. Fast-link macros are more expedient than other macros because they do not issue SVCs that cause system interrupts.
Certain restricted-use TPF system macros now check the authorization level of the requesting program before providing the system service. If a program requests a service that it is not authorized to obtain, the service is not granted. This authorization level is specified as part of a program's allocation information.
Beginning in TPF 4.1 systems,
the only supported path for inter-processor communications is through the
Multi-Processor Interconnect Facility (MPIF) feature. MPIF is a
required feature for the High Performance Option (HPO) feature.
IBM C Language Support
In the TPF 4.1 system, IBM C language support is no longer a product feature. It is incorporated in the base TPF product to allow system and application growth. TPF 4.1 requires installation of either the IBM C/370 or AD/Cycle C Compiler and Library.
Several reports are enhanced to be more usable and present additional information. A new report contains a histogram of storage frame usage.
System initialization is easier in the TPF 4.1 system. The file address compute program (FACE) table generation is handled by a new offline FACE table generator program rather than as part of system initialization process (SIP).
The capture and restore utility controls the maximum number of simultaneous captures allowed for each tape control unit, DASD control unit, DASD channel path and tape channel path, based on the channel path activity.