What Is on Program Update Tape (PUT) 7?
by Thomas Brocker, IBM TPF ID Core Team

The following summarizes PUT 7 support:

• Link map support for C load modules (APAR PJ24845) makes it easier to debug problems that occur in C load modules. C load modules loaded to the online TPF 4.1 system will contain link maps that can be included in certain types of dumps that include C load modules.
• Virtual file access (VFA) (APAR PJ25094) is a storage management facility that dynamically allocates frequently referenced records to main storage.
  
  Adding VFA synchronization to your loosely coupled TPF 4.1 system enhances current VFA support by providing VFA candidacy support for fixed file records and pool records that are synchronized across processors. The synchronization is done by using the locking capabilities of the IBM 3990 Model 3 or later models with the multi-path lock facility (MPLF) installed.
  
  Before VFA synchronization:
  
  - Very few records (except for read-only data records and processor-unique records) were good candidates for VFA in a loosely coupled environment.
  
  - Synchronization of records did not exist. If a record located in the VFA area of several processors is updated on one processor, the other processors then refer to old data until a find and hold macro is issued.
  
  With VFA synchronization:
  
  - There is an effective way in a loosely coupled environment to support VFA candidacy for records that are updated by application programs during normal system operation. VFA synchronization provides the capability to synchronize updates to frequently referenced records in VFA across all processors in a complex.
  
• TPF transaction services (APAR PJ25094) includes support for a transaction manager, resource managers, log manager, and recovery log to ensure a consistent view of the database.
  
• The TPF 4.1 system now provides support for C++ language (APAR PJ25084), which is designed to take advantage of object-oriented (OO) programming concepts. Except for minor details, C++ language is a superset of C language. In addition to the facilities provided by C language, C++ language provides flexible and efficient facilities for defining new data types. You can partition an application into manageable pieces by defining new data types that closely match the logical design of the application. When used well, these techniques result in shorter, easier to understand, and easier to maintain programs.
  
  Dynamic link libraries (DLLs) are now supported. A DLL is a collection of one or more functions or variables gathered in a load module that can be run or accessed from a separate application load module. The key concept in DLLs is that functions or variables can be dynamically linked while the application is running rather than statically when the application is built. You can, therefore, call a function or use a variable in a load module other than the one that contains the definition. This allows you greater flexibility in accessing library functions or variables.
  
• While not totally compatible with Portable Operating System Interface for Computer Environments (POSIX) standards, TPF file system support (APAR PJ25089) provides support for storing and operating on information in the form of stream files.
  
  TPF file system support provides a hierarchical directory structure that allows users and application programs to access objects in the TPF system using TPF file system C functions. TPF file system directory support is similar to the directory support provided in UNIX, which was the model for many aspects of the IBM Disk Operating System (DOS), Windows, and OS/2 file systems. In addition, this support provides features typical of UNIX systems, such as the ability to store a file only once, but to access it through multiple paths using links.
  
• TPF persistent collections support (APAR PJ25098) is a database manager service for application programs that access persistent collections on a TPF database. Persistent collections are abstract representations of data that maintain their state after the entry control block (ECB) that creates them exits. TPF persistent collections support provides three collection lifetimes: persistent long-term, persistent short-term, and temporary. TPF persistent collections support transparently integrates database functionality with the application program and TPF does not need to have any knowledge of the format of the data.
  
• Previously, TPF TCP/IP support required an IBM 3172 offload device for processing the socket application programming interface (API) functions. Now, you can use the Cisco 7500 series router (APAR PJ24746) as your offload device. To use this support, you must install APAR PJ24746 on your TPF 4.1 system. If you are currently using a Cisco 7500 series router, you must upgrade your channel interface processor (CIP) licensed internal code (LIC) to enable the Cisco 7500 series router to connect to your TPF 4.1 system.