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OpenExtensions for z/VM Overview

z/VM makes it easier for your installation to port applications, tools, data, and people skills across multiple systems. This portability can help reduce your overall cost of computing and enable you to produce high-quality applications that take advantage of the facilities on other operating systems.

Port data and applications to and from a wide range of platforms

The implementation of POSIX 1003.1 System Interfaces standard on VM provides a set of UNIX-based programming interfaces that enables the porting of applications from UNIX and other POSIX-compliant platforms to VM. It also allows POSIX-compliant applications to be developed on VM and ported to other POSIX-compliant platforms.

UNIX application support was enhanced in VM/ESA V2R3.0 with the addition of more XPG-4 compliant application programming interfaces and accommodation of certain uses of the UNIX fork() function. UNIX application support was enhanced in z/VM 3.1.0 with the addition of the sockets APIs and several file system APIs. In combination with z/VM preexisting POSIX API support, application developers and solution providers have a functionally rich UNIX environment on VM for their development and porting efforts.

z/VM includes a POSIX 1003.1 compliant file system called the Byte File System (BFS), which is an extension to the CMS Shared File System (SFS). The integration of POSIX BFS into the SFS server structure allows you to store large amounts of data on the host DASD using SFS. SFS capabilities include data sharing, backup and restore, and hierarchical storage management through DFSMS (tm) and ADSM. Through the use of external links, your POSIX applications can access traditional CMS files without performing data conversion.

z/VM also supports POSIX 1003.1a, which provides extensions to the System Interfaces standard. Additional interoperability is provided with support for sockets, an industry-accepted standard protocol for client communications TCP/IP sockets (C-language applications programming interfaces to TCP/IP) correspond closely to sockets used by UNIX applications, enabling additional interoperability.

Develop multitasking server applications

With POSIX 1003.1c threading support, your POSIX application developers have a general set of services, which they can use to develop multitasking applications that require concurrent execution streams.

Creating a new process to run a new program

By supporting POSIX 100.2 shell and utilities, z/VM allows system programmers to have the feel of a UNIX system while developing or porting their POSIX-based applications. Having access to a familiar UNIX-like shell and utilities help enable programmers to reduce their development time.

The VM command and user applications are available from the shell environment, thus giving you the combined functionality of VM commands and applications with POSIX utilities and applications.,

IBM OpenExtensions for z/VM: User's Guide (SC24-6108-01)

UNIX is a registered trademark in the United States, other countries, or both and is licensed exclusively through X/Open Company Limited.