VEL/UNIX, VEL/Linux, VEL/Solaris

VEL/UNIX is the VMS Emulation Layer library of Software Resources International for UNIX platforms, including Linux (VEL/Linux), SUN/Solaris (VEL/Solaris) and HP Tru64UNIX (VEL/Tru64). This library allows VMS applications to be recompiled under UNIX with minimal modifications of the source code, linked with a special VMS-like library and run under the corresponding UNIX platform.

This approach significantly minimizes redesign effort, thus providing the lowest porting cost of VMS applications written in C or C++ to the chosen UNIX platform. The approach still permits minor rewriting of the applications to the native UNIX API if there is a need to optimize performance.

VEL/UNIX emulates VMS system calls as precise as possible to allow every application to work seamlessly. The overall goal of the library is to minimize the porting effort of VMS applications while allowing to improve the application design and to add new functionality using modern programming technologies.

Every VEL/UNIX library is designed to operate with the corresponding UNIX version. All headers are compilable with both C++ and C, and the library can be linked with C files. Internal library code requires C++ compilation.

While the VEL/UNIX library works with C and C++ applications code, Software Resources International provides a source language translation service to convert VMS applications written in Pascal, RTL/2, PL/I, COBOL, Fortran, and ADA to C or C++.

In addition, custom versions of VEL/UNIX can be provided to work directly with these or other programming languages.
VEL / UNIX provides a number of system services and library routines that have no direct equivalent on UNIX and derivatives, thereby greatly facilitating application migrations:
  • mailboxes
  • messages
  • event flags
  • QIO/QIOW - Asynchronous/Synchronous I/O
  • AST
  • Date/Time access functions
  • Time Arithmetic functions

Please contact SRI for documentation or more information.