2 OVERVIEW

As for any software development, for the development of VLT software it is possible to identify:

the process, or how to develop the software.

the product, or what will be output at the end of the process.

The process basically consists of:

· the software life cycle that defines what, documents and code, and when shall be provided (section 3.1).

· the standards and tools to be used for the development (section 3.2).

· the way of keeping control of the product (section 3.3).

· the way of checking the product respect both to the functional requirements and to the process requirements (section 3.4).

The output of the process is the VLT Software that, from a functional point of view, has been divided into:

CCS Central Control Software

HOS High Level Operations Software

INS Instrumentation Software

ROS Remote Operation Software

TCS Telescope Control Software

and one package for each instrument (FORS, CONICA, UVES, etc.).

Each part of the VLT Software can be classified into one of two basic categories:

· application software: (section 4) solution to specific cases and based on the VLT Common Software. Even when solving a specific issue, one should think about a possible reuse of that solution. The tendency should be to move code from the application to common software.

· common software: (section 5) solving problems that are common to several applications. Such software is developed and maintained at a central level and distributed to all developers involved in the VLT Software.

The VLT projects spans more than a decade. The rules for the process and the common software were not available already at the beginning. Both have been developed during the first years of work and are still under development. In addition, and considering the rapid evolution in both hardware and software techniques, it would be too stupid to fix everything for such a long term, without leaving the door open to learn from experience and to profit from new opportunities made available by the market and by the computer community. For such reasons, both process rules and common software will evolve in the future.

Quadralay Corporation http://www.webworks.com Voice: (512) 719-3399 Fax: (512) 719-3606 sales@webworks.com