The Portable Recording System (PRS) Ada 95 rehost effort, associated with the Marine Corps Tactical Systems Support Activity (MCTSSA) Air Defense Systems Division (ADSD) Tactical Air Operations Module (TAOM) at Camp Pendleton, California has been successfully completed. The project consisted of re-engineering an existing multi-language tactical communications support program to an Ada 95 implementation and rehosting the system to new hardware.

The Portable Recording System has been fully re-engineered in Ada 95 and rehosted to a Sun SPARC 20 workstation. The new system uses a standard hardware configuration and replaces a system based on proprietary hardware and programmed in four different languages. The use of existing, standard hardware eliminates the need to transport an entire shelter housing the proprietary hardware when the system is used in field exercises. The project was completed several months ahead of the original schedule. The entire project including training, analysis, design, implementation and testing, was successfully completed in 5½ months.

The PRS is used to extract and record air track data messages from the Digital Data Bus within the TAOM. The old system resided on a 286 PC connected to its own TAOM Bus Interface Controller (BIC) and wrote to a 9-track tape drive. The BIC is a modified proprietary card that is expensive and not easily acquired. The 9-track tape drives are fragile and unreliable. The software was written in four different languages, posing reliability and maintainability problems.

In the PRS project, this system has been rehosted to a Sun SPARC 20 workstation. Messages are received from a gateway via fiber optic cable (rather than a direct link through the BIC) and recorded on either disk files or on 8mm tape. The old system needed to be physically transported to the TAOM site and connected directly to the TAOM. Now, the system may be used anywhere a fiber optic link to a gateway is available. Since the SPARC 20 configuration is already used for many message tracking functions, specialized hardware is no longer required for the PRS.

The software system was developed by ADSD personnel with no previous Ada programming experience. The project was initiated in December of 1995. Requirements analysis began in early January of 1996, followed by two weeks of Ada 95 training in late January. Primary development occurred from February through May. The system was successfully tested during Marine Corps exercises in mid-June of 1996. This project was conducted by the ADSD of MCTSSA with the support of The Ada Joint Program Office (AJPO). Additional technical support was provided, through the AJPO, by the Naval Computer and Telecommunications Station (NCTS) at North Island Naval Air Station in San Diego.

The major goals of the project and the results achieved are:

• Allow the PRS to operate on the new hardware configuration and eliminate the need to transport the old system to exercise and operational sites.

  The PRS now operates on a SUN SPARC 20 workstation. This is the common hardware used for most tactical support functions. Now the PRS system software may be transported on a removable disk drive and used remotely from a TAOM. This eliminates the need for transporting the entire PRS shelter to the TAOM site whenever recording is to be performed.

• Eliminate reliance on unreliable, proprietary communications media.

  The BIC and a direct connection to the DDB are no longer required. Communication with the TAOM via the gateway is achieved through a standard TCP/IP network connection.

• Improve the reliability and maintainability of the PRS code.

  The old system was written primarily in C and 8086 assembly language. The new system is entirely in Ada 95. This eliminates the need for multiple language maintenance and the reliability problems which result. Additionally, effort was made during development to exploit the Ada 95 features which enhance reliability (e.g. strong typing) and supplement the inherent readability of Ada code with thorough comments and documentation.

The PRS rehost project successfully introduced Ada 95 development to the USMC. No difficult problems were encountered in interfacing the new Ada 95 system with existing hardware and software. The GNAT compiler and other tools performed as expected. Support for X based GUI development is scarce but should improve soon. The TAOM development team performed well and had little difficulty adjusting to Ada 95 development.