By John H. Mayer
JARFALLA, Sweden - The benefits of software reuse are hardly restricted to domestic military and commercial aerospace applications. Software engineers of CelsiusTech Systems AB of Jarfalla, Sweden, are reusing code on the Swedish air force Stridslednings-central - Combat Control Center (STRIC). The command, control, and communications system manages fighter-interceptor control, and has 1.6 lines of Ada code in its latest rendition.
Ship project
Although CelsiusTech engineers developed several shipboard systems based on their Ship Systems 2000 system architecture (SS2000), it was not initially apparent whether that work could port to the STRIC project. The SS2000 ran on M68000 microprocessors from the Motorola Inc. Semiconductor Products Sector in Phoenix, the OS9 real-time kernel from Microware Systems of Des Moines, Iowa, and the POSIX operating system interface.
A portable design that developers of the SS2000 system used proved a key factor. Rather than use existing system calls, the SS2000 relies on the base systems components that isolate the operating system by defining a relatively narrow interface. By porting only the base system components that isolated the operating system, CelsiusTech engineers ported the complete applications.
80 percent reuse
The degree of code reuse varied with different layers of the SS2000 system. Approximately 80 percent of the base application framework and the man-machine interface could be reused. But in communications and command and control, reuse was limited to 20 and 10 percent respectively.
Still in an initial test, more than 400,000 lines of code ported to the STRIC in less than 1,000 man-hours or roughly 500 lines per hour. Officials credit the high degree of portability to the original software`s architectural planning and to an effort to minimize code revisions.
