The ASR-9 Processor Augmentation Card (9PAC) is a custom processing card that provides the ASR-9 system with increased beacon and radar processing performance. This paper describes the system and application software that executes on the prototype board, with an emphasis on the interaction between software modules. The application software on the 9PAC determines the position of radar and beacon target reports, replacing software that previously ran on the ASR-9 Array Signal Processor (ASP). The software is organized as a set of cooperating tasks executing under the control of a real-time operating system, PAC/OS, which provides all the services typical of an embedded kernel such as interrupt handling, pre-emptive multitasking, queues, signals, semaphores, mailboxes, and memory management. The deployment of 9PAC will occur in two phases. The Phase I application replaces only the beacon target detector (BTD) and radar/beacon target merge (MRG) functions of the ASP. The Phase I application consists of two executable programs since Phase I uses only two of the C44 processors on the 9PAC. One program, the housekeeping processor, is responsible for all I/O functions and performs the radar/beacon merge operation. The second progam, the beacon processor, is dedicated to processing the raw beacon replies and generating beacon targets which are then returned to the first processor for the merge operation. The Phase II application consists of three executable programs, one for each of the C44 processors on the 9PAC and performs much of the Phase I functionality and adds primary radar processing. The intent of this paper is to provide the 9PAC software support personnel with sufficient information to implement future enhancements without unintentionally compromising some aspect of the overall system.