Real Time Systems Characteristics of Real-Time Systems

Characteristics - 2 Outline  Introduction to an existing RTS  the Electronic Support and Training (EST) System  The characteristics of real-time software

Characteristics - 3 Electronic Support &Training (EST)

Characteristics - 4 EST - Overview  provide realistic electronic warfare training to the Air Force, Army and Navy  19 pods for 10 CE-133 T-Bird aircraft  ECM, ESM and Chaff pods (off-board ECM)  an integrated suite of radar ESM/ECM, communication ESM/ECM and chaff on 3 CE144 Challenger (commercial) aircraft  full situational awareness  “simultaneous” smart jam of 3 radar & 1 comm band  mission planning/debriefing

Characteristics - 5 EST - Systems System Controller Comm ESM/ECM Radar ECM Radar ESM/ELINT Chaff ADC Air Data Computer LIRS Laser Inertial Ref ARINC 429 RS232 ARINC 429 discrete1553 system integrator modified OTS real-time systems existing aircraft systems OTS “dumb” systems EW Suite Aircraft Systems

Characteristics - 6 EST - Sub-system Software  Radar Electronic Support Measures (ESM)  modified USN (1980 vintage) real-time software  classified Secret  Radar Electronic Counter Measures (ECM)  4 band jammer  modified US + developed Canadian real-time s/w  125k + source lines of code (SLOC)  Communication ESM/ECM (+ direction finder)  fully developed Canadian real-time s/w  250k + SLOC  standalone system (PC/Windows NT)

Characteristics - 7 EST - System Controller Software  System Processor  750K SLOC  full MIL-STD-2167A  CF owned & maintained tactical touch display keyboard supplementary touch display (also used as back-up) trackball disk drives System Processor computer

Characteristics - 8 EST - System Processor Partial Task List  Periodic  display (100 msec)  system status (500 msec)  BITE (5000 msec)  ESM (200 msec)  ELINT (1000 msec)  ECM (5000 msec)  CommDF (500 msec)  LIRS (400 msec)  ADC (200 msec)  chaff (500 msec)  record (500 msec)  Asynchronous  keyboard  trackball  CommDF  touch display  System  bootstrap  initialization  maintenance

Characteristics - 9 What might go wrong when developing this type of software?  Requirements formulation / documentation  Design formulation / documentation  Test formulation / documentation / conduct  Schedulability on a single processor  Compatibility among systems  Support for long-term maintenance To name just a few

Characteristics - 10 Characteristics of EST RT software Based upon our review of the EST system and, in particular, its System Processor integration software, what are some of the characteristics of real-time software?

Characteristics - 11  timeliness / scheduleability  real world interaction  concurrency (physical and logical)  reliability  safety  complexity  dynamic internal structure  scalability  distributed Characteristics of RTS Quality of service requirements