1. By:- Sagar Chaturvedi

2.  Systems following timing constraints
 both correctness of computational logic and delivery time
matter
 3 types :-
 hard real time
 firm real time
 soft real time

3.  UNDER DEVELOPMENT AT DIAMP
 ADD A RT KERNEL BELOW LINUX KERNEL
 ADDS FEATURES OF RTOS TO LINUX
 MAKES LINUX KERNEL FULLY PRE-EMPTABLE
 LINUX IS A BACKGROUND TASK FOR RTAI
 HELPS LINUX TO FULFILL SOME REAL TIME
CONSTRAINTS

5.  HARDWARE ABSTRACTION LAYER(HAL)
 INTERPROCESS COMMUNICATION(IPC)
 POSIX THREADS
 INTERRUPT DISPATCHER
 SCHEDULER
 MEMORY MANAGEMENT

6.  DEFINES AN INTERFACE BETWEEN LINUX & RTAI
 A STRUCTURE INSTALLED IN LINUX KERNEL
 EXPORTS LINUX DATA & FUNCTIONS RELATED TO H/W TO
RTAI
 THIS ALLOWS RTAI TASKS TO RUN PARALLEL WITH
LINUX PROCESSES
 MAKES CHANGES IN OPERATIONS EASIER

8.  DISTRIBUTES CPU TO TASKS , ON SYSTEM CALLS
 WHEN SCHEDULING STOPS, FREES THE MEMORY
 3 SCHEDULERS IN RTAI:-
 UNIPROCESSOR(UP) SCHEDULER
 SMP SCHEDULER
 MUP(MULTI UNIPROCESSOR) SCHEDULER

9. SOME COMMUNICATION SERVICES IN RTAI:-
 MAILBOXES
 MESSAGES & RPC
 SEMAPHORES
 FIFO
 WATCHDOG

10.  USER SPACE INTERFACE TO
RTAI
 STEALING TASKS FROM
LINUX
 EXCEPTION HANDLING
 ASYNCHRONOUS I/O

12.  ACTIVATES THE PROPER HANDLER
 HANDLES INTERRUPT CONTROLLER
 TAKES CARE OF PENDING INTERRUPTS OR SERVICE
REQUESTS
 IT IS AN ISR(INTERRUPT SERVICE ROUTINE)

14. TO USE RTAI, THESE SHOULD BE LOADED:-
 rtai:- INITIALIZES ALL CONTROL VARIABLES
 rtai_sched:- REAL TIME SCHEDULER MODULE
 rtai_fifos:- IMPLEMENTS FIFO SERVICES
 rtai_shm:- ALLOWS MEMORY SHARING
 lxrt:- MAKES RTAI FUNCTIONS AVAILABLE TO LINUX
 posix threads