24-07-2015, 03:03 PM
case studies of rtos
RTOS Functional Overview
Process Management
– create/terminate processes
– perform reset or 'power-on' initialization
Processor Scheduling
– selection & dispatch of processes for execution
Inter-Process Communication/Synchronization
– send/receive messages
– signal/wait on semaphores
Storage Management
– allocate/deallocate memory
RTOS Functional Overview [2]
Interrupt Handling Framework
– capture interrupts
– if required, activate a user defined process
Timing Services
– relative [delay] services
– absolute time services
Device Driver Interfaces
– provide standard i/o and specialized interrupt
driven device handlers
Simple RTOS: Requirements
basic requirements
– non-preemptive
– support for processes [creation at init time only]
– priority scheduling [fixed priority]
– message-based interprocess communication
[asynchronous, messages sent in envelopes]
– memory management: message envelopes
– basic timing services
Simple RTOS: Setting
Assumptions concerning RTOS setting
– all processes are known and created at OS
initialization time
– processes are friendly, cooperating and non
malicious
– each process ‘knows’ the process_id of its coworkers
RTOS Functional Overview
Process Management
– create/terminate processes
– perform reset or 'power-on' initialization
Processor Scheduling
– selection & dispatch of processes for execution
Inter-Process Communication/Synchronization
– send/receive messages
– signal/wait on semaphores
Storage Management
– allocate/deallocate memory
RTOS Functional Overview [2]
Interrupt Handling Framework
– capture interrupts
– if required, activate a user defined process
Timing Services
– relative [delay] services
– absolute time services
Device Driver Interfaces
– provide standard i/o and specialized interrupt
driven device handlers
Simple RTOS: Requirements
basic requirements
– non-preemptive
– support for processes [creation at init time only]
– priority scheduling [fixed priority]
– message-based interprocess communication
[asynchronous, messages sent in envelopes]
– memory management: message envelopes
– basic timing services
Simple RTOS: Setting
Assumptions concerning RTOS setting
– all processes are known and created at OS
initialization time
– processes are friendly, cooperating and non
malicious
– each process ‘knows’ the process_id of its coworkers