Introduction to RTOS m4

Introduction to RTOS About SwiftACT • A Technology services startup company o Under establishment • Areas of specialties: o o Mobile telecommunication services development Embedded systems development • Types of services: o o o o Consultation Managed services Sourcing Training Amr Ali Abdel-Naby@2010 Introduction to RTOS About Me • Graduated 2004 o ECE, ASU: yrs distinction • 5+ years in embedded systems development o SDLC, Apps, MW, DD, Porting, • 3+ years in SW engineering o PSP, CMMI, Systematic reuse, • 3+ years in SW testing o IBM certified, ISTQB certified, Amr Ali Abdel-Naby@2010 Introduction to RTOS Copyright • Materials in this course is the property of Amr Ali Abdel-Naby • Reproduction or transmission of the materials in any manner without the copyright owner permission is a law violation Amr Ali Abdel-Naby@2010 Introduction to RTOS Outline • • • • • • Introduction Tasks Semaphores Message Queues Other Kernel Objects Other Kernel Services Amr Ali Abdel-Naby@2010 Introduction to RTOS Outline • • • • • • Introduction Tasks Semaphores Message Queues Other Kernel Objects Other Kernel Services Amr Ali Abdel-Naby@2010 Introduction to RTOS Indirect Message Passing • Messages are sent from task to task via queues o Not sent directly from task to task • Message queues are separate RTOS objects o o Caution: Messages are copied by the RTOS as they enter/exit the queue They are copied twice Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Asynchronous Data Communication • Loosely-coupled operation: Sender shoots & forgets o o o o o Task delivers messages to RTOS, then continues execution Never waits Message normally deposited at the tail of the receiver’s queue Hopes that receiver task will fetch the message Content/Structure of message payload are irrelevant to RTOS  Variable data, pointers, structures, unions, … Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Message Queue Message delivered (msgs ) Message delivered (msgs ) Message delivered (msgs = 0) Queue created (msgs = 0) Empty Not Empty Message arrived (msgs = 1) Message arrived (msgs = queue length) Message arrived (msgs++) Amr Ali Abdel-Naby@2010 Full Introduction to RTOS Message Queues: Traditional Usages • Non-interlocked one-way data communication o • Interlocked one-way data communication o o • = Non-interlocked one-way data communication + Binary semaphore Binary semaphore used for handshake (wait/signal semaphore usage) Interlocked two-way data communication o o • = Indirect message passing message queues Handshake messaging Broadcast communication o = Indirect message passing + multiple receivers Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Examples: Wait/Signal, Credit Tracking Non-interlocked, 1-way Interlocked, 1-way Interlocked, 2-way Amr Ali Abdel-Naby@ 2009 Real-Time Operating Systems Typical Message Queue Operations • Message queue creation and deletion o o Create Delete • Sending and receiving messages o o o Send: non blocking, block with timeout, or block forever Receive: destructive read, or non-destructive read Broadcast • Obtaining message queue information o o Show queue info Show queue’s blocked task-waiting list Amr Ali Abdel-Naby@2010 Introduction to RTOS [...]... block forever Receive: destructive read, or non-destructive read Broadcast • Obtaining message queue information o o Show queue info Show queue’s blocked task-waiting list Amr Ali Abdel-Naby@2010 Introduction to RTOS