16-01-2013, 04:44 PM
RTOS Design & Implementation
1RTOS Design.ppt (Size: 360.5 KB / Downloads: 93)
Introduction
A variant of OS that operates in constrained environment in which computer memory and processing power is limited. Moreover they often need to provide their services in definite amount of time.
Hard, Soft & Firm RTOS
Example RTOS: VxWorks, pSOS, Nucleus, RTLinux…
Components of RTOS
The most important component of RTOS is its kernel (Monolithic & Microkernel).
BSP or Board Support Package makes an RTOS target-specific (It’s a processor specific code onto (processor) which we like to have our RTOS running).
RTOS KERNEL: Memory(1)
Memory is premium in environments where RTOS work.
Supports Virtual Memory (MMU) and Memory Protection (MPU) models.
User space and Kernel space memory.
RTOS KERNEL: Timer(1)
Timer is software entity derived from hardware clock.
Timer provides mechanism to introduce task-delays and/or to help synchronize and provide time off-course.
Watchdog Timers, Programmable Timers
RTOS KERNEL: Device Drivers
A host controller driver enables system to accept a particular type of device.
Client drivers are device specific.
Protocol layer converts device request to form that is understood by corresponding host controllers through their drivers.