Most multiprocessing systems can be classified as either symmetric multiprocessing (SMP) or asymmetric multiprocessing (AMP). AMP involves the use of interprocessor communication to combine the efforts of multiple processors, each with its own local operating system and hardware resources. Also, AMP involves less OS overhead for each individual processor and a more traditional execution environment for applications. AMP seems like distributed system.
The number of peripherals that are supported in today's multicore processors is quickly increasing. Symmetric-multiprocessing (SMP) software is expected to be quickly available to support these peripherals. Basically any OS can be ported to a SMP platform, but the developers must take care of following issues for SMP OS.

• - Handling of task priority or implicit synchronization
• - Spinlocks and synchronization
• - Synchronization between tasks sharing memory
• - Synchronization between tasks and ISRs sharing memory
• - Synchronization between ISRs sharing memory

RTEMS (Real-Time Executive for Multiprocessor Systems) is a commercial grade real-time operating system designed for deeply embedded systems. It is a free open source solution that supports multi-processor systems. RTEMS is designed to support applications with the most stringent real-time requirements while being compatible with open standards.

Symbian Limited announced Symbian OS support for the ARM Symmetric Multi-processor (SMP) architecture. SMP support in future versions of Symbian OS will use multiple CPU cores to provide ;performance on demand - battery life will be improved by accessing cores only when running demanding high-end multimedia applications and powering them down when they are not in use. Symbian and ARM are working together closely on supporting Cortex-A9 MPCore multicore processor-based CPUs in Symbian OS.

The eT-Kernel Multi-Core Edition is a realtime OS for next-generation embedded systems with multicore. It is ideal for high performance embedded systems such as digital home appliances, automobile devices, and mobile devices. This realtime OS is loaded with features specific to multicore software development making the technology accessible even for first-time users.

New Express Logic ThreadX/SMP RTOS Facilitates Development on ADI's dual-core Symmetric Multi-Processing (SMP) Blackfin family.

Altera Japan, Ltd. in conjunction with A.I. Corporation, an embedded software distributor and the TOPPERS Project, a nonprofit organization, announced today the immediate availability of TOPPERS-Pro Multi/FDMP, a function-distributed real-time operating system (RTOS) that provides multiprocessor support for Altera’s Nios® II embedded processor, the world’s most widely used configurable soft-core processor. Targeted at a wide variety of applications in the digital consumer, office equipment and automotive markets, this embedded solution addresses the performance, power consumption and radio noise emission requirements of today’s advanced systems.

PolyCore Software touches every software aspect of a multi- core system below the
application.

Resources

An article for multicore SMP OS development

Using an symmetric multiprocessor model to build hybrid multicore designs.

Multicore Association.

DSP oriented OS

DSPOS, Motorola 56800E DSPs, StarCore, BlackFin DSPs, ARM7/9, features VoIP reference design and Unicoi Fusion Suite.

DSPnano, RoewBots' OS for PIC24, dsPIC30, dsPIC33. A signal processing operating system intended for small signal processors and small DSP networks. Offers an IDE, Compilers, Debuggers, nano-kernel, I/O, and DSP.

EFOS, from Vinjey, an embedded software solution and services company.

DSP/BIOS from TI provides a rich set of deterministic kernel services that enable developers to create sophisticated applications without compromising real-time deadlines. DSP/BIOS is highly scalable with multithreading configurations requiring as few as 1K words. The kernel services may be invoked through either a C function or an assembly language macro interface.

Blackfin Processor OS from ADI site. You can see a lot of well-known RTOSes have already ported to Blackfin DSP/RISC chip.

Read also:
http://dev.emcelettronica.com/embedded-os-non-rtos-and-rtos
http://dev.emcelettronica.com/embedded-os-java-approach
http://dev.emcelettronica.com/embedded-os-linux-co
http://dev.emcelettronica.com/embedded-os-middleware
http://dev.emcelettronica.com/embedded-os-resources-copyright-and-legal-...