Express Logic intros memory-protected application modules for ThreadX RTOS

ESC Silicon Valley 2011, SAN JOSE, USA: Express Logic Inc., a leader in royalty-free, real-time operating systems (RTOS), announced the introduction of ThreadX RTOS Memory Protection for downloadable application modules.

Downloadable application modules, introduced earlier this year, enable ThreadX-based applications to execute functions dynamically loaded from local mass storage or a network. Memory protection for these modules adds a level of safety and security that enables developers to protect other modules and the ThreadX kernel itself against unintended damage from errant external access.

Express Logic achieves memory protection with minimal software or hardware overhead by using the processor’s Memory Protection Unit (MPU) or Memory Management Unit (MMU) and no virtual address space. Any code within a particular module that attempts to access memory outside that module is prevented from making that access, and a system fault is generated.

The RTOS then transfers control to an error handler that the application sets up to deal with the error. The Module might then be disabled while allowing the rest of the system to continue operation, send an error message to an operator, or halt the system to prevent further damage.

As a result of this new memory protection of downloadable modules, applications gain increased reliability, security, and functionality without the cost of increasing overhead or memory. ThreadX memory protection technology is ideal for situations where application code is developed by multiple team members, new application modules need to be added after the product is deployed, or partial firmware updates are required.

“With this introduction of Memory Protected Modules for our ThreadX RTOS, we give developers the functionality previously reserved for larger, more expensive RTOSes, in a small-footprint, high-performance RTOS,” noted William E. Lamie, president of Express Logic. “With Memory Protected Modules, developers gain on-demand reconfiguration and update from remote facilities with solid reliability. This combination, wrapped in the ease of use that a billion ThreadX users have always relied on, demonstrates Express Logic’s commitment to delivering innovative technology hand-in-hand with best-in-class usability.”

Virtual memory, memory protection, and a kernel-module architecture is commonly found in desktop operating systems, such as Windows and Linux, and in larger RTOSes, such as VxWorks and QNX. Such architecture and functionality is not commonly found in small-footprint RTOSes like ThreadX, nor is the “big-system” method of implementation appropriate for such RTOSes, where even a small number of additional instructions can represent significant overhead. Such overhead can interfere with hard real-time response for which these systems are best suited.

Express Logic’s penetration of the RTOS glass ceiling provides a breakthrough for small-footprint, hard real-time applications that require the reliability and responsiveness of ThreadX. Now, with use of memory-protected downloadable modules, developers can achieve an even greater range of reliability and modularity in their designs.