REX OS
The REX Operating System (Real-Time Executive Operating System) is an RTOS developed by Qualcomm for the ARM-based mobile phone Dual-Mode Subscriber Station (DMSS) or Advanced Mode Subscriber Software (AMSS) development. As of 2007 most Korean cell phones run on REX.
| Developer | Qualcomm |
|---|---|
| OS family | Embedded operating system |
| Initial release | 1999[1] |
| Marketing target | Smartphones |
| Platforms | ARM |
| Kernel type | Microkernel based on L4A Pistachio and Iguana |
| License | Proprietary |
REX is an L4A Pistachio embedded micro-kernel and Iguana operating system combination and has extensive Qualcomm and HTC modifications and extensions.[2]
Originally developed for the Intel 80186 it was then ported to ARM and x86 architectures are no longer supported. REX is not POSIX compliant or open source and requires a license from Qualcomm for use.[3]
It does not seem to be actively developed or marketed as of 2012 but is used in currently or recently sold low end cell phones, typically for use by pay-as-you-go customers, like the Samsung SPH-M300.
Features
REX is a Real-time operating system with the following features:
- Preemptive multitasking
- Task management
- Task synchronization
- Exclusive lock
- Timer
- Interrupt management
- Uses less than 5K of ROM[1]
REX does not provide any memory protection features but does have memory management capabilities.
References
- Staff. "REX and Common Software". Retrieved 2012-03-10.
- Edgewall Software. "HTC Vision". Retrieved 2012-03-12.
- Saad Zaman Asif. Next Generation Mobile Communications Ecosystem: Technology Management for Mobile Communications. John Wiley and Sons, 2011-01-11, p. 299.