Spectris Arcom VIPER Quick Start Manual page 30

VIPER RedBoot and AEL Quickstart
Real-time Linux on the VIPER
Linux was not designed with hard real-time capabilities in mind. It usually meets the
needs of soft real-time applications. However, under certain circumstances the
scheduling and other latencies do not meet the needs of hard real-time control and
communication applications.
For this reason, Finite State Machine Laboratories
RTLinuxPro. This is a tested and validated, hard real-time, POSIX operating system
that runs Embedded Linux as an application platform. Within RTLinuxPro, the standard
Linux kernel runs as a low priority task on top of a hard real-time RTOS, RTCore. This
means that RTLinuxPro can meet hard real-time deadlines, while offering the power of
Linux for less performance-critical aspects of applications.
The VIPER Development Kit CD contains an RTLinuxPro demonstration binary for
evaluation purposes. The demonstration consists of an RTLinuxPro-enabled kernel
from FSMLabs, and a RAM disk image containing a simple application to measure the
interrupt and scheduling latency (jitter).
The jitter test measures the total time delta from the point when the interrupt is
generated to the point when the interruption actually happens (i.e. the interrupt latency).
It also measures scheduler entry to decide who needs to run, and includes a context
switch to get the required task in and running so it can sample the clock.
Obtaining RTLinuxPro
The VIPER Development Kit includes an evaluation version of RTLinuxPro for the
PXA255-based VIPER. This is for demonstration purposes only, and cannot be used or
shipped in an end product. The Development Kit CD does not contain RTLinuxPro
development tools or licensed products.
If you want to develop real-time applications using RTLinuxPro, contact FSMLabs
directly at sales@fsmlabs.com.
Source for the parts of the RTLinux demonstration that are licensed under the GPL is
available on request under section 3(b) of the GPL.
© 2005 Arcom Issue D
Real-time Linux on the VIPER
(FSMLabs, Inc) developed
30