Real time Linux in multi-channel scaling

Abstract

Real time Linux is an emerging technology that is finding applications in physics and engineering instrumentation. It is not part of the standard Linux kernel development tree, it is usually an extension, applied as a patch, to the standard Linux kernel. There are two open source real time extensions to Linux: RTLinux and RTAI.
Time critical data acquisition requires measurements at regular time interval with interval spacing in the order of 100 micro-seconds and precision in the order of 1 micro-second. Usually tasks like these are programmed under MSDOS or special purpose computers with all CPU resources utilized by the task. A process implemented this way does not offer flexibility, for instance access to the measured data during acquisition is not possible. In contrast, the multi-tasking and network capabilities of real time Linux allow for room to do things that previously could not be done. For example, it is now possible to do time critical data acquisition in one computer in real time and snapshot of the acquired data regularly sent to another computer via the network for display and analysis while acquisition is going on.
In this report we demonstrate using real time Linux for a multi-channel scaler (MCS) application and also examine the timing precision performance of real time Linux in a time critical application.