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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: ioc daemon |
| From: | "J. Frederick Bartlett" <[email protected]> |
| To: | Christophe Moins <[email protected]> |
| Cc: | [email protected] |
| Date: | Thu, 08 Jun 2006 10:31:46 -0500 |
|
Christophe, Your note does not indicate which operating system you are using; so, my response to your question will be a general one. Since most IOC's have a real-time operating system (RTOS), there is no need to create a daemon process (classically, a process that has no parent) to achieve your ends. One characteristic of an RTOS compared, say, with Linux is that the RTOS scheduling algorithm is usually based on task or thread priorities with preemption of lower priority tasks by higher ones. Each task or thread runs independently of the others and non-interference between tasks is guaranteed by semaphores and other RT synchronization mechanisms, e.g. queues or events. So, instead of creating a daemon process, the usual practice on a RTOS is to create a new execution thread that runs your "daemon" program and use the RTOS synchronization objects to control and communicate with it. EPICS works this way and many of the extensions to EPICS that I have built also follow this model. Fritz Christophe Moins wrote: Hello, -- J. Frederick Bartlett Fermi National Accelerator Laboratory D0 Experiment/Controls [email protected] 630-840-4058 |