1. 1 EPICS Linux Based IOC Support EPICS Meeting at BESSY May 2002 Marty Kraimer

2. 2 EPICS VISION u LINUX REPLACES VXWORKS u BUT: Linux isn’t a real time operating system u Non-preemptive kernel => no context switch while kernel active. u Interrupts can be disabled for long periods of time. u Worst case can be 100s milliseconds. u Future u Development kernel is preemptive. u Work in progress so that interrupts disabled for short times. u Other possibilities u RTLinux u RTAI

3. 3 EPICS Modified Vision u Existing Linux good enough for some Applications. u 2.6 Kernel will be good enough for additional Apps. u Often small part of App has stricter real time. requirements. In this case consider RTLinux/RTAI. u For demanding Apps use RTEMS or stay with vxWorks.

4. 4 EPICS Near Term Goals u Industry Pack Support on Linux IOCs u Work with Tim Mooney’s group u Joe Sullivan working on PCI based motor support. u IP + Motor => usable for some beam line applications. u Expect there will be a lot of interest.

5. 5 EPICS Progress u PCI-40A : SBS Quad IP Carrier for PCI Bus u Linux Kernel support now exists for u Generic IP carrier support (Like ANJs IPAC support) u PCI-40A u IP-488 (Green Springs GPIB IP using the ti9914) u EPICS Gpib driver u Implements Benjamin Franksen’s interface u Talks via file system to IP488 Linux driver u DG535 support works (For awhile before crashing) u Message Passing Facility MPF ported to 3.14 u Lots of cleanup. u Ran several tests successfully

6. 6 EPICS Still to do u IP Serial u IP330 (ADC) u DAC128V (DAC) u ipUnidig (Digital I/O) u BIG ISSUE u Existing support allows MPF support to register with interrupt routine, i.e. user code called directly by interrupt routine. u IP330 allows floating point in interrupt routine. u Initial Strategy u Extract interrupt handlers and use insmod to put them in kernel u Convert floating point to integer.

7. 7 EPICS Additional Tasks u Allow user level to access IP register space. u Have written but not tested. u Is this better than kernel drivers? u What about interrupts? u Work with Tim’s group to support synapps on Linux u APS/ASD can also use Linux IP support. u Many many records for serial I/O. u Quite a few using IP330. u Monitoring Only and not time critical u Future hardware??? PC*MIP, etc, etc.