macdouga@stdc01 (Paul Macdougal) (12/14/89)
I tried to put a DMA device into a Sun 4/110 chassis (3 VME slots) and failed to get it running. I later found out that this backplane and similar 3 slot ones made by SUN are not set up to allow multiple bus masters! Has anyone else seen this problem? Can it be true that only slave VME boards can go into these backplanes? Also, what about the SparcStation 330? with three VME slots? ---> Paul MacDougal macdouga%stdc01@rti.rti.org [[Received later -bdg]] Earlier I posted a mesasge about a problem with having multiple masters in a 3 slot backplane. Here is a clarification of the situation. The Sun 4/110 CPU board was designed without the proper bus arbitration logic to support another VME master. As far as I can tell, this is the only board Sun has made which has this defect. Therefore, you cannot place any VME cards in a Sun 4/110 which require the ability to grab the bus (e.g. DMA devices). This situation is documented in the SUN support literature, but most field service representatives don't know about it. ---> Paul MacDougal rti!stdc01!macdouga macdouga%stdc01@rti.rti.org