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Aucbvax.2883 fa.unix-wizards utzoo!decvax!ucbvax!unix-wizards Tue Sep 1 02:12:45 1981

>From SomeoneOnUUCP@Berkeley Tue Sep 1 02:07:02 1981 Originating from cincy at Wed Aug 19 17:08:08 1981 We have a Ramtek 9200 on our 11/60. It gives us no end of trouble. I believe you would have the same type of interface -- half dr11b, half dr11c, right? (They call it a GPIF interface.) We tend to warn people off the machine when someone wants to use it, because more often than not, it will hang the bus within a few moments. I redid the driver a few months ago to do DMA out of the user's buffer, and that caused me more trouble -- at that speed the bus contention is too much to run it in 'burst mode', that is, it only arbitrates once for the bus transfer. We now run it so it arbitrates on every word (yuck!). But at least it doesn't foul swaps as it used to. I really don't like the device at all, because it is so dumb in how it handles the bus. If anything is wrong (if it gets confused) it won't just set an error bit; rather it hangs the UNIBUS. I would suggest to you that if you can run it in a slow DMA mode, you will probably have more luck.

Chris Kent (pur-ee!purdue!cak)

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