zischke@uunet.uu.net (Mark Zischke) (05/24/91)
Configuration: Sun 4/370 running SunOS 4.1.1, 56MB memory In our Sun 4/370 we have an Ironics MCPL (Multi Crate Pipeline) board installed which we plan to use for fast (10+MB/sec) data transfers between the Sun and another VME chassis (the MCPL board is *not* a VME repeater). We are unable to use the MCPL because it consistently and immediately crashes our Sun. The problem seems to be specific to Sun 4's, since Ironics currently uses Sun 3's for development and cannot reproduce this problem on their equipment. The problem has been traced to a timing problem in the Sun where it doesn't assert DTACK* soon enough. Since the MCPL board releases the VME bus after the Sun asserts DTACK*, the Sun's watchdog timer in turn times out the MCPL board and the crash happens. Sun also told us that this problem is *not* specific to the MCPL board; at least one other group using a board that does a lot of VME traffic (a board that does FFTs) has run across this problem. Sun has sent us a patch which we have installed and tested. However, the patch only lets the test run a second or so longer before crashing. We still do not have a way to transfer large amounts of data quickly from a VME chassis to the Sun. Is anyone in a similar situation and does anyone have any ideas? Thanks for your help! Mark Zischke zischke@trwacs.fp.trw.com or uunet!trwacs!zischke Telephone: 703.876.4260