Interesting list responses:
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Sam Sarasin DTN 339-5413 <sarasin_at_cop.dec.com>
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I have been told that in a 255 the bottom PCI slot uses a shared
interupt. When I install an ATM card into a 255 I move the graphics option
to this slot and use the top two slots for other options. It seems that
most of the graphis options do not care about interupts.
Jim.Zelenka_at_cs.cmu.edu
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It turns out there's a bug in DEC's PCI implementation. Interrupts on
the PCI bus are active-low, so the line is supposed to be held high,
then pulled low for an interrupt. Since PCI adapters share interrupt
lines, the adapters are supposed to tristate when there's no interrupt,
or pull the line low when there is one. Instead, a lot of DEC adapters
(the 350, the KZPSA, and the built-in ethernet on the 255 among others)
keep the line pulled high when there's no interrupt. What happens is
that an adapter will wish to pull the line low, but be unable to.
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Ray Stell stellr_at_vt.edu (540) 231-4109 KE4TJC 28^D
Received on Mon Jul 14 1997 - 17:10:06 NZST