Path: utzoo!attcan!uunet!husc6!rutgers!att!alberta!ubc-cs!van-bc!sl
From: sl@van-bc.UUCP (pri=-10 Stuart Lynne)
Newsgroups: comp.unix.microport
Subject: Re: Losing interrupts?
Message-ID: <1912@van-bc.UUCP>
Date: 6 Oct 88 21:05:20 GMT
References: <1905@van-bc.UUCP> <592@cimcor.mn.org>
Reply-To: sl@van-bc.UUCP (Stuart Lynne)
Organization: Wimsey Associates, Vancouver, BC.
Lines: 31

In article <592@cimcor.mn.org> mike@cimcor.mn.org (Michael Grenier) writes:
>From article <1905@van-bc.UUCP>, by sl@van-bc.UUCP (pri=-10 Stuart Lynne):
>! For example one of the basic differences between SCO 386 and the SysV 386 
>! products is the priority of the interrupts.
 
>! 	SCO			SysV
>!   SPL7	Serial		SPL7	Clock
>!   SPL6	Clock		SPLTTY	Serial
 
>! SysV allows the clock interrupt to take over the machine at a higher
>! priority level than (for example) the serial interrupts.

>I don't think so. Microport has the serial interrupts at SPL7 (the
>highest) and the clock at the lowest (which is probably why the

Can't speak to Microport 286, but I just spent an hour and a half pulling in
Microport's 386 atconf directories off tape and they match the standard 
System V / 386 stuff pretty close. 

The clock is at SPL7 and serial is at SPLTTY. 

For inquiring minds, SPL6 < SPLTTY < SPL7. In other words SPL7 is actually
priority level 8!

In any event I'm not sure it will be possible to distribute a polling serial
driver which needs the clock to be a lower SPL level, the standard release
has a check for what SPL level it is running at and panics with a polite
message if not at SPL7. 

-- 
Stuart.Lynne@wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl     Vancouver,BC,604-937-7532