Path: utzoo!mnetor!uunet!husc6!hao!boulder!cu-den!udenva!news
From: news@udenva.cair.du.edu (netnews)
Newsgroups: comp.unix.questions
Subject: Re: Unix Interrupts
Message-ID: <9815@udenva.cair.du.edu>
Date: 20 Feb 88 00:14:42 GMT
References: <3617@mtgzz.UUCP> <48200002@hcx3>
Reply-To: rneitzel@udenva.UUCP (RICHARD NEITZEL )
Organization: U of Denver
Lines: 37
Summary: CINT a different thing

In article <48200002@hcx3> gwp@hcx3.UUCP writes:
>
>} In article <3102@cup.portal.com>, Chuck_SirVAX_Staatse@cup.portal.com writes:
>}> Does anyone know if UNIX supports a "Connect to Interrupt" facillity
>}> similar to VMS or RSX. 
>
>} UNIX provides a facility called "signals". [ ..]
>} , but it is trivially simple to write a device
>} driver which will send the appropriate signal, to processes that have
>} opened it, when device receives an interrupt.
>
>This is correct, but may not be what is needed, ....

I don't think it is what the original question was asking. Connect to 
interrupt or CINT, allows a single task to directly connect to an 
interrupt service routine (ISR). Note that only this task is connected,
so the controlled device is strictly private. Using a driver would allow
other tasks to use the device. Further, CINT will not let the user 
connect to devices already in use and when the using task exits, it frees
the device for others to CINT to. Also, the ISR has nearly full access to 
all the variables of the non-ISR code directly. CINT does not support any
type of I/O request queue. 

	This is all based on the RSX version, I can't speak for VMS. 
Interestingly, some benchmarks I tried showed that CINT was only marginally
faster then doing the same thing with a driver. Of course, given the
difference in systems, under Unix it may speed up significantly.




				Rich the PDP holdout
				Rockwell International
				Computer Aided Manufacturing and Control
				Golden, CO

Double your VAX's speed and give the performance of the 11/23!!!!!