From:	CRDGW2::CRDGW2::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 18-MAY-1989 23:45
To:	MRGATE::"ARISIA::EVERHART"
Subj:	Re: ASTs within ASTs?

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Date: 18 May 89 17:42:23 GMT
From: wucs1!jim@uunet.uu.net  (James William Studt)
Organization: Washington University, St. Louis, MO
Subject: Re: ASTs within ASTs?
Message-Id: <847@wucs1.wustl.edu>
References: <962@cernvax.UUCP>, <4606@misadel.oz>
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In article <4606@misadel.oz> jeremy@misadel.oz (Jeremy Begg) writes:
>In article <962@cernvax.UUCP>, rbt@cernvax.UUCP (rbt) writes:
>> The problem is the following: ...
   <Wants to have ASTs delivererd while other ASTs are active.>
>
>        ASTs can be interrupted by an AST which executes in a more privileged
>access mode, .....

According to "Version 4.4 VAX/VMS Internals and Data Structures" from
Digital Press there is a system service, $CLRAST, which clears the AST
active flag in the PCB, allowing AST to be delivered while the original
AST is still active.

Of course
	"Note that the $CRLAST system service is not supported by Digital,
	 except for use within Digital software, and is not documented in
	 the VAX/VMS System Service Reference Manual."
---
				- jim studt          jim@wucs1.wustl.edu
				Electronic Radiology Laboratory
				Mallinckrodt Institute of Radiology
				Washington University, St. Louis, MO, USA