From: utzoo!decvax!ucbvax!info-vax
Newsgroups: fa.info-vax
Title: VMS Device drivers and ACP's
Article-I.D.: ucbvax.101
Posted: Fri Mar 25 06:52:09 1983
Received: Sat Mar 26 07:39:30 1983

>From GEOFF5@SRI-CSL  Fri Mar 25 06:50:06 1983
Received: by UCBVAX.ARPA (3.331/3.17)
	id AA08646; 25 Mar 83 06:51:31 PST (Fri)
To: info-vax@sri-csl
Reply-To: PAO@MC
Remailed-Date: 23 Mar 1983 1802-PST
Remailed-From: the tty of Geoffrey S. Goodfellow  <Geoff5 at SRI-CSL>
Remailed-To: Info-VAX@SRI-CSL.ARPA: ;

Several questions/requests:

Has anyone implemented a custom Ancillary Control Processor (ACP)?
Does anyone have information on the necessary interface with the
device and VMS?

Has anyone implemented a device driver in a higher-level language?
If so, what pitfalls must one watch out for when doing so?

Is there a (easy) way for one device driver to initiate I/O on another
driver?  E.g. user issues QIO on device XXA0:;  XXDRIVER then requests
I/O on device YYA0:;  YYA0: completes the I/O;  XXDRIVER massages the
data a little and then completes the I/O request for the user.  It
might be desired to extend this chain to involve three drivers.

	Any help will be much appreciated.
	- Pat