Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!spdcc!m2c!ulowell!page
From: page@ulowell.cs.ulowell.edu (Bob Page)
Newsgroups: comp.sys.amiga
Subject: Re: losing MIDI bytes
Message-ID: <1664@ulowell.cs.ulowell.edu>
Date: Fri, 11-Sep-87 12:47:37 EDT
Article-I.D.: ulowell.1664
Posted: Fri Sep 11 12:47:37 1987
Date-Received: Sat, 12-Sep-87 18:47:48 EDT
References: <689@mtuxo.UUCP> <685@neoucom.UUCP>
Reply-To: page@swan.cs.ulowell.edu (Bob Page)
Distribution: comp
Organization: University of Lowell, Computer Science Dept.
Lines: 22

wtm@neoucom.UUCP (Bill Mayhew) wrote:
>I was wondering about the practicality of putting forbid() and
>permit() on either side of your part of the code that is reading
>the system exclusive data dump.
 ...
>True, it would be a kludge, but would probably be a little simpler
>than writing your own serial device driver.

It won't work.  As soon as you ask the serial device to do the
transfer, the Forbid() goes away, and is restored to you when
serial device finishes the I/O.

You can't use Forbit/Permit around a Wait or any I/O stuff, since it
would disable multitasking...the device handlers would never get a
chance to run.  The Amiga OS protects against this potential system
lockup by temporarily forcing you to give up your Forbid request.

Yes, this explanation is overly simplistic, but you get the point.

..Bob
-- 
Bob Page, U of Lowell CS Dept.   page@ulowell.{uucp,edu,csnet}