Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!well!ewhac
From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Newsgroups: comp.sys.amiga
Subject: Re: OS/2 vs AmigaDOS
Message-ID: <11609@well.UUCP>
Date: 10 May 89 09:07:01 GMT
References: <16952@usc.edu> <7988@killer.Dallas.TX.US> <10848@behemoth.phx.mcd.mot.com> <6796@cbmvax.UUCP>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Organization: Lt. Col. Oliver North, Overseas Shipping and Receiving.
Lines: 21
Quote: "Men, football is war.  GOD, how I love it so..."  -- Coach Bloom

In article <6796@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
>	One problem with VM: Forbid()/Permit() and Disable()/Enable().
>If you allow another task to run when a Forbidden task takes a page fault,
>then the Forbid() is broken.  This is compounded by the fact that many
>(more likely all) HD's use tasks for their drivers, and thus the forbid
>MUST be broken in order to page.  Disable is, of course, worse.
>
	Then establish the following rule by fiat:

	"If you take a page fault while Forbid()den or Disable()d, you
crash."

	The only reason Forbid() and Disable() exist is to arbitrate the use
of shared data areas (am I forgetting something?).  We should start
encouraging the use of semaphores for this purpose.

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
Leo L. Schwab -- The Guy in The Cape	INET: well!ewhac@ucbvax.Berkeley.EDU
 \_ -_		Recumbent Bikes:	UUCP: pacbell > !{well,unicom}!ewhac
O----^o	      The Only Way To Fly.	      hplabs / (pronounced "AE-wack")
"Work FOR?  I don't work FOR anybody!  I'm just having fun."  -- The Doctor