Path: utzoo!attcan!uunet!aplcen!samsung!usc!rutgers!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Env vars under 2.0
Message-ID: <13118@cbmvax.commodore.com>
Date: 10 Jul 90 01:47:50 GMT
References: <44hU02Ktb2DQ01@amdahl.uts.amdahl.com> <13920071@hpfelg.HP.COM>
Reply-To: jesup@cbmvax (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 25

In article <13920071@hpfelg.HP.COM> koren@hpfelg.HP.COM (Steve Koren) writes:
>> > You may request notification when a file changes.  DOS has a couple of
>> > calls (StartNotify() and EndNotify()) through which you can arrange
>> > to learn when a file changes.  For example, IPrefs waits on notification

>Cool!  I like it too.  Question: are these calls implemented by polling
>or by some other method?  In other words, is there any overhead
>incurred by having maybe 50 of them going on at the same time?
>AmigaDos has been very good about that kind of thing in the past, so
>I suspect polling is not used.

	Correct.  No evil polling is used, you are sent a message by the
filesystem when the file changes.  There is some amount of overhead involved,
but under normal circumstances this overhead is fairly minimal.  The Atlanta
Devcon notes have explanations and discussion of this, and some of the neat
"hot link"-like things that can be with them.

	Under the current 2.0 (for the A3000 and developers) notification
only works in the ramdisk.  The disk FS will support it RSN (it accepts the
packets, but never actually tells you anything changed).

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"