Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga
Subject: Re: Changing the library order
Message-ID: <15166@cbmvax.commodore.com>
Date: 15 Oct 90 19:27:41 GMT
References: <1990Oct14.213556.25943@hoss.unl.edu> <15155@cbmvax.commodore.com>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 23

In article <15155@cbmvax.commodore.com> peter@cbmvax.commodore.com (Peter Cherna) writes:
>In article <1990Oct14.213556.25943@hoss.unl.edu> 252u3130@fergvax.unl.edu (Phil Dietz) writes:
>>I suddenly remember hearing about a program that will rearrange the
>>resident libraries so some programs will execute faster.

>The order of resident libraries typically affects only a few operations,
>such as "OpenLibrary()".  If you OpenLibrary("dos.library"), you get
>the library pointer back.  Calls made to dos.library use that library
>pointer -- they don't have to scan the list again.
>
>Rearranging libraries would be of dubious performance benefit.

	Normally, Peter would be right.  However, the 1.3 and before
dos.library was written in BCPL, and whenever it needed to access the
library base, or rootnode, or DeviceInfo structure, it called OpenLibrary
for dos.library.  In 2.0, it no longer does this.  Bill Hawes found you
could get a measurable (though very small, <1%) speed improvement in certain
dos operations by moving dos.library to the front of the library list.

-- 
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!"