Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!purdue!i.cc.purdue.edu!j.cc.purdue.edu!pur-ee!uiucdcs!uiucdcsp!gillies
From: gillies@uiucdcsp.cs.uiuc.edu
Newsgroups: comp.sys.mac
Subject: Re: Philosophical programming question:
Message-ID: <76000119@uiucdcsp>
Date: 10 Feb 88 21:28:00 GMT
References: <870130@hpcilzb.HP.COM>
Lines: 17
Nf-ID: #R:hpcilzb.HP.COM:870130:uiucdcsp:76000119:000:747
Nf-From: uiucdcsp.cs.uiuc.edu!gillies    Feb 10 15:28:00 1988


O.k.  The idea of a handle is very old.  The idea was used in the
protection scheme of the CAL TSS operating system [1].  All objects in
the system were referenced indirectly through a "Master Object Table"
(MOT).  When objects were deleted, the indirect reference was broken.
Cal TSS would relocate blocks in memory, and it would destroy blocks
by breaking the link to the object.

Hence, there is nothing new about Apple's "Handles", except perhaps
the wierd concept of having a block "cleared", necessitating that you
reallocate the block.

Don Gillies {ihnp4!uiucdcs!gillies} U of Illinois
            {gillies@p.cs.uiuc.edu}

[1] Butler Lampson and Howard Sturgis, "Reflections on an operating
system design", Communications of the ACM, 1976.