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Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!decvax!wanginst!vishniac
From: vishniac@wanginst.UUCP (Ephraim Vishniac)
Newsgroups: net.micro.mac
Subject: Notes on _Launch
Message-ID: <810@wanginst.UUCP>
Date: Mon, 15-Jul-85 10:02:08 EDT
Article-I.D.: wanginst.810
Posted: Mon Jul 15 10:02:08 1985
Date-Received: Wed, 17-Jul-85 20:09:05 EDT
Distribution: net
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 18

Maybe the current version of IM is better, but...

The 8/24/84 edition of the Segment Loader chapter neglects some vital
information about _Launch, _Chain, and _ExitToShell.  Most annoying is
that it doesn't explain which volume the program (finder) will be launched
from.  If you guessed "the default volume" (my initial guess), you would
be wrong.  _SetVol sets the default volume, but has no effect on which
volume programs are launched from.

A little exploration revealed that _Launch, et al., use the volume whose
volume reference number is in BootDrive (location $210).  (Did they mean
BootVol?)  So far as I can see, the use of this location is completely
undocumented.
-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay