Path: utzoo!mnetor!uunet!husc6!think!ephraim
From: ephraim@think.COM (ephraim vishniac)
Newsgroups: comp.sys.mac
Subject: Re: (LSC) Deep Dark Secrets Wanted!
Message-ID: <15349@think.UUCP>
Date: 22 Jan 88 20:01:53 GMT
References: <870111@hpcilzb.HP.COM> <817@thorin.cs.unc.edu>
Sender: usenet@think.UUCP
Reply-To: ephraim@godot.think.com.UUCP (ephraim vishniac)
Organization: Thinking Machines Corporation, Cambridge, MA
Lines: 28

In article <817@thorin.cs.unc.edu> steele@unc.UUCP (Oliver Steele) writes:
>tedj@hpcilzb.HP.COM (Ted Johnson) writes:
>>Would someone please share the DEEP DARK programming secrets on how to:
>>	(2)make a DA live forever (i.e., remain active across launching
>>           different applications from the non-multi Finder), unless
>>           you explicitly close it by clicking on it's close box.
>>	   I assume this means patching one or more of the ROM routines....   
>
>Set the DA up to launch a VBL task.  I think da-insect at sumex has
>C source for this.

Actually, it's MDS assembler.  I based my version on the original with
some help from MacNosy, whose output is in assembly language.  (Just
like my output.)  If you're still interested, ftp sumex-aim and get
<INFO-MAC>DA-INSECT-VBL.HQX.1.

Also, "launch a VBL task" is not a very helpful answer.  VBL tasks can
do little.  They can't use any memory manager routines.  They can't
expect unlocked handles to be valid.  They can't use most of the
toolbox.  They certainly can't expect A5 to be current.  In fact, they
can't even expect CurrentA5 to be valid!  (There are ways of checking
on that one, but it's nasty = undocumented.)

What is a VBL task good for?  Gross hacks, like the insect DA, simple
background processing, and forcing timeouts on foreground processing.

Ephraim Vishniac					  ephraim@think.com
Thinking Machines Corporation / 245 First Street / Cambridge, MA 02142-1214