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From: peter@cs.uwa.oz.au
Newsgroups: comp.protocols.appletalk
Subject: Re: Idea for painless copy protection
Message-ID: <1991Feb4.113258.28790@bilby.cs.uwa.oz.au>
Date: 4 Feb 91 11:32:58 GMT
References: <1991Jan27.144523.20674@phri.nyu.edu> <1991Jan27.214310.3870@agate.berkeley.edu> <27A3555F.13566@orion.oac.uci.edu> <48543@apple.Apple.COM>
Sender: glenn@bilby.cs.uwa.oz.au (Glenn Huxtable)
Organization: University of Western Australia
Lines: 40

Some observations, some questions...

Two basic mechanisms exist for netwide copy protection :
1) Serial number exclusion, and
2) Application counts.

Serial number checking suffers from the "endless horizon" problem. "In what
zone does one stop checking for duplicates ?" 

LaunchBreak is an application counting mechanism that has been proposed as a
solution, and it is nice for two reasons: 
1) It gets around the weak copy protection offered by the latest Finder of
files from AppleShare file servers. LaunchBroken applications cannot be used
removed from the network.
2) By having a copy of the software on your local disk rather than the file
server means fast launch times.

Question : 
Does LaunchBreak handle multiple zones ?

Unfortunately both mechanisms suffer from the "endless idleness" syndrome. With
MultFinder it is very easy for people to forget to quit from applications,
leaving them running and excluding usage by others.

AppleShare uses the Finder attribute "Shared" to determine whether an
application is multi launchable. This is restricted in that an application may
either be single launchable or multi launchable but without any control over
quantity. 

Questions :
Could this bit be turned into a byte, representing the maximum
number of concurrently open copies ? 
Could AppleShare could keep a count of currently open copies ? 
When a user asks for a (n+1)th copy, could AppleShare poll the
applications for idle time and shut one down if appropriate ?

Peter Dodd
Computer Science Department
The University of Western Australia
peter@cs.uwa.oz.au