Thread Subject: how to make a time limited stand alone application to distribute for demo purpose?

Hello
I need to know whether we can make a stand alone
application which is time bound i.e. An application that
can run for a specific amount of days, say 30 days
evaluation copy. And it should be so that even if the user
changes the the date or goes backward in the date, the
application should not run if the time period is lapsed.
Any suggestions?
Regards
Vihang

Any suggestions?

"Vihang Patil" <vihang_patil@yahoo.com> wrote in message
<fm7h5r$2hb$1@fred.mathworks.com>...
> Any suggestions?

The only thing I could think is that if you only supported
versions of MATLAB that could make internet requests (which
I think new ones can?), you could activate the program each
time it tried to run -- call a remote server with a key and
authenticate if your record for that user has not run out.
That way you only need to make sure that the receiving
computer keeps an accurate date. You'd have to be quite
obvious about the fact that you were doing that though -- I
don't think people like it when their computers call out
onto the internet without their knowledge. And it would
also force users to have the internet.

However, given that they could likely see the .m code, I'm
not sure how helpful that would be. Maybe it'd be possible
to make a compiled .mex file instead that would be harder
to open up?

Another thing I just thought of was that you could do a
file search and get the date of the most recently modified
file. Assuming they tried to switch their date back, they'd
have to switch the modified dates on all of their files to
get the software to work? This depends on the fact that
files get modified on the computer. Not sure how well that
would work, but maybe also worth a shot instead of going
the internet route. There is software on the file exchange
for doing file searches. Would also be taxing on the
computer to enumerate all files! Maybe you could find a
specific file that you know gets updated/modified very
often and just reference that one.

Hope this helps!

Dear users
After probing into the requirement, I had posted above, I
coded a small program which can be used to serve the above
said purpose. If any one is interested to try out can visit
this page
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=18315&objectType=file

or

tiny url: http://tinyurl.com/yqzpfe

Regards
Vihang

Hi Patil, yours eavluation copy does not work at all! It just shows 0 days left! Are you allowing only for negative numbers of days?

Yumnam Kirani Singh <kirani.singh@gmail.com> wrote in
message
<14955036.1200379725033.JavaMail.jakarta@nitrogen.mathforum
.org>...
> Hi Patil, yours eavluation copy does not work at all! It
just shows 0 days left! Are you allowing only for negative
numbers of days?

Dear Yumnam
The program is doing exaclty as it is supposed to do,
except it is not "0 days left" but it is "0 days in use".
USAGE :
 function [output days_in_use] = evaluation
(num_of_days,msg_on_off)

ex: [out days_in_use] = evaluation(30,'on');
%30 is number of days, the application will run, 'on' is
%the flag set if you want message to pop up on end of
%evaluation

To check whether the 0 days is increasing or not, just
change the system time to say tomorrow and rerun the above
function and you will see it is incremented to 1. To check
whether it stops functioning after 30 days, change the
clock to 31 days from now and see the result.

P.N: You can use "remove_evaluation.p" to remove the
effect of "evaluation.p" function.

HTH
Vihang

"Vihang Patil" <vihang_patil@yahoo.com> wrote in message
<fmhmhn$p3q$1@fred.mathworks.com>...
> Yumnam Kirani Singh <kirani.singh@gmail.com> wrote in
> message
>
<14955036.1200379725033.JavaMail.jakarta@nitrogen.mathforum
> .org>...
> > Hi Patil, yours eavluation copy does not work at all!
It
> just shows 0 days left! Are you allowing only for
negative
> numbers of days?
>
> Dear Yumnam
> The program is doing exaclty as it is supposed to do,
> except it is not "0 days left" but it is "0 days in use".
> USAGE :
> function [output days_in_use] = evaluation
> (num_of_days,msg_on_off)
>
> ex: [out days_in_use] = evaluation(30,'on');
> %30 is number of days, the application will run, 'on' is
> %the flag set if you want message to pop up on end of
> %evaluation
>
> To check whether the 0 days is increasing or not, just
> change the system time to say tomorrow and rerun the
above
> function and you will see it is incremented to 1. To
check
> whether it stops functioning after 30 days, change the
> clock to 31 days from now and see the result.
>
> P.N: You can use "remove_evaluation.p" to remove the
> effect of "evaluation.p" function.
>
> HTH
> Vihang


One more thing, I forgot to mention, is that, if you are
executing the demo application , magic_number.m that I
have bundled along to test this application requires a
small utility which is found here
http://www.mathworks.com/matlabcentral/fileexchange/loadFil
e.do?objectId=12673&objectType=FILE
Copy this file in the same folder where your program
resides.
I have modified my posting on the File Exchange also, but
untill then you can use the above said workaround.

Vihang.