Question

I saw this question in a forum about how an application can be developed that can keep track of the installation date and show trial period expired after 30 days of usage. The only constraint is not to use the external storage of any kind.

Question: How to achieve this?

Thanks
Bala

–Edit
I think its easy to figure out the place to insert a question work. Anyway, I will write the question clearly. “external storage” means don’t use any kind of storage like file, registry, network or anything. You only have your program.

Answer 1

I don’t know if this is possible, as most work I’ve done has been with embedded systems in which I don’t even need to touch the operating system. But would the following be possible?

When compiling your program, leave some extra space at the end (say, 8 bytes), all set to 0. When your application is run, it fetches those bytes and if they’re all 0, replaces them with the current time (That’s the part I’m not sure about. Does the OS let you do that? If not, there might be some work-arounds using multiple processes.), otherwise, if the time difference is greater than 30 days, it notifies the user that the trial period has ended.

Of course, that method would be vulnerable to resetting the system clock.