Hi guys,
How do we delete the system app?? In Casio PRIZM.

You can't delete the Prizm's built-in Add-Ins. You can only delete the Add-Ins that have corresponding files in the calculator's memory (which you can see by plugging the calculator into a computer).

But I was just wondering there a way to hack into the system and delete the application?
Or maybe How to prevent PRIZM from being reset??

There's no way to do that. While it may be technically possible (but very difficult, and good luck finding someone to do it for you) to modify the OS to remove the reset menu, the calculator can always be reset using key combinations, or in case those are rendered ineffective too, the bootloader menus (see http://prizm.cemetech.net/index.php/Secret_Key_Combinations ). I imagine that if a reset circumvention method was found, schools would just start using (and probably even with Casio's approval!) the key combinations instead.

Actually my friends reset my calculator all the time for fun which I don't like all the apps get deleted, any thing I can do to delete add in apps from being deleted??

There might be a program to password protect your calc, which might prevent your friends from helping you clear up space on your calc when they don't have your permission to use it.

There are a few add-ins for this:

One discontinued by gbl08ma, another incorporated into his utility add-in and finally my add-in which does just that http://www.cemetech.net/programs/index.php?mode=file&id=1212 - hope it helps. See more details here http://www.cemetech.net/forum/viewtopic.php?t=11033 but remember to set up you user info and password in the built in system manager as this will be the password my add-in uses. Nothing I know so far will give you high security for the moment but hopefully be deterrent enough for the pranksters in your school. Leave your feedback on http://www.cemetech.net/forum/viewtopic.php?t=11033 or if it is about particular security flaws which would be better not to be advertised here - just PM me.

I also wonder if someone knows if there is away to permanently save add-ins in parts of memory not effected by regular resets - it seams possible from Simon's documentation but I'm not sure how and if it would have any undesirable consequences. Then also a way to autostart an add-in maybe necessary and I don't know if it possible.

Returning to the subject of pranksters, coincidentally I have another add-in which limits things pranksters, etc. could do with your calculator but I decided not to release it to public because it as easily could be used to prank anyone into restricted view which they would not know how to get rid off or it could be used for less moral causes.

On a subject of invoking Initialize All dialog - I don't agree that the school should be allowed to remove the add-ins which came from Casio originally (geometry, pictplot, conv, physium, etc) as they were sold to the pupils and advertised on the packaging and so on. Casio documented how to reset main memory and other bits without deleting add-ins for exam purposes so provided the calculator is pupil's not school's property those original add-ins should be allowed to stay as the calculator is sold as allowed for the school exams, etc. in most countries. So allowing schools to invoke Initialize All/ResetAllDialog would render calculators less functional than they came from the box so I would launch legal proceedings against schools and/or Casio for property loss/misadvertising respectively...

The Utilities add-in for the Prizm also contains a calculator locking feature that enables you to "lock" the calculator with a password that's different (and can be stronger) from the one used to protect the user information.

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amazonka: Casio made Geometry, Picture Plot and etc. add-ins and not built-ins because they specifically want them to be erasable, as some schools and exams may not allow their functionality. Otherwise, and just to mention one example, the Conversion function could be always on, without the need to check for the presence of that silly Conv.g3a.

While add-ins can be removed, they can also be added later, and thus there is no functionality loss. Your argument could also be used against the exam mode included in the newest French versions of Casio calculators, "data storage and add-ins were advertised in the packaging so activating the exam mode constitutes a loss of functionality". Indeed it does, but it's a temporary loss, and an intended one.

After thinking a bit, you'll also realize that if Casio were to make all add-ins as built-in apps, then the OS wouldn't support add-ins, and then there would be no easy way to run custom code in it. In fact, this is what Casio did with the later versions of the Classpad, where the only "add-in" ever made is in fact akin to Conv.g3a on the Prizm, which is only used to enable functionality already coded into the OS:


As for installing add-ins to outside of SMEM it would be even harder than modding the OS to automatically start an add-in (traditionally installed in storage memory) on startup, which would increase the security of lock add-ins while not bricking the calculator. People could still use the bootloader to erase the flash/update the OS, which is a good thing since you'll be surprised at how many people forget their passwords, or have their friends pull a prank on them by changing the password to one that is not of their knowledge.
But even this solution is hard to implement with the current state of things.

All your points make sense and I agree with them. I just will not like it when schools will start unnecessary erase add-ins which they may not be required to erase. They will create a situation when the functionality will be unnecessary restricted as so many pupils will not know how to restore the add-ins or won't be able to do it downloading or/and USB access may also be restricted on school PCs, or even if they have a PC at home they may not know how to restore the add-ins. Thanks again for sharing your views.