TI limits turning code on TI-84 Plus CE-T calculator for cheating – Image and sound – News

“copying” on your calculator is not as old as the road to Rome? I remember well once I entered whole summaries in a TI-83. As a result, I barely needed it during the exam because I learned how to enter it during the haha.

There are several ways to cheat with your calculator. In addition to cheat sheets, you can also use programs to do your work for you. The standard example is the ABC formula, but the same idea applies to any standard problem.

There are numerous simple versions that only print the answer. These simple versions can be “beaten” by a teacher by choosing the test assignment so that the answer is not an integer but a carrot. Then you can check that your answer is correct, but only if you have found the answer yourself first. (And … it is mathematics, if you just fill in the answer in the problem, you can already perform that check anyway.) In this way a test still makes sense.

However, you can also create an advanced version that prints step-by-step how to get to the correct answer. If you literally overwrite that output as an answer, you get full points. Whether you have any idea what you are doing …? No idea, that can no longer be tested with such a program. In the end, we made an agreement with the math teacher I had the most lessons from, that in principle only the simple programs were allowed, unless someone self writes an advanced version.

That rule worked at my school (we had roughly three people with enough knowledge to make that kind of advanced version and, as far as I know, we simply never gave “forbidden” programs to other students; at that time there were no USB cables for your calculator , so we were also the only ones running programs from www.ticalc.org could download) but that will not apply to all schools and a few years later the situation (mainly due to USB cables, but the TI-83 + did not help either) was hopeless anyway.

As for the TI-83 + (and TI-83 + SE and later the TI-84 +; all versions with Flash and thus “Apps”), that made cheating an even bigger problem. In Basic (programs that you can type on the calculator itself), your options are limited. With Assembly you can do more, but only with Apps (no more separate programs, but things that had to be installed) it became really interesting, because then the possibility arose to add functionality to the OS. The best example was Symbolic. If your test requires the derivative of a function, the TI-83 can provide at most a numerical approximation; useful to check if your answer is correct, but it does not help to find the answer. However, the Symbolic app had support for (a limited set of) symbolic edits, so you simply got the correct answer.

Teachers have tried for a while to have calculators reset for each test, but (if the teacher does not know exactly how the TI works), you can even write a fake reset program in Basic. If your teacher knows exactly what to look out for, Assembly can be made into an almost perfect imitation. With the TI-83 +, a reset is perfect to fake if you use a special App.

Because TI did not want to lose this lucrative market, they came up with TestGuard. With this freak the teacher can reset the calculators of all his students for a test; not on their own calculator, but remote. The TestGuard app is on the teacher’s calculator and sends the reset command, via the data cable, to the student’s calculator. This is more difficult to get around (originally only teachers who download App, so that reverse engineering is rather difficult), but that must also be cracked sooner or later … the problem is inherently insoluble. The owner of the calculator actually has full control of the device through Assembly. ^*) This makes it easy to listen to the remote reset command from TestGuard, neatly receive the “command received, I’m going to reset” confirmation and activate your fake reset.

*) When installing Apps and OS upgrades, a cryptographic hash is checked. The key to signing free Apps has been released by TI itself. The key to OS upgrades has been cracked by the community (simply via brute force). As far as I know, only the key for paid Apps has not been cracked: it was of no use to the community, so better not to annoy TI unnecessarily. The only code that cannot be modified is one Flash page of the OS, but it only contains the routines to receive a new OS (so you can simply retry a failed upgrade, instead of having a broken device).

removes the update support for Assembly

Do you know for which models support for Assembly has never been removed … because they never had that support? Among others the TI-81, TI-82 and TI-85. But as the links show, that doesn’t mean you can’t run Assembly on those devices.
Opinions may differ about the TI-83; yes, it had built-in support for running through Assembly, but only through an undocumented easter-egg like trick. For comparison, on the TI-83 + you start an Assembly program with “asm (prgmABC)” while on the TI-83 you “send (9prgmABC” (and so not had to use “send (9prgmABC)”!).

So no, I don’t believe this will make much difference. That the support is gone without it; that makes it much easier. But the possibility to run Assembly is at most a week on vacation, it will be back soon … and then both TI and the community will waste an insane amount of time and energy on a senseless arms race.

It is not possible to undo the update.

I don’t believe that. They mean “we made it harder to undo the update … who wants a challenge?”.

It is much more important that children and young people learn how to acquire knowledge than they are popping out of useless theory that will be repeated in 5 years …

We are talking about high school math here. You can still discuss whether that knowledge is useful for everyone in everyday life, but that material has not changed for hundreds (in some cases, thousands) of years. Yes, yes, I know, “past performance …”, but still, I really don’t see it going to be outdated in five years.

[Reactie gewijzigd door robvanwijk op 25 mei 2020 12:13]

–