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Comment by whoisthisguy | Hacker News Reader

TI-89 basically saved my ass in collage. Not only that, I was the fourth "best student" in collage based on grade average. I modded the firmware so I was able to upload text docs organised in folders. Text filed had TOC, that made navigation easier. I was also able to search within those files.

If you became fluent using all features of TI-89 (integration, derivation, diff. eqs., shortcut keys etc.) and you had a solid abstract understanding of the subject (which of course required some studying), TI-89 basically got the rest of the job done in minutes. TI-89 was magic.

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I had a TI-89 I got in 9th grade and had through the end of college, but I found I had the opposite experience with it. A goodly number of my engineering classmates used their TI-89s as a crutch and forgot most of the details of solving e.g. differential equations and computing integrals. In my case I found it faster to do most of the problem solving by hand, and I just used the calculator to punch in the numbers to get the final answer. I found after a while that my TI-89 just sat in my backpack doing nothing most of the time and all I needed was a scientific calculator for most things. About the only time I found it really useful was for solving for stability characteristics and tuning tedious PID loops for control systems problems. Solving characteristic polynomials for poles and zeros was just a pain in the neck.

It had a nice side effect of saving my bacon several times on final exams. On my engineering electromagnetics final I forgot to change the batteries in my TI-89 the night before and the calculator didn't work. I ended up having to re-derive a small bit of transmission line theory from scratch in order to solve the problems. I somehow managed to be one of the first people done anyway. I did have fun making arcade game clones and custom boot screens in assembly on it though.

And here I thought calculators are not suited for artistic pursuits.

Can you further expand on uploading text docs? I'm not sure I understand why that helped you. Also, what did you get your degree in?

I’m wondering too. I remember when I was in HS, one of my teachers said that they could easily spot if anyone was cheating with their calculators because almost all of the students that were not cheating would be focused on reading and writing by hand most of the time, and only occasionally reach for their calculator to calculate something with it. If someone was paying an abnormal amount of attention to their calculator, it could indicate that they had for example put notes on the calculator, or had some extra programs that had features outside of the allowed ones. So then the teacher might sneak up behind the student and have a glance at what they were doing on the calculator.

Also, to try and combat those kinds of things my school always had us show them the list of programs on our TI-84 Plus calculators before a test started, and we had to delete anything outside of what was allowed. That being said I think the calculator can be modded with custom things that could be hidden. So probably the best way of preventing people from cheating was by paying attention to who was using the calculator too much.

In my HS we had to reset our calculators before exams. I wrote a program that displayed the reset screen. I didn’t have anything exam relevant stored on my calculator but didn’t want to lose my copy of the ‘Penguins’ game.

You must have gone to an excellent high school. I’d be fairly surprised if any classmates of mine had ever installed programs on their calculators, my teacher was pretty surprised when I was showing everyone the game I’d put on mine.

The best way to prevent cheating is to forbid all calculators during the exam ...

I was majoring in CS in one collage and doing Business Management in another collage. Both had class that required us to memorise tons of lexical knowledge. For example I had two semesters of Corporate Finances. Lot of formulas (100+) had to be remembered to calculate different KPIs a corporation. I had all these formulas in a notes uploaded to the calculator. If a test questions required one to use, I opened up my notes, looked up the formula and used it. TI-89 was able to use variables, solve equations for different variables and convert units. Using the right shortcuts I just plugged in the numbers. Of course I understood how to apply these formulas, I just didn't have the patience to memorise them. Another class was Psychology. Had to memorise a complete book. No way I would do that. Instead collected notes from friends, organised them, digitised them, created well structured Table of Contents (all took about two days), uploaded to the calculator and used it during tests. You might ask why it was allowed to use a calculator during a Psychology final test? Answer is easy. At those times no teacher could image that notes could be stored in a calculator. TI-89 was just released, hardy available in the EU. So if they saw me playing with the calculator they thought probably the kiddo doesn't know anything and just pushes buttons to spend time.

Why do you keep spelling it as collage?

they don't like to 'memorise tons of lexical knowledge'

tl;dr cheating on exams

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