
Calculator hackers crack OS signing key, opening a closed platform - modeless
http://www.ticalc.org/archives/news/articles/14/145/145154.html
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mahmud
A man has just become immortal. TI scene will never be the same again; the
TI-83 calculator turns to an open platform today (The 83 is mandatory in U.S.
education and sometimes distributed for free, all American High Schoolers use
it, and did so for at least the last 10 years.) Bonafide 3rd party OSes can be
loaded on it now, no more shells.

Help crack the rest of the keys (Win32 and Linux clients; linux version
requires X I just found out):

<http://boinc.unsads.com/rsals/>

 _Some fun statistics:

\- The factorization took, in total, about 1745 hours, or a bit less than 73
days, of computation. (I've actually been working on this since early March; I
had a couple of false starts and haven't been able to run the software
continously.)

\- My CPU, for reference, is a dual-core Athlon64 at 1900 MHz.

\- The sieving database was 4.9 gigabytes and contained just over 51 million
relations.

\- During the "filtering" phase, Msieve was using about 2.5 gigabytes of RAM.

\- The final processing involved finding the null space of a 5.4 million x 5.4
million matrix._

~~~
jacobolus
> _(The 83 is mandatory in U.S. education and sometimes distributed for free,
> all American High Schoolers use it, and did so for at least the last 10
> years.)_

It's a bit off the subject, but this has always struck me as a terrible scam.
For the material it is used for (introductory calculus) and the way it is
used, one of these TI calculators hurts student learning and understanding
more than it helps, and there is no excuse for schools to force students to
purchase a $100 piece of electronics without a damn good reason. That these
devices are absurdly overpriced compared to the state of the art (~$100
multipurpose netbooks, for instance), and that the models required are made by
a single company with monopolistic coordination with standardized tests and
textbooks, only make things worse.

Learning how to use a calculator is perhaps a useful skill, but it's one that
can be learned quickly if needed and should not be pervasively required: for
most math done for math's sake (that is, as opposed to computations for some
engineering problem), students would be better off if teachers instead made
problems that could easily be worked with pen and paper.

(Personally, I made it through high school and then up through upper-level
undergraduate mathematics, physics, econometrics, etc. courses without ever
buying a graphing calculator, so it’s clearly not strictly mandatory for
current curricula, but students and parents get the impression that it is
essential, and the vast majority of students do buy them, so the effect is
about the same.)

~~~
dan_the_welder
And now a cracked OS allows cheating since they have an approved 'test mode"
to prevent access to stored files.

[http://education.ti.com/educationportal/sites/US/homePage/ns...](http://education.ti.com/educationportal/sites/US/homePage/nspire-
press-to-test.html)

So blinking the led without any access blocking will be an early task for the
subversive TI hacker.

~~~
icefox
Crazy what they have these days. Back when I was in high school (first year
they required the 83) our teachers simply required we showed every step. So we
could get the answer with a few key presses, but unless we showed how to get
the answer we wouldn't get credit. Of course I wrote programs to solve the
problems step by step and print out the answer, but I guess the system works
because in the process of being clever and writing the programs I of course
learned how to solve the problems step by step.

~~~
euroclydon
I had a nice and crazy little Chinese professor for numbers theory in college.
I never knew what he was saying, but he would tell us the questions for the
exam the day before. I asked him if I could use my ti-92+ and he said yes, so
I just programmed in brute force algorithms, entered in the data, then sat
back while the 10MHz processor crunched.

------
blasdel
Unfortunately it's a ridiculously shitty hardware platform to be developing
for in 2009. It's a _motherfucking Z80_ , for $100 -- a vintage Game Boy minus
any decent sprite graphics hardware, with enormous profit margins and a
captive market (enforced by regulation) of a million a year.

Yes, the OS on the TI-83 is dogshit, but I have a feeling that it's pushing
the limits of what's reasonable on the hardware. The TI-89 has a terrific
input language and OS (almost mac-like compared the the apple-II-ness of the
83), but running on a m68k.

Who knows, maybe someone can at least make a firmware that not only forces you
to close your parentheses, but gives you some benefit for doing so.

~~~
jsonscripter
But... it's a _calculator_!

And it has a headphone jack! And a bitmap screen! And a full keyboard!

------
icefox
The post on TI forum reminds me of when decss was cracked and an email was
sent to the list saying something like: "Here are some random numbers that are
good for initializing your card game shufflers and stuff like that" Followed
by several dozen keys. It got printed out and put on a dorm room door :)

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mtrimpe
Oh those good memories of the TI-83, my first and only foray into the world of
assembler programming, trying to cram a complex algorithm in 6 registers, the
good times!

~~~
mahmud
You mean five registers, all of them accessible through the sixth! I had a
nice hand written note for register allocation for the Z-80; I used an stack-
based IR and mapped the TOS to #A. I hope to god my parents haven't trashed my
stuff, would love to see those perversions again :-)

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zokier
What about my oldskool TI-86? No love for that? :(

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ams6110
I guess I have a little taste of what the guys who went thorough school using
slide rules felt like when calculators that could do trig functions came out.

I went through high school trig, calculus, and undergraduate college math
classes with nothing more than a standard 10-digit "scientific" calculator.
Graphs? You plotted those with a pencil.

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makmanalp
What's the legality of this, I wonder? (Toying with the idea of joining the
compute cluster or not)

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srt19170
Isn't this at least technically illegal? (DCMA)

~~~
kragen
You mean DMCA, and IANAL but probably not. The calculator's OS may be a
copyrighted work, but the calculator itself is not.

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xcombinator
hehe, I remember trying to convince my teacher for letting me use the nintendo
DS on exams. You have to try, it's funny to see their faces.

Now you can use: 1.Nintendo DS. You can make or port(from linux) whatever you
want in c, import Lapack libraries, use eigenmath homebrew for everything
else. 2.Iphone.Good support for c too. 3\. netbooks...

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erlanger
So, we can get a native MirageOS? Nice.

