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Building OSs for Flash ROM Calculators

Posted on 6 September 1998

The following text was written by Matthew Stits:

When one looks at the evaluation of the TI series of calculators, one sees more and more people trying to push the envelope of what one can do with them. At first, just a few basic games, then assemblers, all the way up to memory expansion kits. With this in mind, TI did make it a bit harder to make an assembler on the TI series with the 92. I remember many people discussing the problems (of which I do not recall the exact reasons) which gave way to making fargo a very stable shell built on an Operating Sytem never intended for it. With time and the presence of fargo, TI has seen that someone will always find a way to get around what ever obstacles presented and has now put an assembler on their TI-89 and TI-92 Plus models.

At first this would seem great for the TI's. In one single step they have erased the need of so many people who enjoyed their work. Now after explaining some of the history to this saga, I feel TI has given themselves a bit of an Achilles heel. With the ever growing cost of the college student's calculator, TI said, "Hey! Let's put Flash ROM in so they will only have to buy one calculator for a little more." With this in mind a hole was opened that none had previously thought about. Why doesn't someone now make a complete OS for the calculator? It could be anything from a small unix box, to a full fledged GUI OS. Here I'd like to present some examples of it why it should be done. All the registers are out and I am sure that a 10 MHz chip is more than enough for a GUI interface or at least a basic lunix shell to start from.

I think that the biggest problem would be in making a joint inter face for both the TI-89 and TI-92 Plus. It would most likely have to be recompiled for each version with different specs for the first few builds until a set amount of memory is dedicated to output for the LCD screen. There are at least 3 OS's made from this chip and its children already! Mac OS, Norton "that pseudo Palm Pilot" and Sega's very basic ROM reading OS for its genesis and probably a few more. This is by no means to say the that Fargo has no purpose, but what if they made it into a full fledged OS and not a shell on top of an OS never intended to work in the back ground?

When looking at this from the a different angle, one sees a few possible problems. Some (actually most) of us don't have a TI-92 Plus, so Fargo is all that many can use. Fargo is probably a lot better planned than whatever TI had made. Fargo can use libraries, make TSR's, and many other things that I for one doubt TI put that much work. There are already many good programs for Fargo "that could be ported at a later date". As for making your own OS for the calculator, all you could do is turn it into what most (at least at first) would consider a novelty or GameBoy, not to be taken seriously. Why reinvent a calculator that TI paid lots of people to make? I believe a person or small group of people not getting paid would make anything as good or better.

  Reply to this item

Re: Article: "Building OSs for Flash ROM Calculators"
Andrew Hockman

There is a big problem here that is being overlooked. In the past, TI calculators were made with true ROM... read-only. They were confident that when the technology became outdated, consumers would buy more calcs. However, the new "flash rom" gives the possibility for an almost infinately upgradable calc. This would never be good for business, so TI added a little "feature" to the new flash calcs... a limited number of upgrades. Theoretically, at some point in the distant future the calc will completely shut down and refuse to work (at least this is how I understand it). Consumers are then forced to buy more calcs. Perfect... almost. While this may be fine for normal users, in my opinion TI has totally neglected all the programmers and developers that drive the popularity of their products. How many programmers out there want to write, flash, crash, restore, modify, flash, crash restore, and everything else necessary to write quality software if they knew that each calc crash was "eating up" a little bit of their calc's limited life? I'm wary.

Reply to this comment    7 September 1998, 05:35 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"

What I keep hearing(at least from the mailing lists, I haven't heard directly from TI) is that the ROM can be flashed about 10,000 times before it goes bad. For me, this should outlive the restof the calc. Someone please verify my numbers.

Reply to this comment    7 September 1998, 06:32 GMT

Re: Re: Re: Article: "Building OSs for Flash ROM Calculators"

I thought TI would get money by charging for the new ROMs. They can't only let you flash a few times b/c AFAIK they will be releasing new versions of the same calc (like there are different versions of the others) so you can update it to fix a bug in the OS.

Reply to this comment    7 September 1998, 21:05 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"
Seth [SWiFT] Fowler

Hehehe - you're misunderstanding a fundamental property of flash rom. Flash rom can be read from an infinite number of times without the data deteriorating. But it can only be written to a finite number of times before it becomes unreliable. This is not some "trick" TI created to make you buy another calculator. This is just how flash rom works. The number is quite high tho - 10,000 or even more. I don't think that you'll run out of writes before you tire of your calc. There's no conspiracy here - just good old chaos theory ;)

Reply to this comment    8 September 1998, 04:09 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"

Well, if you really are going to flash that thing 10,000 times, you might as well get an emulator... Except VTI doesn't seem to restore states quite well, says something about not recognising the sate I just saved...

Reply to this comment    20 October 1999, 03:52 GMT

Re: Article: "Building OSs for Flash ROM Calculators"

Well, I have a lot to say but i am going to make it short cause i have to try to get to sleep. All of us here are talking about making an os and how cool it would be, nnow, not to imply that i know anything about 68k asm, but i am will to start a group to begin searching for ways to do this os project, I do have a few ideas on how to approach this project. my e-mail is: ajp259@hotmail.com
Somethign that i think that we NEED to talk about it how in the last post the guy said that there is a limmited number of upgrades, this needs to be investigated this is huge, i really need to know wwhat is up with this. I will nwo say anymore about how serious a limit on upgrades would be if there is infact a limit untill i find out in wroiting where that is from ti, and what the actuall number is, okay, I am sorry for all ther mispellings there must be in this thing, i was typing very fast cause i really do have to get to sleep,

Reply to this comment    7 September 1998, 06:34 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"

10000 Times

Reply to this comment    29 July 1999, 09:20 GMT

Re: Article: "Building OSs for Flash ROM Calculators"

Okay, I have a thought about emulating a Mac on a TI-89 as a second OS:

The orriginal Mac was less powerful than the TI-89, at least memory and speed wise. For those of you not familiar with it, it used a 8MHz 68000 with 64k ROM and 128k RAM. With the memory available in the Ti-89, I believe it would be entirely possible to emulate one of these orriginal Macs, even though it would be rather pointless. (The only programs I have that can run on one are System 1.1n and a database program)

Reply to this comment    7 September 1998, 07:26 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"
me again

Don't forget that it had a drive to store things on... unlike what we're using :-)

Also... MacOS is the antithesis of what the typically tech-nerd filled world of TI-xx programmers. It shields the user from the system, and we want closer access. It's like wearing a blindfold instead of glasses.

Personally, I like all of the suggestions of UNIX-like and DOS-like (or CPM/80-like for that matter) OSes for TI calcs...

Reply to this comment    8 September 1998, 07:05 GMT

Re: Re: Re: Article: "Building OSs for Flash ROM Calculators"

The original MacOs ran on a machine with a 400k floppy drive and 128k of ram. Since 22272 bytes were used for the screen, the os must be pretty small. This OS could be made even smaller by removing much of the extra code not used on the calc.

The MacOs does not shield the user from the system anymore than the TI-OS does. TI said that you couldnt use ASM on a 92... Fargo beat that. The same is true of the mac os. If you have a minimal knowledge of how the system works, you begin to see its potential.

Since the old versions of the MacOs are free, and there are plenty of 128k Macs that can be used for testing, the MacOs seems to be the way to go.

Reply to this comment    27 April 1999, 01:16 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"

I think you got your numbers mixed up the ti-89 has a 10 mhz processor (the same as the ti-92)
see http://www.ti.com/calc/docs/faq/83faq067.htm
As far as the size of the ROM you are way off the ti-89 has have about the same size rom as the ti-92 ( a little smaller because the geometry application is not in th 89's rom), and the ti-92's ROM's size I think is about 1 meg or more i am not positive but it is defintaly more then 64k. This is the reaason a GUI OS may be reasonable if you could put it on the ROM memory instead of the RAM.

Reply to this comment    8 September 1998, 21:12 GMT

Re: Re: Re: Article: "Building OSs for Flash ROM Calculators"

Let me clarify: The specs I gave were for the orriginal Mac. What I'm saying is, the TI-89, with over 1/2 MB RAM and a 20% faster processor should be able to emulate a Mac. Why bother? Well, why do people climb Mt. Everest? Because it's there. Why emulate a Mac on a calculator? Because you can. :-)

Reply to this comment    8 September 1998, 23:52 GMT

Re: Re: Re: Re: Article: "Building OSs for Flash ROM Calculators"

My bad I thought you were talking about the ti-89
Even though I am not an avid mac user I think making a mac os for the ti-92 would be pretty cool. I hope someone goes ahead with this project or something simular.

Reply to this comment    9 September 1998, 00:40 GMT

Re: Article: "Building OSs for Flash ROM Calculators"
Jonas Minnberg (Sasq)
(Web Page)

First of all: MacOs on a TI? What's the point?
Without a mouse and with such a small screen it
would be pointless. What we need is a unix-like
OS, and that shouldn't be impossible. Also, a
few 68000-based OS:es was mentioned, but not
the (IMO) most interesting; Amiga OS.
There's a lot to learn from this OS that was
(still IMO) superior to all other OS:es in the
late 80s and early 90s - mainly because of the
fast multitasking and the fact that the entire
OS was composed out a few, well-documented "libraries" (known as DLL:s in the windows world).

I have been thinking about how to make a good OS
for the TI92 for some time... If I ever get
around to it, it will be unix-like with a micro-
kernel (something along the lines of QNX perhaps)
with very simple functionality (priorityless,
round-robin preemptive multitasking) but with
the ability to override and extend everything
with new, more advanced funtionality. This would
allow for a very small OS if all you want is the
ability to run some games (say a kernel around
1-2k) but with the ability for a full-fledged

I also think that anyone considering developing
an OS should think twice about it; it is not
a very good "first" project. I have been
programming for many years, most of the time in
68000-assembler - and I've a good deal of
experience with unix-like OS:es and how they're
built but I still feel it's a very tough
project, especially if you want to get it "right"
and not make all mistakes again (even with lots
of money, time and experience this may happen,
just look at windows ;).

About the flash-limit; If I start this project I
will of course use my emulator as much as
possible :)

//Jonas Minnberg (Sasq)

Reply to this comment    7 September 1998, 13:40 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"
Michael Tin
(Web Page)

I totally agree with the Amiga OS idea. I have a Amiga 500 with the old Workbench and OS. I think that was Excellent for an 80's computer(still have it too) and seeing it on my new '89 would be kinda cool. The Amiga OS was IMHO the best GUI in the 80's because it truly was the predassor of the GUI made by microsoft(eg. Win95). It would be cool to see some of the old amiga games(rick dangerous baby!) on the calc.
Anybody making one Amiga OS tell me!

Reply to this comment    4 October 1998, 05:38 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"
Mark Leverentz

Forgive my ignorance, but when you say 'emulator' do you mean a version of the calc on your pc? if so, where can i get a hold of one of those things?

Or am i just totally misunderstanding?

Reply to this comment    6 November 1998, 05:22 GMT

Emulator info
(Web Page)

Yes. A TI Emulator is a program that mimics a specific TI calc on your computer by using the ROM. You can get a hold of one by going to the reviews section, then to Windows. Read the reviews before download though!

Also, for my own help, I've been trying to dump a ROM from a TI-82, for my own reasons using Gluvna's ROM Dumper software and when I press enter to transmit the ROM my Grahplink software gives me a transmission error. It's not my Graphlink cord or port number because I can transfer program both two and from my computer. Also, if anyone could kindly tell me where I can obtain a TI-89 ROM so that I can program for the calc without having to own it, I would be greatful.

Reply to this comment    6 February 1999, 21:34 GMT

Re: Emulator info
Kevin Kofler

You can get a TI-89-ROM legally at http://www.ti.com/calc/flash/89.htm (but it's use is ILLEGAL (!!!) if you don't own a TI-89!!! (It's against the license agreement!)).

However, here are the instructions: download ti89base.exe and unzip it to extract ti89base.tib. Copy this to the VTI directory (you need VTI 2.0 or higher or the outdated VTI68k) and you can use it.

The same is valid for TI-92+ ROMs.

Reply to this comment    6 November 1999, 10:56 GMT

Re: Emulator info

How do I send programs from VTI to my calc? I made a bunch of programs, and I can't use them! :(

Reply to this comment    20 February 2003, 06:18 GMT

Re: Re: Article: "Building OSs for Flash ROM Calculators"
Rob Taylor

Good to see someone who actually knows something about OS's posting on this topic.. :)
Yes I whole hartedly agree.. an amiga OS port would be the best option.. it' was susch a well designed operating system (and close to my heart - it was written mostly here at Cambridge :)
the Amiga had a lot mroe powere than amiga os acually needed, you know so it should be pretty easy to port it well. The only problem is really filesystems.. has anyone actually ogt an amiga who fancys whackingh the rom and workbench atartup disk onto file so people can start hacking around with it???


Reply to this comment    19 December 1998, 16:20 GMT

Nathan Cassano

First off I do think new rom's are very possible. I person dumped their 89 rom mistakenly and it still booted, but with no extra algebra and calculus stuff. There is a TI OS ROM (size=?), then added software ( 250K-500K ), user archiving ram ( 384K ) and system ram ( 250K, 180K of that available to the user ). That's almost a meg of ram ( the Palm Pilot has 2 megs ). You would have to boot to the TI OS then exec a boot loader from there. Here is my proposal for a new TI-89 OS, I wanted to voice my opinion on what the OS would be like. The entire idea and purpose of an OS would be to make the TI-89 as open and as accessible as possible. The current OS, that TI provides doesn't give us the power we desire out of our calcs. We need more. We need to push our TI's to the max! Here we go.



PC to TI connectivity station
External GNU C/C++/ASM Compilers ( why aren't we using these with good libraries? )

Stable System Kernel ( does the system chores, interupts, blah, blah )
A standard programming library
File System (with compression options)
GUI and text Shell interfaces
Networking Protocal
Standard system DLL's program interfaces
Security System
Scripting language (similar to TI-BASIC but more power and robust, like
Java Script)
Word Processing and other associated applications ( extras )

Reply to this comment    8 September 1998, 07:23 GMT

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