Greetings,
As everyone here knows, at both this site and at TI's web site anyone can submit a program that they have written and if accepted it will be made available to anyone, anywhere in the world. This is a great resource.
What most of you may not be aware of is that this idea of writing a program for a TI programable calculator and being able to make it available to anyone in the world is not a recent idea in this age of the internet. TI has been doing this since the invention of the programmable calculator way back in the early 1980's. TI called it PPX Exchange.
TI's first programmable calculators were the TI-58C and the TI-59. I originally had a TI-58C but soon upgraaded to a TI-59 around 1981. The main difference between the two was that the TI-58C had only half the memory of the TI-59. The other difference was that there was no way to save programs written for the TI-58C so you had to hand enter them each time you wanted to use them whereas the TI-59 had a card reader so you could save your programs onto magnetic cards.
The maximum number of program steps that a program on a TI-59 could have was 960 steps (a step was one key-press) with zero space for memory storage. You could partition the TI's program space between program and memory in chunks of 10 memorys which took away 80 program steps. In order to do anything useful on the TI-59 you would partition it to have 880 steps and 10 memorys.
In some ways it is a shame that some of you here were not able to experience programming this calculator. I think you would have really enjoyed the challenge of trying to squeeze down a rather complex program down to only 880 key presses and use only 10 memories. You had to really give some thought to the order in which the program ran so as to make the best use of data stored in memory. After all, with only 10 memories, you would not want to store data at the very beginning of your program that wasn't used until the end of your program, thus tying up that memory for the whole program.
Having only 880 steps to work with caused me to learn a bunch of math relationships that I could use to squeeze steps out of a program while maintaining the accuracy for the most part. These are concepts that I still use today when writing a program. For example, say you have something like this: +cos(? + 272°.34). This would take about 12 key presses; assuming two key presses to recall ? and one for cos(. First you should realize that +cos(? + 270°) will give you almost exactly the same answer. So you have reduced this to 9 key presses. But you can reduce this even further. If you look up trigonometry reduction formulas, you will find out that +cos(? + 270°) = +sin(?). You have just reduced this down to 5 key presses. As another example, rather then enter the number pi I would use 4*atan(1) (in radian mode); 5 key presses. I also would use logarithms if I wanted to round a number to say 5 significant digits. I'll let you figure out how this is done if you don't know how. I was forever on the hunt in math books for things I could use like this.
In order to share programs you had written with other people TI administered a group called PPX Exchange. After writing a program I could submit it to TI and if they accepted it, they would publish it in their catalog and something in their newsletter where anyone else in the world who was interested could request copies. This was a wonderful experience for it motivated me to try to squeeze down fairly lengthy calculations to fit inside a program having only 880 steps.
For anyone interested check out this .pdf
http://www.datamath.net/Manuals/PPX-V6N6_US.pdf
Scroll down to Page 9 (which is on the 13th page) and check out program 7880691 Astronomical Data for the Sun. It took everything I knew to fit this program into that space.
I know that this post has nothing to do with current programmable calculators, but having used programmable calculators since their inception I thought I might be allowed to muse a bit on them and how much they have improved over the years.
I find my new TI-84 Plus CE to be a great improvement over that 59. The amount of memory I have available to me I find to be luxurious. And you may be surprised to find out that programming the 84 isn't that much different then programming the 59. The only thing different is that the 84 has a screen that displays text, where as the 59 only displayed the numeric key code, one step at a time. However, unlike the 84, the 59 did have a printer that you could plug it into (yes I do mean you plugged the 59 into the printer) and print out a hardcopy of you program.
Thanks for reading my musings.
S. Thomas Bradley
As everyone here knows, at both this site and at TI's web site anyone can submit a program that they have written and if accepted it will be made available to anyone, anywhere in the world. This is a great resource.
What most of you may not be aware of is that this idea of writing a program for a TI programable calculator and being able to make it available to anyone in the world is not a recent idea in this age of the internet. TI has been doing this since the invention of the programmable calculator way back in the early 1980's. TI called it PPX Exchange.
TI's first programmable calculators were the TI-58C and the TI-59. I originally had a TI-58C but soon upgraaded to a TI-59 around 1981. The main difference between the two was that the TI-58C had only half the memory of the TI-59. The other difference was that there was no way to save programs written for the TI-58C so you had to hand enter them each time you wanted to use them whereas the TI-59 had a card reader so you could save your programs onto magnetic cards.
The maximum number of program steps that a program on a TI-59 could have was 960 steps (a step was one key-press) with zero space for memory storage. You could partition the TI's program space between program and memory in chunks of 10 memorys which took away 80 program steps. In order to do anything useful on the TI-59 you would partition it to have 880 steps and 10 memorys.
In some ways it is a shame that some of you here were not able to experience programming this calculator. I think you would have really enjoyed the challenge of trying to squeeze down a rather complex program down to only 880 key presses and use only 10 memories. You had to really give some thought to the order in which the program ran so as to make the best use of data stored in memory. After all, with only 10 memories, you would not want to store data at the very beginning of your program that wasn't used until the end of your program, thus tying up that memory for the whole program.
Having only 880 steps to work with caused me to learn a bunch of math relationships that I could use to squeeze steps out of a program while maintaining the accuracy for the most part. These are concepts that I still use today when writing a program. For example, say you have something like this: +cos(? + 272°.34). This would take about 12 key presses; assuming two key presses to recall ? and one for cos(. First you should realize that +cos(? + 270°) will give you almost exactly the same answer. So you have reduced this to 9 key presses. But you can reduce this even further. If you look up trigonometry reduction formulas, you will find out that +cos(? + 270°) = +sin(?). You have just reduced this down to 5 key presses. As another example, rather then enter the number pi I would use 4*atan(1) (in radian mode); 5 key presses. I also would use logarithms if I wanted to round a number to say 5 significant digits. I'll let you figure out how this is done if you don't know how. I was forever on the hunt in math books for things I could use like this.
In order to share programs you had written with other people TI administered a group called PPX Exchange. After writing a program I could submit it to TI and if they accepted it, they would publish it in their catalog and something in their newsletter where anyone else in the world who was interested could request copies. This was a wonderful experience for it motivated me to try to squeeze down fairly lengthy calculations to fit inside a program having only 880 steps.
For anyone interested check out this .pdf
http://www.datamath.net/Manuals/PPX-V6N6_US.pdf
Scroll down to Page 9 (which is on the 13th page) and check out program 7880691 Astronomical Data for the Sun. It took everything I knew to fit this program into that space.
I know that this post has nothing to do with current programmable calculators, but having used programmable calculators since their inception I thought I might be allowed to muse a bit on them and how much they have improved over the years.
I find my new TI-84 Plus CE to be a great improvement over that 59. The amount of memory I have available to me I find to be luxurious. And you may be surprised to find out that programming the 84 isn't that much different then programming the 59. The only thing different is that the 84 has a screen that displays text, where as the 59 only displayed the numeric key code, one step at a time. However, unlike the 84, the 59 did have a printer that you could plug it into (yes I do mean you plugged the 59 into the printer) and print out a hardcopy of you program.
Thanks for reading my musings.
S. Thomas Bradley