Calculator Off-Mode VS. Cell Phone Sleep Mode

A bouquet of forget-me-nots.

The big difference is that the cellphone battery gets recharged periodically, but the calculator uses disposables and the keep-alive current would probably reduce the battery life significantly...and don't forget the difference in price between the devices.

Many small Casio scientific calcs (including the Casio that I refer to) have dual battery/solar cells to power them so that the battery lasts a very long time; for years.

When the Casio turns itself off after a few minutes of non-use, and you turn it back on, the memory of the last calculation/answer gets lost forever, --not so with T.I. scientific calcs.

Because of this important shortcoming I use a TI-36X Pro scientific calc. But the Casios are less menu-intensive in a number of important math operations, which is why I still like them and still use them.

How hard could it be for Casio to implement a simple memory safeguard feature in the software?

Paper and Pen!

Never fails and can be used later.

Why would you calculate something complicated and not use the result?

Use a T.I. calculator instead. If you are really interested write to Casio. Sometimes they are just simply not aware of why you do not use their product.

Don't buy the ones that say "auto power off"!

I've written to Casio many times; they've never responded. I don't mind using paper and pencil. All scientific and all graphing calculators auto power-off as a matter of design.

Say you're doing homework; you walk away to grab a snack; come back; your Casio has auto-turned-off, --your answer (AND equation) are gone.

I find the contrast between T.I. non-graphing calculators and Japanese non-graphing calculators in this important regard quite astounding.

/Here's wondering if I may be the only person complaining about this.

You are the only one complaining. Maybe not the only one frustrated with it, but the others just accept that they got what they paid for.

In order to do that, the system must either use RAM with a battery or capacitor backup, or EEPROM of one sort or another. EEPROM is way too expensive , requires more overhead and has a finite number of read/writes. Battery backed RAM uses more battery power than you might think. Even with a solar charger, the amount of power it generates is not enough to support RAM for a significant amount of time, so it's really up to the disposable batteries. And what amount of time would it be anyway? 1 week, 1 day, 1 hour? If they did 1 hour, then the person who waited 61 minutes would still be angry. TI has done that, but not told you the amount of time. Casio has done it differently, they just tell you that the time value is zero.

"Say you're doing homework; you walk away to grab a snack; come back; your Casio has auto-turned-off, --your answer (AND equation) are gone."

<Jamie Hynaman voice> "Now THERE'S your problem."

You are not 'thinking through' the match homework properly. You start with the problem ON PAPER and work out the rough equation, which will often be long and complex, with the same variables repeated several times. You then use your knowledge of Algebra to simplify the equation ON PAPER, looking for sections that can be combined, or that cancel each other out. Once you have the equation simplified as far as you can go, and have that equation written down ON PAPER, then and only then to you put in into the calculator to crunch the numbers.

You should also have a rough idea of what the result will be before you pull out the calculator. It is not there to GIVE you the answer, but to CONFIRM your answer.

It's sad, so few instructors these days take the time to teach the students HOW to learn, they just 'zombie march' them through the steps; "To solve this equation, press this sequence of keys on your calculator," instead of taking the time to explain WHAT the equation is and WHAT it means. The more you understand what an equation is supposed to represent, the better you are at using it.

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Pop quiz, what does the following equation describe?: x = e^-t

That is used in a lot of areas, no no matter what your major, you should have run into it, or you will soon.

As I mentioned before, all simple solar/battery scientific calculators auto power-off as a matter of design. Only T.I. preserves what you were working on even after it auto-powers off.

Casio does not have this software feature in its same solar/battery scientific calculators.

And I'm wondering if anyone knows what software step is implemented in the code for this power-off memory protection function in the under $20 calculator market?

"And I'm wondering if anyone knows what software step is implemented in the code for this power-off memory protection function in the under $20 calculator market?"

For the $20 and under market, the calculator is a 'system-on-a-chip' design, with most of the hardware simply to interface the keypad and display to the chip. Under that setup, with RAM, ROM and ALU (Arithmatic/Logic Unit) all on a single chip, there's not much more complexity in making some of the registers into 'non-volatile RAM' so they can hold their data for a long time while the system is 'off.' With the 'massive mass-production of those chips, the cost of the design complexity is spread so thin that it becomes invisible.

As to why some model lines have it and others don't, sometimes it's a case of when that line had its chip design last updated. Some of those calculators are of a very long 'production run,' and the company may not see the point in spending the time and money on a new chip version while the old 'master dies' are still serviceable. Calculators generally aren't a 'big mover' in the Consumer Electronics world; you'll likely buy a total of 1-3 calculators during your entire time in college, and maybe 1-2 more during your working years. Also, when you do 'replace' a lost or broken calculator, you'll likely look for the same model you had before, or at least the same brand, under the assumption that you won't need to 'retrain' yourself on something new, but simply use the new calculator exactly as you used the old one.

Surely today you use your phone to photograph the display?

Good point. It would be so much better if it were the other way round.

This reminds me of the old English saying that still is accurate today:-

"You pays your money and you take your choice!"

See here:-

dictionary.cambridge-you-pays-your-money-and-you-takes-your-choice/chance

"1) Why would Casio not implement a memory safeguard on all of its simple scientific calcs (like T.I. does)?

Both Casio and TI non-programmable calcs are very popular in American high schools and both are allowed in high school and college classrooms, where graphers are sometimes not allowed."

You answered your own question right there, the lack of a 'power off memory' feature is WHY those calculators are allowed; they cannot be 'pre-loaded' with answers, while graphing calculators have a persistent memory and can be used to hold 'cheat sheets.'

Also, cell phones have a lot of expensive circuitry and programming to manage power consumption, while the calculators typically are designed to be as inexpensive as possible. Remember, your cell phone costs several hundred dollars, while you can get a decent 'college level' calculator for around $50 or less. You THINK your cell phone is 'free,' but you're paying for it in all the 'non-itemized fees' that are rolled into your cellphone bill.

As I mentioned before, T.I. scientific calcs with power-off memory protection are allowed on all tests, both in high school and college, (and even on the Fundamentals of Eng and Professional Eng tests).

My question is why Casio has failed to implement this same software feature that T.I. has always had even on their simplest scientific calcs, and both are competing for sales in American high schools and universities (along with Sharp).

My HP 48G has auto off function but when I turn it back on the display is left the way it was when it went off.

I get a kick out of watching other engineers try to add 2+2 on an HP using RPN. If they are not used to HP calculators they cannot figure out even how to add two integers and get a result.

This was where the TI graphing calculators were great, back in the day. With the larger screen, you could type out the equation, and it would look just like the equation you had written on your paper. Such a delight.
I had an HP graphing calculator for about a day, once I got to using it. I needed to learn calculus and had no time for learning to think 2 enter 2 plus on whatever level that would take on a graphing calculator. Several very good engineers I know swear by their scientific HPs, though.

If you ever got to learning how CPU's function, you'd understand Reverse Polish a lot better, because that's how you do the math at the Assembly Language Level:

• LDA 0x02 (Load Accumulator (Register A) with hex value 02
• LDB 0x02 (Load Register B with hex value 02)
• ADD B (Add Register B to Accumulator, result is stored in Accumulator)
• MOVA 0x010F (Copy contents of Register A to memory location 010F, memory addresses are always stated as hex values)

It's also how 'adding machines' work: you punch in the value, then select the math function to use (add or subtract), then pull the lever, and the tape gets printed with the running total.

I never did get to learning how CPUs function, so that's right out, I suppose. I'm a bit shamefaced about that.

After continuous exposure to the HP scientific calculators, I can do a decent little bit with them. Still not my preferred thing. I did get an app for my phone that mimics one of them; perhaps I should fiddle with it. I have no access to an HP graphing calculator, so I suppose those intricacies shall remain an unknown for me.

I bought my HP 48G in 1995. I think I have changed the batteries like 5 times and I use it almost every day at work. But it is not allowed to be used on the PE exam.

I wish I had learned to love HPs. I probably would if HP had continued with their scientific calculator line (not the latest Casio-clones that have the HP logo on them); the Prime is nice, but it's a grapher.

You should change your batteries every year. The worst thing that could happen to your beloved 48G is that old batts could leak causing damage inside. I replaced two button batteries that had already began leaking, but caught them in time before they damaged the inside of my T.I.

A bit off topic but for those who prefer RPN calculators excalibur is a good free PC desktop one.

Lonewolf it's not just software. To save stuff you need to either keep part of the calculator powered up, or, install some non volatile memory like FLASH.