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Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

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Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#101

Earlier quoted context omitted.

I'm not sure I agree it's a good idea at all. 30 years later, and the electric car market is still miniscule. There might start to be a market demand for them when petrol is at least twice as expensive as it is now. But there's some wiggle room to reduce the tax on it a lot.

When gas/petrol goes to 2x what it is now it'll be on a journey that is very fast and shoots to 3x, 4x and beyond. This will cause huge economic shocks and there won't be the time then to start building electric cars.

You could be right. For most European cities this wouldn't have a terrible effect, as everything is close together and we have things in walking distance.

The US however will be absolutely devastated.

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#102
post #99

Earlier quoted context omitted.

Trusting the numbers coming out of a calculator was ALWAYS a bad idea, especially if lives depended on it. It wasn't just the calculator making a mistake - you could have made a mistake keying in the numbers. This is dealt with by: 1. running the results through the inverse equations to verify that you get the inputs back again 2. calculating the results using an independent method to verify them 3. having a differen…

In your opinion, if doing step 5 is cheap enough, do you still need 1-4? (That is, is it "okay"--in a pragmatic sense--to have sloppy thinking, if you can just throw numbers at the wall to see if they stick?)

Doing 5 is rarely cheap enough. It's well known that the earlier in the process errors are fixed, the cheaper they are.

Re: Reversing Sinclair's amazing 1974 calculator hack - half the ROM of the HP-35

#103
post #62

Earlier quoted context omitted.

Might have been better to demonstrate that using subtraction as addition is commutative and thus either one works fine in this case.

One is 27; the other is 36.

LOL, apparently I suck as a parser. I read them as just swaps of the numbers, I.E. 23 4 + vs. 4 23 +.
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