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Keyboard Layouts



#6

I was working with my HP-41 and my HP-28 side by side to compare results. I suddenly noticed something that as a relative newcomer to the HP product line I had not noticed before. The HP-41 has the arithmetical operations keys to the left of the numerical keyboard while the HP-28 has the arithmetical operations keys to the right of the numerical keyboard. Furthermore, reading the operations keys from the bottom up on the HP-41 the sequence is / x + - while for the HP-28 the sequence is - + x / . The layout on the HP-41 seems to have been used on every HP handheld from the HP-35 through the HP-41 with the exception of the HP-10. The layout on the HP-28, which is the same as that on the TI's and most other calculators, seems to have started with the Voyagers and persisted in the HP product line ever since. Back in the HP-35 days the desktops such as the HP-91 and HP-97 had the HP-28 layout.

Why did HP decide to place the operation keys to the left of the numeric keypad on handheld calculators from the HP-35 through the HP-41?

Why was the change made with the Voyagers and beyond?


#7

Hi,

maybe this has been discussed here before,

but I think the 'classic' arithmetic key layout

simply was very ergonomical to use when holding the calc

in the right hand, and pushing the keys with the right thumb.

You'll notice that you'll easily reach the most important keys,

namely plus and minus with your thumb,

whereas you'll have to stretch your thumb more from the

center of the keyboard to reach the multiply and divide keys.

Raymond


#8

I think Raymond's explanation is as good as any. Starting with the Voyagers in 1981, though, HP finally got smart and realized that most users don't hold and operate the calc in the same hand. Since 90% of people are right-handed, prevailing practice is one of the following:

  1. Hold in left hand; operate with right hand.
  2. Place on table; operate with right hand.

With the newer arrangement, the right-handed user does not obscure the numeric keys when pressing an arithmetic key.

This detail of ergonomics also explains why (non-cellular) telephone handsets are connected to the left side of the phone base. Right-handed users would tend to operate the rotary dial with the right-hand index finger. When the handset is held in the left hand, the cord will not drape across the base.

-- KS

#9

You might notice that most younger people hold calculators in both hands and use their left-and-right thumbs (a behavior learned and coordination built from video game controllers). With this behavior, the left side would be the appropriate place for the operators, because when doing a series of operations, the left thumb would always press an operator or ENTER after each number entered, which would be the more-consistant behavior. The right hand would end up "covering" across the keyboard more, dominating the center column of keys more than the left hand, instead of having to move left and right to handle operators (as would happen of they were on the right side).

As a result, there would be space on the right side of the number pad for some keys, which might be shift keys, in which case it would be good to have the more-commonly used shifted functions on the left side of the keyboard (the left hand already being used for many operators, plus it being easier to use both hands instead of one). With the left hand being the main "operator" key, it would make sense to favor the left side for the most-common nonshifted operations as well (the right side of the row containing the ENTER key might be preferred to the keys just above the ENTER key, though).

Of course, this depends on how the person holds the calculator. I know somebody who held his TI-89 in both hands, with thumbs for the lower keys, but his index fingers, instead of sitting behind the keypad, curled up over the sides for pressing shift keys in the upper left and the arrow pad in the upper right.


#10

Quote:
You might notice that most younger people hold calculators in both hands and use their left-and-right thumbs (a behavior learned and coordination built from video game controllers).

This is the method I have always used with my 11c and 15c. That was before any of those video game controllers existed. It is the best way to operate a landscape layout calculator while holding it in your hand, which is why the landscape layout is the layout for hand held use. Thumbs are far more agile than the rest of the fingers, which makes them faster on the keyboard than poking around with your index finger.

Chris W

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