presents

calculator

07/04/07 11:33 category : personal
blog-2007-04-07
I used to use a calculator for my job. But now, almost calculations are computed by Excel or special software, so I didn't use a calculator for a long time. My job is FA (Factory automation) and LA(Laboratory automation), so I used to use so-called scientific calculator.
Today I was cleaning out my desk in my office, I found the calculator shown in an upper left icon of this topic which I was using before. (click an icon to see a larger image.)
This is the calculator which is HP48S of Hewlett-Packard Co. I remember the price was over 30,000 yen. It was expensive for me when I bought it. Despite this, my colleagues said "the useless calculator", because this calculator does not have a "=" key. It has a "Enter" key instead of a "=" key.
The reason is that my calculator is based on RPN input method. However I love RPN input method.

For person who doesn't know the RPN...
A PRN is an abbreviation of "Reverse Polish Notation". Compared with this, a normal calculator is based on "Polish Notation".
For example, when you calculate 5 by 2, each input method are as follows.
  • Polish Notation
    [5] [x] [2] [=]
  • Reverse Polish Notation
    [5] [Enter] [2] [x]
On the face of things, RPN is more complex or strange than normal input method, however when you compute bracket operation, situation will be different.
For example, when you calculate (5 x 2) + (7 x 3), each input method are as follows.
  • Polish Notation
    [5] [x] [2] [=] [M+] [7] [x] [3] [=] [M+] [RM]
  • Reverse Polish Notation
    [5] [Enter] [2] [x] [7] [Enter] [3] [x] [+]
In this case, RPN is more easy than normal input method if you get used to RPN.
For an additional example, when you calculate (5 x 2) / (7 x 3), each input method are as follows.
  • Polish Notation
    [5] [x] [2] [=]
    remember result 10
    [7] [x] [3] [=]
    remember result 21
    remind results (10 and 21) then re-input.
    [10] [/] [21] [=]
  • Reverse Polish Notation
    [5] [Enter] [2] [x] [7] [Enter] [3] [x] [/]
This example shows how RPN is powerful method for bracket operation. Interestingly, The input order of RPN is a similar word order to Japanese.
More detail (or good explanation) please refer the Wikipedia.
Anyway above-mentioned explanation tells you how I strongly love to RPN.

I decided reuse the RPN calculator for the first time in many years. Of course, my calculator batteries are dead, so I changed new batteries. Then I powered-on my PRN calculator!
But... nothing happened... Is my calculator dead? Any electric company is not manufacturing the RPN calculator today!
I searched out the customer service of the Hewlett-Packard Japan immediately, but my calculator was already out of support in Japan. And Hewlett-Packard Japan announced on this web-site that the customer support relegated to another oversea company (Broadwin). So I have to contact the Broadwin for repairing my RPN calculator. What should I do?
(to be continued)

tag :

|