Small 
Museum 

Jan van de Veen, Nijkerk, The Netherlands


Some mechanical calculaters that are in the museum too  


MonroeMatic This
is an electric driven mechanical calculator made by Monroe. It still works. It was mainly
used to carry out simple statistical analyses. You could quite easily make sum of squares
and total sum of squares that are needed when doing Analyses of Variance. For more complex
analyses the Institute used timesharing of HoneywellBull on a 300 baud teletype !. 

Friden
SBT 

Friden
1151 This electronic calculator was bought by the Institute in 1969.
It had a paper writer and 4 numbers could be stored in memory. It was even possible to
make a small program of 15 steps at a maximum. Today we would call it a macro as the
machine ' learned' what to do, because you performed the calculation with the 1151 set to
learn mode. You would than enter the starting values and had the program running.


This image shows the simple keyboard
of the Friden 1151. The learn button is at the right, just next to the wheel where you
could set the number of decimals to be printed. How do you find the square root of a number ? Suppose you want to know the square root of 285. You know that it is more than 10, but less than 20, so make a guess in between, say 15. Now, you divide 285 by 15 with 19 as result. Take the mean of (15+19) = 17 and start again, dividing 285 by 17 with 16.75 as result. Take the mean of (17+16.75) = 16.87. Again divide 285 by 16.87 with 16.89 as a result. It is now clear to see that 16.88 is the square of 285 and that we found this result in an iterative way, using only 3 cycles. When the Friden had learned this trick, you would enter the number you want the square root off, than enter your guess, and hit the auto button. The result would be printed and the program had to be stopped manually as soon as there was no more change in decimals in the printout. 

This is a Friden 130 from 1963. It was the first all electronic calculator with a 4 line CRT display. Although never used on the Institute, I did add this calculator because it has delay lines as memory. Please visit the site Vintage Calculator Web to learn more about this calculator.


Return to the main menu
or goto WANG 2200 or
WANG desktopcalculators or other
WANG equipment 
All rights by :
Jan van de Veen 